BAI H O C KINH NGHIEM VE CONG TAC H O A N THIEN Gie'NG
TAI BE CJU LONG
ThS. Vu Manh H^o, ThS. Le Quoc Trung, KS. Le Vu Quan Vi$n Ddu khf Viet Nom
Email: [email protected] Tom t ^ t
Be Cdu Long Id khu vUc co nhieu md ddu dugc phdt hien vd dang trong glai doan khai thde nhumd Bach Ho, Rdng, Rgng Ddng, SU TdDen, SU Td Vdng... Dieu kien dja chdt eda be khdng cd phdc tap Idn, tuy nhien trong qud trinh khai thde dd xdy ra mdt sosUcd: cdt xdm nhdp, ngdp nUdc vd ldng dpng paraffin... ddn den gidm tuoi thg gieng, tdng chi phixdlfsucdvd sda chda gieng, Idm gidm hiiu qud khai thde. Bdi viet ddnh gid hien trgng cdng tdc hodn thien giing, rut ra bdi hge kinh nghiem cho cong tdc thiet ke, thi cdng vd djnh hudng sddung cdng nghe hodn thiin gidng trong tuang lai.
TUkhda: Hoan thien gieng, be CCfu Long, cdt xdm nhap.
1. Gidi thieu
Cdng tac hoan thien gieng la moi quan t i m hang dau eua cic nha thau dau khf de d i m b i o cho q u i trinh khai thic dau khf lau dai va hieu q u i . Suthanh cdng cua cdng t i c hoan thien gieng gdp phan cho gieng van hanh an toan, giam thieu thdi gian va ehi phf cho cdng t i c sda gieng sau nay.
Dja tang tram tfch be Cdu Long cd anh hudng Idn den cdng tac hoan thien gieng. Khu vUc n i y chu yeu la cac tram tfch cd tudi Miocene, cd tinh bd rdi v i dd gan ket yeu, do dd nguy CO cat xam n h i p vao gieng rat Idn.
D i mdng trudc Cenczoic d be Cdu Long chu yeu la cac da xam n h i p granitoid vdi thanh phan khdng ddng nha't do daoc ket tmh d cac dieu kien dja chat va thdi gian khic nhau. Dac tfnh chda eua da mdng d be Cdu Long khdng ddng deu trong mdt md va gida cac khu vUc.Tai be CCfu Long, cic gieng khai thac ddi tUong mdng ehlem gan 50%, cic gieng deu duac hoan thien kieu than tran do di't da thanh he d day cd tfnh ran chic va dp dn dinh cao. Tuy nhien, do ddi tUpng nay cd d i e tfnh bat ddng nhi't cao, vdi nhieu khe ndt, nirt ne Idn; cac gieng dapc hoan thien kieu than tran, gay khd k h i n trong viee kiem soit hien tUpng ngap nude.
Trong bai viet nay, nhdm t i e g i i d i n h gia viec ufng dung cdng nghe trong edng t i e hoan thien gieng tai tren 350 gieng khai thac d be CCfu Long. Tren co sd do, nhdm t i c g i i phan tfch hien trang khai t h i e eua cie md, de xuat phuong i n thiet ke h o i n thien gieng phu hpp, danh gia ddng t h i i gieng va tim ra eic nguyen nhan gay ra cac khd khan, phUe tap trong cdng tac hoan thien gieng.
12 OAUKHl-Sd 12/2014
2. Cong tac hoan thien gieng be Cfru Long 6 be Cdu Long, cac gieng khai t h i c tai tang cat ket Miocene va Ollgocene sd dung cdng nghe hoan thien gieng don de khai t h i c mdt hoae nhieu tang sin pham ddng thdi, sd dung cdng nghe hoan thien gieng kep de khai thac c i c tang s i n pham rieng blet. Phaong phap hoan thien via chufa thudng sd dung la t h i ong chdng, tram xi mang va ban due 16 dng chdng. Tai cac khu vUc cd nguy co khai thac c i t cao, phan via chufa hoan thien kieu than tran ket hop lap d i t ludi chan eat. Tai tang mdng, cac gieng thudng dupe hoan thien bang each sii dung mdt cdt dng khai thac, phan via chda hoan thien kieu than tran.
