Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bach Hd" GlAl PHAP CONG NGH$ GIA TANG HE S 6 THU H 6 | DAU M 6 N G BACH H 6 Nguyen HL/U Trung VienDaukhf ABSTRACT This paper evaluates the potential of[.]
Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bach Hd" GlAl PHAP CONG NGH$ GIA T A N G HE S THU H | DAU M N G BACH H6 Nguyen HL/U Trung VienDaukhf ABSTRACT This paper evaluates the potential of enhanced oil recovery target for White Tiger basement, the m oil producer in Vietnam By analyzing the current waterflooding status in basement and production profile paper proposes the preliminary solution to enhance the ultimate oil recovery of White Tiger basement Enhanced oil recovery should be based on improving the sweep and displacement efficiency of the waterflooding process, while permitting improve/maintain the oil production rate of the field The paper provides detailed steps from feasibility study project to implementation of this project for one suitable p platform and for entire field i.MdoAu Nang cao he sd thu hdi dau EOR (Enhanced Oil Recovery) la cdng tac quan trpng dieu hanh quan ly md nham tan thu tai nguyen Idng dat Qua trinh dac biet quan trpng eae md da chuyen sang giai doan khai thac thu cap tUe la da bam ep nude hoae vao via nham tri ap suat md Ke tu nam 1986 cho den thdi diem hien tai cac md dau dang khai thac d them luc dia Viet Nam bao gdm: Bach Hd, Rdng, Rang Ddng, Ruby, Dai Hung, PM-3 Cac md dau se phat trien tuang lai gan la Su TLT Den, Lan Dd, Lan Tay, Hai Thach, Rdng Ddi, Rdng Ddi Tay Theo bao cao, san lugng dau khai thac tdng cdng tu them luc dia Viet Nam hien tai khoang 350 ngan thung/ngay (khoang gan 50 ngan tan/ngay Dai da sd cac md xem xet deu dang d giai doan khai thac thU cap (Bach Hd, Rdng, Dai Hung) hoae chuin bi dua vao (Rang Ddng, Ruby, PM-3), su dung bam ep nude de tri ap suat tUe la khai thac thdng dung hoae mdi ehi la gia tang thu hdi thdng dung so vdi khai thac sa cap, Md Bach Hd nam be Cuu Long XNLD Vietsovpetro dieu hanh va dugc dua vao khai thac tU nam 1986 Day la md dau Idn nhat tai Viet Nam vdi ty phan khai thac chiem han 3/4 tdng sd dau khai thac tU tat ca cac md dang khai thac d Viet Nam Trong dd lugng dau khai thac tU mdng Bach Hd chiem den han 90% san lugng toan md Bach Hd Mdng Bach Hd se la ddi tugng ehinh ap dung cac bien phap nang cao thu hdi va gia tang san lugng khai thac cua cac gieng Thyc hien Nghi quyet cua Hdi nghi chuyen de "Day manh cong tac tham khai thac giai doan 20012010", trich tu edng van sd 5202/TDKT eua TCTDKVN 20/12/2000, XNLD Vietsovpetro ed nhiem vu "Dam bao tri san lugng khai thac on dinh va an toan td cac mo Bach Ho, Rong va Dai Hung a mirc ISIS.5 trieu tan dau/nam va giu mirc khong it han 11-12 trieu tan dau vao nam 2005" Day la van de nan giai ddi vdi XNLD Vietsovpetro ndi rieng va ddi vdi ca Petrovietnam ndi chung neu biet rang theo sa dd cdng nghe md Bach Hd da dugc phe duyet 1999 thi san lugng khai thac tU mdng se dat dinh khoang 11.5-12 trieu tan va giam manh sau nam 2002 Cung theo cdng van nhiem vu cua Vien Dau Khi (trich din) la: "Nghien ciru