7 Linner Cementing
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7 Liner - Cementing Preparation and Procedure Checklist
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(1 vote, average 4.00 out of 5)
This article is an example of a checklist for cementing a 7" liner.
Hold pre-job planning meeting. All equipment to be checked and personnel familiar with the pl
The final cement programme to be issued to the rig and approved by the Drilling Superintenden
Ensure that BJ needs to blow out water from the lines after performing pressure test to avoid fro
in cold weather.
Before cement job begins, ensure that the cement is fluffed and transferred from one tank to anotransfer in the cold weather.
Prior to start cementing, ensure to perform the following:
o Total required volume of technical water to be stored on the rig site some days in advan
o Pre-job analysis of technical water, slurry and spacers. Perfrom tests for possible fluid c
program.
o Be sure the slurry formules is fit to avoid flash setting due to possible slurry dehydration
Prepare cement mix water in the batch mixers and store in the KPO tanks, prepare spacers in th Confirm that the Technical water is being supplied directly from the LMP. Do not use water fro
supervisor to check the water.
Avoid using NaCL Brine to perfrom BJ lines test until a contamination test has been performed
Ensure correct tanks and drill water are delivered at least 24 hours in advance of the cementing
Check that cement chemicals have been added to the mix water in the correct order.
Thoroughly mix each chemical after adding them to the mix water. Take samples of final mix f
verification tests.
Ensure all BJ washer and spacers should be prepared in the batch mixer and pumped by the Cemcontrol avoid preparing washer and spacer in rig pits and avoid using rig pumps.
Take 5 gallons dry cement sample in advance of the cement job so that pilot testing at cementin
carried out.
Take 1 gallon mix water sample during the cement job.
Check that the following equipment is available at the rig site: Weatherford circulating tool; LoDrilling Contractor?).
Mud Logger to ensure stroke counters set to zero before pumping spacer and displacement.
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While preparing the slurry, continue to circulate and check the following:
o Cement head bearing is secured to the derrick prior to rotating the liner
o The tugger must be manned at all times during rotation.
o There is a minimum of 20 Klbs (10 tonne) of drillpipe weight onto the liner prior to rota
of HRD tool in HRD profile of ZXP packer to allow rotation of liner.o Establish circulation and rotation (generally ensure continued circulation during all rota
monitor rates and pressures.
o Note torque readings at 20 and 30 RPM with a minimum weight of 20 Klbs (10 Tonne)
o Check that the top drive is set properly in order not to limit the torque below programm
cementing job.
o Make sure there is good communication possible between the rig-floor and the cement u
location.
Ensure that TDS IBOP is closed before hooking up the cement lines. Open the low torque valv
If losses encountered during drilling 8 hole section, attempt to cure losses before mixing and If possible use the caliper log to calculate the slurry volume required.
o The Liner should be set 100m inside the 9 7/8" casing. Reduce the slurry top to 50 - 100
excess and TOC should be agreed & communicated to the team once the logs are run.
o Before the job check & calibrate all saipar and WFD-Datalog sensors and stroke counte
Pump the required amount of cement as per cementing programme, allowing for volume of app
Top (with the DP connected to the hanger). Observe and note the torque required to rotate the
Stop rotation to allow safe release of the Drill Pipe Pump Down Plug as follows (it is not allow
whilst rotating).
When cementing the 7'' liner after bumping the plug to pressure up to 1000psi over final displac
mins.
Responsibilities during cementing
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(4 votes, average 4.50 out of 5)
Planning and supervision is crucial in cementing operations. This article describes the key responsibilit
Cementing Engineer, Mud Engineer and Drilling Contractor.
Operations Engineer
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ensure cement, mixwater and additive samples are sent in time to the service company for testin
check that the cementation proposal meets the objectives of planned cementing operation
ensure cement, additive and mixwater samples are despatched correctly marked and packaged
check log downhole temperature and compare with slurry design temperature.
