Basic Cementing [PDF]

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TRICAN WELL SERVICE BASIC CEMENTING

Trican Well Service Ltd. | 2900, 645 – 7th Avenue SW | Calgary, Alberta | Canada T2P 4G8 |P 403.266.0202 | F 403.237.7716 TricanWellService.com

DOCUMENT REVISIONS Revision

Description

Originator

Reviewer

Approval

Date

1

First release

K.C. Thompson

Benjamin Carlier

Tom Kaufmann

May 2015

1.1

Revised and Edited

Tom Kaufmann

June 2015

1.2

Revised and edited

Tom Kaufmann

Nov 2015

1.3

Reviewed

Training

Training

Training

Feb 2017

DISCLAIMER This document is proprietary to Trican Well Service Ltd. ("Trican") and is intended solely for the information and use of parties operating the equipment described herein. The document was created as a collaborative effort of many resources within Trican. No part of this document shall be used, reproduced, translated or disclosed to any other parties for any other purpose without the expressed written permission of Trican. Trican does not make any representations, warranties or guarantees, express or implied, as to the accuracy or completeness of this document and users should be aware that updates and amendments will be made from time to time. Neither Trican nor any of its directors, officers, employees or agents shall be liable to any person for any loss, damage, injury, liability, cost or expense of any nature, including without limitation incidental, special, direct or consequential damages arising out of or in connection with the use of the document. © 2015 Trican Well Service Ltd.

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TABLE OF CONTENTS 1.

OILFIELD CEMENTING ............................................................................................................... 1 1.1

2.

Oil Well Cementing in North America ........................................................................................... 1 CEMENT JOB OVERVIEW .......................................................................................................... 1

2.1

The Cementing Process ............................................................................................................... 1

2.2

Primary Cementing ....................................................................................................................... 3

2.3

Remedial/Squeeze Cementing ..................................................................................................... 5

3.

CEMENT AND CEMENT ADDITIVES .......................................................................................... 5 3.1

Bulk Oilwell Cement ...................................................................................................................... 5

3.2

Cementing Chemicals ................................................................................................................... 5

3.3

Mud Removal ................................................................................................................................ 7

3.4

Cementing Chemical Safety ......................................................................................................... 7

4.

EQUIPMENT OPERATOR RESPONSIBILITIES ......................................................................... 9

5.

CEMENTING EQUIPMENT ........................................................................................................ 10 5.1

Cement Pump Unit ...................................................................................................................... 10

5.2

Cement Bulk Equipment ............................................................................................................. 13

5.3

Bulk System Safety ..................................................................................................................... 16

5.4

Treating Iron ................................................................................................................................ 17

5.5

Triplex Pump ............................................................................................................................... 18

5.6

Pressurizer Pump ....................................................................................................................... 19

5.7

Mission Pump.............................................................................................................................. 21

5.8

Mixing Tub................................................................................................................................... 22

5.9

Conventional Mixing Equipment ................................................................................................. 23

5.10

Dustless Mixing Equipment......................................................................................................... 24

5.11

Prairie Mixer (Jet Mix) ................................................................................................................. 26

6.

PUMPING ACCESSORIES ........................................................................................................ 26 6.1

Plug Loading Head ..................................................................................................................... 27

6.2

Squeeze Manifold ....................................................................................................................... 30

7.

WORKING WITH DRILLING RIGS............................................................................................. 31 7.1

Rig Floor...................................................................................................................................... 32

7.2

Derrick ......................................................................................................................................... 33

7.3

Draw Works................................................................................................................................. 33

7.4

Substructure (Cellar) ................................................................................................................... 33

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7.5

Mud Circulation System .............................................................................................................. 34

7.6

V-Door and Pipe Conveyance .................................................................................................... 34

7.7

Spotting Equipment for Rig-In ..................................................................................................... 35

8.

THE CEMENT CREW................................................................................................................. 39 8.1

Supervisor ................................................................................................................................... 39

8.2

Lead Operator ............................................................................................................................. 39

8.3

Second Operator ......................................................................................................................... 40

8.4

Bulk Cement Operator ................................................................................................................ 40

9.

PAPERWORK............................................................................................................................. 40 9.1

Job Procedure Sheet .................................................................................................................. 40

9.2

Loading Ticket ............................................................................................................................. 41

9.3

The Call Sheet ............................................................................................................................ 41

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LIST OF FIGURES FIGURE 2-1: FLUID FLOW PATH DURING CASING CEMENTING ............................................................................ 2 FIGURE 2-2: TYPICAL CASED W ELLBORE SCHEMATIC ....................................................................................... 3 FIGURE 9-1: EXAMPLES OF CEMENT CHANNELING ............................................................................................ 7 FIGURE 4-1: TYPICAL CEMENTING RIG-IN ....................................................................................................... 10 FIGURE 5-1: BODY LOAD SINGLE CEMENT UNIT .............................................................................................. 11 FIGURE 5-2: TRAILER MOUNTED SINGLE CEMENT UNIT ................................................................................... 12 FIGURE 5-3: TRAILER MOUNTED TWIN CEMENT UNIT ...................................................................................... 12 FIGURE 5-4: CEMENT BULK TRANSPORT ........................................................................................................ 14 FIGURE 5-5: CYCLONE OR SURGE TANK ON A CEMENT BULK TRAILER ............................................................. 14 FIGURE 5-6: PRESSURIZED CEMENT SILO OR P-TANK ..................................................................................... 15 FIGURE 5-7: CEMENT GRAVITY SILO .............................................................................................................. 16 FIGURE 5-8: TREATING IRON RACK ON A TWIN CEMENTER .............................................................................. 17 FIGURE 5-9: FIGURE 1502 DRAWING.............................................................................................................. 17 FIGURE 5-10: TRICAN TRIPLEX CEMENT PUMP ............................................................................................... 18 FIGURE 5-11: PRESSURIZER CENTRIFUGAL PUMP........................................................................................... 19 FIGURE 5-12: MISSION CENTRIFUGAL PUMP ................................................................................................... 21 FIGURE 5-13: MIXING TUB AND DUSTLESS MIXING SYSTEM ............................................................................. 22 FIGURE 5-14: CONVENTIONAL JET MIXING BOWL ............................................................................................ 23 FIGURE 5-15: CONVENTIONAL JET MIXING CEMENT ........................................................................................ 24 FIGURE 5-16: DUSTLESS MIXING HEAD .......................................................................................................... 25 FIGURE 6-1: CEMENT PLUG LOADING HEAD (PLH) ......................................................................................... 27 FIGURE 6-2: CEMENT PLUGS ......................................................................................................................... 29 FIGURE 6-3: SQUEEZE MANIFOLD .................................................................................................................. 30 FIGURE 6-4: MULTIPLE CEMENT UNIT RIG-IN .................................................................................................. 31 FIGURE 7-1: DRILLING RIG COMPONENTS ....................................................................................................... 32 FIGURE 7-2: RIGGING IN THE CEMENT SUPPLY................................................................................................ 35 FIGURE 7-3: EXAMPLE CEMENT JOB LAYOUTS ................................................................................................ 37 FIGURE 7-4: PRESSURIZED SILO (P-TANK) ON LOCATION ................................................................................ 38 FIGURE 8-1: JOB PROCEDURE SHEET ............................................................................................................ 40 FIGURE 8-2: LOADING TICKET ........................................................................................................................ 41 FIGURE 8-3: MIXING TUB ............................................................................................................................... 42 FIGURE 9-4: DUAL CEMENTING UNITS RIGGED IN............................................................................................ 43 FIGURE 9-5: TWIN CEMENTER OPERATOR'S PANEL ......................................................................................... 43

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1.

OILFIELD CEMENTING

1.1

OIL W ELL CEMENTING IN NORTH A MERICA

The 1850s saw the first commercial oil wells drilled in North America, in places such as Petrolia (Ontario) and Titusville (Pennsylvania). Early drilling and production methods were crude and inefficient, but quickly advanced as more accessible and affordable petroleum products were sought. The first rotary drilling rigs were introduced around the turn of the century, but cable tool drilling was still commonly used right up to the 1950s, and in some areas even into the 1980s. The first recorded use of cement to shut off downhole water was in 1903 in Lompoc Field, California. Frank Hill, working with the Union Oil Company, mixed and dump-bailed 50 sacks of neat Portland cement into the well. The procedure worked, and the treatment became the accepted practice. It soon spread to other fields in California. The dump-bailer technique was replaced by the two-plug method in California by A. A. Perkins in 1910. Perkins' method meant the birth of the modem oil well cementing process. The patent issued to Perkins specified two plugs. Prior to 1940, wells were cemented using construction sacked cement mixed by hand and with very few additives. In the 1930s, no additives were used. As wells became deeper, more flexibility in cement performance than could be achieved with available construction cements was required. With the advent of bulk cement usage and delivery cement, blends became more diverse. Bulk cement delivery was first introduced in the 1940s, but sack cement was in use in many areas right up until the 1970s.

