Cementing Book

BUKU PETUNJUK PRAKTIS

“DSF REMEDIAL CEMENTING”

Heavy Oil Wellwork 2005

Daftar Isi Buku: • Daftar Isi ………………………………………... 1 • Cementing Job Ground Rules…………………… 2 • Cementing Decision Flow Process ……………... 3 • CBL Guideline ………………………………….. 4 • Cara Membaca VDL ……………………………. 5 • Cara QC CBL …………………………………. 6 • CAST-V / USIT Guideline …………………….. 7 • Menentukan Squeeze Interval ………………….. 9 • Menetukan Slurry Design ……………………… 10 • Menentukan Jumlah saxs Cement …………… 11 • Contoh Cara Menentukan Slurry Design dan Jumlah Cement ……………………………….12 • Cementing Technique …………………………. 13 • Contoh Pumping Chart ……………………...… 14 • Procedure Persiapan Sebelum Squeeze job …… 15 • Bullhead Cementing Procedure ………………. 16 • Contoh Perhitungan Bullhead Cementing …… 18 • Equalize Cementing Procedure ……………….. 19 • Contoh Perhitungan Equalize Cementing ……. 22 • Contoh Cementing Report ……………………. 23 • Contoh Cementing Score Card……………..…. 24 • 2005 HOWW Cementing Team...…………..…. 25

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Cementing Job Ground Rules • WW Reps mempunyai accountability terhadap Cementing Jobs • Cementing Focus Team akan membantu WW Reps untuk menentukan squeeze interval, slurry design, placement technique, perhitungan and onsite support jika diperlukan • WW Reps and Cementer harus mempunyai Design dan Perhitungan Cementing yang sama dan benar • WW Reps harus witness Cementing job (Injectivity test, Pumping water head, Pumping Cement Slurry, Water displacement and Hesitation) • WW Reps mengisi form Cementing Score Card dan menyerahkan ke Cementing Team • Cementing team akan mengumpulkan dan mengevaluasi Cementing Score Card untuk meningkatkan kualitas cementing Job

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Compiled by Iwan Wijanarko 2005

Squeeze Cementing Decision Flow Process WWReps

Cementing Team

Serco reps

TL Operation

Pre-job meeting

Planning

Discuss the plan forward

Evaluate and Re -design

Execution

Squeeze Job I

Success?

Next Squeeze job(s )

N

Y

Continue next program

Y

Resqueeze? N

N Success? Y

Continue next program

•Other alternatives •Continue next program •Pack well off

RMT/PMT

3

Tabel CBL Guideline Csg. Size

Csg. Wt.

(in)

(ppf)

TT Expected Transit Time ( µ sec) Free Pipe Amplitude

3 - 1/2 4 - 1/2

5

5 1/2

7

9 5/8

10 3/4

Class "H" cement Compressive Strength 3000 psi 100%

Good Bond

Cement

Cut Off

POZ Mix ‡ Compressive Strength 1500 psi 100%

Good Bond Cut Off

Interval req'd for Isolation (ft)

mV

(mv)

(60%)

cement (mv)

9.3

239

92

N/A

< 1.0

N/A

N/A

5

9.5

254

81

N/A

N/A

5

5

0.2

2.3

11.6

0.6

4.6

13.5

1.0

7.0

77

(60%)