witness and check quality control of calliper logs
check cementation proposal and reports
discuss with cementing contractor about new equipment/chemicals
Drilling Supervisor
overall responsibility for the conduct of the cementation
compare job calculations with those of the Cementer
supervise the Cementers and Drilling Contractor in the performance of their duties
inform the Mud Loggers, Mud Engineer and Driller:
1. of the volume of each type of mixwater to be used for both lead and tail cement
2. from which mud pit each type of mixwater will be drawn
3. of the expected gain, per barrel of mixwater blended with cement, for both lead
4. of the expected total volume of returns during the cement job and the expected o
co-ordinate the execution of the cement job
ensure that all relevant personnel are issued with a detailed programme of the cement job, highl
(the detailed programme must include volumes, pressures and pump rates for the cementing and
ensure that all relevant personnel are issued with contingency plans (flowcharts) to assist in rap
something go wrong
witness:
1. no changes are made to the agreed programme without the prior approval of the
2. the landing and hanging off of the casing, including the pressure testing of hang
3. pressure testing of the surface lines before the job
4. the circulation test
5. the placing of the cement plugs in the cementing head6. the preparation of the cement slurry and spacers (no deviation from the recipe sh
7. the pumping of spacers and cement slurry
count the number of tanks and fractions of tanks for the calculation of the volume of slurry pum
use chart recorders during cementation to record as many relevant parameters as possible, such
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1. pumping pressures
2. times of the various actions
3. cement slurry gradients
4. losses
ensure equipment is in a state of readiness
collect samples of mixwater, cement and additives during the cement job
confirm stock levels of cement and additives
supervise preparation of spacers, mixwater cement slurries and additives.
ensure dry cement is fluffed as per Contractor recommended procedure
prepare all cementation reports.
complete checklists prior to commencement of cement job
arrange loading and backloading equipment
confirm receipt of the cement test report recipe for the cement and spacer from the Operations E ensure that all checks are performed.
Two days before the cementation is started, he will collect the checklists and address any problecarry out the checks, sign off the checklists and return them. A copy of the checklists shall be fa
Drilling Contractor
operate and maintain the bulk air supply and mixing systems
provide personnel for loading and backloading of supplies and equipment
assist with sampling prior to, and during, the cement job assist with measuring the gradient of the slurries pumped
complete the minimum checks and procedures detailed in the checklists and pass completed che
prior to commencement of the cement job
provide lines for cement and water from supply boat
hook up cement/water lines as needed
Cementer
maintain and operate the cement unit and all associated equipment on the rig to the highest stan
ensure that the unit is functioning efficiently and has valid certification
record and maintain quality control of stock levels of cement/additives and physically check all
prior to any cementing operation
ensure that:
1. liquid additives are checked by use of a hydrometer
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2. adequate spare parts and consumables to support the operation are maintained
3. all materials used and delivered are recorded in a log book
carry out individual cement calculations and compare these with the calculations of the Drilling
perform the cement job as per the programme specified by the company, including the use of d
complete the minimum checks and procedures detailed in the checklists and pass completed che
prior to commencement of the cement job
advise drilling supervisor of any changes in cementing program
send the test results to the Operations Engineer and the Drilling Supervisor for verification at lescheduled.
confirm the laboratory bench tests at the well site.
distribute the checklists, which clearly define the responsibilities of personnel involved in the e
Mud Engineer check the mixwater for contamination and measure salinity
ensure mud is in good condition (no foam)
ensure the mud has been pre-treated to minimise cement contamination problems
ensure that there is sufficient volume of mud available on surface prior to commencement of th
ensure sufficient space is available for spacer or additives to be stored
monitor pit volumes throughout the cementation
measure cement gradient as required
check fluid returns for presence of cement, spacer or drilling fluid.
Mud Loggers
monitor pit volumes throughout the cementation, independently of the Mud Engineer
report to Drilling Supervisor immediately in case of discrepancies during displacement.
Last Updated on Friday, 10 June 2011 20:10Copyright 2011 wipertrip.com. All Rights Reserved.
Cement Programme Preparation
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(4 votes, average 4.25 out of 5)The Cement Programme gives a brief explanation as to the objectives in setting casing, i.e.:
isolate hydrocarbons isolate different pressure regimes
provide a pressure conduit of full integrity for drilling and completion
allow installation of BOP, completion etc.
General Preparation Guidelines
The following guidelines should be applied to the preparation of the Cement Programme:
The Drilling Supervisor shall prepare a call out fax seven days before the job. The Cement Programme shall be sent to the Drilling Superintendent and Operations Engineer fo
The final version of the Cement Programme, including the final details, shall be sent to the Dril
Operations Engineer.
No last minute changes to the Programme shall be made without the prior approval of the Drilli
A copy of the Programme shall be distributed to all rig personnel involved in the operation.
