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PETROVIETNAM Nghien cCru lua chon dung djch khoan cdc gieng ddu khi trong dieu kien dp sudt cao nhiet do cao TS Pham Quang Hl£u Bgi hgc fljfd Dja chdt ThS Truong Hodi Nam Tdp dodn Ddu khi Viit Nam Tro[.]
PETROVIETNAM Nghien cCru lua chon dung djch khoan cdc gieng ddu dieu kien dp sudt cao - nhiet cao TS Pham Quang Hl£u Bgi hgcfljfd-Djachdt ThS Truong Hodi Nam Tdp dodn Ddu Viit Nam Trong qud trinh thi cdng ede giing khoan khai thdc ddu d dieu kiin nhiit dp sudt eao - nhiit cao, chdt luang vd khd ndng tdi mun khoan eua dung dich khoan: nhdt, thdi nUde, tinh chdt luu biin bf dnh hUdng rdt nhiiu Thue tiddi hdi phdi cd hi dung dich ddp Cfng duae ede yeu cdu cua edng tde tdi mun khoan khdi ddy gling diiu kiin nhu vdy Bdi bdo nghiin cUu sU dnh hu^g trin ccfsddd nghiin cijfu dixudt cda dp sudt cao - nhiit dd cao tdi tinh chdt eua dung djch khoan, logi dung dich khoan phd hap thi cong diiu kien ndy ChuTc nang cua bOm ruTa gieng khoan Cac chyc nang chinh cua dung djeh khoan Id ldm sach Lap mat e l t nhiet gieng khoan Van de chu y i u de nhin b i l t bdn chat eCia dung dich mun khoan d ddy va dUa mun khoan len mat dat; tao nen khoan HPHT Id lap mo hinh mat elt nhi&t theo than gilng cot dp thuy tTnh can bang dp suit via; Idm mdt bd khoan t i t ed cae giai doan khoan Lap mo hinh khoan bat cu va g\\i d\iac hat mun d trang thai lo lyng ngi/ng d l u ty md hinh gieng, dd gdm cd mat elt nhiit t u I n hoan Khoan va hoan thien gilng cac d i l u kiln cac khoang than gieng khac vd nhiit tUOng dp suit day cao vd nhiet dp cao (HPHT) la hoat ddng vd yng cCia ddng chay ciing khd khan vd phUc tap Nhiet dp d ddy gilng la mdt nhC^g yeu td q u y l t djnh, cd anh hudng d i n tinh chit luu b i l n vd dp thdi nUdc cua dung djeh khoan qud trinh khoan B l nhan b i l t day dO ve anh hUdng cCia nhiit dp d i n q u i trinh khoan, can b i l t nhiet dp cua dung djch tren day Dung djeh khoan di chuyen theo thdn gilng, t i l p nhan nhiit t y mdi trUdng xung quanh va tda nhiet vao mdi trUdng (Hinh 1) MUc dp trao ddi nhiet phu thudc vdo nhiet dp va van tdc ddng chdy cua dung dich, tinh d i n nhiet cda via, gradien dia nhiet via nguyin trang, t j nhiet dung cua dung djeh vd cdc y i u td khde gieng cung nhu quy luat bien ddi nhi&t dp thdi gian Khi dung djeh chdy vdo gilng se xdy sy truyen nhiet tuIn hodn Ty dd, xac djnh mdi lien quan giya nhdng ehl thuan ty via eho dung djeh khoan Khi den chodng sd ndy, phat hien cac quy luat va dnh hudng cua chung khoan, dung djeh khoan van eon lanh hon mdi trUdng dat tiep theo qud trinh tram xi mang cdt dng chdng da bao quanh via Khi dung djeh ddng len mat, dung dich Tuy nhiin, phu thudc vdo dp suit ddy va nhiit dp ma tinh c h i t cua dung djch khoan thay ddi, dnh hudng khdng tdt d i n vile xac djnh ehinh xac ty- trpng vd dp nhdt cOa t i l p tuc dupc thu nhiet cho d i n mdt d i l m - tai nhiet dp eCia via va dung djch cIn bang.Tytren d i l m ndy, ddng t i l p len mat, dung djch khoan se ngudi dan dung dich khoan tren mat cOng nhU d i l u kien b Thdng thudng giai doan dau bOm rya, nhiet day Trong cac gieng HPHT, sU thay ddi cd the bj han dp la thap nhlt Sau do, nhiet tang l l n d i n eho d i n c h l vi su an toan khdng cho phep Vi vay, dy bao nhCfng dat d i n trj sd tdi da nhat djnh va tri d i n cudi giai hilu ung cd y nghia q u y l t djnh ddi vdi k i t q u i khoan doan bom rya D i l u eho thiy, lUc b i t dau bOm rCfa, gieng HTHR Mat khac, nhyng sai sd quan ndy phan than gieng d ben tren dung djch t u I n hodn tinh toan dp suat dung djch khoan khodng cCia via trang thdi ndng vUa, sau dd nhiet dp ciia dung djch cd the bj bd qua, liin quan den hoac la nhiet dd hodc la tdng nhanh va tiep theo sU xuat hien dung djch vdi nhiet vdi cac tinh chat cua dung djch khoan dp cao hon Rd rang, nhiet dp tdi da dUpe xde dinh t y DSUHHI 507/2012 25 THAM DO - KHAI THAC D A U KHl Ml '^1 i i Hinh Tinh chdt cua nhi^t dd khdng xde dinh - nhl$t d$ dung djch khoan cIn khoan vd khodng khdng vdnh xuyIn, giCfa c^t cIn khoan vd 6ng chdng Trong khodng