15.0

239

0.9

5.7

2.3

10.1

18.0

236

2.4

10.4

4.6

16.5

21.0

234

3.8

14.7

7.3

21.0

15.5

248

0.7

4.7

1.6

8.2

17.0

247

1.0

6.1

2.4

10.3

20.0

245

2.2

9.4

4.1

14.9

23.0

243

3.4

13.2

6.1

18.5

23.0

272

1.0

5.6

2.4

9.3

26.0

270

1.8

7.8

3.4

12.1

29.0

269

2.5

9.4

4.5

14.6

32.0

267

3.3

11.8

6.1

17.1

35.0

266

3.9

13.1

6.9

18.1

38.0

264

4.9

15.2

9.0

20.7

40.0

263

6.1

17.1

10.2

22.4

40.0

313

1.7

6.7

3.2

10.6

43.5

312

2.5

8.7

4.1

12.6

47.0

311

2.7

9.1

4.7

13.7

53.5

308

3.7

11.8

6.6

16.4

40.5

334

1.1

5.0

2.4

8.4

45.5

333

1.7

6.5

3.2

9.7

48.0

331

2.3

8.0

3.8

11.2

51.0

330

2.5

8.5

4.2

12.0

54.0

329

2.6

8 .9

4.6

12.8

55.0

329

2.8

9.2

4.9

13.4

71

61

52

50

Used for Old Cement †

†

7.5

10

15

18

Used for New Cement < 24 hrs

Bond Cut Off for Class ‘H’ Cement must be used as the Bond Cut Off guidel Old Wells and Wells where the cement has been in place more than 24 hours (for Primary or Remedial Cementing, the Compressive Strength is estimated to have reached 3000 psi). ‡ Bond Cut Off for POZ Mix Cement can be used only as the guideline for w the cement has been in place for less than 24 hours (after Primary or Remedial Cementing, Compressive Strength is estimated to have reached only 1500 psi).

ine for

ells where

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Cara membaca VDL Cement Bond yang bagus selain dari Amplitude, juga ditentukan dari bacaan VDL. VDL digunakan untuk menentukan apakah ada cement bond dari casing ke cement dan cement ke formasi. • Casing to Cement Bond: èBacaan VDL di sebelah kiri agak kabur (Putih untuk HLS log dan abu-abu untuk Schlumberger log) • Cement to Formation Bond: èBacaan VDL di sebelah kanan tidak lurus, biasanya mengikuti pola Gamma Ray. Gamma Ray

Amplitude (mV)

VDL

Bad Bonding

Good Bonding

Amplitude: Lihat tabel di atas untuk menentukan cut off good bonding

Good Bond Casing-Cement: Kabur/ Putih

Good Bond Cement-Formation: Polanya tidak Lurus mengikuti pola Gamma Ray

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Bagaimana QC CBL? • Pastikan CBL tersebut ON-DEPTH dengan mengkorelasikan pada Mark Log / CBL sebelumnya • Pastikan bacaan Free Pipe Amplitude sesuai dengan Estimate Free Pipe Amplitude (Lihat Tabel) • Pastikan bacaan Transit Time sesuai dengan Estimate Transit Time (Lihat Tabel) • Bacaan Amplitude harus sama antara Main Log dengan Repeat Section

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CAST-V / USIT Cast-V atau USIT adalah ultrasonic log yang bisa menggambarkan acoustic impedance Z (~ compressive strength) material yang ada di belakang casing dan ditampilkan dalam 360 degree image sehingga bisa diketahui jika ada chanelling di belakang casing. Ultrasonic log ini di run jika hasil CBL tidak memenuhi cut-off good bonding yang kemungkinan disebabkan karena adanya Micro Annulus. CAST-V-Halliburton Skala Z plot berdasarkan warna: • 1st block (red): 0 to 0.34 MRayls (indication of gas) • 2nd block (light blue): 0.34 to 1.03 MRayls (indication of fresh water) • 3rd block (medium blue): 1.03 to 2.06 MRayls (indication of water and/or drilling mud) • 4th block (light yellow): 2.06 to 2.41 MRayls (indication of foamed cement, contaminated cement or heavy mud) • 5th block (light brown): 2.41 to 3.44 MRayls (indication of cement, depends on density and compressive strength developed) • 6th block (dark brown): 3.44 to 4.47 MRayls (indication of cement, depends on density and compressive strength developed) • 7th block (black): 4.47 to 5.50 MRayls or higher (indication of high strength cement)

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USIT-Schlumberger

Skala Z plot berdasarkan warna: Material Gas (red) Liquid (blue) Cement (brown to black)

Z (Mrayls) < 0.30 0.3 – 2.6 >2.6

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Bagaimana Menentukan Squeeze Interval? • Tentukan Zone Interest berdasarkan Program – 240 to Surface – Rindu to 240 – Rindu to Surface – PK zone to Rindu • Tentukan Posisi Masing-masing Top dan Bottom Sand 240, Rindu dan Pertama • Tentukan Posisi Shale yang menjadi target squeeze • Bandingkan dengan posisi Bad Bonding hasil CBL. • Interval Squeeze paling ideal adalah pada Bad Bonding di daerah Shale dan berjarak minimum 10ft dari interval sand A Top 240