General responsibilities (execution and QA/QC) fo
Activity Execution Quality Control
Prepare the detailed
Cement Programme
Cementing Contractor Operations Engineer
Dispatch samples to
laboratory
Cementing Contractor Logistics / Materials
Supervisor
Test samples and preparerecipe
Cementing Contractor Operations Engineer
Verify Cement
Programme complies
with planned cementoperations
Operations Engineer Drilling Superintendent
Prepare well for
cementing
Drilling Contractor Drilling Supervisor
Mix, pump and displace
cement
Cementing Contractor Drilling Supervisor
Operations Engineer
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Conduct rig floor
operations
Drilling Contractor Drilling Supervisor Tool
Pusher
Prepare Job Report Cement Contractor
Drilling Supervisor
Drilling Supervisor
Operations Engineer
Programme Design Consideration
The design considerations given in the following table should be taken into account when preparing the
Activity Design Consideration
Check shoe track andaccessory configuration.
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Run and land casing as
per programmed casing
tally.
Proposed circulation test rates with corresponding
annular velocities (assuming gauge hole).
Pressure test surface
lines.
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Mud Engineer checks all
tank levels.
When possible, mud returns shall be diverted to a
different pit to that used for suction during
displacement.
Mud Logger To adjust chart to monitor volume pumped and
volume returned.
Batch mix cement If feasible
Pump spacers ahead. Calculate volume, fluid type, gradient, fluid loss
Drop first plug ahead of
spacers.
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Pump scavenger slurry. Calculate volume, gradient, cement sx., mixwater
volume
Drop bottom plug. -
Pump lead slurry. Calculate volume, gradient, fluid loss, cement type,
cement sx., mixwater volume, recipe, excess(referred to basis of calculation).
Pump tail slurry. Calculate volume gradient, cement type, cement sx.,
mixwater volume, recipe, excess (referred to basis
of calculation).
Drop top plug. -
Pump spacer behind Calculate volume, fluid type, gradient, over/underbalance
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Mud engineer checks all
tank levels.
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Displace cement. Calculate volume, fluid type, gradient, rate
before and after catch up.
Calculate volume of mud pumped whencement starts to flow into annulus (pressure
increase)
Total volume pumped when rate must bereduced for bump.
Total volume pumped at bump.
Bump pressure (casing pressure test) and
duration.
Pump efficiency.
Maximum permissible over displacement
past theoretical value to avoid physical overdisplacement of the slurry.
Annular velocity.
Flow regime of spacers and slurry.
Contact time for any critical point in the
wellbore - eg., across a particular gas sand.
Mud Engineer checks all
tank levels.
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Bleed off, check
backflow.
Proposed course of action if backflow is observed.
Cut / Back out landing
joint.
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Cement Testing - QA/QC
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(4 votes, average 4.25 out of 5)
All slurry and spacers are designed and tested at the Cementing Contractors Laboratory. Samples of cem
mixwater must be sent from the well site to the laboratory for this purpose. Testing is carried out accord
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General Guidelines
Bulk cement shall be sampled for testing purposes.
After retaining a portion for bench testing, the remainder shall be despatched to the Contractor,
The Laboratory test results shall be reported to the Operations Engineer/Drilling Superintenden
Samples of all products used during the cementing operation shall be retained in case further tesLaboratory is required.
Note: If necessary, the key cement properties may be reported by telephone or fax.
Despatch of Cement, Additives and Water Sample
Sampling GuidelinesProper sampling of cement, additives and mixwater is essential to obtain accurate and representative tescarried out by the Drilling Supervisor.
The following guidelines should be applied:
During unloading, the Drilling Supervisor shall take a sample directly from the supply line at a
from the silos. It is essential that the cement sampled is representative of the cement to be used
operation.
When powdered additives samples are requested by the laboratory, they must be taken from a s
be used in the forthcoming cementing operation.
When liquid additives samples are requested by the laboratory, they must be taken from the batcementing operation. The liquid additive must be well agitated before sampling.
Cement, additives and water must be sampled properly and stored/despatched in the appropriat
clean.
Excess air must be removed from the containers since exposure to humid air may affect the resu
exercise useless, potentially leading to problems during cementation.
Samples of all products, including a 1 gal sample of the actual mixwater, must also be taken dur
operations and kept on the rig until a few days after the cement job in case the laboratory requir
of the cementation.
Samples QuantitiesThe sample quantities required are listed in the following table:
Material Quantity
Cement 10 kg
Mixwater 1 gal (2 sample bottles)
Powdered additives one full plastic bag (to be kept in laboratory)
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Liquid additives 500 ml (to be kept in laboratory)
Bentonite 10 kg (to be kept in laboratory)
Sample Labelling
Cement Samples
All cement samples should be labelled with:
rig name
silo number
well number
the type of cementation forthcoming date received
date despatched by flight
expected date of first cementation.
