Penyemenan Ulang AH

Kuliah 11Kuliah-11

P UlPenyemenan Ulang

D I A d H li MMDosen : Ir. Andry Halim, MMUniversitas Trisakti - Jakarta

2012

Objective/Sasaran• Konsep Dasar Penyemenan Ulang• Konsep Dasar Penyemenan Ulang• Penerapannya di lapanganp y p g

Daftar Pustaka

• Allen S.O. and Robert A.P. ”Production Operation”, Vol. I Oil and Gas Consultant International Inc.

• Peter E. Clark,”Well Completions : Stimulation and Work Over”.• Pertamina Hulu,” Teknik Produksi”, Jakarta, 2003• H.K. Van Poolen,”Well Completion and Stimulations Program”.• Peter E. Clark,”Well Completions : Stimulation and Work Over”., p• Jonathan Billary,”Well Completions Design”, PetroleumElsevier,

2009• Semua buku perihal Komplesi dan uji Sumur• Semua Jurnal tentang Komplesi dan uji Sumur

Penyemenen Ulang

Penyemenen Ulangy g

Penyemenen Ulang

Penyemenen Ulang

Penyemenen Ulang

Penyemenen Ulang

Remedial CementingRemedial Cementing

Penyemenan ulangI. SQUEEZE CEMENTING- INTRODUCTION

Squeeze cementing has long been a common operation. Numerous squeeze jobs are performed daily under a wide variety of downhole conditions, and considerable experience has been accumulated over five decades of field practice. Although excellent literature describing this technology has been published and is readily available, misconceptions still exist and operating failures are not uncommon,

lti i i d d illi d l ti tresulting in increased drilling and completion costs. A properly designed squeeze job causes :1. the resulting cement filter cake to fill the opening(s) between the formation and the casing. 2. Upon curing, the cake forms a nearly impenetrable solid (Suman and Ellis, 1977). 3. In cases where the slurry is placed into a fractured interval, the cement solids must develop a filter y p p

cake on the fracture face and/or bridge the fracture. Squeeze cementing has many applications during both the drilling and the completion phases. The most commonly cited applications are listed below :1. Repair a primary cement job that failed due to the cement bypassing the mud (channeling) or

insufficient cement height in the annulusinsufficient cement height in the annulus. 2. Eliminate water intrusion from above, below, or within the hydrocarbon producing zone. 3. Reduce the producing gas/oil ratio (COR) by isolating the gas zones from adjacent oil intervals.4. Repair casing leaks due to corroded or split pipe. L5. Abandon a nonproductive or depleted zone. 6. Plug all, or part, or one or more zones in a multizone injection well so as to direct the injection into

the desired intervals. l Seal off lost-circulation zones. 7. Protect against fluid migration into a producing zone

II. SQUEEZE CEMENTING-THEORY R dl f th t h i d d i j b th tRegardless of the technique used during a squeeze job, the cement slurry (a suspension of solids) is subject to a differential pressure against a filter of permeable rock. The resulting physical phenomena are :1. filtration, ,2. filter- cake deposition and,3. in some cases, fracturing of the formation. The slurry, subject to a differential pressure, loses part of its water to the porous medium, and a cake of partially dehydrated cement is formedformed. The cement cake, forming against a permeable formation, has a high initial permeability (Fig. 13-l). As the particles of cement accumulate, the cake thickness and hydraulic,resistance increase; as a result, the filtration rate decreases, and the pressure required to dehydrate the cement’slurry further increases. The rate of filter-cake buildup is a function of four parameters: 1. permeability of the formation, l2. differential pressure applied, 3. time, and3. time, and 4. capacity of the slurry to lose fluid at downhole conditions.When squeezed against a formation of given permeability, the rate at which slurry dehydration decreases is directly related to the fluid-loss rate (Fig. 13-2). Wh d i t l bilit f ti l i ithWhen squeezed against low-permeability formations, slurries with low fluid-loss rates dehydrate slowly, and the duration of the operation may be excessive.