2.

CEMENT JOB OVERVIEW

2.1

THE CEMENTING PROCES S

Cement is used to bond casing pipe into the ground during the drilling and construction of a well. The hole (wellbore) is drilled into the earth by a drilling rig. The rig then pulls out the drilling pipe string along with the drill bit, and lowers another pipe string – the casing - into the freshly drilled wellbore, which is still full of drilling fluid. After conditioning the drilling fluid that is currently in the well, cement is pumped into the casing pipe and displaced with another fluid. This displacement fluid is commonly water, but drilling mud systems and many other types of fluids may be used to displace cement from casing. During displacement, the cement is forced out of the casing and travels out of the bottom and upwards, back up the hole in the space between the well wall and the casing pipe. That space is referred to as the annulus. Annulus: The space between two concentric objects, such as between the wellbore and casing, or between casing and tubing. Pipe may consist of drill pipe, casing, or tubing.

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Figure 2-1: Fluid Flow Path During Casing Cementing

Once the cement has been displaced into the annulus, the cement hardens to form a barrier that seals off the annulus and protects the casing pipe from the formation. If this is done correctly, we end up with a good bonding of cement to the wellbore wall, and a good bond to the casing pipe itself. When the cement has hardened (or gelled to a sufficient strength), the drilling rig lowers its drilling string, along with a smaller OD (outside diameter) drill bit back into the casing pipe that is now cemented in the wellbore. Once the new drill bit reaches the bottom, the rig continues to drill down into the earth towards the reservoir formations that hold oil/gas. The well is normally drilled and cased in sections. These sections are commonly known as the conductor pipe, surface casing, intermediate casing, and production casing or liner. The process of drilling down, pulling out the drill bit (tripping out), running casing pipe back into the hole, and cementing the casing in the hole, is repeated many times. Once the total depth of the well is drilled and the last casing string is run in and cemented, we end up with multiple layers of cement and pipe. Each time this process is repeated; the subsequent hole and casing sizes become smaller. Figure 2-2 below shows a basic layout of cemented casing strings. You can see the layers of casing pipe, and cement filling the different sizes of wellbores.

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Conductor Pipe

Surface Casing

Intermediate Casing

Production Casing

Figure 2-2: Typical Cased Wellbore Schematic

2.2

PRIMARY CEMENTING

It is widely accepted in our industry that primary cement jobs are THE most important phase of any oilwell construction operation. A poor cement job usually results in a poor performing well. The cure for a poor cement job is usually another (albeit different) type of cement job, which usually results in additional costs to the customer who is drilling the well. Depending on the issue, these problems may take considerable extra time and money to correct. Functions of Primary Cementing:

▪

Casing Support: A well-placed cement column helps to support the weight of the casing string that is in the hole. The casing will also support the wellhead/BOPs when installed. Annular Isolation: The cement provides isolation between zones in the wellbore, thereby protecting production zones as well as freshwater zones from cross-contamination (also called communication). Casing Protection: A sheath of cement around the casing protects that string from corrosion, collapse, and subsequent damage caused by further drilling.

Note: These three functions are equally important; they all add up to produce a quality cement job. Primary cementing is a category of cement jobs generally performed during the initial construction phase of an oil well. The main goal of a primary job is to provide casing support, annular isolation, and casing protection. The following are examples of primary cement jobs: Conductor Pipe Surface Casing Intermediate Casing Production Casing Liner Multi-stage Casing

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Primary cementing operations make up a large majority of the total cementing jobs performed by Trican each year. The consequences of a poor primary cement job can be catastrophic in terms of loss of life or personal injury, loss of equipment, and environmental damage. Wells are planned, designed, and have a set budget for construction. This budget and the expected revenue to be generated from the well are finely balanced. It may take a few years of production from a well until it becomes profitable. If cement jobs are done poorly, the result is usually expensive remedial work. A well, even though it is producing, may never become profitable during its expected service life if preventable extra expenses are added (such as fixing a poor primary cement job).

2.2.1

SURFACE CASING CEMENTING

One of the most critical cement jobs we do is the surface casing cement job. It is often underrated, because it is one of the easiest cement jobs to perform. Once the surface casing is cemented, blowout preventers (BOPs) are installed and the wellbore is isolated from underground water sources. Most governing jurisdictions define that a surface casing must be run to a minimal depth to protect fragile ground water reservoirs. This depth will change depending on the geographic location of the well and the types of formations the bore will be drilled into.

2.2.2

INTERMEDI ATE CASING CEMENTING

Once the surface cement job has been completed, the rig crew drills a hole with a smaller diameter. Once they’ve reached a predetermined depth, the rig crew repeats the process of pulling out the drilling string and running in casing pipe. The procedures are generally the same as in a surface casing job, usually there will be more than one cement slurry pumped. The composition of intermediate cement slurries will, in most cases, differ greatly from a surface casing cement. There will most likely be retarders and friction reducers in the blend, and you will probably notice a large volume of lightweight lead cement. Some of the largest volume cement jobs performed in the field will be intermediate casings. This is because they generally have larger annular volumes.

2.2.3

PRODUCTION CASI NG CE MENTING

After either the surface or the intermediate casing, the drilling rig will drill to the desired depth and tap into the formation of interest. The rig will then run the final casing - called the production casing - into the wellbore. Production casing jobs will follow a similar format of an intermediate cementing job.

2.2.4

LINERS

Liners are shorter strings of casing that when run into the well will not extend back to surface. Typically, they are run using a liner hanger assembly on the top of the liner string that is connected to surface by drill pipe. When these strings are cemented, the liner is “hung off” or anchored in the previous casing string and the drill pipe is retrieved after cementing, leaving only the liner string cemented in the hole.

2.2.5

MULTI-STAGE CEMENTING

Multi-stage cement jobs are basically two cementing jobs performed on one casing string. This is accomplished by running a stage collar (valve) at some point in the casing string. This enables the customer to cement the bottom part (first stage) of the casing string first and then open the stage collar and cement the top part of the string (second stage).

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2.3

REMEDIAL/SQUEEZE CEMENTING

Remedial or “Squeeze” cementing jobs are typically done to try and repair different downhole problems that occur after the well has been drilled and completed. There are many reasons to use remedial cementing. Examples of problems where remedial cementing can be used:

▪

Leaks in existing casing Repairing poorly completed primary jobs Controlling gas migration Seal lost circulation zones Zonal and oilwell abandonments

Remedial cementing is commonly called “squeezing”, because this is usually how we place cement into the desired location. Instead of pumping cement into an open flowing annulus, we are squeezing cement into the formation without direct return flowback to surface. Types of remedial cement jobs: Retainer Squeeze Braden Head Squeeze Circulation Squeeze Bullhead Squeeze Abandonment Plug

3.

Cement and Cement Additives

3.1

BULK OILW ELL CEMENT

The main product used in cementing operations is dry powdered cement. It is usually stored in onsite silos or bulk trucks. Oilwell cement comes in various types or classes. The most prominent class used in Canada is Oilwell Class “G”, but Class “C” or Class “A” may be used as well.

3.1.1

TRICAN CEMENT SYSTEM S

There are also many different blends of cement and other products that are designed for specific well conditions or situations. Innovative thinking, new technology, and an ability to “think outside the box” has given Trican Well Service a very competitive edge with our many cement systems.

3.2

CEMENTING CHEMICALS

In addition to the chemicals used in special cement blends, there are also a myriad of products that are used to alter different properties of a cement slurry. They can be used to alter setting times, viscosity, or compressive strength, just to name a few. Following is a brief description of the most common additives that are used in cement slurries.

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3.2.1

ACCELERATORS

Chemicals which reduce the setting time of a cement system, and increase the rate of compressive strength development. e.g. Calcium Chloride

3.2.2

FLUI D-LOSS ADDITIVES

Fluid loss additives are chemicals which control the loss of an aqueous phase of a cement system to the formation. (They keep the water in the cement slurry). e.g. CFL-20, TLF-1

3.2.3

DISPERSANTS

Dispersants are chemicals which reduce the viscosity of cement slurries. (They make it runny). This helps the cement slurry to flow without added pumping pressure. Dispersants, to a certain extent can also affect the setting time and fluid loss of cement slurries. E.g. CFR-10

3.2.4

RETARDERS

Chemicals which extend or lengthen the setting time of cement systems are called Retarders. Generally, these are used to make sure we have enough time to pump the job and get the cement slurry in place before it starts to thicken or setup. e.g. LTR or THR-100

3.2.5

SPECIALTY ADDITIVES

Trican Well Service also has an extensive array of Specialty Additives, that provide and promote various desirable characteristics to our Cement Systems. They may be Light Weight Materials (Extenders), Lost Circulation Materials (LCM), Weighting Agents, Gas Control Additives and AntiFoams.

