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
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
Compiled by
Iwan Wijanarko
2005
Squeeze Cementing Decision Flow Process
WWReps
Pre- job meeting
Serco reps Cementing Team
Squeeze Job I
Success?
Continue next program
Evaluate and Re -design
Next Squeeze job(s )
Success?
Continue next program
TL Operation RMT/PMT
Planning
Execution
Discuss the plan forward
Re-squeeze? N Y N Y Y •Other alternatives •Continue next program •Pack well off
Tabel CBL Guideline
Class "H" cement † POZ Mix ‡
Csg. Size Csg.Wt. TT Expected Compressive Strength 3000 psi Compressive Strength 1500 psi (in) (ppf) Transit Time
(µsec) Free Pipe 100% Good Bond 100% Good Bond
Amplitude Cement Cut Off cement Cut Off
mV (mv) (60%) (mv) (60%)
Interval req'd for Isolation
(ft)
3-1/2 9.3 239 92 N/A < 1.0 N/A N/A 5
4-1/2 9.5 254 81 0.2 2.3 N/A N/A 5 11.6 0.6 4.6 13.5 1.0 7.0 5 15.0 239 77 0.9 5.7 2.3 10.1 5 18.0 236 2.4 10.4 4.6 16.5 21.0 234 3.8 14.7 7.3 21.0 5 1/2 15.5 248 71 0.7 4.7 1.6 8.2 7.5 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 7 23.0 272 61 1.0 5.6 2.4 9.3 10 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 9 5/8 40.0 313 52 1.7 6.7 3.2 10.6 15 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 10 3/4 40.5 334 50 1.1 5.0 2.4 8.4 18 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 †
Bond Cut Off for Class ‘H’ Cement must be used as the Bond Cut Off guidel ine for 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 ells where the cement has been in place for less than 24 hours (after Primary or Remedial
Used for Old Cement
Used for New Cement < 24 hrs
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.
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
Gamma Ray Amplitude (mV) VDL
Good Bonding Bad Bonding
Bagaimana QC CBL?
• Pastikan CBL tersebut ON-DEPTH dengan meng-korelasikan 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
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
USIT-Schlumberger
Skala Z plot berdasarkan warna:
Material Z (Mrayls)
Gas (red) < 0.30 Liquid (blue) 0.3 – 2.6 Cement (brown to black) >2.6
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
Top 240 Btm 240 Top Rindu Btm Rindu Top Pertama
=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 A B C 240 Sand Rindu Sand Pertama Sand
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 Injectivity Pressure
(@0.6 bpm)
Slurry Design Loose Injection Profile <50 Psi Lead slurry atau
Lead + sedikit Tail Slurry Moderate Injection Profile 50 -200 Psi Lead + Tail Slurry
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.
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.
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
Contoh Pumping Chart
Pumping Cement Slurry – Water Displacement
Hesitation A B C D Pressure Time
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)
C-D: Water Displacement
PROCEDURE
Procedure Persiapan Sebelum Squeeze job
1. Pressure test Casing sampai400 psiuntuk wellbaru
atau 200 Psi untuk well lama. Pressure test BOP untuk memastikan BOP dalam keadaan bagus
2. Diusahakan well bore dalam kondisi full dengan 2%
KCl water.
3. Buka annulus valve antara surface casing dan
production casing
Gali sekeliling WH untuk memastikan FM seal tidak bocor
4. Pasang pressure gauge 0 - 1000 psi pada BOP
connection valve.
5. Run CBL, record max. temperature, perforate squeeze
interval. Lakukan injectivity test menggunakan rig pump. (Lihat procedur menentukan squeeze interval).
6. Set OE tubing +/- 10 feet dibawah squeeze interval. 7. Rig up cementing unit & pressure test surface line,
manifold sampai dengan 2000 psi sebelum mulai job.
8. Reverse out, ambil BHCT dan lakukan injectivity test
w/0.6 BPM, dengan 2 % KCl water.
9. 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
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
17
B
Pump Cement Slurry Displace Tubing = Vol line (A) + Vol OE Tubing (B) Est TOC A C D E Displace annulus = Volume C Displace tubing = Volume D Hesitate = Volume E
Total Volume Displacement + Hesitate
= Vol Line + Vol OE Tubing + Vol Casing antara Ujung OE tubing ke Est TOC ) = A + B + (C + D + E)
Contoh
Perhitungan
Displacement Volume Bullhead Squeeze Example:
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 Calculation:
Tubing volume (B) = 70 ft x 0.0087 bbl/ft = 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
Assume line volume = 0.5 bbl
Total displacement volume = 24.5 bbl
420’ 400’-410’ 70’ 340’ Cement Water
Hesitation volume (E) = 3 bbls
(0.5+0.6) Bbls from tubing 5 BBbls from annulus 19 Bbls from tubing Hesitation = 3 bbls Displacement (B +C) Hesitation (E) Line (A) OE tubing (B)
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.