thdi gian gida t u I n hodn dn dinh va cdc d i l u ki|n tinh hpc xlc djnh, ta cd cle mIt elt nhiet thay ddi theo thdi gian (Hinh 2) Khi ngung t u I n hodn t r i n 24 gid, nhiet dp cua dung djeh khoan khodng vdnh xuyIn ngoai dng gin bdng gradien dia nhiit Sau thao tdc k l o - thd sutuSn hodn Idm dung djch lanh nhanh t r i n ddy (dUdng 1), dd n h i i t dp cda dung dich khoan t y day ding len mSt tang l l n (dUdng cong 2) Chilu slu b i t d l u ty d6 ngufii dan, thay ddi theo l l n t r i n theo thdn gilng vdi thdi gian Hinh Mat cdt nhiit cua dung dich khoan d i n khodng g i n 1/3 c h i l u slu t r i n ddy (dUdng 3) Sau khodng gid, dung djch t u I n hodn dung djch dat den dn dung djch t y t r i n day gilng chdy ra, ed nghia Id chat Idng b I n g ddng lUc, khodng thdrt gian dd mat cdt nhi^t rda gilng t u I n hoan dd hodn thdnh mdt nda chu ky (theo dp v l n giy nguyin Mudn vly, de dy bdo dp suit ddytdng chieu dai dudng) Thdi gian xuat h i i n diem cue dai nhi|t sau b i t d l u khoan, eIn t h i l t x l y dyng md hinh bSn dp phu thudc vao cdng suit eua mIy bom, dudng kinh c h i t n h i i t dd chua d i l u chinh gilng va chilu sau gilng Mat dd vd dd nhdt eua dung djch khoan thay ddi theo thdi gian SU thay ddi ndy c I n dupc b i l t chinh xac de tinh dp suit tTnh vd dp suat ddng tai mdi khodng khoan [1] Mat elt nhiet dp cd the xde djnh dUoe bIng cdch tao V I ly thuyit, sau ngimg t u I n hodn yeu elu khodng 16 gid d l nhiit dd dung dich khoan dat d i n khodng 10% gradien dja nhiit, dd n h i i t dd dung djeh khoan t u I n hodn chi eIn gid d l edn bIng [1 ] Oudng bilu di^n nhiet dd cIn d y bdo nhiit dd d l ed t h i tinh dp suit dif lap md hinh tuong Cfng Theo thdi gian, sucan b I n g nhi^t bom vd sau thay ddi lUu lupng bom Nlu h6 ed t h i tinh bdng hai phuong phap: sau dung djch sd an todn khdng Idn, sy gidm dp suit tinh sau ngC^jg ngyng tuIn hoan hole cac dieu kiln t u I n hoan khdng t u I n hodn ed t h i dat tdi han Sau I l p duac mat cjt thay ddi Mat cat nhiet dd dn dinh se g i n bdng vdi gradien n h i i t dO gieng khoan, cdn cy vdo tuong quan giOa m l t ^ dja nhiet, dd mat elt nhiet t u I n hoan thay cue bd, dp suit vd n h i i t dp cd t h i tinh mdt dp dung d p ddi phu thude vdo nang suit bom h i l u dung Tren hinh ve mat elt nhiet t h i n g ddng dng M^t dp dung djch t u I n hoan tuong dUong (Equiy^ chdng vd cdt cIn khoan xd ly theo p h l n m I m MudCADE Circulating Density - ECD) g i l n g HPHT t h U d n ^ cua Dowell Sd lieu d l u vao - la ty n h i i t dung vd dp hon mdt it so vdi m I t dp dung dich h i l u dung kh^ dan nhiit cua tyng thdnh phan, cdn cdc sd lieu chinh d l u vdnh xuyen giCia cIn khoan vd thdnh gieng (Hinh 3).|| I 26 OAU KHi-sd 7/2012 PETROVIETNAM tinh theo sd dp nhdt cCia dung dich khoan nhat dinh Tfnh i p suat day cua dung djch khoan khdng gian vdnh xuyIn va tang l l n tdng luu lupng mdy bom, Cac phUPng phdp tinh ndy ed phln phyc tap hon nhdt thay ddi theo nhi^t dd e l tinh dp suit thCiy lye ddy l l n via gilng HPHT dupe chinh x^c, thay cho sCr dung m|t dd dung djch hilu dung vd mdt dp dung djch tuIn hodn tuong dUOng (ECD), Mat dp tuong duong eua dung djeh khoan t u I n hodn ta sd dung dp sudt tinh (P,), dp sudt ddng (P^) cya dung la t^ trpng hieu dung eua dung djch khoan dang t u I n dich vd dpsudtcdamun khoan {PJ - day Id cdc thdnh p h l n hoan d mdt dp slu n h l t dinh gilng khoan; thUdng cOa dp suit tdng ciia dung djch tde ddng l l n ddy gilng Idn hon v} trpng dung djch tren mdt, tdn t h I t dp Ap suit tTnh ciia dung djch khoan vdi ehIt Idng gde dupc suit eho ma sat khoing vdnh dng vd myn khoan p h l n tich theo nhiit dd - t h i tich - dp suit (PVT) Dung l l n dung dich Theo ddi ECD tr^n ddy nhd ed dyng djch khoan cd gdc chit Idng hydrocarbon cd tinh n i n cao cu dp suit khoing khdng vanh xuyIn qud so vdi dung djeh gdc nude trinh khoan (APWD) giup cho viec du bdo phyc tap qud trinh rCfa gilng trUdc x u l t hien ket [1] ECD = d+—-— 0,052D Trong dd: d:Trpng lUpng rieng (ppg) ciia dung djch Ap suit thuy tinh ciia cdt dung dich khoan gilng khoan Id yeu