3.2.6

PRE-FLUSHES & SPACERS

Trican Well Service has developed several pre-flush and spacer systems that are compatible with both mud systems and cement systems allowing a clean interface between the two. Specially designed to clean the well bore and the casing these spacers allow the cement slurry to adhere to both. A pre-flush is a fluid used to clean the drilling mud and/or filter cake out of a casing before cement slurry is pumped. This “washing” is necessary because if the mud is not thoroughly removed from the casing and annulus after drilling, a good cement bond cannot be achieved. Water is often used as a “wash” fluid, however, chemical washes (containing various additives) are more common. Spacers are pre-flushes that have been specially designed to exhibit chemical and physical properties that are particularly compatible with the job in which they will be used. Generally, spacers will have increased viscosity and density over pre-flush fluids.

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3.3

MUD REMOVAL

Mud removal is vital to a successful cement job. To achieve a good cement sheath around the entire diameter of the casing, the drilling mud and filter cake in the well must be completely removed. Otherwise, channelling of cement through the drilling fluid will not be able to cement all the areas of the casing and wellbore. An area without cement on any portion of the casing is not fulfilling the three main functions of primary cementing (providing casing support, annular isolation, and casing protection). Cement Sheath

Channeling Figure 3-1: Examples of Cement Channeling

3.4

CEMENTING CHEMICAL S AFETY

You will encounter many different chemicals throughout your time with the cement department. There are only a handful of chemicals you may see on a regular basis, but there is always the potential that you will encounter a different kind of chemical for which will work best for this situation. Most of the chemicals Trican uses for oilwell treatments are a form of irritant. While one chemical additive may just dry out your skin, the one sitting next to it in the bulk plant could be a carcinogen or corrosive material. There are controls and safety procedures in place to keep you out of harm’s way. Anytime you are confronted with a chemical you are unfamiliar with, take three minutes to read the SDS. The precautions and PPE requirements are not suggestions, they are necessary! If you see a fellow crew member not following PPE requirements, it is your duty to make this person aware and tell him or her to wear the proper PPE. Bulk Cement Powder: The powdered forms of our cements are hazardous and a lung irritant. Long-term exposure of silica dust can result in silicosis, which is a lung disease. Always use a respirator with proper filters, anytime you will be exposed to dust from bulk cement. Possible high-dust zones you will encounter are: the admix bottle at the bulk plant, loading and discharge areas of the bulk plant, loading and discharge areas of a bulk trailer, the loading and discharge area of a gravity bin or P-Tank, and the mixing tub/degasser of the pumping unit.

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Supervisors are the only members of the crew who should be in the hot zone when mixing cement. Bulk operators should wear appropriate PPE when they are loading or offloading product. Pump operators do not require a respirator if they are in a unit equipped with a caboose (if the door and windows are shut). If you are operating a unit with open air controls, it is recommended to wear PPE because wind conditions may change during the job. Wet Cement Slurry: It will be common to get wet slurry on your coveralls during the wash-up and mixing processes of a job. Due to the properties of the cement and additives that may be blended into the mixture, cement tends to burn if you leave it on your skin for a prolonged period. Wash it off with plenty of water right away. Do not use gloves that get soaked with wet cement slurry. If, for whatever reason (and it does happen), you get covered with cement, remove your coveralls and any soaked clothes and put on fresh clothes/coveralls. Do not reuse coveralls even after the cement has dried. Wash your work clothes thoroughly before using them again. Anti-foaming Agents (AFA): These products help to keep foaming of the cement slurry during the mixing process to a minimum. Trican uses powdered and liquid forms of AFAs. The powdered will be blended into the bulk cement, the liquid AFA is added to the mix tub during cement operations. AFAs are highly flammable and you should take precautions to keep the chemical away from flame and spark. They will irritate your skin and may cause burns. Barite: Barite is a common weighting agent we use to make fluids heavier. It is added to our mixtures to raise the density of the fluid and increase viscosity. Just like our bulk cement, barite is a severe irritant to your respiratory system. Always use a respirator when working with barite. The particles of barite powder are usually smaller than most of our cement blends; therefore, they pose a greater risk of inhalation. Optimum Flush: Optimum flush is a common additive we use for pre-flushes and spacers. It is derived from the guar plant, and mostly plant-based. Chemical-resistant gloves and splash goggles should be used when you are working with optimum flush. KCl Water: Potassium chloride water (KCl) is commonly used for a displacement fluid during certain cementing treatments. It is an irritant to the eyes and skin; therefore, proper PPE should be worn when working with the material. Drilling fluids of any kind should be handled like a chemical that can splash or produce vapours. Drilling fluids consist of gels, weighting agents, diesels, base oils, etc. Just like our cement blends, many different additives are mixed together to make a successful drilling fluid. A lot of those additives are components we don’t want to get on our skin, in our eyes or inhale for a long time. The minimum PPE any cementer should have with them are: safety glasses, fire-resistant coveralls, steel toed chemical resistant boots, a respirator with appropriate filters (full face or half mask), splash goggles, dust goggles, chemical-resistant gloves, chemical-resistant coat and waders, a hard hat, hearing protection (ear plugs, ear muffs) and protective gloves for rigging in. As always, PPE is not a complete protective shield. It is the last line of defense and doesn’t substitute proper control of hazards, good housekeeping, or a good brain able to decide if something is a good idea or not.

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4.

Equipment Operator Responsibilities

The responsibilities of a Cementing Equipment Operator are many and all tie together to ensure a safe and quality job is performed every time. Over and above your responsibility to complete and keep current all required training and understand Trican's Best Practices and Operating Procedures, you will benefit from seeking out additional training as identified in your positions ‘Training Matrix” or listed within the LMS library. The operators of all equipment will have various responsibilities depending on the type of job being performed. Regardless of the individual responsibilities, each operator has the following things that need to be taken care of for all our equipment. 1. Overall Cleanliness – Both the exterior and the interior of the unit. This means regular washing and cleaning of the outside of the unit as well as keeping the tractor cab, operating cab, and storage boxes clean and organized. 2. Iron, Hoses, and Fittings - Make sure that all the necessary iron, hoses, and fittings needed to perform the everyday function of the unit are on the unit and securely fastened in place. Where needed, the operator is also responsible for making sure that all required tire chains are securely stored on the vehicle and in usable condition 3. Inspections - Make sure that daily, weekly, and annual inspections are being done and documented accordingly. The operator should be competent in the both the pre-trip inspection process as well as the pre-job inspection and checks prior to starting or operating their equipment. You should also be aware of when your treating iron is due for inspection if applicable. 4. Maintenance and Servicing - Perform routine equipment maintenance as needed, including weekly services and helping to do 500 hour services when due. Not all maintenance can be done by the operator, so when mechanical or electrical repairs are needed the operator should help the repair person where possible. Each unit of any type should be fueled up at the end of each day so that it is ready to go on short notice. This is especially important in colder climates where partially filled tanks can lead to water condensation in the fuel tanks. This in turn can lead to frozen fuel lines and other water related problems. 5. Documentation – The operator is responsible for making sure that all paperwork is up to date and in place. This includes vehicle registrations, permits, bills of lading, TDG, etc. Also, in accordance to Federal and Provincial regulations, the operator must maintain a daily driver’s log book current to the last duty status change.

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Figure 4-1: Typical Cementing Rig-in

5.

CEMENTING EQUIPMENT

As a member of a cementing crew you will work with different types of equipment, such as a bulk cement delivery truck, pressurized cement silo, single pump, or twin pump cement unit. There are different ancillary pieces of equipment depending on the type of job they are designed to do. If each piece of equipment used is properly maintained and outfitted, service quality incidents involving equipment failure will be greatly reduced. We will look at the equipment, pumpers, bulkers, iron, and tools that we use to perform a successful cement job as well as cover the various components of a cement pumper, and how those components work together to send cement into a well.