De nang cao hieu q u i khai t h i c , dam b i o an toan trong q u i trinh van hanh khai thac, g l i m thieu chi phf, eic nha thau da ap dung nhieu giai p h i p , cdng nghe va thiet bj tien tien hien dai trong qua trinh hoan thlfen gieng nhU:
Sd dung packer truong nd de khai t h i e ddng thdi nhieu tang sin pham va kiem soit hl^n tUOng ngap nUdc, dae biet khi khai t h i c tai tang mdng.
Ap dung cdng nghe hoan thien gieng kep trong viee khai t h i c neng biet nhieu t i n g sin pham.
Sd dung ludi chan eat ddi vdi cic md cd nguy cd bl catxam nhap eao.
Cac yeu to anh hUdng den cdng t i e hoan thien gieng gdm: dieu kien dia chat, chieu sau mUe nude bien, nhiet dp va i p suit via, t h i n h phan H^S va CO .... Tuy nhien c i c yeu t d nay khdng i n h hudng idn vi cic ket q u i nghien edu
PETROVIETNAM
cho thay dieu kien dja ly t u nhien cCia be Cdu Long khdng q u i phdc tap, ham lapng CO^ va H^S thap. Mdt sd md khai t h i c tai ddi tupng Miocene d khu vUc dat da thanh he cd tfnh chat bd rdi, lien k^t kem, d i xay ra hien tUpng c i t xam nhap v i o gieng. C i t xam n h i p tap trung nhieu d khu vUe Ddng Bac be Cdu Long noi tram tich Miocene ed dd rong > 19% (Hinh 1).
Do tinh chat dau tai be Cdu Long cd ham lupng paraffin eao (mdt sd md cd ham lUpng paraffin > 25%), tfnh chat cua node via, sU thay ddl nhiet dd i p suat trong gieng... nen trong qua trinh khai t h i e x i y ra hien tapng l i n g dpng paraffin, lam giam s i n lupng khai t h i c [1,5].
Hinh 1. So do (demo xual hien cdt xdm nhap tai be Cilu Long
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2.1. Cong ngh4 va thiet bj hoan thien gieng 2.1.1. Doi tuong Miocene va Ollgocene
Cic gieng tai be Cdu Long chu yeu i p dung phuong p h i p hoan thien gieng don. Mdt sd gieng d md Ruby, Pearl... sd dyng phuong phap hoan thien gieng kep.
PhUPng phap md via phd bie'n nhat ddi vdl cie gieng khai t h i e tai ddi tUpng Miocene la ban due Id dng chdng. Day la phuong phap hoan thien don g i i n v i tiet kiem chi phi, song ed the xiy ra hien tUong cat xam nhap vao gieng.
Do vay, viec ap dung phUPng phap nay chi dat h i i u qua tai eic md khdng cd nguy co xiy ra c i t xam nhap trong qua trinh khai thac. Tai cac gieng khai t h i c tai ddl tUpng Ollgocene md Bach Hd, d i e tinh dat d i e d dp on djnh cao hon nen ap dyng phuong p h i p md via kieu than tran.
Ddl vdi cac md cd nguy co cat xam nhap cao, phaong p h i p hoin thien via dang t h i n tran ket hpp vdi ludi ch^n eat la giai p h i p tdi Uu nhat. Dieu nay da dupe minh chdng bang hieu q u i kiem soit c i t tot tai cac gieng d md SaTCf Den, Rang Ddng.
De kiem soit cat thudng sd dung ludi chan cat ddc lap, lUdi c h i n c i t chen sdi, ladi chin cat gian nd...
Trong do, lUdi chan eat ddc l i p dupe sd dung phd bien tai md Su Td Den, Rang Ddng, Pearl be Cdu Long, do tiet kiem chi phf va hieu qua k i l m soit c i t va khai thac cao (Hinh 2). Phuong phap kiem soit c i t bang ludi chan c i t chen sdi dupc i p dyng tai mdt sd gieng md Ruby, song hieu qua khdng cao do c i t bit nhet xung quanh ludi, lam g i i m kha nang khai thic.
2.1.2. Doi tugng mong nutne Mdng nut ne la ddi tapng khai t h i c chinh eua be Cdu Long vdi gan 200 gieng khai thac va bom ep. Cic gieng h o i n thien trong mdng dUOc thiet ke vdi eiu true mdt cdt dng khai t h i e va hoan thien via kieu than tran.
hiili chSn cat a6c Bp Lifcit chan cat chen s(
PhUorng phap kiem sodt cdt
Hinti 2. Phucmg phdp hem sodt cdt dp dung cho cdc gieng khoi thac tai Miocene
Packer trUong nd dUdc i p dung tai nhieu gieng md SuTdDen, SuTd Vang, Ci NgU Vang nham ngan each olu KHi-sd 12/2014 13
khoing n g i p nUdc ddi vdl cic gieng khai thac tai tang mdng (Hinh 3).