240 Sand

Btm 240

B Top Rindu

Rindu Sand C

Btm Rindu

=Focus area of Squeeze Interval •240 to Surface = A •Rindu to 240 = B •Pertama- Rindu = C •Rindu to Surface = A & B •Pertama to Surface= A & B & C

Top Pertama

Pertama Sand

9

Menentukan Slurry Design Dasar menentukan Cement Slurry Design: 1. Circulating Temperature 2. Injectivity Pressure Standard Cement Slurry Design yang bisa dipilih: • Slurry working temperature o 90 F o 105 F o 125 F • Cement Slurry Type o Lead Cement Slurry o Tail Cement Slurry

Pemilihan Cement Slurry Design berdasarkan Injectivity: Type Loose Injection Profile Moderate Injection Profile Tight Injection Profile

Injectivity Pressure Slurry Design (@0.6 bpm) Lead slurry atau 200 Psi

Lead + Tail Slurry Tail Slurry

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Menentukan Jumlah saxs cement: Jumlah cement yang akan digunakan berdasarkan panjang squeeze interval dan injectivity pressure. Berdasarkan job-job sebelumnya yang hasilnya bagus, table berikut ini dapat digunakan sebagai referensi untuk menentukan jumlah cement berdasarkan injectivity-nya: Tabel Cara menentukan Jumlah Cement yang dibutuhkan Injectivity Pressure (Psi) Min Cement (sxs) Max Cement (sxs) 0-50 200 300 50-100 150 200 100-150 125 150 150-200 100 125 200-250 75 100 >250 50 75

Note: Guideline diatas untuk pekerjaan squeeze IB dan Squeeze casing leak. Sedangkan untuk perkerjaan Squeeze off interval yang intervalnya panjang, jumlah cementnya dilebihkan.

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Contoh Cara Menentukan Slurry Design dan Jumlah Cement 1. Pekerjaan squeeze IB Hasil Injectivity: 125 Psi @ 0.6 bpm Circulating temperature: 95 deg F Maka: • Jumlah cement: 125-150 sxs (lihat tabel di atas) • Design Slurry o Temperatur design: 90 F (standard) o Jenis Slurry : 50% Lead + 50% Tail 2. Pekerjaan squeeze off interval (panjang interval 20’) Hasil Injectivity: 40 Psi @ 0.6 bpm Circulating temperature: 110 deg F Maka: • Design Slurry o Temperatur design: 105 F (standard) o Jenis Slurry : 75% Lead + 25% Tail • Jumlah cement: 250 sxs (lihat tabel di atas) Untuk interval yang lebih panjang, sebaiknya jumlah cement ditambah.

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CEMENTING TECHNIQUE Remedial Technique di Duri ada 2 macam: • Bullhead Technique (tubing di atas) è Paling sering di pakai untuk kondisi normal • Equalize Technique (tubing dibawah) Diaplikasikan untuk kondisi: o Well sand problem yang berpotensi menutup squeeze interval dan menghalangi cement o Jika ada beberapa squeeze interval yang letaknya berjauhan dan akan di squeeze sekaligus o Untuk squeeze / shut off interval yang kondisi wellnya Loss Circulation atau Low pressure

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Contoh Pumping Chart Pumping Cement Slurry – Water Displacement Pressure

D

A B

C

C-D: Water Displacement

A-C: Pumping cement slurry A-B: Pressure turun karena air di wellbore digantikan cement yang densitynya lebih besar B-C: Pressure kembali naik karena cement slurry mulai masuk formasi (blocking effect) Time

Hesitation

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PROCEDURE Procedure Persiapan Sebelum Squeeze job 1.

2.

3.

Pressure test Casing sampai400 psiuntuk wellbaru atau 200 Psi untuk well lama. Pressure test BOP untuk memastikan BOP dalam keadaan bagus Diusahakan well bore dalam kondisi full dengan 2% KCl water. Buka annulus valve antara surface casing dan production casing Gali sekeliling WH untuk memastikan FM seal tidak bocor

4.

5.

6. 7.