Penyemenan ulangAgainst a high- permeability formation,.a slurry with a high fluid-loss rate dehydrates rapidly; consequently, the wellbore may become choked by filter cake, and channels which otherwise would have accepted cement would be bridged off. ot e w se wou d ave accepted ce e t wou d be b dged o .The ideal squeeze slurry should thus be tailored to control the rate of cake growth, and allow a uniform filter cake to build up over all permeable surfaces. The basics of the theoretical and practical work regarding the f d t l f filt k d iti i tifundamentals of filter-cake deposition in squeeze cementing can be found in the publications of :1. Binkley, Dumbauld, and Collins (1958) and 2. Hook and Ernst ( 1969).

1.1 Binkley, Dumbauld, and Collins Study

These authors developed the law of filter-cake formation for a suspension (such as a cement slurry). When a volume c/Q of filtrate passes through a planar permeable surface of area A afiltrate passes through a planar permeable surface of area A, a filter cake of thicknes dS and of porosity O is deposited. This relationship is illustrated in the following series of equations.

Penyemenan ulangAssuming that the pressure drop across the filtration surface is negligible, Binkley et al. (19.58) applied Darcy’s law to the flow of the filtrate through the

k t bli hi th f ll i ticake, establishing the following equations

Penyemenan ulang

Penyemenan ulang1.2 Hook and Ernst ( 1969)

f h ff f fl id l l ddi i diff i l d f i bili hof the effects of fluid-loss control additives, differential pressure, and formation permeability upon the rate offil- ter-cake buildup. Their conclusions are presented in Ta- bles 13-1, 13-2, and 13-3. Table 13-1 is a compilation of permeability measurements conducted on filter cakes which were formed with different concentrations of a fluid-loss addilive. The per- meability ofa neat-cement filter cake was measured to be about 5 md-a value lower than that of many producing 13-3y p g

SQUEEZE CEMENTING

ZONE ISOLATION SQUEEZE CEMENTINGPACKERS

Squeeze Cementing - DefinitionSqueeze Cementing Definition

Injection of Cement Slurryinto the voids behind theinto the voids behind thecasing

Dehydration of cementyrequires: fluid fluid-loss, porous(permeable) matrix,differential pressure, time.

Injection below or abovefracture pressure

Squeeze Cementing – Applications

1. Primary cement job repair1. Primary cement job repair2. Unwanted Water Production3. High Gas-Oil Ratio (GOR)4. Casing Splits or Leaks5. Nonproductive or Depleted Zones6. Formation Losses7. Top of Cement Column8. Alter Injection Profiles9. Block Squeeze10. Liner-Top Leaks

Squeeze Cementing – Methodsq g

Pumping techniqueHesitationRunning

Placement techniqueHigh pressure - above frac pressureL b l fLow pressure - below frac pressure

ToolsPacker/RetainerBradenheadBradenhead

Coiled tubing

H it ti SHesitation Squeeze

Intermittent pumpingLow pump ratesLow pump ratesSmall slurry volumesLong job timesApplicationspp c o s

� Channel repair� Long perforated interval� Long splits in casing

i i� Lost circulation� Natural, man-made, caused during breakdown fractured situations

Running Squeeze

Continuous pumping until final squeeze pressure is attained Clean fluid in the holeL l lLarge slurry volumesLow or high pressure squeezeApplications

� Water flow� Water flow� Abandon perforations� Increase cement top� Casing shoes� Liner tops� Block squeeze� Lost circulation zones

Low Pressure SqueezeLow Pressure Squeeze

Squeeze pressure below fracture pressureBest way to squeeze the pay zoneBest way to squeeze the pay zoneUse small volume of slurryApplicable for :

� Multiple zonesp� Long intervals� Low BHP wells� Naturally fractured formations

High Pressure Squeeze

Fracturing is necessary to place cement in the voidRequires placement of large volumes of slurryApplicable for

shoeliner topblock squeeze

Planning the Job

Problem determinationTemperature logCBL/CET/USINoise logWater-flow logTracer serveyTracer servey

Select tools and locationCasing integrityType of squeezeType of squeezeVolume of the slurry

Fluid in the wellWell conditions (pre-squeeze clean-up if necessary)Well conditions (pre-squeeze clean-up, if necessary)Type of squeezeSlurry design and amountPressure limitations