td quan nhlt, nhd dd chat luu via khdng phut len mat d I t ndi them cIn khoan, thao tdc klo - thd, thdi gian ngyng bOm vd md ddi dp tdng khdi lupng ri^ng ciia dung dich khoan se ndng cao sy dn djnh cya gilng P: Ap suit (psi) khoing khdng vanh xuyIn D:Chilusau(ft) Trong thdi gian t u I n hoan, sy gia tang dp suit d l t h i n g ma sat khoing khdng vdnh xuyIn vd bom dung dich khoan t y chieu slu n h l t djnh l^n mat, la tdn that dp suit ngoai dng (APL) APL tang len tang lUu lupng bom va nhdt eCia dung djch, bd sung eho dp suat thuy tTnh, tang dp suit day tdng l l n thdi gian t u I n hoan Luu lUpng cda may bOm khdng dUOc g l y I p suat dung dich khoan Idn hOn dp suit nurt via Moi tri sd luu lupng bom cd the tinh dUoc mat tUong duong cua dung djch tuan hoan d l ed dupc tdng dp suit nhu t h i tai chilu sdu nhat djnh Bdi vi tdn that dp suit phu thude vao dp nhdt va cac tham sd hinh hpc cda gilng vd hieu b i l t v l ECD rat can t h i l t dp nhdt dUOc xac djnh chinh xac APL cd the lap md hinh phu thudc vao lUu lupng may bom dung djch Ap suit tinh d day dupc xac djnh theo ty cua dung djch khoan tren mat dIt, dd dp suit bd sung xult hien qud trinh tuan hoan, cd the xac dinh tuong quan giya luu lUOng dung dich khoan vd cdc tinh chit luu bien cua dung dich Mdt dp eua dung djch cd t h i b i t d l u tinh tUtr^n mIt, nhd tryc tiep dp suit vd nhiit Ap suit thOy tinh dy bao va nhi|t dp eho phep tinh ty trpng tiep theo ehilu sau gilng Tren khoan trudng n i n ty trpng eiia dung djeh de nang cao chinh xle cac sd lieu ban dau Cung vdi cdc sd lilu PVT, ta cd the tinh dUpc dp suit thuy tTnh tai mdi chieu slu nhd bd phln m I m Dowell MudCADE va DSHyd Ap sudt dong bao gdm tdn t h I t ap suit ngodi dng chit Idng trdn lan nhau, van tdc ehuyen dich cdt can (hilu yng pittong) vd dp suit quIn tinh xuat hien keo thd cdt cIn vd dp suit dude pha hCiy gel xuc biln (Hinh 4) Khi djeh ehuyen can khoan chit long nhdt sinh sy trUpt Idp gidi han liin k l vdi dng, tao Cfng suit trupt chat Idng U'ng suit trUpt bang hieu sd DP chat Idng, nd dupc bd sung vdo dng suit thCiy tTnh (a) Ap suit day giam di nlng can "hut theo"(b) vd tang l l n thd can "day" (c) Nhyng sU biln ddi dp suit phu thudc vdo dd nhdt cQa chit Idng, ede thdng sd hinh hoe eua gilng vd van tde nang dng Khi keo cIn vdi van tdc Idn, cd t h i g l y hien tUpng sut dp suit gieng dudi dp suat thuy tTnh, dan d i n phut khL Nguoc lai, Hinft 3.fi/ldtdo tuang duang cda dung dich khoan tuan hodn (ECD) thd dng vdi van toe qua Idn, se lam tang nOft vd thCiy lye Diu KHi sd 7/2012 27 T H A M DO - KHAI THAC D A U KHI dp suit t u I n hodn l l n chodng khoan VI v^y.^j} suit tii miin khoan cd t h i khdng e h l blng su thay ddi v l n tdc khoan Ap suiSt tSng (P^) dupe tinh: Trong dd: P.,: Ap suit thCiy tinh P^: Ap suit d0ng P^: Ap suit mun khoan Ap suit tdng ed t h i c I n bdng gida dp suit Hinh Hliu ung pittong via Ldp md hinh cdc yng sudt ddng hi|u dng pittong eho ph^p xde djnh v l n tdc an todn thao tdc k l o - thd Mudn d u bdo thdnh p h l n dp suit ddng dp suit tdng cIn xly dUng md hinh luu b i l n cua dung dich khoan Mdi tuong quan ciia Ung trUpt vdi v l n tde trUpt vd xde djnh dd nhdt ddng vdi mdt vdn tdc trUpt n h l t djnh tTnh an todn t h i p n h l t vd dp suit tuIn hoin dat eao n h l t dat d i n cdc d i l u k i l n c l n bSng tuang yng khde Ap suit t h i p n h l t dat dupc cIn khoan k l o l l n khdi ddy bom sach mun khoan d ddy Ap suft cao n h l t khoan vdi luu luong bom cao, v l n tdc co hpc khoan eao, ngyng t u I n hodn hodc thd cdt can via dung dich cd dd nhdt eao vd nhiet dp, cd nhieu d i l m khde Tuy theo loai dung Trong khoan, cdc tinh c h i t cua dung djch c6tM dich eu the ta lua chpn md hinh luu b i l n tuong yng, t r i n thay ddi theo thdi gian den mdt gidi han ndo dd de c6 the CO sd d i l u ehinh dudng cong luu b i l n doi vdi cdc nhdt thay ddi md hinh lUu b i l n da chpn ban d l u CIc tinh chSt k l thi nghiem n h l t dinh d i l u kien HPHT Vd ngUOc eiJa dung djch thay ddi tam thcrf ed the xly ciing lai, tinh chit cda dung djch khoan cd t h i