Additive and Mixwater Samples
All additive and mixwater samples should be labelled with:
rig name
well number
date despatched (to whom)
contents
expected date of first cementation
Cement Testing
Consistometer Test Conditions
The Pan Am(erican) Consistometer test is used. It is performed under dynamic conditions with the cemThe test conditions used are defined the following table:
Parameter Unit Definition
Depth ft True vertical depth of the cementation
Test pressure psi Expected maximum pressure during the
cementation (according to API recommendation)
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Test temperature oF Expected circulating bottom hole temperature
(according to API recommendations and related to
average temperature gradient)
Slurry Composition
In general, additives for cement slurries are added to the mixwater with the exception of weighting matthe initial cement slurry or may be dry blended into the cement if batch mixing is not feasible. Dead vo
consideration when batch mixing.
The amount of dry powder additives to be used is given on the form in % weight by weight of dry ceme
amount of liquid additives in % gallons per sack (GPS). In addition the amount of water and chemicals
mixwater is also given.
The base for mixwater will be specified on the form as industrial (fresh) or sea water. The salinity of in
300 ppm chlorides.
The water/cement ratio (mixwater requirement) and slurry yield are given in cu.ft/sk.
Slurry PropertiesThe following key slurry properties are given on the cement test form:
Parameter Unit Test Details
Slurry gradient ppg
Pumpability time minutes Pan Am consistometer test measured atBottom Hole Circulating Temperature
(API tables)
Thickening time
Compressivestrength
psi Strength of the cement at cementationdepth, after the time shown, as determinedaccording to API recommended practices
HTHP fluid loss cc/30 min Determined at 1 000 psi pressure
differential and bottom hole circulating
temperature
Fann VG MeterReadings
Dial readings obtained at 600, 200, 100, 6and 3 RPM measured at BHCT to a
maximum of 200oF.
Rheology 600 rpm reading
300 rpm reading200 rpm reading100 rpm reading
6 rpm reading
3 rpm reading
Tested at standard temperatures 80o F and
457oF
Notes:
* The pumpable time of the slurry must exceed the planned job time, including mixing, by a contingenc
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which may be experienced. As a general guide, one hour contingency should be used for casing cemen
back cementations.
* The final strength of cement typically used for primary cementations must be greater than 3 000 psi wshoe.
Tests at the Well Site
General Guidelines
The following general guidelines should be applied during bench tests:
Bench testing shall be carried out at the rig site since it is the main mechanism for quality control on thcomparison with the results of the Mud and Cement Laboratory to confirm that the mixwater of the rig
contaminated.
Testing must be carried out according to the procedure detailed in this section using representative sam
Testing should be completed well in advance of the job, so that time is left to make new mixwater and t
Bench tests must be carried out with samples of the mixed slurry to give an indication of when the cem
sufficiently to proceed with operations. It is important to note that the downhole pressure will accelerat
Procedure for Testing Mixwater
1. MIX 500 grams of properly sampled cement with enough mixwater to achieve the planned water/cem
the mud mixer (Hamilton Beach) at high speed.
2. PLACE the slurry in a plastic bag in a water bath controlled at expected static bottom hole temperatuis lower.
CALCULATE the expected SBHT.
3. CHECK every 15 minutes for thickening time and hardening time.
Notes:
Make sure that the mixwater/additive mixture is homogeneous before sampling.
If the cement job is delayed by a substantial amount of time, with the mixwater having been prepared e
to ensure that additives have neither settled out nor deteriorated. The bench test should be repeated sho
enough time to prepare new mixwater if required.
Spacers for cementing
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Spacers are any fluids other than cement slurry or mud, pumped ahead (preflush) or behind (postflush)
Preflushes are used to:
prevent contamination of cement slurry with mud
improve mud displacement and mud cake removal.
Postflushes are used to prevent:
the plug from spinning when it will be drilled out (cement on top)
contamination with the fluid used for displacement.
General Guidelines
The following guidelines shall be adhered to during the use of spacers:
Scavenger slurries shall not be used if the top of cement (TOC) is critical eg., to allow for a pos
Reduction in hydrostatic head due to spacers pumped must be carefully calculated. If the overbthe minimum required overbalance, at any stage of the cementation, a weighted preflush shall b
spacer.
When water is used as a spacer over productive intervals, it shall be treated with 2 % KCl w/w
Lines shall be flushed thoroughly to ensure the contamination of mud, spacers and cement slurr
Muds requiring extra long spacers or spacers of a special composition will be advised by the M
If oil has been added to a water base mud for any reason, then +/- 2 % v/v surfactant should be
In general, plug flow and plug flow spacers are only used for stinger cementations where turbul
cannot be achieved.