2.2. sued phdc tgp vd biin phdp khde phuc Qua trinh hoan thien gieng ed vai trd quan trpng, anh hudng den k h i nang khai thic va tudi thp cua gieng. Vi vay, trudc khi gieng dua v i o hoan thien, cae nha thau tien h i n h nghien cdu, lUa ehpn cdng nghe va thiet bi phu hpp d i m b i o k h i nang khai t h i c tdt nhat. Su cd xiy ra trong q u i trinh hoan thien gieng duoc xdly kip thdi.
Trong qua trinh khai thie, cac md thadng xua't hien hien tupng lang dong paraffin va mudl vd cP, lam giam sin luong khai thac, tang thdi gian va chi phf sda gieng. Cic gieng khai thac d tang cat ket Miocene x i y ra hien tUpng c i t xam nhap, neu khdng sd dung bien phap kiem soit c i t se gay mdn thiet bj Idng gieng va cac thiet bj khai thac be mat, lam g i i m kha nang khai thic cua gieng.
2.2.1. Hiin tugng cdt xam nhap
Cit x i m n h i p la hien tupng thadng g i p tai cic gid'ng khai thac doi tupng c i t ket Miocene, ndi ma t h i n h he cd tinh bd rdi va gan ket kem. Hien tUpng nay xiy ra tai mot so md Ruby, Rang Ddng, Rdng.
Tai md Rang Ddng, c i t xam nhap x i y ra tai mpt so gieng khai t h i c tang Miocene. Trong do, gieng RD-1 da phai ddng gieng de sda chda va nao vet c i t , do cat chay cao 200 Ift/ngay (2003). Sau dd, gieng dupe tiep tuc dUa vao khai thac va sin lupng khai thac cua gieng hien nay dat khoang 700 thiing/
ngay (Hinh 4) [3].
Da so cac gieng khai t h i c tai md Rang Ddng khdng lap dat lUdi ehan cit. Vi viy, phUdng phap kiem soit c i t hien nay la kiem soit gieng de cd the khai thac an toan khi ham lapng cat t d 0,01 - 0,1 % the tfch va cac thiet bi dupc n g i n chan mai mdn bang cac bp t i c h Ipc eat tren be mat. Khi ham luong c i t vUdt ngudng tren thi g i i m cdn hoac ddng gieng.
Cac gieng khai thac cua md Ruby da phan khdng sd dyng bl^n phap kiem soat cat, do dd c i t xuat hien trong sin pham vdl ham lapng tCf 5 - 1 Opptb (pound per thousand barrel), tham chf cd gieng ham lapng c i t vuot q u i gidi han cho phep la ISpptb. Mdt sd gieng lap dat ludi chan c i t chen sol nhang khdng dat hieu qua cao. Trade tinh hinh do, phuong thde q u i n ly md dapc xem xet va cap nhat cho phu hop nham phyc
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Hinli 4. San iuong khai thac cua giSng RD-1 BAng 1. Thong k^ ham luang cot khai thde tai mot so gieng mo Ruby T e n g i e n g
RB-1 RB-2 RB-3 RB-4 RB-5 RB-6 RB-7 RB-8 RB-9 RB-10
T h d i gian k h a o sat 1/3/2011 2/3/2011 I 5/3/2011 7/3/20ri_
9/3/2011 17/10/2010 15/10/2010 10/3/2011 16/2/2010 18/10/2010
D o i lu'dng M i o c e n e - 1 0 / 2 0
M i o c e n e - 9 fVliocene-9/10/20
Miocene-9/~l 0 IVliocene-10 IVliocene-20 IVliocene-9/10/30
M i o c e n e - 9 / 1 0 M o n g M i o c e n e - 9 / 1 0
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Hinh S. Trong r/?a/ khai thac cua cdc gieng tai lang mong mo Sif lUBen 1 4 DAU KHU 3612/2014
PETROVIETNAM
vu khai thac dau mdt each hpp ly nhU: theo doi va giam sat ham luong c i t trong sin phi'm dau tung gieng nhd hon mde eho phep ISptb; thudng xuyen khao sat gieng de kiem soit bang chenh ap va ddi khi can thiet g i i m cdn khai thic; djnh ky kiem tra tinh trang Idng gieng de cd g l i i p h i p kjp thdi, nghien cUu lap dat lUdi chin cat de kiem soat cit. Thdng ke lupng c i t trong qua trinh khai thac tai mdt sd gieng md Ruby (Bing 1) [3],
2.2.2. Vdn de ngap nUdc doi vdi cdc gieng khai thac tgi tang mong
Do d i e thil cua khai t h i e t h i n d i u mdng ndt ne, do ngap nude eua gieng t i n g len r i t nhanh. Mdt sd gieng khai thac d ddi tupng mdng md Bach Hd, SuTdDen, SUTd Vang deu xay ra hien tupng nay. Cac gieng khai thac ed dp ngap nude cao gay i n h hudng xau den he thdng khai t h i c nhU: ddng gieng, chuyen sang khai thac ddi tUOng khic hoac p h i i Ung dung cae phUPng p h i p cp hpc hay chuyen sang khai t h i c theo chu ky... Trang t h i i khai t h i c v i mde dp n g i p nUdc eda cac gieng tai tang md SuTdDen, SUTd Vang daoc the hien tren Hinh 5 va 6 [3].