phii hpp sy mdt c h i t Idng vda ddng thdi Id dung dich theo mo hinh phu thudc nhat djnh kieu md hinh c h i t Idng d I o Bingham hdm sd mu, vdo thdi d i l m khlc - la chat Idng dIo Bingham, hole md hinh ham sd mu vdi cdc thdng sd da lua ehon d l ke cd cung mdt khodng khoan gieng Cd the H&i tao cac tinh c h i t dung djch khoan theo y i u c l u hdnh so sdnh bdn c h i t thuc t l ed hai md hinh trUetilpt^ Chuong trinh phan mem Dow/ell DSHyd vd MudCADE gdm t h u l t toan de tinh ap suat ddng t r i n co sd md hinh chat Idng d I o Bingham hole md hinh hdm sd mu Uu diem cua chung la cho cdc thdng sd luu b i l n d l so sanh vdi cac sd thdng sd duoc tai khoan trudng vdi cac nhdt ke thudng diing Ap sudt miin khoan - mdt thdnh p h l n bd sung eua dp suit tdng, xle dinh bdi su tieh tu mun khoan Mac du khoan gilng HPHT vdi dung dich cd ty trpng cao vd cd xu hudng gidm tich tu miin khoan, nhung dp suit miin khoan phan dp suit tdng cua dung dich khoan khdng the bd qua Bdi vi miin khoan ed t^ trpng Idn hon dung dich khoan, cho nen moi sy tich tu mun khoan khoan trudng va chpn md hinh tdt n h l t - cd Uu dilm la de d u bao chinh xde tdn t h I t dp suat khodng kh6ng vdnh xuyln.Trong thyc t l , phdm m I m DSHyd thudng cho sai sd trung binh giya dp suit dU b l o vd dp suit trin dudng dng khodng 2% K i l m sodt dp su£t Nguy hiem ehu y i u Id khoan cdc gilng HPHTIifin quan vdi dp suat via di thudng eao Ly tudng nhlt doi vS nhUng g i l n g ndy n i n khoan vdi dung dich khoan c6 mSt d0 tuong ddi cao, vupt dp suit 16 rdng Khi dd, dung djch khoan ehl eIn du d l gidm thieu n h i l m ban via vd nSng eao v l n tdc ca hoc khoan l l n tdi da gilng cung dan den sy gia tang ty cua dung Via cd dp suit dj thudng cao trd thdnh phyc tap kh' djch Ap suat mun khoan phu thudc vdo van tde CO hoc dp suit ndt via thuy lye tai vOng tuong Cfng g i n bSng ip khoan, nlng suit bom, kich thUdc vd sy phan bd hat mun Khi t i n g van tdc khoan se cang tieh tu nhilu mun khoan va tao cac hat cd kich thUdc Idn vd l i n g suit di thudng D i l u dd d l xdy x u l t hien v l gay n* via thuy lye, dd se xdy m I t dung djch khoafi kh6 k i l m sodt nhanh Mac du cd^the han c h l sUgia tang va lang k i t miin Thdng thudng eIn cd g I n g tranh nut thCiy lycv| khoan bIng each tdng luu luong bom, song se lam tdng nhung d nhCfng ehilu slu tdi han thi chenh lleh [ip 28 DlUKHi-Sd7/2012 PETROVIETNAM suit an todn) giOa dp suat 16 rdng vdi dp suit nyt thuy lUc suit tdng cd the dy bdo nhd cd bd phan m I m DSHyd via, mpt so gilng khdng Idn l l m - khodng 3,4 MPa hole MudCADE Khi t h i l t k l gilng ed the xac djnh va sCf Neu nhu ap suat tdng g i n bdng dp suit nyt thuy lye via, dung vdn tdc tdi Uu cdc thao tdc klo thd thi dau tien can gidm dp suit ddng O^ d i l u chinh ap suit tdng, CO t h i d i l u chinh gia tri nhdt, t;^ trpng eua dung djch, hdm lupng pha rIn, lUu lupng mIy bom vd vdn tde CO hoc khoan Chinh xle hda gia trj ap suit du b l o dUa tren cdc sd lieu tai gieng, cd t h i ehpn mdt cdch tuong ddi ede thdng sd, d l tri eac tinh c h i t dung djch khoan d day Mudn vdy, cd the gidm bdt lUu lupng mdy bOm hoac dd nhdt cua dung dich, ddng thdi tri luu lupng mdy bom d mdc cao cho phep de rda gilng vd gidm dp suit miin khoan V l n d l chii y i u la tim gid tn tdi Uu luu luong may bOm d l gidm thieu dnh hudng ciia dp suit ddng vd dpsultmUn khoan De d i l u chinh I p suit ddng bdng g i l m dd nhdt dung djeh khoan, nhat thiet phai theo ddi chat che phu gia Idm LUu lupng bam - Luu lupng tdi t h i l u cua mdy bom bom rtfa gilng thudng khdng Idn sy ndi cua mijn khoan dung dich khoan cd t^^ trpng cao Vi vay khoan cdc gilng thing dyng HPHT bom rda than gilng thudng khdng phli la yeu td tdi han va tUu lupng bPm cho cdc gilng nhu t h i dUOe nhanh chdng xac djnh bdi cdc y i u td khde Mac du lUu lupng mdy bOm t h i p tri ECD thip, chuong trinh khoan cdc gieng cd t h i y i u c l u lUu luong bom Idn hon d l rut ngln thdi gian xdi rda ddy vd d l kip thdi t i l n hdnh phln tich thach hoe mun khoan, chl sd va pha rln ciia dung djeh khoan Phuong ^n tdt n