Nâng cao hiệu quả xây dựng giếng khoan dầu khí trên quan điểm ổn định trạng thái bền cơ học

PETROVIETNAM NANG CAO Hieu QUA XAY DUNG GIENG KHOAN DAU KHI TREN QUAN DIEM ON DjNH TRANG THAI BEN CO HOC TS Nguyin Van Lcl\\ T5KH Tran Xuan Dao^ TS V6 Quoc Thing', TS Nguyen Thj Hoai', ThS Ngo Sy Tho' 'Bai hoc Dau Viet Nam ^Lier) doanh Viit - Nga "Vietsovpetro" 'Van phdng Chfnh phO Email: loinv@pvu.edu.vn Tdm t i t Vdi ddc thii rieng cda cdc gieng khoan c6 tyie giUa ehieu ddi vdi dudng kinh thdn gieng lin den 12 - 20 nghin Idn theo cap dudng kinh, nen tinh ben cahgc cda bd dung cu khoan cd dnh hudng true tiep den trgng thdl vd hieu qud idm viec cda choong khoan qud trinh phd hdy dat dd Ngodi ra, hinh dang vd quy dao thdn gieng cung gdy nhieu phdc tap cong tdc thi cdng xdy dUng gieng Tren cdsdphdt tri4n ket qud Lubinski, nhdm tdc gid dUa cdch tinh tdi trgng tdi han xdy hien tuang uon doc cho bd dung cu khoan g6m lien ket cdc can ndng vd dinh tdm, cung nhu tinh todn vd ddnh gid ve dd cu^g chju u6n cua bp dung cu khoan cho cdc cap dUdng kinh khdc nhdm Idm cusdxdy dUng bd khoan cu cho cdng tdc thi cdng giing khoan TCfkhda: Tdi trgng tdi han, dd cCfng bd khoan cu ben dong hoc bd khoan cu, thiet ke gieng khoan I.Mddau De phd huy ddt da, chodng khoan lam viee dUdi mdt tai dpe true tuong ijftig vdi dp ben cd hpc eua dat dd khoan qua Viec tao tdi dpe true dupe thuc hien tren ca sd lupng ri^ng cCia cac thiet bj (gom eae doan ong cd dudng kfnh va be ddy khdc nhau) dupe lap dat tr^n choong.Trong toan bd chuoi can khoan dupe chia thdnh doan cd Ung suat lUc khac dau, phan tr^n cOa chuoi can khoan chju Ung suat keo, eon phan dudi ehiu Ung suat n^n.Trong doan can khoan chju nen, vdi gia trj tdi doe true Idn se Idm bd dung cu khoan phan tren chodng khoan bj bien dang udn hinh sin Neu bd dung eu khoan thudng xuy^n 1dm viee dieu kien se dan den trang thdi lam viec cua chodng khoan mat tinh 6n dinh va ben co hoc, hl^u qud phd hdy dat da cung bj suy gidm Van de tinh todn vd xdc djnh Ung sudt tdi han uon, cung nhu dp eUng ehju u6n cCia thiet bj dong vai trd quan trong viec thiet k^ va xdy dung bp khoan eu ddm bdo tinh ben co hpc va trang thai dn djnh co hoe eOa he thdng dong hpc qua trinh pha hCiy ddt da, Mdt s6 nghien cUu ve tfnh dn dinh va ben eO hpc cua chodng khoan dUa tren L^ thuyet tai bien, Ly thuyet re nhanh, Nguyen 1^ nang lupng CO hpc ri^ng c6 t h ^ ducfc tim thay cdc cdng bd gan day [1 - 3] thdnh phdn theo phUdng ngang vd phUOng dpe Khi he thdng can khoan bj uon dpe, se xuat