Injection Test

Perforations are open and ready to accept fluidEstimate of the proper cement slurry injection rateEstimate the pressure during squeezest ate t e p essu e du g squee eEstimate the amount of slurry to be used

Washes and Spacers

Perforations, surrounding voids, and formation face clean-out to ensure complete fill-up and dehydration

Clean-up us a separate stage with chemical wash orhydrochloric acid to remove

water-based mudmud filter cakecarbonate scale

During placement slurry needs to be isolated aheadDuring placement slurry needs to be isolated aheadand behind

5 to 10 bbls of chemical wash or water50 - 100 gal/ft of perforationsg p

Slurry properties

Fluid lossFilter cake developmentViscosityV scos tyGel strengthFree waterThickening timeCompressive strength

Slurry Volumes

Length of the interval and number of perforations to be squeezedPlacement technique to be usedace e t tec que to be usedInjection rateSlurry volume to be left in the wellboreExcessLocal experienceRules of thumb� Do not exceed capacity of the work string

T k f f f f� Two sacks of cement per ft. of perfs� Should not be greater then could be reversed� Minimum 100 sks if 2 bpm after breakdown, 50 sks otherwise

Bradenhead Squeeze

Done through tubing or drill pipe without packer

AdvantagesNo tool are used (simplicity)Cost

DisadvantagesCasing and wellhead areCasing and wellhead areexposed to pressure

Packer with tailpipe Squeeze

Downhole Isolation tool

Casing and wellhead protection

Tailpipe for placement

Long intervals

Multiple setting of packer

P k ith t t il i SPacker without tailpipe Squeeze

Downhole Isolation tool

Casing and wellhead

protectionprotection

Short intervals

No tailpipe

Suicide squeeze

Cement Retainer Squeeze

Drillable Isolation Tool

Similar to packer withouttailpipe

Applications

Squeeze pressure trappedSqueeze pressure trapped

Job Procedure

Coiled Tubing Squeeze

ApplicationsProducing wellsTh h t biThrough tubing

AdvantagesCostCostAccurate placement

Critical slurry design

Job procedure

S C ti J b C lSqueeze Cementing - Job Cycle

Design• Well conditions• Well conditions• Slurry properties

Execution• Slurry placementS u y p ce e• Surface pressures• Equipment

Evaluation• Final squeeze pressure• Pressure test• Inflow test• Logs

PACKERS

PACKERS

Objectives

All k ill tt i f th f ll i bj ti h thAll packers will attain one or more of the following objectives when they are functioning properly :

1. Isolate well fluids and pressure.p

2. Keep gas mixed with liquids, by using gas energy for natural flow.

3 Separate producing zones preventing fluid and pressure contamination3. Separate producing zones, preventing fluid and pressure contamination.

4. Aid in forming the annular volume (casing/tubing/packer) required for gas lift or subsurface hydraulic pumping systems.

5. Limit well control to the tubing at the surface, for safety purposes.

6 Hold well servicing fluids (kill fluids packer fluids) in casing annulus6. Hold well servicing fluids (kill fluids, packer fluids) in casing annulus.

Tubing-To-Packer Connections

There are three methods of connecting a packer and a tubing strings, and the tubing can be set in :1. Tension 2. Compression 3. Left in natural (no load on the packer, tension nor compression)

Packers ClassificationPackers Classification

1. Retrievable2. Permanent or semi permanentp

Consideration for Packer Selection

1. Surface/Downhole Equipment Coordination2. Packer Mechanics3. Corrosive Well Fluids4. Sealing Element5. Retrievability6. Fishing Characteristic7 Through Tubing Operation7. Through Tubing Operation8. Purchase Price

Cementing ServiceCementing ServiceCementing Service Cementing Service EquipmentEquipmentq pq p

Cementing Service EquipmentCementing Service Equipment

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Cementing UnitCementing UnitPumping Truck