It is preferable to pump spacers between cementing plugs.
Preflush Formulations
Cement scavenger slurries are dilute mixes of cement and water, pumped ahead of the cement slurry inremove gelled mud and filter cakes. The following guidelines shall be used when pumping scavenger sl
The gradient should be between mud gradient and the main cement slurry gradient with a maxim
Cement Contractor should be consulted for the optimum gradient. To prevent fast setting of the scavenger slurry, a cement retarder shall be added to the mixwater
mixing logistics.
Recommended Preflushes for Water Based Muds
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High Annular Velocity Displacements
The recommended preflushes for water based muds for high annular velocity displacements are given i
Application Pumping
Order
Spacer Size
(annular
length)
Spacer Type
20in casing - - -
Intermediate casing13.3/8in / 9.5/8in
1 500 ft Sea water / Industrial water
2 500 ft Sea Water or spacer /
scavenger slurry (10 ppg)
Production casing
/liner 4.1/2in / 7in
1 500 ft Spacer
2 500 ft Scavenger slurry (10 ppg) /Dual spacer
Cement Plugs and Squeezes
The recommended preflushes for fresh water muds when setting cement plugs and squeezes are given i
Mud Type Pumping Order Spacer Length
(annular length)
Spacer Type
Water based mud 1 300 ft ~ 10bbls Fresh water
Postflushes
Standard Cementations
In standard cementations, after the top plug has been dropped cement slurry should be pumped behind t
when it is being drilled out.
The postflushes listed in the table below should be used in all cementations including plugs and squeez
Number WBM OBM Size (ft)
1 Cement Cement 35
2 Fresh water Base Oil 500 or 10 bbls
Cementations Using Stinger
The postflushes listed in the table below should be used in all cementations in including plugs and sque
Number WBM Size (ft)
1 Fresh water As required to balancecement plug
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menting Job - Preparation Guidelines
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This article presents guidelines for: 1. Treatment of Mud Prior to Cementing, 2. Hole Volumes and Slur
Treatment of Mud Prior to Cementing
Before pulling out of hole to run casing, the hole shall be circulated clean (150 % of casing contents) un
To improve displacement efficiency, the mud shall be conditioned to reduce the rheology during circula
Solids control equipment shall be run to remove drill solids from the mud thus reducing PV to the lowe
Dispersants / thinners shall be added to reduce the YP and 10 minute gel strength. (YP not reduced in h
The mud must be completely free of gas after circulating. Circulation must be continued until a full ann
Hole Volumes and Slurry Volume Calculations
Cementations shall be based on volumes calculated from a calliper log (plus 10% excess) if available. T
If off-scale washouts occur, make a best guess of hole volumes. Most calliper logs will give an integrat
previous casing shoe as a check. In the case where an integrated hole volume is given, the tool should b
Circulation Test
Prior to a plug type cementation, at least 150 % of the casing content must be circulated. During this cir
Commence circulation at a very low rate.
Increase flow rate in increments of 2 bbls/min or to limitation due to ECPs.
After each increase, wait at least five minutes to observe for losses and to allow pressures to stabilise. E
Reduce the pump rate as soon as losses are observed or as soon as the maximum equivalent circulating
In addition, a check shall be made on the circulation pressure at the rate that will be used to bump the pl
Notes:
The surface pressure losses through the wellhead and return surface lines must be included. No general
If losses are observed at a rate substantially below the maximum rate as predicted with regard to ECD c
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a rate where slight losses are induced. Once the losses have stopped, the rate can be carefully increased
When running 7 hydraulic hanger and ECP circulation rate and pressure depends on rating of shear pin
Coarse LCM is not to be used before cementing due to risk of plugging the float equipment
Cementing Checklists
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(6 votes, average 4.17 out of 5)Cementing Checklists for planning, during and after cementi
PRE-JOB Checklist
Water sample sent to town for analysis
Pre-job safety brief held with all parties
Bottom hole temperature from logs consistent with no
Caliper run. Is hole under/in/overgauge
Casing drifted, threads clean, consumables in place a
Strokes to bump
Plan to monitor returns/ losses
Contingency for losses - minimum turbulent flow, ma
Open-hole excess volume determined
Cement and additive stocks sufficient
Chemical inventory before slurry and spacer preparat
Has the Cementer been told how much excess mixflu
contingency
Cement truck checked out and run recently
Cement calculations done by at least 2 people and cro
Spare chicksans available on floor or catwalk
Plug dropping head and plugs inspected. Operation o
Loading of PDH witnessed by Drilling Supervisor. V
Strokes to bump plug and strokes to fill pipe calculate
What is the plan for handling fluids at surface. Can pbriefed
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Radios checked
Stroke counter functioning OK
If displacing with rig pump, use one pump only.