hi&n mdt phdn lUc nUa tai diem tiep xdc giUa he va he thdng can khoan He ngoai lUc tac dung len he thdng can khoan duc^c the hi$n Hinh 1: Tili tdi han cho hien taong u6n doc cua cSn khoan 2.1 MdMnh Lubinski Nhdm tdc gid sU dung md hinh Lubinski [4] 64 tinh todn tdi tdi han ISn ehodng khoan cho hi&n tupng udn doc eCia h& thdng can khoan Gld sU he thdng cin khoan Id mdt ehu6l dng liSn ti^p khong cd chi ti^t ndi, v^ hai dau cUa h6 thdng cdn khoan 6Mc xem la nhOng khdp bSn ';^ Do dd, phdn iuc d hai dSu he thdng edn khoan se cd eac Hinh I Ngoai luc tdc dung ISn chuoi c6n khoan [4] IIIIIIIIIII-S6 3/2016 ZC 17 I T H A M D O - KHAI THAC D A U KHI LUe hudng len tren W^ la phdn lUe tai khdp bdn le tren dinh LUc eat, dupe djnh nghTa la tdc dp bl^n Luc hudng len tren W, la phan lUc dpe cCia phdn lUe day 16 khoan tac dung len he thong can khoan, ddy chinh la tdi trpng l^n thien eCia moment udn, dat dupe bang edeh dao ham phuong trinh (1) theo X: ehodng khoan = E! Luc F^ la phan lUe ngang eua day 16 khoan tae dung len he thdng can khoan LUe ngang F,, la phdn lUc cCia true tdc dung l§n he thong can LUe ngang Fid phdn luc cCia thdnh h§ l i n h&thdng can khoan nd bi udn dpe Hai lUe khong xuat hien Hinh la trpng lupng cCia he thong can khoan (lUc doc hudng xuong dUdi) va lUe noi (lUe dpe hudng len tren), cd hai lUe tren d^u tdc dung vdo trpng tam eua he thdng can khoan Anh hudng cua lUe nhdt tae dung bdl dung djch khoan va lUe day eua tia nUde d ehodng khoan dMc bd qua vi rat nhd so vdi tdi trpng tdc dung l§n choong khoan Chpn true tpa dp OXY nhU Hinh 2, Id diim trung hda {tUc Id di^m tren ehuoi can khoan ma tai lUe nen va lUc keo cang bdng 0).Trye X va Y dupe tinh theo dOn vj feet (ft) Moment uon cua he thdng edn khoan ed the dMc bilu diln bang phUPng trlnh: (1) Trong do; M: Moment udn (ft.lb); E; Module dan hdi Young eCia thep (Ib/ft^); (2) dX^ LUc eat eCia mat c i t ngang ndo day dpe theo h i thong can khoan, v( du mat cat MN Hinh 1, cd t h ^ dupc xdc djnh bdng phuong trinh (2) Cdc lUc tdc dung len doan can khoan nam dUdi mat cat MN dUpc bieu dien Hinh 3.Trpng lUpng cua he thong can khoan dUdi mat cdt MN dUOe bieu dl^n b^ng vector W va lUe d^y ndi tae dung bdi dung djeh khoan len can dupe bi^u dien bdi vector B, Ap lUe thily tinh B^ khdng tac dung len mat cat MN n i n thdnh phdn ndy bj lUoc bd tu luc dd'y n6i B, de dat 3il(3c lUc ndi thUc Bdi doan can khoan dang xetd trang thai cdn bang, nen tdng eae lUe bang (Hinh 4) Tr&n Hinh 4, AB dai dien cho tdi trpng len ehodng khoan, BC