5.1

CEMENT PUMP UNIT

The cement pump unit is the hub any cementing operation. The operator controls almost all the aspects of mixing and pumping the cement slurry from the pump unit control cabin. The pump unit has all the pumps and other devices that are needed to mix a consistent cement slurry. It is on the unit that the dry

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cement powder is mixed with the required amount of water and pumped into the well. Also, the mix water and displacement fluid can be gauged by using the two displacement tanks mounted on the unit. Each unit is self-sufficient in that they carry all the necessary items needed to rig-up for and pump a cement slurry. A typical cement pump unit will have the following equipment: o

Triplex positive displacement pump for pumping the slurry into the well

o

Mission centrifugal pump to supply the mix water to the system

o

Pressurizing centrifugal pump to help mix the slurry and push it to the triplex pump

o

Micro-motion flowmeter for measuring the slurry density and pump rate

o

Mixing tub and mix head for receiving the cement and water and combining them into a slurry

o

Displacement tanks for storing and measuring mix water or displacement fluids

o

Iron racks for storing the treating iron and hoses needed for the job

o

Engine and transmission for powering the triplex pump

o

Hydraulic system for running the centrifugal pumps

o

Control cabin for operator to run the unit and record the parameters

Figure 5-1: Body Load Single Cement Unit

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Figure 5-2: Trailer Mounted Single Cement Unit

Figure 5-3: Trailer Mounted Twin Cement Unit

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Trican uses three different types of cementing pump unit. Body mounted and trailer mounted single cementers, and trailer mounted twin cementers. The main difference between a single and twin cement unit is the twin has redundancy for every pump on the unit. This allows the unit to continue pumping a job if any of the pumps or engines on the unit fail. Also, by having two triplex pumps the twin cementer can achieve higher downhole pumping rates if needed. Single pump units are used mainly for shallow cementing and remedial cement jobs, where twin cement units are in demand on the larger volume or deeper wells being drilled.

5.2

CEMENT BULK EQUIPMENT

Cement bulk equipment is used to either store the dry cement on location or at the base bulk plant, or transport the cement blends from the bulk plant to the location. Oilfield cements are blended, transported, and stored as dry powder. To efficiently load/offload these powders, Trican uses a method that incorporates pressurized air. Our bulk systems come in many styles and sizes, but once you become familiar with the basic concepts, you will be able to operate any of our bulk storage equipment in use in the field. We load our cementing materials, chemicals, and other additives into a storage container at the bulk plant. Then, we transfer the entire mixture back and forth to another container until we achieve a consistent homogenous blend. This blended cement is then transferred to bulk trailers, which then transport the bulk cement to the location. Our cement is usually transported to the job site ahead of time and stored in holding bins. Examples of storage units we use on location are a pressurized tank and a gravity bin. A cement bulk plant is a storage system very like our P-Tanks. Another example is the guppy storage trailer - basically the same as a bulk trailer - except that it can hold much more cement powder. A guppy storage trailer is used for large projects on the same site, or remote stocking of cements. Because of the weight of cement a guppy trailer can potentially hold, it can only be transported empty. Our bulk systems differ from most other cementing companies in that they operate at a much lower pressure. Our bulk plant, trailers, and P-Tanks should never exceed 14 psi (100 kPa) operating pressure. Gravity bins, however, are normally operated at a maximum of 1 psi (7 kPa). The air in a gravity bin is strictly used to run agitators to help in the discharge of the bulk product.

5.2.1

BULK CEMENT TRAI LER

The bulk trailer is a large pressure vessel. It is pressurized with air from the blower unit. Powder is usually loaded into separate pods on the trailer. The bulk operator can select individual pods to send the load powder out the outlet line. When the operator opens an outlet valve on a pod, the pressurized air wants to escape. It will push the cement powder out the discharge line. A purge bypass takes air directly from the blower and shoots it down the outline to increase the flow of the cement powder and to blow clear the bulk lines if needed.

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Figure 5-4: Cement Bulk Transport

5.2.2

THE CYCLONE

The cyclone on our bulk trailers is used in conjunction with conventional mixing equipment. Powder from the bulker trailers pods is sent into the cyclone; where the air from the trailer is separated from the powder. Once the powder has been freed of excess air, it is dumped into the cement hopper of the conventional mixing system. The air removal and powder dumping happen simultaneously.

Figure 5-5: Cyclone or Surge Tank on a Cement Bulk Trailer

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5.2.3

PRESSURIZED CEMENT S ILO (P-TANK)

The P-tank is used with dustless mix systems and operates like one pod of a bulk trailer. Air is supplied by the blower on the pumping unit and has the same inlets and outlets of a bulk trailer. It holds more cement powder than a bulk trailer, but unlike bulk trailers and gravity bins, P-tanks have only one compartment so therefore they are only able to hold one cement blend type at a time. Once the blower is tied into the system, the supply of air tee’s off going to TOP AIR and to aerators located in the cone of the tank. P-tanks should be checked regularly to ensure the check valve on the blower line is operating normally. If this check valve malfunctions, the P-Tank might blow down incorrectly. This can lead to cement being forced into the blower itself, seizing the system and ruining the entire blower. Therefore, it is a good practice to always turn the blower over on a pre-trip to ensure the blower wasn’t accidently filled with cement powder on the last job.

Figure 5-6: Pressurized Cement Silo or P-Tank

5.2.4

GRAVITY CEMENT SILO

Gravity bins are used with conventional mix systems. Just like P-Tanks, these gravity bins hold a lot of powder, but are not unloaded using air pressure. Like cyclone bulk trailers, they have air supplied by blowers. However, the supplied air is mostly used to operate agitators and fluffers to make the powder in the bin flow easily to the outlet sock. The bottoms of these tanks are sloped to aid in the discharge of bulk cement. Most gravity bins are two bins in one; they have an “A” and a “B” side. The lead cement may be in the A side, the tail in the B. Like the cyclone, some bins are equipped with outlet spouts or socks. Because of the A and B sides, care should be taken to ensure you are mixing what is desired at the time. ALWAYS CHECK THE LOADING TICKETS!!

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Figure 5-7: Cement Gravity Silo

5.2.5

AIR BLOW ER

The blowers used by Trican provide air flow for our various bulk systems. The blowers we use are designed to provide a dry oil-free air. If we used regular air compressors, the air would be moist and contain oil. This would eventually mix with our cement powder and clog our systems. The blower is generally driven off a pto on the bulk trailer tractor or by hydraulics on the cementing unit. Blowers can be used to pressure up p-tanks or bulk trailers for unloading, or as a source of the air flow needed for properly unloading gravity cement bins.

5.3

BULK SYSTEM SAFETY

Even though most of our bulk systems are operated at “low” pressures (less than16 psi – 110 kPa), the shear amount of surface area involved in this equipment makes them a dangerous hazard. Always follow the best practices and use caution when connecting/disconnecting fitting, pressurizing systems, and operating valves. It only takes a moment of complacency to put yourself and others in the area in harm’s way. It is common practice to use a rubber mallet to check volume levels on the different bulk systems. Ensure you use a soft rubber mallet. Never use a metal or dead blow hammer. Puncturing or deforming the bulk tank is a considerable safety risk. Never trust your gauges. Always assume the system is pressurized. Do not stand in front of a fitting you are working on. Stand on the side and always wear appropriate PPE.

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5.4

TREATING IRON

Figure 5-8: Treating Iron Rack on a Twin Cementer

Trican uses solid metal treating iron and pressure rated hoses to connect to the wells. Generally, cement treating lines have a 2” ID and are rated for a pressure of 103.4 MPa (15,000 psi).

5.4.1

TREATING IRON OPERAT ION

Trican uses Weco Fig. 1502 connections on all its treating line equipment. When connecting to a drilling rig, ensure that the styles of the unions match. It can be very easy to mismatch unions, because a few different styles will thread into a Fig.1502 union. In these cases, however; there will not be a proper seal achieved that can withstand pressure. Male Sub

Wing Nut

Seal Ring

Female Sub Figure 5-9: Figure 1502 Drawing

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Most other service lines (nitrogen, frac and coil) view how we rig in cementing iron as “backwards”. We begin the rig in of our treating line at the pumping unit. On the other hand, most other services will begin rigging up starting at the wellhead. The basis of which direction your iron runs is all about starting from a fixed point. To tighten the connections properly, they must start from a fixed point. In cement, we use the pumping unit as our fixed point and tighten from there. The other service lines generally use the wellhead as their fixed point. Every time we must rig up to the rig floor, there will be a nearly vertical section of treating line running from the ground to the rig floor. This vertical section of treating line is called the “standing iron”.

5.4.2

TREATING IRON SAFETY

Making up connections should be a task we take very seriously due to the hazard of the pressure they help contain within the line. Ensure a connection is solid and not loose before joining up the next piece in the line. Even though we sometimes connect to the well with our flexible mud line hoses, it should be noted that these hoses cannot withstand the same kind of pressure as our treating iron. Under no circumstances are the mud lines to be used to pump through with our triplex pumps for any main stage of a job! A third party can convey displacement and other fluids to us through these flexible hoses, or we can use these hoses to help flush systems with a centrifugal pump. FLEXIBLE HOSES ARE NOT TO BE PUMPED THROUGH! 1. If a line does not appear to break apart normally, assume it is under pressure. STOP and re-assess the situation before proceeding. DO NOT BREAK APART LINES UNDER PRESSURE.