Nude xua't hien trong ddng san pham khai thic tai tang mdng md Bach Hd t d cudi nam 1994. Chi sau vai
S^nlirongkhaith^o gieng m i Si/TCf Ving
Hinh 6. Trgng thdi khai thde cUa (dc gieng tai tdng mong mo SU Ti Vdng
t h i n g , dp ngap nude len tdi 70 - 80%, khien nhieu gieng ngUng phun. Do ngap nude trung binh eda ddl tuong mdng md Bach Ho tai t h i n g 1/2007 la 12,7% va chi cdn 30 gieng khai thac eho ddng san pham khdng lan nude.
Trong dd, 11 gieng cd san lapng rat thap. Bing 2 the hien dp ngap nUdc trong giai doan 2006 - 2007 eCia mot sd gieng khu vUc trung tam md Bach Ho.
Trudc tinh hinh dd, Vietsovpetro da thuc hien cac bien phap can thiep va sda chda gieng, dac biet la each ly khoang ngap nadc tdt, do dd do ngap nude trung binh cua ca ddi tUdng mdng tang cham, dp ngap nudc trong san pham nam 2008 la 17% [4].
2.3. Bdi hge kinh nghiem trong eong tdc hodn thien gieng 2.3.1. DOI tuang Miocene, Ollgocene
Theo cac tai lieu tdng hpp, cic phddng p h i p h o i n thien gieng tai be Cdu Long gdm: md via bang chdng dng, tram xi mang va ban due Id dng chdng (dupe ap dung chu yeu tai cac md Bach Hd, Rdng, Ruby - Pearl, Rang Ddng - Phuong Ddng); md via t h i n tran ket hdp lUdi chan c i t (dUdc i p dung chu yeu tai md SuTdDen va mdt sd gieng khoan md Rang Ddng - Phuong Ddng).
Cdng nghe hoan thien gieng ddn va cdng nghe hoan thien gieng kep:
Cdng nghe hoan thien gieng ddn dupc sd dung chu yeu tai cic md va cho hieu qua khai thac cao.
Cdng nghe hoan thien gieng kep dupe Petronas ap dung thanh cdng tai mdt sd gieng khai t h i c md Ruby, Pearl de khai thac rieng blet cac tang sin pham. Cie gl^ng h o i n thien kep deu cho sin lupng khai t h i c dau cao hon cie gieng hoan thien don khi khai thac cung ddl tupng san pham. Dieu nay da dUOc minh chUng tai 2 gieng RB- 1P, RB-2P sd dyng hai cdng nghe h o i n thien gieng khic nhau de khai thac cung ddi tupng chinh Mlocene-9 va Mioeene-10 (Bing 3, Hinh 7 - 9) [1 ].