dia chat va cac giai phap cong nghe mai Unh vi/c dia vat ly, khoan, khai thac nhSm nang cao hieu qua TDKT (bao gom khai thac thir cap cac mo dau), nang cao he so thu hoi dau, dac biet chii vao da mong nirt ne" Vdi muc dich dap Ung yeu cau san lugng ndi tren vao nam 2005 bao cao cua Vien Dau "Giai phap cong nghe gia tang he so thu hoi dau mong Bach Ho" de xuat y tudng hieu chinh sa dd edng nghe mdng Bach Hd cua xi nghiep lien doanh VSP, 31 Hdi thdo khoa hoc "Ndng cao he sd thu hdi ddu md Bach Hd" II Dl/BAO SAN Ll/ONG KHAI THAC MONG BACH H Jheo sd dd cdng nghe da duyet 1999 san lugng khai thac va tinh trang ngap nuge se nhu Hinh 1, Tinh den het nam 2001 ta da thu hdi gan 90 trieu tan dau (khoang 20.7% tru lugng tai ehd) va ehi cdn khai thac tiep dugc khoang 73.4 trieu tan dau lai vdi tinh trang khai thac hien tai (chay tir gian va bam ep nuac) vdi he sd thu hdi dau eudi cung trung binh khoang 37.5% OIIP cho den het nam 2020 Tuy nhien dy bao khai thac tiep 73.5 trieu tan den 2020 cd rat nhieu rui ro va phu thudc rat nhieu vao cac bien phap dieu chinh sa cong nghe, dac biet la mirc ngap nuac tai cac gieng khai thac (Hinh dy bao muc dd ngap nude se den 50% vao 2005 theo sd dd edng nghe hien tai) Mpt diem nua can chu y la tudi thp cac cdng trinh ngoai khai da sd ket thuc vao nam 2010 cho nen hien thyc han la chi edn khai thac cd 54 trieu tan vdi he sd thu hdi eudi eiing khoang 32.6% vdi sa dd edng nghe hien tai 100 95 90 85 80 75 70 65 60 55 ;; 50 45 40 35 30 25 20 15 10 25,000,000 • 20,000,000 •Qoil ^ • Water c ut •B 15,000,000 O) c 10,000,000 I' 5,000,000 / / \ ' ^ / c \ EOR s w 1,985 1,990 1,995 2,000 2,005 Nam 2,010 2,015 • 2,020 Hinh San lugng khai thac va dp ngap nude mdng Bach Hd Tinh toan cung cho thay vao 2005 san lugng mdng Bach Hd chi edn khoang trieu tan dau (Hinh i) Nhu vay nhiem vu tri 10-11 tneu tan dau tU md BH, Rdng va DH cua VSP theo tinh than CV 5202/TDKT thi san lugng tU mdng thieu hut tU 1,5-2 trieu tan (tam tinh san lugng mdng luc dd edn chiem khoang 80-90%), Tu dd rut sy can thiet dieu chinh sa cong nghe, dam bao tri san lugng va nang cao he so thu hoi dau tai mdng Bach Hd III TI^M N A N G GIA T A N G H E S6 THU H | DAU KHf MONG BACH H Van de tri san lugng mdng Bach Hd ddi hdi trudc het danh gia dung tiem nang gia tang thu hdi dau ciJa mdng Diem xuat phat tiem nang gia tang he sd thu hdi dau la lugng dau tai ehd da dugc xac minh (OIIP) Tren quan diem khai thac, lugng dau xac minh tai ehd eua mdng Bach Hd 434.5 trieu tan (1999) cd the phan chia nhu sau[1]: - Tru lugng da dugc khai thac (produced oil); - TrQ ludng xac minh (proved oil): Tru lugng xac minh ban dau trU di tdng sd dau da khai thac; - Tru luong dau du (oil residual): Phan dau bat ddng (immoble) via tren ca sd bam ep nude thdng dung; - Tra lugng linh dpng cdn cd the thu hdi bang eae phudng phap cai thien bam ep nude 32 Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bqch Hd" Tru lugng da khai thac dugc edng ddn tU san lugng khai thac, tru lugng xac minh la tru lugng xac minh cdn lai ed the thu hdi bang cac phuang phap thdng dung (ty nhien, bam