5.5

TRIPLEX PUMP

Figure 5-10: Trican Triplex Cement Pump

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The triplex pump is a positive displacement pump. A positive displacement pump moves the same amount of fluid per stroke, regardless of the resistance pressure on the outlet line. The triplex pump is a piston pump with three pistons that stroke in series (hence the triplex name). The triplex is made up of the power end and the fluid end.

5.5.1

TRIPLEX PUMP OPERATION

The Triplex pumps on our cementing units are powered by diesel engines. The pumps are coupled to the engines via a gearing system and drive shafts. The power ends of the pump convert the rotational energy from the engines into reciprocation to stroke the pump pistons. The fluid end is charged by the pressurizer pumps, which provides a high flow rate of fluid into the pump.

5.5.2

TRIPLEX PUMP SAFETY

Whenever working on a triplex, the unit’s power and engines should be off and locked out. This prevents getting caught with your hand in a plunger hole when the pump decides to rotate. Always lock out your unit before performing maintenance work. BEFORE PUTTING ANY TRIPLEX TRANSMISSION INTO GEAR, YOU MUST VISUALLY CONFIRM THE POSITION OF THE RETURN AND DISCHARGE VALVES! Unless you are signed off to operate your pump unit, never engage the triplex except if you are under the supervision of a competent employee. Complacency and inexperience are the main reasons for overpressure situations. Nine times out of ten it is a mistake from the pump operator. Slow down and take the time to assess your task. We use these pumps every day, but we must always be professional and always be aware of the consequences of misuse.

5.6

PRESSURIZER PUMP

Figure 5-11: Pressurizer Centrifugal Pump

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The pressurizer is a centrifugal pump, not a positive displacement pump. Centrifugal pumps operate by rotation of an impeller inside a housing or volute. The rotation of the impeller draws water into the pump from the center and slings the water outwards through the discharge port. The pressurizer is mainly used to charge the triplex pump. The function of the pressurizer is like that of a supercharger on an internal combustion engine. The pressurizer’s secondary duties are to provide recirculation for the cement slurry mix system.

5.6.1

PRESSURIZER PUMP OPERATION AND MAI NTE NANCE

The pressurizer consists of the following main components:

▪

Casing Impeller and Shaft Packing

The components must all be maintained to ensure maximum efficiency of the pressurizer. Attention must be taken to make sure that the seal on the pump shaft and casing do not leak and allow air into the system. Performing a cement job by today’s standards is next to impossible without a fully functioning pressurizer. Most new cement pumpers that Trican operates do not carry the necessary ancillary equipment to mix cement without a pressurizer.

5.6.2

PRESSURIZER PUMP SAFETY

Safety concerns with the centrifugal pump are like the ones for the displacement pumps. It is tempting to be complacent with a centrifugal pump, as we tend to view them as less hazardous than triplex pumps. If operated incorrectly, the centrifugal pump with fluid slip can build up a lot of heat due to the trapped fluid. When shut in, it can cause explosive pressure releases and severe burn hazards to anyone in the vicinity. Hot fluid and steam can come out downstream in the plumbing of the pumper, depending on the route of open valves. WHEN NOT USING THE PUMP, ENSURE IT IS OFF! ALWAYS CHECK FOR FLOW WITH A PRESSURIZER BEFORE WE ENGAGE THE TRIPLEX.

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5.7

MISSION PUMP

Figure 5-12: Mission Centrifugal Pump

The mission pump operates like a pressurizer and is mostly used as a water supply pump for mixing cement slurries. It provides water to mix cement and wash up mixing equipment, and brings fluid to the displacement tanks. Like the pressurizer, the mission is also a centrifugal pump. The outer casing of the mission pump differs from the pressurizer in that it has a concentric casing instead of a volute casing. The concentric design eliminates vibrations, and cavitation when pumping water. This is desirable because it eliminates the frothy bubbly flow of water, which makes cement mixing more difficult.

5.7.1

MISSION PUMP OPERATION AND MAINTE NANCE

The same rules as for the pressurizer apply to the mission pump. Ensure the pump is properly maintained and in good working order. Adding new packing and regularly repacking the entire mission will ensure good operation over the long run. Make sure the system is receiving proper greasing to know how often you must repack the pump.

5.7.2

MISSION PUMP SAFETY

As opposed to the pressurizer, the mission pump is more likely to be hazardous because of the way we operate it. The mission pump is mainly used for water, and water tends to heat up faster in a shut-in mission than many of the other fluids we are sending through a pressurizer. For example, if we shut in a mission full of 20oC (68oF) water and turn the throttle up to a high rpm, it is just a matter of seconds before the pump starts to generate steam and builds up pressure. WHEN NOT USING THE PUMP, ENSURE IT IS OFF! It is very dangerous to operate the mission pump incorrectly. If the pump is left shut in and rotating, the temperature of the fluid trapped inside the pump will heat up quickly. Operators have been scalded by the spray of fluid/steam generated from inside a running mission pump. If left long enough at a high rpm, the water in the pump turns into steam. Try to avoid this from happening.

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5.8

MIXING TUB

The mixing tub is a tank plumbed into the pressurizers, the mission, and the mixing equipment. As such, it really is the main hub of the cement pumper. The mixing tub is where the cement slurry stirs and shears while it is mixed to the proper density. The slurry is then pumped to the triplex and pumped downhole.

5.8.1

MIXING TUB OPERATION AND MAINTENANCE

Take care to keep this area free from the buildup of hard cement. Clean the tub regularly to ensure proper operation of the cement pumper. A buildup of hard cement in the tub may break loose and lodge itself into a pressurizer or the dustless mix head. A chunk of hard cement into a pressurizer can stop the impeller (and therefore, the cement job). Problems are usually caused by plumbing that gets clogged, or a wrench or other tool that made it to the mixing system and damaged a pump. Always check the tub for loose objects before taking on fluid at the beginning of a job.

Figure 5-13: Mixing Tub and Dustless Mixing system

5.8.2

MIXING TUB SAFETY

During mixing, the mixing tub and surrounding area are considered a Hot Zone. A high concentration of cement dust and other chemicals will be present in this area. Always wear proper PPE when you must enter this area during mixing. Occasionally, we will be asked to hand dump additives directly to the mix tub while mixing cement. A respirator, splash goggles, chemical resistant gloves, and even a splash suit should be worn in the area. When washing up the tub at the end of a job, always wear proper eye protection. Safety glasses are not enough to protect your eyes from splashing fluids. A full-face mask respirator is required by Trican policy. In addition to the cement itself, the other chemical additives that may be present in the cement blend are also not something we want to encounter. SLOW DOWN AND WEAR THE PROPER PERSONAL PROTECTIVE EQUIPMENT

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5.9

CONVENTIONAL MIXING EQUIPMENT

Figure 5-14: Conventional Jet Mixing Bowl

The conventional mixing system is a tried-and-tested method for mixing and pumping cement. The equipment consists of basic components and is viewed by many as the easiest way (from an operator’s point of view) to mix cement.

5.9.1

CONVENTIONAL MI XING OPERATION AND MAINTE NANCE

Conventional mixing consists of a few main parts:

▪

Mixing Bowl Witch’s Hat (Hopper) Water Lines Riser Hose Mix Tub (and Pressurizers for Recirculation)

The dry bulk cement is dumped into the hopper, called the witch’s hat. This cone feeds the cement powder into the mixing bowl. The mixing bowl houses two separate water jets; the water jet line and the bypass line. The dry cement powder first meets water at the jet-line outlet. The outlet on the jet line will have differently-sized nozzles, depending on what type of cement is being mixed. After the powder is mixed with water at the jet line, the flow of the jet pushes the mix downstream to where the slurry will meet the water bypass line. The act of the jet moving fluid down the line also creates a vacuum above it, sucking in more dry powder. A similar process happens in the dustless mix head. The bypass line is where we fine tune how much water we mix with the powder. At this point, the slurry is forced down the line and into the mixing tub.

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The jet line provides more or less cement because this is the line that grabs the cement first. The bypass line provides more or less water (even though there is water already mixed in the slurry from the jet line). The flow rate of both these water lines is controlled by the pump operator. The water is supplied to these lines by the mission pump. It takes a bit of practice to keep a constant density and fluid level in the mix tub. Make sure you know how your specific unit acts at certain RPMs and how much mission pump throttle will provide a good water flow. Practice under the supervision of an experienced operator.

Figure 5-15: Conventional Jet Mixing Cement

5.9.2

CONVENTIONAL MI XING SAFETY

The general rules of safety apply when mixing cement, no matter what method you are using. Use T.R.A.C.K. (Trican’s on-the-job hazard assessment program) and follow the procedures you were trained to do.