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
21
•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
D E Displace tubing to TOC1 (C) •Raise up tubing to TOC1 •Reverse out •Raise up OE to 60 ft •Displace (D + E) •Hesitate (F) Equalize Cementing Choke F Note:
TOC1 = ~ 100 ft above top interval
OE TOC1 A+B-C Water Cement C C
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] - [0.6 + 0.0087 (250)]
=(12.9 + 0.53 - 2.8)bbls = 10.6 bbls
Displace Vol Tubing toTOC1 = = vol line + vol inside tbg 250 ft = 0.6 + 0.0087 (250)
= 2.8 bbls
• Continue with raise up OE to 250’ • Reverse out
• Raise up OE to 70’
• Displacement =Vol casing (340’-250’) – Vol Hesitation
CALCULATIONS
Equalize/ Braden head SqueezeCasing 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:
Expected top of cement slurry (TOC1) is ~ 250 ft Estimate Final TOC 340 ft
Pump Slurry = Total volume – Volume to be equalized
420’ OE 415’ TOC1=250’ Displacement Hesitation 420’ 415’ 340’ 250’ 70’ A+B-C Cement Water C 400’-410’
LAMPIRAN 1
Contoh Report yang harus di isi setiap Cementing Job
COMP-001 REV.5. June-03 (NI)
WELL INFO
Grid No : 6R20A i.e 6N83A Well Type :
Area : 6 Comp. Type : I.e CHGP, OHGP, SS, PSD etc
Well ID : D-2716 i.e D-1933 Casing Size : Inch
Program No : IBBPRO0620050002 Rig / CTU : SPA # 03 i.e BN-11 or CTU H-1
Job Type : IB i.e SQ/IB/CL/IS Job Sequence : SQZ 1 i.e 1, 2 or 3 and next
Job Date : i.e 07-JAN-2003
Injectivity Test : 0.6 BPM 170 Psi BHCT 130 Deg F
Target Interval 1: Upper : 250 ft 1: Lower 252 ft 2: Upper : ft 2: Lower ft 3: Upper : ft 3: Lower ft 4: Upper : ft 4: Lower ft 5: Upper : ft 5: Lower ft
Total GP sand : Sxs (Sqz Pack Job)
Temp Slurry design : 125 Deg F Total Cement Usage: 125 Sxs
Cement Type : "G" CMT ("G", "MMC") LCM Used: 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 NameBIDNER SIANTURI Total Cost 4209.8 US$
Placement Technique OE set @ FT
Braden Head (Equalize) Bullhead (Cement Retainer) TOC @ FT (estimate)
XBullhead (OE Tubing) NA TOC @ FT (actual)
Krypton Result Good Bad NA
Result for SQ/IB/CL/IS Good Bad Leak NA For IB Only MV ft
WW Representatives: RAFLIATA # 15893 i.e ERS Hesitation
Compresive strength 500 psi: 5 hrs Initial Press 133 Psi
WOC: 5 hrs Final Press 400 Psi
Test Target Interval: 400 Psi Hesitate Total 2.5 BBls
Sueeze Result: CIF 29.5 BBls
LEAK : BPM , PSI CIP 14:15 HRS
24-Apr-05
70 195
Pressure
REMEDIAL CEMENTING REPORT
OHGP 10-3/4"
LAMPIRAN 2
Contoh Score Card yang harus di isi setiap Cementing Job
REMEDIAL CEMENTING SCORE CARD WELL: 6R-20A # 2716 WW REPS: RAFLIATA # 15893
DATE: 24-04-2005 SERCO : DOWELL
ACTIVITY Start-Time Compl-Time Remark
Call Cementing Unit 16:30 22:00 Cementing Unit Rig-Up 3:30 4:00 Injectivity test 4:30 5:00 Discuss Slurry design and
Placement technique Yes Yes Yes Mixing slurry 8:00 10:00
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….. W/O 10 MNTS 2. Voulme : …0.5………… bbls Pumping pressure: IP …92 PSI….…..
FP: …119 PSI……….. W/O 30 MNTS
3. Voulme : …0.5………… bbls Pumping pressure: IP 87 PSI…….…..
FP: 133 PSI………….. W/O 30 MNTS 4. Voulme : …0.5………… bbls Pumping pressure: IP 92 PSI….…..
FP: …179 PSI……….. W/O 30 MNTS
5. Voulme : …0.5………… bbls Pumping pressure: IP …130 PSI….…..
FP: 400 PSI………….. HOLD PRESS 6. Voulme : ……… bbls Pumping pressure: IP …….….. FP:
…………..
7. Voulme : ……… bbls Pumping pressure: IP …….….. FP: …………..
8. Voulme : ……… bbls Pumping pressure: IP …….….. FP: …………..
WOC FOR 5 HRS 14:15 HRS 0.80208 DOC
Pressure test with ____ Psi ____ minutes
Call CBL CBL Truck Rig-Up Run CBL (after squeeze)
Date : 24April 2005
0;6 BPM 170 Psi. Temp 130o F WW Reps Calculation and Procedure WW Reps Calculation and Procedure
Same Calculation and Procedure between WW Reps and Cementer Date : 23 April 2005