h l t Id t h i l t k l dp suit t r i n d l u cCia may bOm t h i p hon cdng suit cua t h i l t bj khoan Dieu eho phep sd dung sU t i l u I m ddng va tang dang k l dp suit ddng nhd nang cao van tdc ddng chay khoing khdng, cang cd the sy dung t i l n hdnh ede bien phap v l kilm sodt gilng nang ludn d trang thdi lo Idng Khi pha rIn cua dung djch khoan tao thdnh huyin phu se xdy sy phan Idp theo ti trong, hien tupng iang k i t Su tao nut pha r l n la mpt tinh hudng g l y phUc tap tren day khdng kilm sodt day dy dp suit ddy Mat dp eua dung djeh tang dot ngdt ed t h i gdy cac khe nCft khdng lUdng trUdc va lam mat dung djch, luc dd n l u mdt dp ciia nd thap kich thich ddng chdy cua chat luu vd lam m I t dn djnh gilng Sy ling k i t dung djch cd the xdy cac dieu kiln ddng cung nhutTnh, LUa chon dung djch khoan Dung djch khoan dupc sy dung khoan cac gilng dau thudng gdm cd: - Dung djch khoan goc nUdc gdm: dung dich khoan khdng phdn tan; dung dich khoan phdn tdn; dung djch khoan hoat tinh eanxi; dung djch khoan gdc nudc hilu qud cao; dung dich khoan ham lupng pha ran t h i p ; dung djch khoan polime; dung dich khoan gde nude mudi (khodng) nhUng khdng lau sau no xdy ele dieu kien van tdc trupt thap d i n dat dupc dp nhdt tTnh - Dung djch khoan gdc d l u md gdm: nhu tuong "dlu nudc"dd la nhu tUOng d l u - nUde; dung djch khoan Gidm dp suit tdng bang each d i l u chinh dp suat tTnh d l u md cd the thuc hien nhd he sd an toan dp suit, Idn hon dp suat 16 rong Khi gilng d giai doan tdi han, he sd ndy - Dung djeh khoan tdng hpp, cd tinh c h i t tuong t u cd t h i gidm hem nda theo thdi gian vdi dp suit tuan hoan nhu dung djeh gde d l u , nhung rat it t i e hai d i n mdi bd sung, ngan ddng phun Sau do, trUde t i l n hanh keo trUdng thd, eIn thay dung djch gilng bIng dung djeh dac hon Trong nhdng trudng hpp t u y l t ddi t h i n tiep cIn khoan, bdi vi khdng cd dp suit ddng de xdy gieng phun (thdng vdi khQ Khi keo - thd cot can khoan phdi t i l n hdnh d l u deu, Moi mpt loai dung djch cd Uu d i l m v l gia thanh, tac ddng d i n mdi trudng va dac tinh khoan Trong 10 nam gan day, dung djch khoan gdc fomiat' (mudi eCia axit focmic H.COOH Fomiat natri, kali vd xezi) dupe sCf dung nhilu dung djch khoan Trong gilng nhe nhang, han che tdi da thao tde g i l t Can theo ddi iUu HPHT thu hep d i n dung djeh khoan truyen thdng dya lupng mdy bom thay the dung djch ty trpng thap hon vdo gdc halogen Chat long chda halogen nhiet dp bang dung djch ddc hOn trudc thd can khoan NhU eao se gay an mdn rat manh t h i p va tac dpng xau d i n vly, thdi gian keo thd ap suit miin khoan se bang mdi trudng xung quanh Vdi trj sd kiem pH cua dung khdng Anh hUdng cua vdn tdc klo thd va gia tdc d i n dp djch, tdc dp an mdn sCf dung dung djch gdc fomiat Diu mi-SO 7/2012 29 THAM DO - KHAI THAC DAU KHI Bang Iinii < luil (im (king dk!} Do nhCTtdi^o kiioan C i c 6hc tinh cSin thi^t de khoan g i e n g HPHT Tinh chat dung dich khoan Cmq < I (|{''qi,ini thiijii ly i r o n q t i f d n i j d u o n y c u a d u n g dich khoan tuan n(|( Du d r nq.iii 'MI l.'iiiq ki'i, '.nnq khnni) i|u."^ can doi vdi «ng suat tri/Ot tinh hoac ap Do thainuOc l i o n q dkni kir Tmh luu bien HPHT Du t l ) ihe ihrip dp ncj.in ngi/a n h i e m b.'^n via va rui ro kel chenh ^ p bo can khoan Diincj d(? ki(?m ira sif ISng k^t, p h ^ l Iri^n Ung sual i r i f o i tinh va ty t r o n g tuong dUdng cua d u n g dich khoan (ECD) Ti[ li nen L P C i n ph.ii ro rang de x^c djnh ^ p suSt ddy va ECD Do o n din h d o i v 11 n On d m h co khi, d u n g djch m u i v^ xl m a n g hoa ta C m Ihic'l 66 phSt h i ^ n chinh xac p h u n vii ISp m o h m h Tir b o n d nh the n h Tmh t h i i t kh6ng Ihay ddi t h e o l h c f i gian k h o n g n h i / n g t r o n g cac dieu kien linh ma c^ dii'ii kien d o n g Dl h kel Va i m u , khf n nang Tinh chat k h o n g lien k^t v6i m u n khoan Co ihe lam nang nhanh khi p h u n se thip Vi vly, de tri dd pH cIn thi^t ciia dung dich dng tdng l l n MAGMA-TEQ Id h | dung djch gdc dlu loai khoan thudng sy dung chit d&m tU carbonate Khde vdi dung dich