5.10

DUSTLESS MIXING EQUI PMENT

Dustless mixing is the current method for mixing and pumping cement. Similar systems have been used in our industry for a long time. The dustless system eliminates the need to feed dry powder into a mixing bowl. It also provides a more accurate way to control the amounts of powder and mix water.

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Figure 5-16: Dustless Mixing Head

5.10.1

DUSTLESS MIXING OPER ATION AND MAINTENANC E

1. The dry powder is pneumatically forced into the dustless head from a bulker or P-tank. The dry cement powder is blown with air at a constant flow from the bulk storage. 2. The bulk powder enters the mix head and passes through a metered gate valve, commonly called the “knife gate”. The knife gate can adjust the amount of powder that is entering the system; from 100% to 0% flow (shut in). We can fine-tune the knife gate as to provide the optimum product flow for mixing at any given pump rate. The flow can be adjusted in 0.1% increments, which allows for very fine control when maintaining optimum density of our cement slurries. Remember that this gate only controls the amount of flow; if you have bad flow from your bulker, the knife gate will have a tough time regulating it. 3. After passing the knife gate, the dry powder meets the mix head recirculation outlet, which is where the powder meets water/recirculated slurry for the first time. The mix head recirculation also provides a little bit of suction to the system, it will suck powder from the bulk supply line.

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4. Downstream in the mix head, the mixed slurry then meets the water wheel. The water wheel is a metered valve that allows us to make fine adjustments to the amount of mix water that is added to the system. Once the slurry exits the water wheel, it is forced into the degasser. 5. The degasser is an open bottomed barrel. Once exiting the mix head, the slurry is still joined with the air that was used by the bulk systems that send the powder to the unit. It is in the degasser where the slurry is separated from the bulk supplied air. As the slurry exits the mix head it slams against the wall of the degasser where the air is forced out of it. The flow of slurry is forced out the bottom of the degasser and the excess air escapes out the top. 6. The slurry exits the degasser and enters the mixing tub, where it is pumped through recirculating lines or to the Triplex pump by the pressurizer.

5.11

PRAIRIE MIXER (JET MIX)

The jet mix system is only used for batch mixing cement, or mixing a pre-flush/spacer with a densityincreasing material such as barite. It consists of an inlet for powder from a bulk unit, and one jet line of mix water. The prairie mixer is operated by recirculating the mix water through a pressurizer and Triplex pump. The fluid is drawn out of the tank and circulated back to the same tank via the valve tree. The mix water is preloaded to a specific volume and the amount of powder used is predetermined. Note: The batch mixing process is mixing all the required cement and pumping the slurry downhole. This greatly differs from the “on the fly” simultaneous mixing of the other two systems. Special considerations, such as the thickening time for this specific cement, must be taken when deciding to batch mix cement. Some cement blends must never be batch mixed. For example, SPC cement blends produce hydrogen gas when water is added. Over a short period, enough hydrogen gas can be produced for it to become a safety hazard.

6.

PUMPING ACCESSORIES

Besides the pumping and bulk units, there is additional equipment that are all parts of a successful cementing job. For example, plug loading heads and swages make it possible to tie our pumping equipment into the piping strings of wells we are treating. Valve manifolds let us control the direction of flow during the different stages of a job. In this section, we will cover some of these accessories and explain their operation as well as their best practices.

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6.1

PLUG LOADING HEAD

Figure 6-1: Cement Plug Loading Head (PLH)

The Plug Loading Head (also called the cementing head) is an accessory that is attached to the last joint of casing once casing has fully been run into position. It provides connections so that mud and cement can be pumped into the casing. A plug loading head can be designed to hold one, two, or more plugs. Balls, darts, and bombs can all be launched from a plug loading head.

6.1.1

PLUG LOADING HEAD OPERATION AND MAINT ENANCE

The Plug Loading head (PLH) operates in tandem with a valve manifold. The plugs are held in place by drop away bars and pull out pins. The head operator selects where he wants fluid to flow via the manifold. When launching a plug, the corresponding pin is pulled and the valve that controls flow above the plug is opened. When fluid is pumped through the open valve, the plug is forced ahead of the fluid. Take great care when operating the plug loading head and manifold. Always confirm the position of the valves on the manifold before engaging the pump. Only service supervisors or authorized personnel under the direct observation of the supervisor are allowed to operate the plug loading head. Take care not to create an overpressure situation or to launch a plug at the incorrect time. Before loading plugs into a plug loading head, the operator (supervisor) must check all the tool’s functions. •

Confirm that the pin or drop bar operate properly.

•

Count the number of turns it takes to pull the pin or drop the bar.

•

Plugs should only be loaded with a qualified witness, preferably the oil company’s representative on site. If the representative is unavailable, the driller, tool push, or a non-Trican third-party should witness that all systems have been checked and that the head has been loaded properly. If no one else is available, a member of your crew should witness the head being loaded.

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•

The PLH should be thoroughly checked prior to every job. Check the PLH before leaving the shop; we do not want to show up on lease with the wrong size of PLH or a PLH that does not function properly.

•

All threaded connections should be checked for damage and wear.

•

The operation of the pin (or drop bar) should be checked prior to leaving the shop. If taking a top drive crossover, the fit of that crossover should be physically checked in the PLH before leaving.

•

The

•

The

•

Regardless of which style you use, always confirm its proper operation prior to loading the PLH.

6.1.2

pins and the drop bar mechanisms should be greased at regular intervals to push out water and ensure ease of operation. In colder temperatures, greasing the pin will keep the mechanism free of water. PLH you are using will determine what type of plug launch indicator will be present. Some PLHs will have built-in indicators that signify if the drop bar is in position. Others have a wire indicator installed in the top cap of the head. This wire is physically attached to the plug inside the head. When the plug leaves, it pulls the wire with it. When using a top drive on heads that have a wire-style indicator, we will usually install a plug indicator into the back side treating line connection. Because the top cap will not be present when we tie into a top drive, the indicator is usually the only way to have a plug launch indicator on the PLH.

PLUG LOADING HEAD MANIFOLD

The valve manifold controls the flow from our pumpers on the treating line into the PLH. The manifold can either put the flow above or below the plugs to be launched. When launching a plug from the head, we pull the pin, holding the plug in the head. Then, we open the valve above the plug and shut the valve that was below. Pumping is then resumed and confirmation that the plug has left the head is checked. Besides the valves that are physically on the PLH, there will usually be a few more valves attached to our treating line present on the rig floor. We will most likely have a pump out line installed via a “Tee” and valve. This line is used to flush the treating line of fluids between certain stages of the job. Another valve that will be installed via a “Tee” will be a backup connection. The Kelly hose (mud hose) of the rig will be installed into our treating line to take over pumping duties in case of equipment malfunctions. The rig can either finish off a displacement, or entirely displace cement out of hole in the event of any major issues.

6.1.3

CEMENTING PLUGS

There are two types of plugs: top and bottom. They consist of elastomers molded over drillable aluminum or plastics housings. Bottom plugs precede the cement down the casing. They are fitted with an integral bypass or flowthrough feature that, once the bottom plug has landed on the float mechanism, allows flow through the plug. This usually consists of a hollow core plug and a rubber diaphragm. The bottom plug also serves as a seat for the top plug to land on and seal off displacement fluids. Top plugs are sometimes used alone. They are designed to withstand the pressure and forces generated by landing abruptly. When using top and bottom plugs, ensure they are loaded into the PLH in

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the correct order. Commonly, bottom plugs are red, orange, or pink. Top plugs are usually black. However, never assume this is the case. Always confirm which plug is which, and in what order they must be loaded into the head. Always check the bottom plugs for a burst diaphragm and that the top plug has a solid core.

Bottom Plug

Top Plug

Figure 6-2: Cement Plugs

6.1.4

PLUG LOADING HEAD SAFETY

Take your time when operating the PLH and think about each step when you are loading the head, operating pins, and swinging valves on the manifold. The pump operator should always confirm the position of the valves with their supervisor - during engaging their pump and discharging off the pumper. In the past, a pump has been brought online when completely shut in at the manifold. Risk of over pressuring our equipment and injuring our crew is something we must control. Always follow the golden rules of pumping. When installing the PLH onto casing, we will be working around a suspended load (the PLH itself). Never stand under the load, use a tag line, and get assistance from the rig crew when necessary. Always follow proper procedures when using a top drive crossover. There is a risk of damaging the PLH thread connections if the crossover is torqued up incorrectly. Use hand chain tongs to gain a proper seal on the top cap threads. Manifold valves should be greased after every use. If a faulty valve is found, it should be taken out of service and replaced.

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6.2

SQUEEZE MANIFOLD

The squeeze manifold is different from the regular setup of valves we use on the rig floor. It consists of four valves, T’s, and two spots for pressure recording. The setup of this manifold allows us to do the following: •

Pump down the piping string and return from the annulus.