8.

9.

Pasang pressure gauge 0 - 1000 psi pada BOP connection valve. Run CBL, record max. temperature, perforate squeeze interval. Lakukan injectivity test menggunakan rig pump. (Lihat procedur menentukan squeeze interval). Set OE tubing +/- 10 feet dibawah squeeze interval. Rig up cementing unit & pressure test surface line, manifold sampai dengan 2000 psi sebelum mulai job. Reverse out, ambil BHCT dan lakukan injectivity test w/0.6 BPM, dengan 2 % KCl water. Lakukan pre-job meeting untuk membicarakan kondisi downhole (tight, moderate, or loose injection type), volume cement slurry yang akan di pompa, minimum pumping rate dari cement slurry, maximum pressure, pumping procedure, dan menentukan langkah-langkah yang harus diambil jika terjadi sesuatu. 15

Bullhead Procedure 1. Raise-up OE tubing ke 70 feet di bawah rotary table atau seperlunya. 2. Buka BOP dan tutup annulus, fill up well dengan 2% KCl water, tutup BOP. 3. Pompa 2% KCl water sebelum mixing cement slurry. 4. Mix dan pompa cement slurry berdasarkan injectivity test 5. Displace lewat tubing dan annulus dengan 0.6 bpm water secara bergantian. 6. Hesitate lewat tubing dengan 0.2-0.3 bpm water untuk mendapatkan maximum pressure ~ 300 Psi. Estimate top cement slurry 50 ft dari top squeeze interval. Tutup OE tubing valve. 7. Hold pressure & WOC minimum 4 jam, RDMO cementing unit. Langkah Perhitungan: 1. Tentukan est TOC ~ 50 ft diatas top perforasi 2. Hitung Vol line dan Vol OE tubing 3. Tentukan perkiraan Hesitate Volume ~ 3 bbls 4. Tentukan Total Displacement =Vol Line + Vol OE tubing + Vol (est TOC – OE tbg) – Vol Hesitate

o Displacement I (Tubing) = Vol Line + Vol OE tubing o Dispalcement II (Annulus) = 1-2 bbls o Dispalacemet III (Tubing) = Total Displ – Displ II – Displ III

16

A

B

C D E

Pump Cement Slurry

Displace Tubing = Vol line (A) + Vol OE Tubing (B)

Displace annulus = Volume C

Displace tubing = Volume D

Total Volume Displacement + Hesitate = Vol Line + Vol OE Tubing + Vol Casing antara Ujung OE tubing ke Est TOC ) = A + B + (C + D + E)

Est TOC

Hesitate = Volume E

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Bullhead Squeeze

Example: Cement

Casing size = 10-3/4”, Capacity = 0.0981 bbl/ft, PBTD @ 420 ft Interval will be shut off = 400’ - 410’ Tubing size = 3-1/2”, Capacity = 0.0087 bbl/ft, Set @ 70 ft

Line (A)

Water

OE tubing (B)

Calculation: Assume line volume = 0.5 bbl Tubing volume (B) = 70 ft x 0.0087 bbl/ft Hesitation volume (E) = 3 bbls

70’

Displacement (B +C) Hesitation (E)

400’-410’

340’

= 0.6 bbls

Proposed top of cement slurry left inside casing at 340 ft, then Displacement volume = {(340 - 70) ft x 0.0981 bbl/ft} + 0.6 bbl –Hestitation vol = 26.4 bbl + 0.6 bbl – 3 Bbls = 24.0 bbl

420’

Total displacement volume Hesitation

= 3 bbls

= 24.5 bbl

(0.5+0.6) Bbls from tubing 5 BBbls from annulus 19 Bbls from tubing

Contoh Perhitungan

Displacement Volume

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Equalize Technique Procedure 1. Set OE 5 ft dibawah bottom perforasi 2. Buka BOP dan tutup annulus, fill up well dengan 2%

KCl water, tutup BOP. 3. Pompa 2% KCl water sebelum mixing cement slurry. 4. Pompa Cement Slurry 5. Choke Annulus, Equalize cement slurry sesuai kebutuhan. 6. Displace pump truck line dan OE tubing dengan air 0.6 BPM. 7. Raise-up OE tbg +/- 100 ft diatas squeeze interval, reverse out the slurry 8. Raise-up OE tbg ke ~ 70 ft. Fill up dan tutup BOP 9. Hesitate lewat tubing dengan 0.2-0.3 bpm water untuk mendapatkan maximum pressure ~ 300 Psi. Estimate top cement slurry 50 ft dari top squeeze interval. Tutup OE tubing valve. 10. Hold pressure & WOC minimum 4 jam, RDMO cementing unit.