nhij tuong d l dupe nghiin cOU vd yng dung galogenua, fomiat de pha huy sinh hpc, nen cd t h i sd ede edng trudng khoan Loai dung djch dn djnhd dung khdng han c h l l n h hudng d i n mdi trudng sinh thdi n h i i t dd 316°C vd dp suit d i n 30.000psi Fomiat hodn todn hda tan tdt nUdc vd cd t h i sd Oe thda man t i t c l cdc yeu cau khoan, cdc he dung dung de tao nhu tUOng ngUpc hodc nUdc mudi khdng dich cIn dupc tinh todn cu t h i vd k i l m tra Dde diem sii chda pha rln cd ty trpng dudi 2,370; gidm lupng c h i t Idm dung cua dung djeh khoan phdi tUOng iifng vdi vln toe ly ndng eua nude rya Giam ham lupng pha r l n thudng lam thuyet k l o thd dung cu khoan b l o d i m he sd an toan tang van tdc khoan co hoc khoan gieng vd cdi t h i i n dp suit vd dd b i n tat cd cdc d i l u ki|n kiem soat eac thdng sd luu biln cOa dung djch khoan Hoat tinh cua nudc nudc mudi fomiat thip, nen nhd qua trinh tham thau se khdng gdy trUOng nd manh s i t vd tao sU dn dinh thdnh gieng Ddi vdi dung dich khoan gde d l u , cd Uu d i l m Id D4 thu dupc cdc thdng sd eua dung djeh th6a man ede y i u c l u Idm v i l e ed t h i d i l u chinh ba biln so: nhdt, mat dp eCia dung djch va luu lupng cua may bom Trin hinh ve ta t h i y rd, mdi mdt gid tri khac ciis cdc thdng sd ndy d i n d i n ede thdng sd dung dich khac cac gieng HPHT Id tinh dn dinh (cung nhunhutinh luu b i l n VI du, mye dp nguy co nut via t h i p (ty trpng tUdng va tinh thim) Loai dung dich khoan gdc hydrocarbon ed duong cya dung dich t h i p ) dat dupe nhd m I t dung dn djnh gidi han nhiet dd eao n h l t Id 230°C djch t h i p , dd nhdt t h i p vd dng suit trupt tinh vd liw 16 gid thi nghiem phdng Dung dich gdc dau ehdng ket cd chenh dp tac ddng \&n can khoan, bdo ddm an toan via va su dn djnh gieng dd diep thach sit, s i t vatang mudi Nhupc d i l m dung djch khoan gdc d l u sd dung lupng bom t h i p •'' Cdc y i u cSu ddi vdi dung djch khoan CIc yeu c l u chung ddi vdi dung djch khoan e6the tdng hpp Bdng dieu kiln HPHT la hda tan vdo c h i t Idng gdc, g l y Khi t h i l t k l dung djch khoan HPHT, can phli tfnh M khd khan eho viec phat hien phun khL Ddng thdi, x l m nhilu chl t i l u D l gidi quylt v l n d4 nay, Dow/ell da t i S nhap hda tan, dpng lai dung djch vd giy nguyen t h i k l mdt phuong phdp tdi Uu cdc thdng sd dung djch,tlffi tieh cua dung dich, ke cd len den g i n tren mat Khi m I n t i t cd cdc y i u elu edng tac khoan (Hinh 5) [1,3] thoat ngoai, the tich tang rat nhanh, ddi hdi phdi phan dng kjp thdi de kiem sodt gilng khoan Ngoai ra, D i l u chinh cdc thong sd dung djch khoan dung djch khoan gdc d l u cd tinh giln nhiet eao hon so Trpng lUpng riing eCia dung djeh khoan dupe lUa choii vdi dung djch gdc nude, dieu dd Idm cho ap suit dy ngoai can cy vdo ede d i l u kiln ngan ngi/a sy x u l t h i i n dau kHi I 30 Oitt KHl - sd 7/2012 PETROVIETNAM Trong cdc h$ dung djch khoan d l dat ty trpng cao hdm luong barit cho vdo cd t h i dat den 78% khdi lupng Dung dich ty trpng cao vd 45% t h i tich De ed dung djch khoan ed ty trpng cao, hdm lupng pha r l n ed the dat d i n tdi da, dung djch d l t i l p thu trd thdnh tao gel trudng hpp t h i m Ipc Hdm lupng pha rln cd t h i gidm, sO' dung phu gia Idm ndng cd dung cao nhu hematit Trong mpi trudng hpp phdi hdm lupng pha rln vd dO thdi nudc di b l o d i m y i u elu quy dmh cdc thdng sd t h i l t k l khoan LUu lu'ong bOm nho Hinh Toiuu hda dung dich khoan sut Id dat da khoan qua Yiu td xde djnh Id dp suit via (16 rong trong) cOa c h i t lUu; I p suit t y phfa gilng khoan can phai du d l ngan ngCfa ddng chdy khdng kiem soat Trpng lupng rilng cua dung djch cang tdng thi sy an toan khoan gilng edng cao Ddng thdi, tang trpng luong rilng se lam tang ch&nh dp l l n ddy, tang ham lupng pha r l n dung dich khoan, dan d i n g i l m tdc dp cP hpc khoan va lam nhiem ban t i n g sdn pham Trpng lupng rieng la mpt nhung y i u td ehinh bao dam dn i^nh thdnh gilng khoan De ngan ngda sut Id thdnh gilng khoan bao dam tdc khoan cao phdi xuat phdt tH sy lya chpn gia tri tdi uu cua trpng lupng rilng De