•

Pump down the annulus and return from the piping string.

The manifold allows us to switch flow direction without having to break apart our iron and tie into the desired area. The manifold also aids to hold back pressure on the return line, used extensively for squeezing.

Figure 6-3: Squeeze Manifold

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Figure 6-4: Multiple Cement Unit Rig-In

7.

WORKING WITH DRILLING RIGS

Drilling rigs are mobile structures, consisting of many different individual components for drilling operations. They can be mounted on trucks, track, skids, and trailers; or are more permanent structures based on land or sea. The basic components of a rig include: derrick, rig floor, substructure, pumps, draw works, engine houses, pipe conveyance, and much more ancillary equipment. A rig is manned by rig workers (commonly known as roughnecks), lease hands, derrick man, motor hand, mud engineer, and the driller. It is best to hang back and let the rig workers do their jobs. As a Trican employee, you are not expected to do the rig workers’ jobs. Never touch controls on a drilling rig, even when asked to do so! Stay focused on your job. Develop a good working relationship with the rig crew and work as a team to achieve a quality cement job. Look after your equipment and ask for help from the drilling crew if required.

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Figure 7-1: Drilling Rig Components

7.1

RIG FLOOR

The rig floor is where most of the interaction with the well takes place during drilling operations, and where most interaction with a rig takes place during primary cement jobs. The rig floor sits on top of the substructure and supports equipment such as the rotary table/kelly bushing, the draw works, the derrick, and the drilling controls. All measurements for depth in the well are taken at the Kelly bushing. If a job proposal lists the well as 100 m (330 ft) TVD (true vertical depth), that means 100 m (330 ft) down from the Kelly bushing. Once casing has been lowered into position in the well, the top of the casing well can be suspended in the wellbore by the slips of the rotary table. This is where the cementing crew can install the PLH and tie their iron onto the casing. The rig floor one of the most hazardous places to be on a drilling rig. A lot of rig floors are small and congested with moving equipment, pipe, and crew members. Look, listen, and pay attention to everyone while on the rig floor. Don’t be on the rig floor unless you have something to do, stay with your cement unit and only go to the rig floor when necessary. The driller sits at the controls, which are usually located on the rig floor next to the rotary table. The driller’s station can also be located inside the dog house or a tower, but the drilling controls are always within sight of the hole and the equipment it operates.

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The roughnecks are the hands of the driller. Their job is to help with the operations required to run pipe in and out of the hole (called tripping). They make and break connections of pipe joints, install tools on the pipe string, perform operations pertaining to a top drive, install casing accessories, and many other tasks beyond the scope of this course.

7.2

DERRICK

The derrick is one of the most iconic pieces of equipment in the oil industry. The derrick is the vertical mast most of us will imagine when we think about a “drilling rig”. The derrick helps transporting piping strings in and out of the hole. It houses many pieces that work with the draw works. The derrick man can be found on the monkey board of the derrick during drilling operations. His position involves working with the top end of pipe joints that are going in and out of the hole. He positions joints for the travelling block to lift, and moves pipe joints in and out of the pipe stand.

7.3

DRAW W ORKS

The draw works raise and lower pipe in and out of the hole. Along with the derrick and substructure, they support the weight of the pipe string during tripping and drilling. The draw works is a series of pulleys that start at the cable drum and ends with the travelling block. The block is essentially a large pulley. The crown block at the top of the derrick is the stationary section, the travelling block is freely moving. The swivel or top drive is underneath the travelling block. All this allows the pipe joints to be transported in and out of hole. The travelling block can also be attached to a top drive. The top drive system replaces the rotary table and Kelly spinner for drilling operations. When working with a rig that is equipped with a top drive, rigging into the casing changes slightly as the PLH is usually tied into the top drive equipment to reciprocate pipe during the cement job. There are many hazards associated with top drives and automated roughnecks. Always pay attention and ask your supervisor what the specific dangers are in these situations. Always stand clear of the treating iron once you have tied into a PLH that is attached to a top drive, as they can have torque pressure. When the driller lifts the casing string out of the slips, sometimes your iron may swing. You don’t want to get hit with the iron or pinched between it and the derrick or pipe stands.

7.4

SUBSTRUCTURE (CELLAR)

The substructure is the foundation of the rig. It supports all components above the wellbore. It houses BOPs, mud return lines, and a lot of other equipment needed to drill a well. It is in the cellar that we see fluid return to surface from the wellbore. Depending on the phase of oilwell construction, you may see the returns bubbling up out of the annulus, or the mud circulation system may be tied on to the annulus here. Cementers work in the cellar to rig iron into the annulus, or to flush out rig equipment after a cement job. Use caution when entering the cellar. It is easy to slip or fall into the conductor hole or rat hole. The rig crew may not be aware that you have entered the cellar. Always ask your supervisor if you can go in, and

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pay attention to others who are working around/above you. Be aware that the hazards in the cellar will change throughout a cement job.

7.5

MUD CIRCULATION SYSTEM

Modern drilling techniques rely on the use of drilling mud to transport cuttings out of the hole and to cool the drill bit during drilling. Drilling fluids come in many forms and flavours, but they are usually referred to as “mud”. Drilling mud plays several roles during the drilling and cementing phases of a well. It is common for cementers to pump large volumes of drilling fluid to displace cement. The mud is pumped through the drilling string downhole and out through the bit. It then proceeds up the annulus, back to surface. When the drilling mud reaches the surface, it is transported to the shaker system. The shakers separate sand and cuttings out of the drilling fluid, then return the “clean” fluid back to the holding tanks, where it remains until it is sent back downhole. It is at these shakers where we can witness cement returns coming back to surface. When cement is seen, it is diverted from the mud system to disposal bins, or pits.

7.6

V-DOOR AND PIPE CONVEYANCE

The V-door, catwalk, and pipe racks are all part of the pipe conveyance system. Joints of pipe are loaded onto pipe racks, which roll down towards the catwalk. Catwalks can have skates, others come with pulleys and winch lines. On the catwalk, individual joints of pipe are slid up the V-door to await their turn to be tied into the well. Standing pipe for the treating iron (a vertical section of treating iron from the ground to the rig floor) is usually up the V-door. Don’t forget to get the keys for the V-door before rigging in! Some modern drilling platforms have a fully automated pipe conveyance system, consisting of hydraulic arms that move and lift pipe joints into position above the wellbore. There are always inherent hazards when working with large pieces of moving machinery. Whenever you come across a drilling rig that you are unfamiliar with, ask your supervisor of any specific hazards this rig may present. Your supervisor will be informed of these during his initial meeting with the location HSE and the company representative. Don’t hesitate to ask any rig crew members if you have any concerns.

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Figure 7-2: Rigging in the Cement Supply

Drilling and support equipment will be positioned on lease before and during a cement job; we must be able to adapt to the countless ways a location may be set up. Sometimes, drilling operations are set up with very little forethought on how a cement crew consisting of two bulk trailers, three bulk bins and two pumping units must be brought on lease to do an intermediate casing job.

7.7

SPOTTING EQUIPMENT F OR RIG-IN

When arriving on location, the Trican supervisor will meet with the company representative and go over site hazards and HSE requirements. Once that is done, a pre-rig in meeting will be held with all Trican personnel on location. During this meeting the supervisor will lay out how the units will be spotted into position, explain how the rig in will proceed and go over any site-specific hazards for that job.

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IT IS TRICAN POLICY THAT WHENEVER A UNIT MUST BE BACKED INTO POSITION, A GUIDE OR GUIDES BE USED! A guide can be very useful to guard against backing a unit into something or someone, but ultimately it is the driver’s responsibility to drive the unit safely. If you lose sight of your guide, stop, and wait until you can see (the guide) again. If you are unsure what is behind you, take the time to get out and walk around the truck. A pylon can be used instead of a guide, but usually there is someone on lease to help guide you. Nothing is more embarrassing than having to wake up someone because you backed up your bulk trailer into the pipe racks. This does not give the customer the confidence that we can properly and safely perform the services they are paying us for. There are two things your supervisor must look at when spotting equipment prior to rigging up. •

Where the water supply is located.

•

How the water will be conveyed to the pumper.

Will the water be drawn from the rig tank, a 400 bbl (64 m3), is it coming off a bulk hauler, or a combination of all three? Do we have a backup source of water in case there are problems? How the pumping unit will be spotted on location depends on where the water is coming from. Then, the supervisor will think about the bulk cement, positioning bulk trailers, or finding a happy medium between the water source and where a bulk bin is sitting. The main concern for spotting the pumper will almost never be rigging in the treating line. Cement pumpers carry a lot of treating line iron. Most of the time, this will remain unused. We carry a lot of extra treating iron, flush hoses, bulk hoses, etc. The extra lines allow us to be flexible in how the unit can be positioned for the job. How we spot our units boils down to WATER, BULK CEMENT, IRON, and SAFETY.