Cementing Skid Unit

Pumping Truck and Mixing SystemSURGE CAN

HOPPER

CENTRIFUGALPUMP

TRIPLEX PUMP

HOPPER

MIXINGBOWL

SLURRYTUB

JETSTUB HIGH PRESSURE

LINE TO WELLHEAD

Bulking System for Cement Supply

Bulker TrailerCutting Bottle

Compressor Pressurized Tank

Mixing Fluid Preparation

Water Tank/ Mixing Tank Batch Mixer

Cementing Job designCementing Job designg gg g

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Data GatheringTo run applicable preliminary design, the following data is required:• Type of job• Well Description:p

– Casing/Liner/Drill size, weight– Survey Information– Hole size and anticipated excessp– BHST from logs or estimated from offset well

• Mud properties (type, expected weight and rheologyTo run applicable preliminary design, the following data is required:pp p y g , g q• Expected pore pressure• Expected frac pressure• Expected well problem:p p

– Lost circulation– Gas formation– High formation pressureHigh formation pressure– Salt Formation, etc

• Any known client system limitation or special instruction

Software CemCADE• Job Volume

• Pumping schedule

• Well Security

• Pumping Time

• Temperature Simulation

Cement properties:- Density

- Fluid Properties

-Circulating Temperatureg p

Laboratory design• Request specific performance parameters:q p p p

• Density• Rheology ( PV, YP & Gel Strength)• Fluid Loss

By Design Engineer with Client Approval

• Thickening Time• Free Water• Compressive Strength

Approval

Based on Well problem andp g

• Collect:• Water sample from location

C l l i

problem and cementing objective

• Cement sample location• Additives on location

Critical Points

Laboratorium Equipments

LABORATORIUM TESTLABORATORIUM TEST

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Cementing Job ExecutionCementing Job Executiongg

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Pre-ExecutionPre Execution• Hole Circulation:

– Conditioning mud– Conditioning temperature

• Mixing Fluid Preparation:Collect sample– Collect sample

• Loading Plugs……….Critical• Pre Job Safety Meeting:Pre Job Safety Meeting:

– Safety Issue– Delegation of responsibilities– Contingency plan

Execution

• Cement Slurry Quality:D it t R l Ti t– Density parameter….Real Time measurement (Densitometer)

– Mud balance…..Manual measurement• Pressure Monitoring:

– Well securityL t i l ti– Lost circulation

– U-tubing Effect• Slurry sample collected:Slurry sample collected:

– Surface sample– Indication of hard cement

Cementing Job EvaluationCementing Job Evaluationgg

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Proper way to evaluate cement job

• Real time indication on cement job:F ll t t f– Full returns to surface

– Cement returns – Density quality and Sampling

• Pressure Testing:– Casing Shoe Pressure Test– Liner Lap Pressure TestLiner Lap Pressure Test– Leak Off Test (LOT) or FIT (Formation Integrity Test)

• Acoustic log:C t B d L (CBL) d V i bl D it L (VDL)– Cement Bond Log (CBL) and Variable Density Log (VDL)

– Segmented Bond Tool (SBT)– Cement Evaluation Tool (CET)– Ultrasonic Imaging Tool (USIT)

Example of a good CBLExample of a good CBL

CBL

VDL

Example of a “bad” CBLp

CBL

VDLVDL

USIT sample

CBL VDLUSIT

Squeeze Cementing

Squeeze Cementing

SQUEEZE CEMENTING FAILURES

SQUEEZE CEMENTING FAILURES

SQUEEZE CEMENTING FAILURES

SQUEEZE CEMENTING

FAILURES

SQUEEZE CEMENTING FAILURES

SQUEEZE CEMENTING FAILURES

SQUEEZE CEMENTING FAILURES

SQUEEZE CEMENTING

FAILURES

EXERCISES

EXERCISES

EXERCISES

EXERCISES

EXERCISES

EXERCISEEXERCISES

EXERCISES

EXERCISES

EXERCISES

Penyemenen Ulang

Penyemenen Ulang

EXAMPLE 1• Data Given :

Casing dimensions : OD 20 in (508 mm)ID 18 73 in (475 7 mm)ID 18.73 in (475.7 mm)133 lbm/ft (198 kg/m)