Double the chemical requirements calculated availab
Check water to be used (salt content is too high/ Mg l Set the oven to the test temp. before the job starts.
Discuss the complete job when contractor arrives on
Be present when the cement chemicals are being adde
occurs).
Calculate:
o 1. the volume and strokes to cement equalised
o 2. the expected differential pressure at bump.
o 3. based on the planned height of cement in th
Litecrete: re-blend and test the dry blend cement at th Litecrete: more mix water must be prepared.
Preprare several copies of the cement program Make
Cement samples sent to town
Have cementers check stock for next casing job
JOB PLANNING Checklist
BHST and BHCT consistent with recipe
Spacers compatibility been checked
Is fluid loss additive required? It is cheaper to use sta
If a new system is introduced, has a sensitivity test be
Are the spacers recommended cost effective
Is free water acceptable (high angle cementation onl
DURING JOB Checklist
Note times of arrival of contractor and other significalines, plug dropped, bumped etc.).
Have with you the program and the pre-calculation, a
Set up non-oral method of to advise cementer of slurr
Use rig personnel to assist with monitoring job
Sampling: - take two samples of final slurry, one to bin and two out of the oven.
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If a tail slurry is planned take 2 samples also.
AFTER JOB Checklist
Prepare a cement job report and send to Drilling Supe Have cementers rig down equipment as soon as possi
Insure that personnel do not remain on the wellsite if
Confirm chemicals used and returned.
Cement Additives (function and definition)
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This article describes the function of the various classes of cement additives and also to highlight wpurpose.
The additives to be used and their concentration shall be decided by the Cement Contractor, after te
samples of cement, additives and mixwater despatched from the rig. This has to be then approved b
Superintendent.
No deviationfrom the recipe, as determined by the Cementing Contractor is permitted unless speci
the Superitntendent.Note: % BWOC it means percentage by weight of dry cement. One sack of cement is 94lbs.
Accelerators
Accelerators may be added to the mixwater to reduce the thickening and setting times of the slurry,unnecessary time spent waiting on cement.
Calcium Chloride is the most common type of accelerator used. Other, less frequently used acceler
Potassium Chloride.
Additive Formula Concentration Comments
Calcium Chloride
(Accelerator)
CaCl2 1 - 2 % BWOC High gels may form at higher
concentrations. Flash setting mayoccur above 3 %.
Sodium Chloride
(Accelerator)
NaCl Up to 20 lbs/bbl
of mixwater
Acts as an accelerator and
adversely affects other additives
at higher concentrations than 20
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lbs/bbl.
Sea Water
(Accelerator)
Use as mixwater Contains NaCl in the correct
concentration range. Main
application is shallow depthcementation offshore.
Potassium
Chloride
KCl As required Equivalent to NaCl and CaCl2 but
more expensive.
Notes:
1. In general accelerators increase the viscosity of the cement slurry and decrease the effectiv
2. Calcium Chloride can cause skin burns and sever irritation to eyes, nose and lungs. Glovesduring mixing. Calcium Chloride is available in 50lb sacks.
RetardersAs the temperature increases, the chemical reaction between cement and water is accelerated which
Increased depths and formation temperatures may require the use of retarders in order to extend the
Thixotropic slurries may require retarders at shallow depths and low temperatures.
Effects on Viscosity
Most retarders affect the viscosity of the cement as follows:
Type of Retarder Effect on Viscosity
Lignin Derivatives (HR 5, HR 6 etc) Reduce
Organic Acids Reduce
Cellulose Derivatives (CMC) Increase
Note: The combined use of retarders and accelerators in the same mix should be avoided.
High Density Additives
There are two main methods of increasing the gradient of the cement slurry:
reducing the water/cement ratio
addition of a weighting material.
Reducing the Water/Cement Ratio
This is the preferred method of increasing cement gradient, particularly when cementing across gas
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approximately 17.0 ppg can be attained by this method.
Addition of a Weighting Material
The preferred material is hematite (iron oxide) but barite may also be used. It is preferable to batch
material rather than to use pre-blended cement since weighting materials additive in pre-blended ceFurthermore, handling different blends of cement on one rig may result in operational mistakes.