Id thdnh phIn ngang F^ cCia phdn lUe cua day 16 khoan tac dung len chodng, CD la khdi lupng W cua doan can khoan dUdi mat eat MN, DE la lUc diy ndi B, vd EF Id lUc dd'y noi B^ Bau tien, x4t trUdng hpp udn dpe nhUng ein khoan van chUa tiep xdc vdi thdnh he, do luc F = Trong Hinh 4, lUe FA la phdn I: Moment qudn tfnh eCia mat cdt ngang (ff) '••'^cj; X Hlnh2.HStga3dl4J '• R lllllKlll. FG = (AB - CE)sina - BCcosa dieu kien dang x i t , gdc a rat nhd, dd ta co the F, = FG = (AB - CE}tana - BC =0 (13) Thay (9) vao (1): xem eosa = va sina = tana Phuong trlnh tren trd thdnh: M = pm^^ dx^ {3) (14) Phuong trlnh (7), (8), (12) va (14) ehi rdng dv d^v a:, y,-7^,-7-=^ vaC la nhUng dai lupng khdng thUnguyen He sd lUe day ndi dUpe djnh nghia bdng: Pddl( B.F = 1- El Do do, cdc phdn tich chUa edc dai lUdng se khdng phu Pt thudc vao tinh chat eUa he thong can khoan vd dung djch Trong dd: khoan p^^i^: TJ trpng rieng cua dung djch khoan; dy z=-r dx Goi: p,: Ty trpng rieng eua thep Gpl p la trpng lUdng ddn vi cCia h i thdng cdn khoan dung dich (don vj lb/ft), dai lUpng bang tfeh eua luong that eCia he thong can khoan vd he sd lUc day ndi B.F Gpi X, vd X^ lan lUpt la toa dp theo true X cCia hai diem dau mut cCia he thong can khoan, ta cd: Thay phuong trinh (15) vdo phuong trinh (13), phuong trinh vi phdn cCia hiin tUong uon dpe edn khoan trd thanh: ^-b xz-\-c = dx^ (16) Nghiem z d phuong trinh tren ed the dupc viet dudi dang chuoi liJythUa: (4) X^ = - - Thay phuong trinh {4) vao phuong trinh (3) va thay dY , , tana = - — - , t a e o : dX 05) z=2, '^^" Phuong trinh (16) dd se eo dang: y n(n - l)a„;c"-2 -F ^ Onx''^^ + c = (17) Fs = [W2 - p0i2 - X)]tana - F^ = " P ^ ^ " ^z (5) Nghiem eua phUdng trinh tren: Thay phuong trlnh (5) vao phuong trinh {2): y = aS(x) + b T(x) + cU(x) +g dY d^Y dX^'^' (6) (18) ~ = aF{x) -F bGix) + cH(x) dx Phuong trinh (6) Id phifdng trinh vi phIn cOa hien (19) ^ = aP(x) -F bQix) -F cRix) dx^ tirong u6n doc can khoan Go]:X=mx; Y=my (7) Trong do: ^^'"^^TJH" m [k hSng sd cho nr"= — , dan \n feet Do do: dY dy dX dx d'Y Id'y dX'' mdx^ dV dX3~ m}dx^ 2.3.5.6.7~ 2.3S6.8.10* J rM = Jl.J^.^^ (8) (9) (10) (20) g la hang so ' -^ I2 U(,J=-^\l.^.