Hole size : 26 in (660.4 mm)Casing setting depth : 350 ft (107 m)Mud weight : 65 pcf (8.7 ppg or 1.041 kg/l)Cement properties :Cement API Class G with 4% bentoniteSlurry weight : 106pcf (1.7 kg/l)Slurry yield : 1 5 ft3/sack(43 03 l/sack)Slurry yield : 1.5 ft3/sack(43.03 l/sack)

EXAMPLE 1EXAMPLE 1Water requirement : 7 6 gal/sack (28 8 l/sack)Water requirement : 7.6 gal/sack (28.8 l/sack)Pumping rate : through drillpipe 100 gal/min (1700 l/min)

through casing 300 gal/min (2385 l/min)Drill pipe : OD/ID 5 in/4.276 in

19.5 lb/ft (29.02 kg/m)Allow 15 min for the release of plugs and assume casing to be p g gcemented to surface.a. Calculate required quantities of cement and bentonite for a conventional cementing job. A shoe track of 80 ft (24 m) is to be g j ( )used. Also allow 100 % excess cement in the open hole.b. Calculate volume of mixing water.c. Calculate total time for the job, assuming that the mixing ratec. Calculate total time for the job, assuming that the mixing rate is 10 sacks/min

EXAMPLE 1EXAMPLE 1

Answer :a. Annular area (Hole-casing) = (π/4).(262-202) = 216.77 in2 =

1.5053 ft21.5053 ftAnnular slurry volume = 1.5053 ft3/ft x 350 ft = 527 ft3

Total annular volume = calculated volume + excess= 527 + 100% (527) = 527 + 527 = 1054 ft3= 527 + 100% (527) = 527 + 527 = 1054 ft3

Capacity of 20 in casing = π/4 (ID2)/144 x 1ft = π(18.73)2/4x144= 1.9134 ft3/ft

Cement volume in shoe track = 1.9134 ft3/ft x 80 ft = 153 ft3

Total required slurry volume =1054+153 = 1207 ft3 (34 1721)

EXAMPLE 1Number of sacks of cements = slurry volume (ft3)/slurry yield (ft3/sacks) = 1207/1.5 = 805 sacksMass of bentonite = 4% x total weight of cementMass of bentonite 4% x total weight of cementWeight of cement = volume x density = 1207 ft3 x 106 ibm/ft3

= 127942 lbmThereforeTherefore,quantity of bentonite = 0.04 x 127942 lbm = 5117.7 lbmNumber of sacks of bentonite = 5117.7/94 lb/sack = 54 sacksb. Volume of mix water = number of sacks x water requirements per sacks = 805 sacks x 7.6 gal/sack = 6118 gal = 6118/42 = 145.7 bbl (23 m3)

EXAMPLE 1c. Total job time = mixing time + time for release of plug + displacement timeTotal job time = 805 sacks/10 sacks/min + 15 minTotal job time 805 sacks/10 sacks/min 15 min + internal capacity of casing excluding shoe track/pumping rate = 80.5 + 15 + (1.9134 ft3/ft x (350-80) ft/300 gal/min x ft3/7.48 gal) = 80.5 + 15 + 12.9 = 108.4 min (or 1 h 48 min)

.

EXAMPLE 2Hole depth: 13900 ft (4237 m)Hole size: 8 ½ in (2215.9 mm)Casing shoe: 13891 ft (4234 m)Casing shoe: 13891 ft (4234 m)Mud weight: 87 pcf (1.394 kg/l)Casing dimensions: OD/ID = 7 in/6.184 Grade C95 29#Cement: cement column should be 6562 ft (2000 m)

long, as follows:from shoe to 656 ft (200 m), use API Class G cement from 656 ft to 6562 ft (200-2000 m), use API Class H cement with 2% bentonite and 0.3% HR-4 (Note: HR-4 is a type of cement retarder)

EXAMPLE 2To prevent contamination of cement by mud, 30 bbl (4770 l) of fresh water should be pumped ahead of the cement.Allow 15 min for release of plugsAllow 15 min for release of plugsShoe track: 80 ft (24 m)Calculate:1 Quantity of cement from each class;1. Quantity of cement from each class;2. Volume of mix water;3. Total time for the job