Note: When drilling with a mud gradient of 14.8 ppg or more, a batch mixing unit and sufficient w
contingency. If very large volumes need to be mixed, batch mixing is not achievable
Low Density Additives (Extenders)
Low gradient slurries are used for cementing weak formations or when there is a possibility that th
heavier slurry was used.
Preparation
A low gradient slurry is prepared by adding extra mixwater. Bentonite is usually pre-mixed at a con
freshwater to reduce free water separation of the resultant slurry.
Bentonite must be fully hydrated before any other additives are added to the mixwater. To achieve
industrial water or dry bentonite may be hydrated in industrial water. In the latter case, the minimu
may be longer, depending on the type of bentonite used. Consult the Cementing Contractor for exp
type of bentonite for best results is Wyoming bentonite.
The bentonite content must be checked using the methylene blue test (MBT).
Compressive Strength
As a result of the decreased cement concentration of extended slurries, the compressive strength of
than that of neat slurries.
Friction Reducers (Dispersants or Thinners)
Friction reducers are dispersing agents which can be added to the slurry to reduce its viscosity and
the system while displacing (or squeezing) the cement. As a result, higher pumping rate are possiblefficiencies may be achieved
Fluid Loss Control Additives
Fluid loss control additives are added to cement slurries for the following reasons:
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To reduce the possibility of dehydration opposite porous zones and consequently flash setti
Loss of fluid from the slurry will result in increasing slurry viscosity and gradient and high
Excessive fluid loss will reduce slurry volume and give less cement fill.
When squeeze cementing it is desired to get an effective squeeze against the entire formatiointo it.
Most fluid loss additives tend to viscosify the slurry and consequently, dispersants are often added
Additives for Thixotropic Slurries
The main application of thixotropic slurries is cementing in lost circulation environments.
During pumping the slurry behaves as normal, however, a gel structure develops rapidly when stati
in cementing across gas zones.
The major disadvantage of thixotropic slurries is their relatively high viscosity which may adversel
Defoamers and Antifoams
While mixing cement, and/or when preparing mixwater, containing retarders, salts, fluid loss additi
often experienced. To control such problems antifoams and defoamers are available.
Antifoams should be used before adding any other chemicals.
Defoamers remain effective when added after foam-causing chemicals.
In practice, such distinction may be difficult to ensure and therefore both antifoams as well as defo
re-circulating cement mixer.
Gasblocking Additives
During the hardening process, the cement slurry passes through a semi-solid phase in which the liq
overburden pressure will be lost thus permitting gas migration into, and through, the cement matrix
Surfactants added to the slurry will form a stable foam with the gas bubbles preventing their transp
Additives may be incorporated into the slurry which act to block the gelled cement pore structure p
Cementing Job - Preparation Checklists
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http://www.wipertrip.com/cementing/planning/271-cementing-job-preparation-checklists.htmlhttp://www.wipertrip.com/cementing/planning/271-cementing-job-preparation-checklists.html?tmpl=component&print=1&layout=default&page=http://www.wipertrip.com/cementing/planning/271-cementing-job-preparation-checklists.pdfhttp://www.wipertrip.com/cementing/planning/271-cementing-job-preparation-checklists.html -
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5
(5 votes, average 4.20 out of 5)This article presents Cementing checklists for Drilling Supervisor, Mud Engineer, Driling contractor an
Checklist for Drilling Supervisor
# Time Description Post-job remarks
1 5d Cement proposal checked/acceptable.
2 3d Cementer called out. Competence verified through the Contractor
Base Manager.
3 2d Proposal approved by ODE/1X.
4 6h Tasks appointed; Scenario ready.
5 6h Diagram of all lines / valves OK and checked.
6 6h Annotated execution flow chart ready.
7 1h Hole OK. (Clean, losses cured, overbalance OK).
8 1h Mud OK (Rheology in spec., mud mobility in annulusmaximised).
9 1h Mixwater and spacer checklist OK.
10 1h Rig Eqt. OK. (Compressor, Transfer-and Mud Pumps, Silo's)
11 1h Cement Eqt OK. (Cmt Unit, Cmt head, Surface/ Lines)
12 1h Plugs and launcher OK (plugs, P test, Ids of cocks, XO, DP, etc.
for liner).
13 1h Safety Eqt OK. (Dusk mask, Goggles, Earplugs, Gloves, Eye
Wash, Fire Fighting)
14 1h All involved Personnel briefed; 'What if' discussed with keypersonnel.