^ ' -^ 213 ^^- ] 3.4.5 3.4.6.7.8 3.4.6.7.9.11 J '-^ 4.5.6 4.5.7.8.9 4.5.7.8.10.11.12 '('^i'-f3'zir6'iiiEi-9' J ] DAUKHI-S03/2016 19 THAM DO - KHAI THAC D A U K H I G(x) = x\l- — + ^ 3.4 3.4.6.7 Hfx) = ' ^ x^r, „,, pfx) = x^ ~ + 3.4.6.7.9.10 x^ x' \1 + 21 45 4.5.7.8 45.7.8.10.11 x^r, x^ X* x^ \1- •+ J ^S + J R(x) = -x\l-^-^^ ^ •' I 2.4 2.4.5.7 + 2.4.5.7.8.10 • S ^ i \ %m I ::|:I J ijH : J B \ iSf mut phia tren va phia dudi eua he thong can khoan vdi tpa nrr dp gde la diem trung hda Goi P,,Q,,R,,S, Id gid tri cCia P(x), HE Q{x), R(x), S(x), x = X, vd P^, Q,, R^, S^ Id gld trj eua P(x), Q(x), R(x), S(x) x = Xj, d hai dau mut eua he thong can 8" khoan, moment udn bdng 0, do cdc phuong trinh (14) vm h vd (20) cd dang: aP^ + bQ^ + cR^ = 11 ' tW-y = ffi :83 s • ••Mr] Gpi x, va Xj lan lupt la gia trj cua toa dd x cCia cdc diem aP^ + bQ^+cR^ = HlJllg %'m 1 :|^ifl^ iS + 3.5 3.5.6.8 3.5.6.8.9.11 Q(x) = \l + -•*• ^ ' ^ L 3.4.6 3.4.6.7.9 J E ^ •tff^ 1• • + r m '• rfU :(, MI '•IW ; 1: ^ IITT fi IB :^I=Fff T • - ^ r r "ã Hf H (21) :: ôa (22) eon vikhfinc tho nguyfi d hai dau mut tpa y = nen phuong trinh (18) eho ta: Hinh Bieu kien tdi han bdc [4j aS^ + bT^+cV^+9 = Suy trpng lUpng (don vj pound) cCia ehieu dai he aS^ + bT2 + cU^ + g = => a(S^ - SJ f b(T^ - T^ ^ ecu, -U^ = thong can khoan tuong duong vdi mdt ddn vj khong thiJ (23) nguyen: Tpa dp X, va Xj tim dyscic bdng each gidi cdc phuong trinh (21), (22) vd (23), tUc Id gidi djnh thUe sau: I ^1 Pz Qi Qi fii I ^2 = l5i-52 Ti-Tj [/i-t/jl mp = ^EIp^ Nhan mp vdi 1,94, ta se cd tdi trpng tdi han l i n chodng (24) BSng phuong phap dicing dan, phuong trinh (24) dupe gidi d^ tim x, vd x^ NhUng gid trj dupe bieu dien Hinh khoan cua hientupng udn dpe can khoan bdc l,tUe Id: Fcrf =3,94^/£V (25) Trong dd don vi tfnh cua cae dai lUpng la: E (Ib/ft^); I (ft*); p{lb/ft) va F^^, {lb) TrUdng hop bd khoan eu ed eac ehi tiet ndi giUa can K^t qud Hinh cho thdy gid tri tuyet doi cCia x, nhd, khoan va can nang (vdi dudng kinh khdc nhau) thi tdi tUe la 16 khoan rat ndng, cln mdt tdi trpng Idn hOn len trpng tdi han len chodng khoan cOa hiin tupng uon dpe chodng 6i cdn khoan bj udn dpe, Khi 16 khoan sdu hon, dupc tinh theo edng thUe {[4]): gia trj tdi han cCia tdi trpng len ehodng gidm xuong dat tdi gid trj tiem can d gid trj ndo day Trong dieu kien khoan thuc te, X, r^t Idn va gid trj x^ se bdng gidi han tiem can Hinh cho thKy sal so ed the bd qua, gidi han tiem can datdUpckhlx, = -6vdgidtritUPng Ung cUaXj= 1,94, day la dieu kiin tdi han cUa hiin tUpng uon doc bdc Vi m^ =—, ehieu ddi cCia mdt don vi khong thU P nguyen dupe xae djnh bdng: ^ 7n nlii Hul F^ = lS4^^EIpl + L, (p, - p j (26) Trong do: p^, p^: Lan lupt Id trpng lupng rieng eua can ndng vd cdn khoan; L :T6ng ehieu ddi eCia can nang 2.2 Tinh todn cho s6 liiu cu the Trong cdng thUc (25) va (26) thi E - Module