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Langkah Perhitungan Equalize Technique: 1. Tentukan est final TOC ~ 50 ft di atas top perforasi 2. Tentukan est top slurry setelah equalize ~ 100 di atas top perforasi (TOC1) 3. Hitung volume yang akan di equalized = Vol Annular (TOC1-Top perf) + Vol Metal Displacement tubing (TOC1-OE tbg) – (Vol line + Vol Tubing displacement to TOC1) 4. Hitung Volume cement slurry yang akan dipompa sebelum equalize = Total Slurry – Equalized Volume 5. Tentukan perkiraan Hesitate Volume ~ 3 bbls 6. Tentukan Total Casing Displacement = Vol (est TOC – Est TOC1) – Vol Hesitate

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Equalize Cementing C Choke

TOC1

C

D

Water Cement

E A+B-C

F

OE

•Set OE tubing 10 ft below bottom interval •Pump Cement Slurry =Total Slurry – Volume equalized

•Choke Annulus. •Equalize cement = A + B - C =Vol Annular (TOC1-Top perf) + Vol Metal Displacement tubing (TOC1-OE tbg) – Vol Line and Tubing Displacement to TOC1 Note: TOC1 = ~ 100 ft above top interval

Displace tubing to TOC1 (C)

•Raise up tubing to TOC1 •Reverse out

•Raise up OE to 60 ft •Displace (D + E) •Hesitate (F)

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CALCULATIONS Equalize/ Braden head Squeeze Casing size = 10-3/4”, Capacity = 0.0981 bbl/ft, PBTD @ 420 ft Interval will be shut off = 400’ - 410’ Tubing size = 3-1/2”, Capacity = 0.0087 bbl/ft, OE Set @ 415 ft Annulus 10-3/4” – 3-1/2” = 0.0862 bbls/ft Metal Displacement 3-1/2” tubing: 0.00321 bbls/ft

Calculation:

Estimate Final TOC 340 ft

Pump Slurry = Total volume – Volume to be equalized Cement

Expected top of cement slurry (TOC1) is ~ 250 ft Volume to be equalized = A + B - C = annulus volume (Top Intv – TOC1) + Metal Displc tbg (OE-TOC1) - Line and Tbg volume to TOC1 = [(0.0862 bbls/ft) x ( 400-250) ft ] + [0.00321 bbls/ft x(415-250)ft]

Water

C

- [0.6 + 0.0087 (250)]

70’

=(12.9 + 0.53 - 2.8)bbls = 10.6 bbls TOC1=250’

250’

Displacement Hesitation

A+B-C

340’

Displace Vol Tubing toTOC1 = = vol line + vol inside tbg 250 ft = 0.6 + 0.0087 (250)

= 2.8 bbls 400’-410’ OE 415’ 420’

415’ 420’

22

• Continue with raise up OE to 250’ • Reverse out • Raise up OE to 70’ • Displacement =Vol casing (340’-250’) – Vol Hesitation • Hesitation = ~ 3 bbls

LAMPIRAN 1 Contoh Report yang harus di isi setiap Cementing Job COMP-001 REV.5. June-03 (NI)

REMEDIAL CEMENTING REPORT WELL INFO Grid No : 6R20A Area

i.e 6N83A

Well Type :

: 6

Well ID : D-2716

i.e D-1933

INJECTOR

Comp. Type : Casing Size :

10-3/4"

Inch

Rig / CTU :

i.e SQ/IB/CL/IS

Job Date : 24-Apr-05 Injectivity Test

OTHER

I.e CHGP, OHGP, SS, PSD etc

Program No : IBBPRO0620050002 Job Type : IB

PRODUCER

OHGP

Job Sequence :