tri dp suat ddy gidi han Idm viec, can phdi thudng xuyIn kilm tra trpng lupng rilng cCia dung djch Sau lya ehpn duac c h i t Idng gdc, b i t d l u x l y dUng md hinh trpng lupng rieng tren cac sd lieu dp suit - the tieh nhiet dp (PVT) tai diem cu the Khi dd, cIn tinh dp suat tinh di bao ddm tdng cao hon ap suat 16 r6ng vdi he sd an todn t h i p nhat tai mdi chieu sau khlc Vat lieu lam nang dupc lUa ehpn de dat d i n lupng rieng dung djch yeu c l u dUa vao ap suit cdc gieng khoan lan can va nhyng yeu td nhu khlc nhU sU ling k i t vd ddng dde dung djch khoan Barit la phu gia lam nang dupc nghiin mjn d i n kich thUde ed hat y i u elu (thudng Id 75mm) Ddi vdi dung djch d l khoan d i l u kien HPHT, quan trpng nhat la chat lUpng cda barite, vi cac tap chat b i n hoac kfch thudc hat p h l n bd khdng d l u cd the phdt sinh them van d l phUe tap mdi trUdng HPHT Su hlln d i l n eCia eac tap chat s^t barit c6 t h i tao elu true d nhiit ddl35°C Dd nhdt eIn phdi du d l giy pha rln trang thdi lo ICfng Gidm dd nhdt ndi chung cd hieu qud tdt khoan: gidm chi phi nang luong cho t u I n hoan dung djch khoan, Idm sach tdt day gilng nhd sy chdy rdi sdm cua ddng dudi chodng, t h i hiin khd nang thuc hi&n edng suit thuy lUc l l n chodng, gidm tdn t h I t dp suit khodng khdng vdnh xuyIn gieng khoan Ge/vd chit Idng dd nhdt cao cd dnh hudng v6 eung Idn d i n dp suit dung djeh khoan, d i n tie ddng len via thao t i e k l o t h i Giai quylt van d l bang cdch phdi hpp cdc phu gia phu hop ddi vdi dung djch khoan nham muc dich ngan ngifa tao elu true qud Idn cung vdi gid eho cdc chit Idm nang trang thai lo Idng Nlu nhu dng suit trupt tTnh eCia gel vd dp nhdt cd the xac djnh dieu kiln day, thi cd the lap md hinh v l dnh hudng ciia chUng l l n dp suit ddng Trong cac trUdng hpp, ddng chay khdng dupc bi han e h l bdi van tdc va gia tdc nlng cdt cIn khoan, cIn cd cac quy djnh ddc b i l t d l t i l p tuc tien hdnh edng tde Don gidn nhlt la tang mat dp eua dung djch khoan trudc nang cdt eIn khoan Ong sudt truat tfnh can phli dCi d l giy pha rln ciia dung djch khoan trang thdi lo lyng, dac biet se can d i n dp suit dy cao de pha hiiy gel Ap suit, eIn t h i l t d l phuc hdi t u I n hodn, cd t h i lap md hinh giai doan t h i l t k l , edn gid tri eua cdc dp suit ddng phu tinh den thuc hien thiet k l Ijng suit truot tinh la sy dung dung djch khoan khoan gilng, cung nhu Idm n d n g b l n g c a c v l t lieu barit, hematit, manhetit,galenit ehCi y i u giy vun d I t da dtrang thai lo lyng thdi gian t u I n hodn gian doan Vi vly, mdt nhyng y^u elu ehinh ddi vdi dung djch khoan la tang cUdng xuc b i l n eua chiing ddng chay Cfng suat truot tTnh qud Idn cd t h i k l o theo sU nguy hiem khac - "ket dp suit" Ddng chat lUu via x l m nhap vao dung dich tao gel se khdng phat hien dupc ddng trdo t r i n mieng eho den gel chua vd va cd the x u l t hiin ddng ehly manh, t y dd dan den tinh hudng eue ky tdi t l viec kiem soat gilng Vln d l edng nghiem trpng bdi khd nang ddng khi, THAlVI DO - KHAI THAC D A U KHI mpt sd d i l u kiln ndo dd se xly sy t^o gel dung Trong elc g i l n g HPHT, sy dn djnh nhi|t dd djch khoan gdc nudc Nlu nhu cd ehya khf carbonic djch khoan Id thdi d i l m chCi y i u t h i l t k l dor (COJ), pH gilm xudng, gidm hilu qud cdc chit Idm phln Sy g i l m luu lupng dung djch khoan vd cdc t h tdn vd d l y carbonate vd ion bicarbonate vdo dung djch cua chyng l l l n quan vdi cdc y i u td nhi|t d$ vd ( khoan t i l p tuc phdt triin sy tao gel Dun^ djeh gel tam thdi vd cd t h i dnh hudng d i n t i t cd cde tfn^ gdc nude ed cdc hdm lupng h?t rln cao d$c bi|t nhay cdm dung djeh khoan Dung djeh khoan gde nudc vdi hilu yng nSy D l gidm thilu "dp suit c6 kit", tinh chit d l u cd t h i x l u dl t^o c l u trdc nhl|t dd cao, n tao gel cua dung djch khoan n i n tri d mye t h i p ed t h i c h l ndy khde DO thdi nude t i n g l l n theo nl Ong sud'f tfupT ddng: Ldm sach mun khoan gilng khoan nhd vdn tde ddng chdy l l n vd yng suit trUpt d^ng cua dung djch khoan Mde du v l n di kilm sodt l i n g dpng mun khoan bdng bom