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1.

Drilling Rig

2.

Rig Tank

3.

400 bbl Tank

4.

Fluid Hauler

5.

V-Door

6.

Catwalk

7.

Pipe Racks

8.

Cement Bulker

9.

Twin Cementer/Single Cementer

10.

P-Tank

11.

Mud Shakers

12. Existing Well

Figure 7-3: Example Cement Job Layouts

These examples only show two very specific arrangements of equipment, but it displays how a pumper would be spotted to have easy access to water and bulk supply. Never begin a job unless a backup source of water is rigged up and ready to go in case a problem arises with the main source! Only proceed with one water source if all available options have been investigated, the customer has been made aware of the risks, and you have made a phone call to the office.

7.7.1

PRI MARY CEMENTING RI G IN

In this section, we will look at a few excerpts from the Best Practices Manual regarding rigging in and job procedures. Treating Line: 1. Inspect the two-way swivels for wear. All wings and threads should be cleaned and oiled; the rubber insert checked for cracks, wear, dirt or debris behind the seal. Begin with a wing onto the permanently mounted discharge iron on the back end of the pump unit. 2. All iron (including wings, threads and rubber inserts) should be visually inspected by a qualified employee, then cleaned and oiled prior to assembly. The employee shall ensure that all iron has current inspection bands in place.

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3. Long joints or pup joints may be necessary to reach the ground where another swivel will be needed to connect to long joints running to the base of the rig. Where possible, the use of a long joint from the ground to the rig floor is recommended to prevent a union between the ground and rig floor that cannot be reached from the ground. 4. Upon reaching the rig floor, attach another swivel to the long joint riser pipe. From this point, an assortment of pup joints, long joints, and steel hose loops (sweeps) are arranged to attach to the casing swage or plug-loading head. If the casing is to be lifted and lowered (reciprocated) through the job, sufficient length of treating iron will be required to accommodate this. The required length should be discussed at the pre-job safety meeting and a designated floor monitor assigned during the job. 5. When connecting to casing via a swage, a plug valve should be inserted, followed by a double wing chiksan, which will then attach to the steel hose loops arranged on the rig floor. 6. When connecting to casing via plug loading head (PLH), a threaded plug loading head manifold with two plug valves will connect to the threaded outlets on the PLH. A double wing chiksan will then be used to connect the PLH manifold to the steel hose loops, which have been arranged on the rig floor. 7. PLHs and swages shall be secured to the rig bails by an approved safety sling to prevent it from falling onto the rig floor in case the connection between the casing and swage/PLH fails. 8. Treating iron on the rig floor shall be hung by a cat line or air hoist to aid in swivel mobility during reciprocal movement of the casing string during cementing.

Figure 7-4: Pressurized Silo (P-Tank) on Location

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THE CEMENT CREW

8.

A cement crew usually consists of two to four members. Supervisor Lead Operator Second Operator Bulk Cement/Third Operator

▪

We must all work as a team. We must all work together to manage our time. As operators, we must keep the supervisor in the loop of our log book hours. If we are close to houring out or getting tired, we must let our supervisor know.

8.1

SUPERVISOR

The supervisor’s duties consist of managing the cement crew. He finalizes job procedures and pumping schedules. He meets with the customer representative on the job site to discuss how to approach the job. The supervisor hosts safety meetings for his crew and will usually chair the safety meeting with everyone on lease prior to beginning the cement treatment. The supervisor is also in charge of the training of his crew members. The maintenance of the pumping equipment, job performance, and scheduling are all responsibilities of the supervisor. The supervisor can delegate maintenance duties and job duties to other crew members, but if something goes wrong or maintenance is not up to par, the supervisor is responsible. A lot of pressure and responsibility rides on his/her shoulders.

8.2

LEAD OPERATOR

The lead operator’s duties mainly consist of ensuring the pumping unit is properly maintained so that it is ready for work. The lead operator will operate the pumping equipment during the job by following the instructions and pump schedule as provided by the supervisor. Maintenance of the unit may be completely up to the operators, while the supervisor will help when he can. Duties include and are not limited to: •

Mixing cement and maintaining desired density.

•

Preparing pre-flushes.

•

Rigging in and out the pumping unit as per supervisor’s directions.

•

Washing up the unit at the end of a job.

The lead operator is largely responsible for the training of new operators. Everyone on a cement crew is responsible for helping new hands, but it is the lead hand who will be the one who trains a new hand how to operate the pumping unit. Once a lead operator has a second operator able to competently perform his/her duties, a lead hand is free to shadow a supervisor to begin training as a supervisor, if his/her duties are still being performed. Once a supervisor is assured of a lead hand’s abilities to perform the duties of a supervisor, the supervisor and the lead hand may take turns pumping/supervising jobs.

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8.3

SECOND OPERATOR

The second operator (sometimes called the ground hand or junior operator) has the same responsibilities and duties as the lead operator. The title of lead operator is just a matter of experience level and seniority. There may be two lead hands on a cement crew; the second operator is the one who is not actually pumping the job at hand. It is common for operators to switch off pumping duties once they are both competent at the task. One will pump the truck, while the other is the ground hand. On the next job, they switch positions. It’s just like taking turns driving the pumper to/from location. Second operators are the hands of the lead operator. They will swing valves, operate P-tanks, gauge displacement tanks and perform other duties for the supervisor during a job. Just because the second operator is not pumping the job doesn’t mean there isn’t anything to do while we are mixing cement.

8.4

BULK CEMENT OPERATOR

The bulker’s duties consist of making sure the bulk unit is properly maintained and ready for work. He/she must check loading tickets and ensure that everything that is required for the job is transported. The blends and additives on the loading ticket should be reviewed to ensure they match what is on the call sheet.

9.

Paperwork

On every operational level of a cement crew, there is paperwork that must be understood and dealt with accordingly.

9.1

JOB PROCEDURE SHEET

The Job Procedure sheet is one of the forms you will see daily. This form outlines the scope of a cement treatment. It lists all pertinent information a pump operator may need during the job, the order of fluids to be pumped, exact volumes and densities for each fluid, pressure tests, and expected pressures for different stages for the job. Your supervisor may not give you the actual Trican Job Procedure sheet, but instead may just copy the pertinent information onto some scrap paper. The Job Procedure sheet does not hold all the information you need for the job. Make sure to pay attention in the safety meetings and ask your supervisor if anything is unclear, or you do not fully understand the topic. As always, clear communication is key. Follow proper Trican radio procedures and follow the directions of your supervisor.

Figure 9-1: Job Procedure Sheet

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9.2

LOADING TICKET

A Loading Ticket is another sheet that operators will often be confronted with. Loading tickets are one of the most important documents to any cement job. Besides from physically testing a sample in the lab, there is no way to tell one blend of cement from another. It all looks like grey dust; which is why we need the loading tickets. They identify the type of cement in the container and the additives in the blend. The bulk plant operator will fill out the Loading Ticket as he blends and loads a bulk trailer with cement. He gives a copy to the bulk truck driver, who should check the blending and additives are what is required for the location he is heading to. Finally, when the bulker arrives on location, the bulk operator gives the loading ticket to the supervisor. Alternatively, once he has off loaded into a bin, he will leave a copy of the loading with the bin. This identifies what is in the P-Tank, who loaded it, and how much was loaded into the tank. The bulk operator should also fill out identification tags and attach them to discharge valves after a tank has been loaded. If everyone does their job properly and checks the loading tickets versus job proposals, we can avoid costly mistakes and - more importantly save our customers time and money. When receiving a loading ticket, check the cement blend on the ticket against what is listed for the blend on the call sheet. This is of the utmost importance. It is easy to get complacent and skip comparing the loading ticket with the call sheet. Be diligent and check every additive!

Figure 9-2: Loading Ticket

9.3

THE CALL SHEET

Supervisors are supposed to provide all units in a convoy with a Call Sheet prior to leaving for a job. The call sheet outlines specifics such as:

▪

Directions to the jobsite. LSD for the well the job will be performed on. Customer name and representative contact information. The type of cement that was ordered. Chemicals required for the job. Additives and volumes that are in the blend required for the job.

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The call sheet will also contain important notes the dispatcher has added for that specific job. For example: “50% road ban on RR20, must take RR23”, or “bulk will arrive two hours late to job, pump first stage and wait on bulker”. Not all the information on this document will affect our lives as operators, but it’s always useful to have proper directions and to know the type of job we will be heading to.

Figure 9-3: Mixing Tub

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Figure 9-4: Dual Cementing Units Rigged In

Figure 9-5: Twin Cementer Operator's Panel

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