ddn hdi 1^ d?i lupng dd biet; I - Moment qudn tfnh true (cm") dilc?c tfnh todn theo cdng thUc sau [6]: PETROVIETNAM R=Ilk E2J2 Trong do: E: Module ddn hoi (Mpa); J: Moment chong udn (em^) '='"='" = ,P Gid trj moment ehdng udn dupc tinh theo cong thdc J: Xet khodng khoan tU 4.596m den 4.775m than gi^ng thing ddng Ty trpng dung djeh la ^,05g/cm^ Bd khoan cu gom: Trong dd: Chodng khoan dudng kinh 165,1mm, ehieu dai 0,2m, (trpng lupngl5kg); d: Dudng kinh (em) D: Dudng kinh ngoai (em); Dau noi chuyen tiep dudng kinh ngodi 120mm, ehieu dai 0,8m; TrUdng hpp liin ket giUa can nang ed dudng kfnh khacnhau: Can ndng dUdng kinh 120,65mm, ehieu dai 266,0m {trpng lUpng riing khdng khi: 47lb/ft); Doan can nang phia t r i n {D|, d,) Doan cdn nang phia dUdi (D2, d2) Dau ndi 127mm, ehieu ddi 0,41 m; Can khoan 127mm - phan cdn Iai (trpng lUpng rieng khong khi: 19,5lb/ft) Gid trj dp cUng udn R cCia liin ket dupe xac i^nh theo cdng thUe sau: Ta cd: E = 4,176 x 10^(lb/ft') vd I = 6,87 xlO^* (ft") R-M_-i4;5| EJ, D,dt-df Detfnh p^, p^trUdctiin ta can tinh h i so Bouyaney (BF) 1,05 (g/cm^) = 1,05 x {1/454) lb: (1/30,48)^ ft^ - 65,49 (Ib/ft^) BF = (489 - 65,49): 489 = 0,866 ,27, Doi v6i bo khoan cu co sir dung cac d|nh tam, gia tn cijrng bleu kien duoc tinh toan theo cac cong thijc sau [51: Bo khoan cu sCf dung mot dinh tam: TU suy ra: p^ = 16,89 {lb/ft), p^ = 40,7 {lb/ft) Do ta thu dMc F„|^21017,69 (lb) = 9.458kgf Thue te khoan mong vdi ehodng khoan eo dudng kinh 165,1mm, gia tri tdi trpng dpe true thudng sU dung t u 10.000 -14.000kgf Gid tri Idn hon nhieu so vdi gid trj tai trpng tdi han tinh todn is tren cho thay bp dung cu khoan se bj bien dang, day chfnh Id nguyin nhdn cdn trd hieu qua Idm viee cua choong khoan De khde phuc hien tUpng nay, cdn phai gia co bd dung cu khoan bdng edc dinh tam vdi dudng kinh tdi da bang 165mm eho F„ nhd nhat cung phai bang 14.000kgf Hay ndi each khac la dp cUng ehju uon eua bd khoan cu mdi phdi gdp 1,5 Idn so vdl bo dung cu khoan chi vdi cIn nang dUdng kinh 120,65mm Danh gia cuTng chju uon cOa bo khoan cu co Up datcacdi;^ 'af" D6^ mvj chju uon cCia thdnh phan bd khoan cy dupe xdediri'n '•Usau: ".t ' Al-kll- - O.SL,)tO,S(L - L, - Lj] (28) Bo khoan cu sirdung hai djnh tam: R„=^i—lL,[L-0,5L,]tLXL-0,SL,-l,-L^* ^ ^ *l(L-L,-L,-2L,Y\*^L,{L-0,5i,-L,-L,]\ 2^ IJJ ^^ »l - (29) «JJ Bo khoan cu sijrdung ba dinh tam: R,, = -iyl-lL.fL -0,51,]* L.fi - 0,51, - L, - i,)» tl,iL-0,5L,-L,-l,-2L,)* (30) *-IL-L,-L,-L,-3LJU^L,IL-O,51,-L,-L,-LA Trong do: m, m^: He sd tuong