G i e n g k h o a n edngap 1/2006 nudc(%) 1/2007
BH-1 49,1 79,9
Sdng 2. Bg ngdp nudc cua cdc gieng crkhu vifc tmng tdm n BH-2
55,2 24,9
BH-3 0 64,2
BH-4 23,1 67,3
6 Bach Ho BH-5
74,9 70,2
BH-6 2,5 76,4
BH-7 14.5 46,9
Gieng Kieu hoan thien Ddi tupng khai thac chinh
Luu lupng dau khai thac trung binh (thiing/ngay) San luang dau khai thac cpng ddn (trieu thung) Op ngap nudc trung binh (%)
Bdng 3, Bdc trung. sdn iUong khai thac ddu cua gieng RB- IP, RB-2P RB-1P
H o a n t h i e n k e p MiOcene-9; fVliocene-10
800 0,95
RB-2P Hoan t h i e n d o n Miocene-9; (VIiocene-10
500 0,7
THAM DO - KHAI THAC DAU KHI
Nhuvay, SO vdi gieng h o i n thien don RB-2P, gieng hoan thien kep RB-1P cho hieu suat khai thac tdt hon. Ket q u i khai t h i e cho thay do n g i p nUdc cua gieng RB-1 P sau khi tang eao (tren 20%) thi den nay ehi cdn khoing 1 % va lUu lUpng khai t h i e on djnh vdi tren 500 thung/ngiy.
Ddl vdi gieng RB-2P, dp ngap nadc hien nay khoang 15%, tuy nhien lau lupng dau khai t h i c thap (dudi 100 thung/
ngay). Do Uu diem eda gieng hoan thien kep, Petronas da ap dung bien p h i p hoan thien gieng n i y cho cac gieng mdi dUa v i o khai t h i c cCia md Pearl. Ket q u i cho t h i y gieng cho sin lUdng dau khai t h i c cao (tren 2.000 thiing/ngiy). Petronas dang tiep tue nghien cdu i p dung cdng nghe h o i n thl&n gid'ng kep cho cac gieng p h i t trien khai t h i c s i p tdi, dac biet tai cae khu v\Jc cd nhieu tang san pham va cd tfnh chat via tdt.
Cau true h o i n thien gieng don va h o i n thien gieng kep dien hinh tai cac gieng khai thic md Ruby, Pearl dupe the hien tai Hinh 10 [2].
Cdng nghe hoan thien gieng sd dung ludi chSn cat ddc lap:
Trong qua trinh khai thic, hien tUdng eat khai thac xuat hien tai nhieu gieng md Ruby, Rang Ddng, Rdng. Ddi vdi cie gieng khdng l i p dat thiet bi kiem soat cat d giai doan dau phat trien md, phai g i i m chenh i p de han ehe c i t x i m nhap. Bien phap nay chi mang tfnh tinh the vi i i m giam lUu lupng khai t h i c va hieu qua kiem soat cat khdng cao. Vi vay, cae gieng mdi p h i t trien khai thic g i n d i y {ed nguy cd khai thac c i t cao), dupe de xuat lap dat thiet bj kiem soat c i t de ngan ehan c i t trong sin pham khai thac.
Cae gieng sddung ludi chen sdi tai md Ruby, trong qua trinh khai t h i e cho thay hieu q u i khdng cao, khdng ngan dupe hien tapng c i t x i m n h i p v i o gieng v i g i i m hl^u q u i khai thac. Gieng R-3P md Ruby sau khi ddde l i p dat lUdl chen sol va tien hanh xd ly acid, san lUpng khai t h i c t d tren 1.000 thung/ngiy g l i m xudng chi 16 DJiU KHi-SO 12/2014
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cdn khoang 600 thCing/ngiy, sin lupng hien tai cua gieng chi cdn khoing 400 thung/ngiy (Hinh 11) [3].
PhUPng phap kiem soit cat sd dyng eho eac md d khu vue la sd dung ludi ehan c i t ddc l i p v i sddung phUPng phap chen sdi. Ludl c h i n c i t ddc l i p la g i i i phap tdt nhat cho eic via Miocene tai cac md eda Cuu Long JOC,
PETROVIETNAM
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W/nft 70. Cong nghe hoan thien gieng dan (ben trdi), gieng kep (ben phdi) tai mo Ruby va Pearl
Hinh 11. San luang khm thac cua gieng R-iP, mo Ruby
6ng l(?c qudn ddy (WWS dng loc dang ludi IPS) Hinh 12. Cdu tao liten chdn cat dgng qudn ddy (WWS), dang lilcn (PS)
JVPC, Petronas. Cic gieng khai thac tai d i y dUdc lap dat ludi chan c i t ddc lap va trong q u i trinh khai thac khdng xay ra hien tUdng cat xam nhap vao gieng.