SPA # 03

i.e BN-11 or CTU H-1

SQZ 1

i.e 1, 2 or 3 and next

i.e 07-JAN-2003

:

0.6

BPM

Pressure

1: Upper : 2: Upper :

250

ft ft

1: Lower 2: Lower

3: Upper :

ft

3: Lower

ft

4: Upper :

ft

4: Lower

ft

5: Upper :

ft

5: Lower

ft

170

Psi

252

ft ft

BHCT

130

Deg F

Target Interval

Total GP sand

:

Temp Slurry design :

Sxs (Sqz Pack Job) 125

Cement Type : "G" CMT

Total Cement Usage :

Deg F

LCM Used :

("G", "MMC")

125

Sxs

NO USAGE

Lead :

14 Bbls

Fluid Loss 256

cc/30min

Density

15.8 ppg

Thickening Time

1:55

(hh:mm)

Tail :

21 Bbls

Fluid Loss 144

cc/30min

Density

15.8 ppg

Thickening Time

2:20

(hh:mm)

Service Comp : DOWELL

Cementer Name BIDNER SIANTURI

Total Cost

Placement Technique Braden Head (Equalize)

X Bullhead (OE Tubing) Krypton Result

Good

Bad

Result for SQ/IB/CL/IS

Good

Bad

WW Representatives : Compresive strength 500 psi : WOC : Test Target Interval : Sueeze Result :

Bullhead (Cement Retainer)

OE set @ TOC @

NA

TOC @

4209.8 70 195

US$

FT FT

(estimate)

FT

(actual)

NA Leak

NA

For IB Only i.e ERS

RAFLIATA # 15893

MV

ft

Hesitation

5

hrs

Initial Press

133

Psi

5 400

hrs

Final Press Hesitate Total

400 2.5

Psi

CIF CIP

29.5 14:15

LEAK :

Psi BPM ,

PSI

BBls BBls HRS

23

LAMPIRAN 2 Contoh Score Card yang harus di isi setiap Cementing Job REMEDIAL CEMENTING SCORE CARD WELL: 6R-20A # 2716 DATE: 24-04-2005 ACTIVITY

Call Cementing Unit Cementing Unit Rig-Up Injectivity test Discuss Slurry design and Placement technique

WW REPS:RAFLIATA # 15893 SERCO : DOWELL Start-Time

Compl-Time

16:30 3:30 4:30

22:00 4:00 5:00

Remark

Date : 23 April 2005 Date : 24 April 2005 o 0;6 BPM 170 Psi. Temp 130 F WW Reps Calculation and Procedure

Yes

WW Reps Calculation and Procedure

Yes

Same Calculation and Procedure between WW Reps and Cementer Yes

Mixing slurry

8:00

10:00

Date : 24April 2005

Pumping slurry __35_____ bbls

Pumping Rate: 0.8 BPM

Pumping pressure: IP 170 , FP: 133

Displacement __9.7_____bbls

Pumping Rate : 0.8 BPM

Pumping pressure: IP: 146 FP: 110

Hesitate __3_____ bbls

1. Voulme : …0.5………… bbls

Pumping pressure: IP 92 PSI….….. FP: …114…PSI….. Pumping pressure: IP …92 PSI….….. FP: …119 PSI……….. Pumping pressure: IP 87 PSI…….….. FP: 133 PSI………….. Pumping pressure: IP 92 PSI….….. FP: …179 PSI……….. Pumping pressure: IP …130 PSI….….. FP: 400 PSI………….. Pumping pressure: IP …….….. FP: …………..pressure: IP …….….. FP: Pumping ………….. Pumping pressure: IP …….….. FP: …………..

2. Voulme : …0.5………… bbls 3. Voulme : …0.5………… bbls 4. Voulme : …0.5………… bbls 5. Voulme : …0.5………… bbls 6. Voulme : …………… bbls 7. Voulme : …………… bbls 8. Voulme : …………… bbls

WOC FOR 5 HRS DOC Pressure test with ____ Psi ____ minutes

W/O 10 MNTS W/O 30 MNTS W/O 30 MNTS W/O 30 MNTS HOLD PRESS

14:15 HRS 0.80208

Call CBL CBL Truck Rig-Up Run CBL (after squeeze)

24