ep nude thdng dung), tru lugng dau du duac xac dinh tu he sd bao hoa diu du hay cdn gpi la dau bat dpng (immobil oil) khdng the thu hdi neu vin sir dung nude bam ep, tru luang phan dau linh dpng la phan dau dpng edn lai via ed the thu hdi them bang cac phuang phap cai thien bam ep nude Tru lugng xac minh phu thudc vao he sd thu hdi dau bing cac phudng phap khai thac thdng dung dugc dy bao sa dd edng nghe va thay ddi theo md, Gia tri dp bao hoa du phu thudc vao ban chat dat da cua md va thay ddi tU md sang md khae Tam tinh mdt gia tri trung binh So, = 0.4 [6] cho da mdng nUt ne Bach Hd ta ed tiem nang gia tang thu hdi nhu sau: *Ghi chu: TrU lugng tai cho ban dau mong Bach Ho lay bang B + C1 + % C2 phan trd lugng C2 chiem khoang 20% Hinh Phan bd trur lugng mong BH, 434.5 trieu tan (Thdi diem 01/01/2002) 97.50(22.4%) • TrOr iLfdng da khai thac B TrCf lUdng xac minh hien tai D D a u d u , bat dpng O TrOrlUdng d a u linh dpng 89.85(20.7%) 73.35(16.9%) 0173.80(40% Can can trU lugng cho thay rang tiem nang nang cao thu hdi dau la rat ign Tru luang thu hdi tiem nang nhd ap dung cac bien phap cai thien, nang cao he sd thu hdi dau nam phan tru lugng dau du bam ep nude va phan dau linh ddng edn sdt md Nhu vay cai thien khai thac va gia tang thu hdi dau md ed the theo hai hudng sau: - Cai thien tinh trang bdm ep nude : Bao gdm eae bien phap dieu ehinh khai thac va bdm ep nham gia tang khai thac them phan dau linh ddng sd 97.5 trieu tan tren ca cd gia tang he so bao quet nugc £, mdng - Giam dp bao hoa dau du, bat ddng: Bao gdm eae bien phap cai thien chat lugng tac nhan day dau nhu: Bam ep HC, CO2, N2 (miseible/immiseible), dung dich polymer, HDBM, kiem, eae phuang phap khae nhu vi sinh, tao rung, ty trudng nham nang cao he so day dau E^ mdng Theo [7] gidi han ky thuat tdi da cd the giam bao hoa dau du tU 0.4 hien tai xudng edn 0.3 tUc tiem nang giai phdng them khoang 43.8 trieu tan nua Nhu vay, phan trU lugng dau tiem nang c6 the thu hoi theo ly thuyet bSng cac phuang phap cai thien va nang cao he so thu hoi dau (goi la tru lugng EOR) khoang 140 trieu tan, chiem khoang 32% luang dau tai ehd ban dau OIIP Trong dd tiem nang gia tang thu hdi dau ehi nhd cai thien bam ep nude chiem chu yeu va de kha thi nhat vin tri tiep tue sa dd cdng nghe khai thac thir cap Cho rang ta ehi thu hdi them dugc khoang 20% phan tru luang EOR cai thien bam ep nude (khoang 5% tru lugng tai ehd) thi da ed them 20 trieu tan dau, bang ca mdt phat hien Idn d them luc dia Viet Nam Nhu vay phan dau de dat: - Khai thac sa cap va thU cap 37.5% ( hoae 32.6% vao 2010); 33 Hdi thdo khoa hoc "Ndng cao he sd thu hoi ddu md Bach Ho " - Khai thac nhd gia tang thu hdi EOR 5% Nhu vay phan dau he sd thu hdi dau eudi cung dat khoang 37.6-42.5% (2010-2020), Nhu vay dy kien can can tru luang mdng Bach Hd nhu sau: Hinh Phan bd tra lugng mdng Bach Ho 434.5 trieu tan OIIP(1/2002) 89.9 (20.7%) 129.8(30%) BTrir luong da khai thac • Tru luong xac minh hien tai D Du kien khai thac thera nhd EOR 44.0(10% 77.5(17.8%) 20 (4 6°/ ) '-' T'™ n3ng cai thien bom ep • Tiem n&ng cai thien d^iv DDau dukv