Phuong phap chen sdi dUoc ap dyng tai mot sd gieng md Ruby da lam tang he sd skin va g i i m hieu qua khai thic.
Ladi c h i n c i t ddc lap sd dyng ludl Ipc d trudc khoing khai thac, ed the ap dung trong hoan thien gieng than tran va gieng chdng dng. Khac vdi lUdi chen sdi, khoang khdng vanh xuyen gida lUdl va gieng khdng chdng dng (hoic da chdng dng) rdng.
Cd 2 loai lUdi thdng thadng dupe sd dyng la: dng loc quan day (wire wrap screen - WWS) va dng Ipc dang lUdl (premium screen - PS) (Hinh 12). Ong Ipc quan day (WWS) gdm 3 bd p h i n ehfnh: dng dye 16, thanh cai (support rod) va day quan (wire w/rap).
6ng loc dang lUdl (PS) cd 5 bd phan chfnh: dng dye 16, Idp thi'm thau (drainage layer), Idp Ipc trung gian (filtration layer), Idp Ipc tang cudng (filtration enhancement) va Idp bao ve ben ngoai (outer shroud). Ong Ipc dang ladi cd Uu diem la dd ben va k h i nang kiem soat c i t cao, song g i i t h i n h cao hdn dng Ipc quan d i y [6].
Chde nang chinh cua ladi c h i n cai la b i o ve va ngan ehan cat, tao nut chan va chdng xoi mdn.
Hien tUdng xdi mdn g i y ra do ddng c h i y chat lUu tap trung trong lUdi, khi khoang glCfa ludi va gieng OAunil-Sd 12/2014 17
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Thiet bIbO trir nhlit Quantum packer Nipple "XW'4«' Quantum paclfer 6ng ching 9-5/8' Lutlri chdn cdt Mc l^p (premium) Packer tri/ang nd Phiu hi/ing cSdng Hinh 13. Cdu true hodn thiin giing cd siid{ing iifdi chdn cdt ddc Idp toi
mdSuTHSen
Hinh IS. Cdu trdc hodn thi(n glfng eda giing SD-1 A, md Su TiBen 12]
Hinh 14. Sdn iuong khai thde ddu eua gieng SD- IA, md SuTii^Ben than tran/gl^ng chdng dng cd dp tham cao khi^n ddng chiy co tdc dp cao.
LUdi ehin e i t ddc l i p ed g i i t h i n h t h i p , d5 thi^t k^ v i l i p dit hPn so vdi lUdl chin c i t chen sdi. Vi§c sd dyng ludi c h i n c i t ddc l^p trong h o i n thifen gl^ng t h i n tran cd t h ^ eung c i p k h i n i n g d i n tdt hPn. CSu trdc h o i n thidn gl^ng sd dung ladi c h i n c i t ddc l i p dUpc t h e h i & n t r g n H i n h l S .
2.3.2. Ddi ti/gng mdng ndt ni
Packer trUOng nd daoc nghi&n cdu v i sCf dung tai bl^n Bic Na Uy t d n i m 2001, ed t h ^ hoat ddng trong eic di^u kien mdi tradng nhl§t dd, i p suit cao hoac cd t h ^ ap dung vdi eic gi^ng dOn than, da thin... Hi^n nay, packer tradng nddupc sddyng rdng r i l tr&n th^gldl v i eho t h i y k h i n i n g b^n nhl&t va chiu i p suit cao, k h i n i n g l i m kfn tdt, cich ly tdt khoing n g i p nadc v i mu khf.
Packer truong nd da dupc dng dung t^l nhi^u gl^ng md SUTd Den, SuTCf Ving, C i NgdVang, Rang Ddng... K^t q u i eho thcfy gl^ng dupc khai t h i c dn djnh hon, kl^m soit hi^n tupng n g i p nadc tdt trong q u i trinh gi^ng v i n h i n h khai t h i c .
Cdng ngh& packer truong nd ngan cich t i n g ng^p nudc d i dUpc i p dung tai nhi^u gl^ng khai t h i c md SUTLT Ben. Trong dd, gl^ng SD- 1A thl^t k^ sCrdyng 2 packer traong nd t^i t h i n t r i n ctia gi^ng nhim dn djnh bd thigt bj Idng g l l n g v i n g i n cich, t^o ra c^c khoing khai t h i c rlfing bl^t (Hinh 15). Cic t h i l t bj t u i n h o i n dUpc sd dyng t?l khoing giufa 2 packer 6i t h u i n tl$n di4u chinh luu lupng v i ddng/
md khoing khai thic, n i n g eao hi^u q u i khai thic. Khi khoing khai t h i c phfa dadI b| ng^p nudc, ehi c i n ddng v i cich ly khoing khai t h i c niy, g i i n g vdn cd t h i t i l p tyc khai t h i c d tSng t r i n .