rda gilng khdng phli Id v l n d l Idn, cd t h i tryc t i l p ddnh gid khd ndng vd I n h hUdng cua l i n g cd I n h hudng Idm g i l m sut phy gia hda hpc vd s true Cudi cung, hdm lUong pha r l n b i l n ddi khdi k i t qud d$ thdi nUdc cd t h i cd sy tdc d^ng m^n nhdt CLia dung djeh ed hdm lupng pha r l n eao, < khoan cdc g i l n g HPHT kit, Lip md hinh dnh hudng ling k i t khdng d l vd thdng Kilm tra c h i t lupng nguyin IJIu cd y ngl thudng nd dUpc ddnh gid bdng thue nghi|m phdng trpng d i n chit lupng dung djch quy djnh V ng thi nghilm vd tinh todn khd ndng dUpe gidm thilu Cdng trpng vi|c xde djnh l i n g k i t vd tinh lUu bit ty Shiumberger t i l n hdnh nghiin eyu cdc d i l u ki|n thudc h?t Sd hi|u vd quy dinh d i l u c h l bdo nhiit dp phdng vdi ede gid tri dp suit, sd dung b6 dung djeh khoan bom vdo g i l n g theo khd ndng thd ling k i t ddng, t r i n co sd dd da xlc dinh dupc nguyin tuong yng vdi thdnh p h l n vd m l u thye hi$n trwi t i c ehi djnh I n h hUdng cya cde phu gia Idm nang, cdc co thi nghilm Sau da cd k i t qud thi nghilm vd ti c h l ling k i t vd cac phu gia, loai try sU ling k i t manh Cle dung djch khoan thdnh p h l n cCia nd cd t h i ddi bien phdp gidi t h i l u chuong trinh khoan v l tdi Uu d i l u c h l tai khoan trudng hda tinh ehIt eua dung djeh khoan v l thao tdc keo - thd cho phep gidm t h i l u h l u qud l i n g k i t [1] Trong ede dieu kiln khoan, lupng l i n g k i t xdy Hiin nay, d l k i l m tra l i i n tue c h i t tUpng di khoan d i l u k i l n HPHT, ngudi ta surdi FMP (hlng Dowell) - cd t h i ghi lai cdc sd li|u ^ dung djch khoan, cd the tinh theo thdnh phan mjn it n h l t lupng rilng, n h i i t dd, tinh c h i t luu b i l n (Omg si vd nhieu nhat eua dung djch duac bom vdo Sau xlc ddng vd dd nhdt d I o tai m^t n h i i t dd n h l t £^nh djnh dupc t h i tieh ling k i t dung djch bom vdo l i l u dung djch khoan duac p h l n tich bIng miyi dupc sddung phuong phdp tuong yng, de thyc h i i n ling cho bd chuang trinh k i l m solt cdc cdng viec th« k i t den tdi thilu Ode bilt, neu nhu ty cya dung djch dupc t h i h i i n dudi dang dd thj cde tham s6 dt cd sU bien ddi vd x u l t hien phan Idp theo t^" trpng, dieu dd theo thdi gian cd nghia Id khdng nen sy dyng c h l dd ddng chdy tang lUu lupng mdy bpm t h i p vi d l tao sy ling k i t Till lilu tham khio Sau xac djnh dupc bdn chat l i n g kit, qud • Truong Hodi Nam Lua chon gidi phdp Id trinh t h i l t k l cd the xem cdc tinh c h i t thuy lue cua don giing phdt triin md Hdi Thgch diiu kiin pha che dung dich khoan De t h i l t k l mdt dung djeh nhU - dp sudt cao Lu^n v l n thac sy ky thudt, Dai hoc, the, nd se t i l p tyc hoat ddng gidi han giiia dp suit c h i t HdNdL 2010 Id r6ng vd ap suit nyt thiiy lUc via mpi thdi gian Nhyng gidi han dp suat ndy xac dinh khe hd (cda sd) dp suit lam viec tdi han vd cIn phdi cd gidi han, chi dp suit dpng x u l t hien hieu yng pitstong keo t h i Tinh Sn dinh cOa dung dich khoan: Nhiet dp cao Idm g i l m dp dn djnh eCia dung djeh sit Nghien cdu cho thay, d nhiet dp binh thudng on dinh cua dung djch dap yng cdc yeu cau khoan thi d n h i i t dd 120=C ed the giy dupc chit lam nang I 32 DlUHd-Sd 7/2012 A.G Kalinin, R.A Gandzunmian, A.G Mes nang Ky sU - Cdng nghi khoan cdc giing sdu TrUo Nguyin XuIn Thdo, Pham Thdnh, Tran Van Bdn d xuat bdn Khoa hpc va Ky thu|t, Hd Ndi 2006 A.T BourgoyneJr.etaL^pp//edDri//ing£ng SPE 1991 Bernt Anadnoy et al Advanced Drilling \ Technology 2009 ... phdn tan; dung dich khoan phdn tdn; dung djch khoan hoat tinh eanxi; dung djch khoan gdc nudc hilu qud cao; dung dich khoan ham lupng pha ran t h i p ; dung djch khoan polime; dung dich khoan gde... i t dung djch cd the xdy cac dieu kiln ddng cung nhutTnh, LUa chon dung djch khoan Dung djch khoan dupc sy dung khoan cac gilng dau thudng gdm cd: - Dung djch khoan goc nUdc gdm: dung dich khoan. .. PETROVIETNAM Trong cdc h$ dung djch khoan d l dat ty trpng cao hdm luong barit cho vdo cd t h i dat den 78% khdi lupng Dung dich ty trpng cao vd 45% t h i tich De ed dung djch khoan ed ty trpng cao,