(Note: Mix cement at the rate of 25 sacks/min and displacecement at 300 gpm (1136/min);

4. Pressure differential prior to bumping the plug;p p g p g;

EXAMPLE 25. Annular velocity during chase;6. Total mud returns during the whole cementing operation.Solution:from cementing tables (Halliburton or Dowell Schlumberger), the properties of the two classes of cement including the addtives are as follows:

Class G cement Class H cementClass G cement Class H cementSlurryWeight 118 pcf of 15.8 ppg 115 pcf of 15.5 ppgSlurryVolume 1.15 ft3/sack 1.22 ft3/sackMixWater 5 gal/sack 5.49 gal/sack

EXAMPLE 21. Sacks of cement requiredClass GVolume of Class G slurry = volume of shoe track + volume ofVolume of Class G slurry = volume of shoe track + volume of pocket + volume of 656 ft of annular space = π/4 x (6.184)2 x 1/144 x (80 ft) + π/4 x (8.5)2 x 1/144 x (9 ft) + π/4 (8.52-72) x 1/144 x (656) = 16.7 + 3.5 + 83.2 = 103.4 ft31/144 x (656) 16.7 3.5 83.2 103.4 ftNumber of sacks of Class G cement = 103.5 ft3/1.14 ft3/sack =90Class HVolume of slurry = (6562 656) x annular capacity = 5906 x /4Volume of slurry = (6562-656) x annular capacity = 5906 x π/4 (8.52-72) x 1/144 = 748.9 ft3

Number of sacks of Class H cement = 748.9 ft3/1.22 ft3/sack = 614614

EXAMPLE 22. Volume of mix waterVolume of mix water = water required for Class G and Class H cement = (90 sacks x 5 gal/sack) Class G + (614 sacks x 5.49cement (90 sacks x 5 gal/sack) Class G (614 sacks x 5.49 gal/sack) Class H = 3820.9 gal = 91 bbl3. Total job timejob time = mix time + (time for release) + displacement or chasejob time = mix time + (time for release) + displacement or chase time of plugs = total number of sacks/mixing rate + 15 + inner capacity of casing excluding shoe track/pumpping rate = (614 + 90) sacks/25 sacks/min +15 + π/4 x (6.184)2 x 1/144 (13891-80) 90) sac s/ 5 sac s/ 5 π/ (6 8 ) / ( 389 80)ft3/(300 gal/[min] x ft3/7.48gal) = 28.2 + 15 + 71.8 = 115 min

EXAMPLE 24. Differential pressure The 30 bbl of water pumped ahead of the cement will occupy in the annulus a height, h, given byh= 30 bbl x (5.62 ft3/bbl)/ 0.128 ft3/ft = 1330 ft(annular capacity = 0.1268 ft3/ft)Apressure differential exist during the cementing operation due to density differences between mud, cement and the water

R f i t Fi 11 29 th t t l diff ti lspacer. Referring to Figure 11.29, the total pressure differential, ∆p, is given by∆p= pressure differential due to density difference between:(i) mud in casing and cement’ (Grade G) in annulus for a hight of(i) mud in casing and cement (Grade G) in annulus for a hight of (656-80) = 576 ft+ (ii) mud in casing and cement (Grade H) in annulus for a height of 5906 ftheight of 5906 ft

EXAMPLE 2+ (iii) mud in casing and water spacer in annulus for a height of 1330 ftAssuming the density of fresh water is 62 pcf, thenAssuming the density of fresh water is 62 pcf, then∆p= 576 x (118-87)/144 + 5906 x (115-87)/144 + 1330 x (62-87)/144 = 124 + 1148.4 + (-230.9) = 1042 psi5 Annular velocity5. Annular velocityUsing Q = VA (where V= velocity; Q= volume flow rate; A= annular area)V= Q/A = 300 gal/min/ /4(8 52 72) in2 (ft3/7 48 gal)/(ft2/144 in2) =V= Q/A = 300 gal/min/ π/4(8.52-72) in2 (ft3/7.48 gal)/(ft2/144 in2) = 316 ft/min