Trong q u i trinh khai t h i c g i i n g SD-1 A, h i m lUpng nudc trung binh duy tri 6 dudi 15%, luu lupng d i u k h i cao d?t trfin 3.000 thung/
ngiy. LUu lupng d i u khai t h i c cua g i i n g SD-1 A theo thdi gian dupc t h i h l | n t r i n Hinh 14 [3].
PETROVIETNAM
3. Kdx luan
Do t i n g Miocene v i Ollgocene taong ddng ve dac diem dja chat nen cSu true hoan thien gieng khai t h i c it hai tang trdn gidng nhau. Tuy nhien, dat d i d vung Miocene cd dd rdng cao hdn, d§ bd rdi nen thudng x u l t hi^n c i t trong qua trinh khai thic. K i t q u i thdng ke tai b l Cdu Long eho thay, eic md ed dd rdng > 19% de xay ra hif n tupng e i t x i m nh?p v i o g i l n g khai thac. PhUdng p h i p sddyng ladi chin c i t ddc lap giup kiem soat eat xam nh^p. Cdng ngh^ h o i n thl^n gieng kep dapc Petronas ap dyng t?i mdt sd g i l n g cua md Ruby, Peari de khai thac nhieu t i n g sin p h l m dat hieu q u i cao. Do dd, can xem xet dng dyng edng ngh? nay cho cac gieng mdi phat trien khi khai t h i c t^i khu vac cd d i e diem tuong ddng.
Cic g i l n g khai thac tai ddi tUdng mdng ndt ne chu y l u ap dung phUdng phap hoan thien gieng t h i n tran.
Phuong p h i p kiem soat hien tupng ngap nude tai cic g i l n g khai t h i e eCia Vietsovpetro phd bien la dd cau xi m i n g de cich ly khoing ngap nude ben dudi, sau dd tien hanh b i n via d l khai t h i c khoang phia tren. Ngoai ra, packer trUPng nd cung dupe mdt sd nha thau i p dung de kiem soat hieu q u i hi^n tapng ngap nudc.
Bii b i o la k i t q u i nghidn cdu thu dupe t d vide thuc hi^n Hpp ddng sd 02/KKT/2010/HD-NCKH.
T i l l i l u tham k h i o
1. Vu Manh Hao va nnk. TSng kit ddnh gid cdng tdc hodn thien gieng khai thde tqi bi Cdu Long. Viin D i u khf Vilt Nam. 2012.
2. Bdo cdo hoan thiin giing (Well completion report.
Completion procedure, end of well report) cOa cdc giing khai thde tgi be Cdu Long.
3 Sdn lugng khai thde. Bio c i o khai t h i c djnh ky (ngay, t h i n g , nam) cua cic g i l n g md SuTdDen, SuTd Ving, Ruby - Peari, Rang Ddng.
4. Nguyen Hai An va nnk. Nghiin cdu tai Uu quy dao vd phuong dn hodn thien giing khoan khai thdc/bom ip dp dung cho thdn dau mdng ndt ni mo Bgch Ho. Vidn Dau khf Viet Nam. 2009.
5. Bdo edo phdt triin mo (ODP, FDP) cdc md tgi biCdu Long.
6. Jonathan Bellarby. Well completion design. 2009.
Lessons learned from well completion practices in Cuu Long basin
Vu Manh Hao, Le Quoc Trung, Le Vu Quan Vietnam Petroleum institute Summary
Cuu Long basin is the area where many discoveries of oil and gas have been made and put Into production such as Bach Ho, Rang, Rang Dong, Su Tu Den and Su Tu Vang, etc. The geological characteristics in the area is not very complex. However, some damages have happened during production, especially the migration of reservoir sand and fines into a wellbore, water breakthrough, and paraffin deposition which can shorten the lifetime of a well, increase operating costs, and decrease well profitability.
This paper reviews the current application of well completion technologies In the Cuu Long basin and draws lessons for well completion design and execution and technology application In the future.
Key words: Well completion, Cuu Lorig basin, sand production.
OAUKrf-SO 12/2014