15 1h Check lines/valves (tanks, cmt unit, surface (P test), return)
16 5d Send samples of water, cement and additives to lab . Label
and telex.
17 5d Send cementation form to lab. Preliminary recipe received.
18 2d Received recipe for cement and weighted spacer from lab.19 2d Prepare cementation programme.
20 1d Update cement programme with caliper and temperature from
logs. The Lab must be informed of any variation from
estimated temperature.
21 1d Compare job calculations with those of Cementer.
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22 2h Perform circulation test. Establish pressure at bump rate.
23 1h Dust mask, gloves and ear and eyes protection, eye wash.
Checklist for Mud Engineer
# Time Description Post-job remarks
1 1d Fill mixing tank with water to required level and check chlorides
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4. Lines flushed.
Mud pumps
1. Relief valve (pressure test).
2. Control power supply, switches.
3. Pistons OK (pre job cleaned).
4. Liners OK (pre job cleaned).
5. Valves OK (pre job cleaned).
6. Suction lines/strainers (pre job cleaned).
Tanks
1. Line up to cement unit OK.
2. No leaks on tank or valves.
3. Level indicators OK.Surface lines
1. Pressure test .
2. Size adequate (avoid bottlenecks).
3. Cement dump line operational.
4. Ensure that valves in lines are in good condition.
Manifold
1. Hook up as on diagram.
2. Integrity of the valves OK.
3. Check lines (flushed/clean).
4. Contingency lines clean and ready for hook up.
Return line
1. Lined up as per diagram.
2. No Leakages into line from outside
Cement silo's
1. Pre fluff and circulate around.Surge tank
1. Maintain pressure differential.
Checklist for the Cementer
# Time Description Post-job remarks
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General
1. Job calculations done.
2. Chemicals quality and quantity checked.
3. Dust mask, gloves and ear, eyes protection; fire extinguisher,
eye wash station.
Pre-Job
1 Check quantity / appearance of cement and additives
2 Flush lines from mix tank to cement unit with water
Cementing unit
1. Air system - check air cleaner, lubrication, tanks and drain
moisture.
2. Diesel fuel - check level, drain water and sediment from
bottom.
3. Engine oil - check level twice for consistency.
4. Radiator/heat exchanger - water level.
5. Fire hose for cooling engine stand-by.
6. Fan belt - tension, crack or damage.
7. Transmission oil - check level.
8. Chain case oil - check level.
9. Power end oil - check level.
10. Hydraulic oil - check level.
11. Plunger oiled - check reservoir tank level and alemite pump.
12. Gauges - check for operation.
13. Emergency kill system - check operation.
14. Pneumatic operating butterfly valves - check operation.
15. Centrifugal pumps - bearing oil level, packing seal, impeller
(dry run),
16. Output pressure and rate.
17. Pressure sensor diaphragm - pumped up and leak-free.
18. Start engine - check starter.
19. Circulation - check for strainer, suction and discharge lines.
20. Valves condition.
21. Over pressure shutdown system - check operation by
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pressuring.
22. Pressure test - test unit to 1,000 psi. above expected working
pressure.
23. Sensors - pressure, gradient and flow rate, calibrate if
necessary.
Re-circulating mixer
1. Slurry tub - strainer, clean and cement-free.
2. Knife gate (metering valve) - check operation, grease.
3. Mixing bowl - correct jets size.
4. Centrifugal pump - check for output pressure and rate, leaks onseal, wear in bearing
5. Check operation of cement, water quick shut off valves &
recirculating valve.
Batch Mixer
1. Centrifugal pump - check for output pressure and rate, leak on
seal, wear in bearing
2. Paddle - operational.
3. Electric motor - cables, switches, coil resistivity test.
4. Chemical hopper - clean, jets good, lines clear.
5. Dry cement inlet - clean and operational.
Surge Can1. Check can clean and empty.
2. Pre fluff through air jets and blow clear through vent line.
3. Check all gauges, zero the gradient indicator.
4. Load cell - pumped up, leak-free.
5. Sight glasses - clean and not cracked.
6. Hatch cover - hinges, bolts secured, leak-free.
7. Relief valve - check last serviced and tested.
8. Check all lines, jets, hoses and check valves.
Cementing heads
1. Correct size - pressure rating (stump test).
2. Manifold valves - greased, pressure tested.
3. Plug retainers - greased, operation.
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4. Plug release indicator - operation.
5. Cross-over - o rings, correct thread.
6. Circulating heads - non welded, pressure rating.
7. Check quantity/appearance of cement and additives