EXAMPLE 26. Mud returnsMud returns = steel volume + volume of water ahead + total slurry volume = π/4 (72-6.1842) x 1/44 (ft3/ft) x 13891 ft + (30 bbl)slurry volume π/4 (7 6.184 ) x 1/44 (ft /ft) x 13891 ft (30 bbl) + (748.9 + 103.5) ft3 = 815.1 ft3 + 30 bbl x 5.62 ft3/bbl + 852.4 ft3= 1836.1 ft3 = 326.7 bbl

EXERCISE 1• Data Given :

Casing dimensions : OD 20 in (508 mm)ID 18 73 in (475 7 mm)ID 18.73 in (475.7 mm)133 lbm/ft (198 kg/m)

Hole size : 26 in (660.4 mm)Casing setting depth : 500 ft (107 m)Mud weight : 67.4 pcf (9 ppg)Cement properties :Cement API Class G with 5% bentoniteSlurry weight : 106pcf (1.7 kg/l)Slurry yield : 1 5 ft3/sack(43 03 l/sack)Slurry yield : 1.5 ft3/sack(43.03 l/sack)

EXERCISE 1Water requirement : 8 gal/sack (30.3 l/sack)Pumping rate : through drillpipe 150 gal/min (1700 l/min)

through casing 350 gal/min (2385 l/min)g g g ( )Drill pipe : OD/ID 5 in/4.276 in

19.5 lb/ft (29.02 kg/m)Allow 20 min for the release of plugs and assume casing to beAllow 20 min for the release of plugs and assume casing to be cemented to surface.a. Calculate required quantities of cement and bentonite for a conventional cementing job. A shoe track of 80 ft (24 m) is to be

0 %used. Also allow 50 % excess cement in the open hole.b. Calculate volume of mixing water.c. Calculate total time for the job, assuming that the mixing rate i 15 k / iis 15 sacks/min

EXERCISE 2Hole depth: 13900 ft (4237 m)Hole size: 8 ½ in (2215.9 mm)Casing shoe: 13891 ft (4234 m)Casing shoe: 13891 ft (4234 m)Mud weight: 87 pcf (1.394 kg/l)Casing dimensions: OD/ID = 7 in/6.184 Grade C95 29#Cement: cement column should be 7000 ft (2133.5

m) long, as follows:from shoe to 1000 ft (305 m), use API Class G cement from 1000 f 000 f (30 2133 ) C1000 ft to 7000 ft (305-2133.5 m), use API Class H cement with 1% bentonite and 1% HR-4 (Note: HR-4 is a type of cement retarder)

EXERCISE 2To prevent contamination of cement by mud, 50 bbl (7950 l) of fresh water should be pumped ahead of the cement.Allow 15 min for release of plugsAllow 15 min for release of plugsShoe track: 80 ft (24 m)Calculate:1 Quantity of cement from each class;1. Quantity of cement from each class;2. Volume of mix water;3. Total time for the job

(Note: Mix cement at the rate of 20 sacks/min and displacecement at 300 gpm (1136/min);

4. Pressure differential prior to bumping the plug;p p g p g;

EXERCISE 25. Annular velocity during chase;6. Total mud returns during the whole cementing operation.CLUE :from cementing tables (Halliburton or Dowell Schlumberger), the properties of the two classes of cement including the addtives are as follows:

Class G cement Class H cementClass G cement Class H cementSlurryWeight 118 pcf of 15.8 ppg 115 pcf of 15.5 ppgSlurryVolume 1.15 ft3/sack 1.22 ft3/sackMixWater 5 gal/sack 5.49 gal/sack

Questions ?

PR-111. Sebutkan fungsi penyemenan dan jenis-2 penyemenan2. Apa yang dimaksud dengan squeezed cementing3. Sebutkan aplikasi squeezed cementing4 Sebutkan parameter yang menyebabkan terjadinya filter4. Sebutkan parameter yang menyebabkan terjadinya filter

cake pada penyemenan ulang5. Apa yang dimaksud Squeeze Cementing - Job Cycle6. Sebutkan metoda Squeeze Cementing7. Sebutkan cara melakukan evaluasi hasil cement job