thuat Detien sosanh, phan bd tru lugng thu hdi tai My (1981) la: - Khai thac sa cap va thu cap (chua ap dung EOR): 34% tru lugng tai cho; - Khai thac ap dung EOR: 6% tru luang tai cho (Con sd chac chan da dugc cai thien nhieu d thdi diem hien nay) Tai Na Uy theo [7] thdi diem nam 2000 thu hdi dau nhd EOR dat 19% va he sd thu hdi dau eudi cung trung binh dat 44% Na Uy dang nham dich 50% vao 2005 IV, TiNH TRANG KHAI T H A C HIEN TAI MONG BACH H Mdng Bach Hd dang d giai doan khai thac thu cap, sii dung bam ep nude de tri ap suat tire la khai thac thdng dung hoae gia tang thu hdi thdng dung so ya\ khai thac sa cap Tinh trang ngap nuac xay phd bien d cac gieng khai thac mdng Bach Hd Mpt sd gieng da ngUng khai thac ngap nude hoan toan hoae thiet bi bam dien ngam (ESP) hong nhiet dp va ap suat cao Van de sa lang parafin lam giam san lugng khai thac tai nhieu gieng d Bach Hd va khd khan cho van chuyen Chat luang khoan hoan thien gieng, goi dong cung lam anh hudng dang ke den kha nang san xuat eua gieng: Tinh trang ap suat giua dng chdng chat luang bam tram xi mang, mat dung dich khoan qua cac ddi nut ne lam anh hudng dang ke chat luang tang san pham, gay khd khan cho edng tac goi ddng giam san lugng gieng khai thac, Theo sa dd cdng nghe da duac phe duyet 1999 d phuang an tdi uu nhat san luang dinh plato mdng Bach Hd dat khoang 11,5-12 tneu tan dau vao nam 2001 va bat dau giam manh sau nam 2002[2] Tren quan diem quan ly md, tan thu tai nguyen can cd cac bien phap tri san lugng gieng sau nam 2002 va nang cao he sd thu hdi dau eudi cung cua md, Hieu qua cac bien phap nang cao he sd thu hdi dau the hien d phan khai thac dau them EOR (Hinh 1) Nhu vay nguyen tac chung van hanh md, gia tang thu hdi dau tap trung vao hai muc tieu ehinh nhu sau: - Duy tri, gia tang san luang gieng d myc dinh cho phep: Cac bien phap tac ddng Idng va vung can day gieng nhim cai thien dieu kien chay cua dau (WWO) 34 Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bqch Hd " - Giu thdi gian khai thac plato cang lau cang tdt: Cac bien phap can thiep via nham cai thien he sd day, quet nang cao thu hdi dau (EOR) Theo sd lieu phan tich hien cd tinh trang ngap nude mdng (01/01/2000) tinh theo diem cao nhat xuat hien nude gieng [5] nhu Hinh Cd the nhan thay mUe nude ngap via trung binh d khoang 3650 m d thdi diem phan tich 01/01/2000 (chac chan da d muc cao han nhieu d thdi diem hien tai 8/2001 udc khoang 3450-3500 m) Tuy nhien muc dp phat trien rat khdng deu Cd the xac dinh rd bd'n ludi nude chinh phat trien manh gay ngap sdm cac gieng khai thac: Khu vyc gieng 2, khu vyc gieng 417 va 430, khu vyc gieng 801, khu vyc gieng 802, 803 M6 Bach H6 Doi tirong mong, V6in Tning tam 4J2 420 'W3 i.iS 428 409 417 - N6c mdng Fill l(?c 430 41J MH 410 902 904 m\ - dng chftng khai ihic •Thin tran SOT Sit (102 Khoang ban via HinhHO Sadddinhvi cac khoang ngap nude den 01/01/2000 Nguyen nhan ehinh chu yeu mUc khdng ddng nhat mdng, nude phat trien theo cac nUt vd chinh bd qua cac vung dau ed dp tham thap han d phia sau lam giam hieu qua bao quet [4] Ngoai cdn mdt nguyen nhan quan trpng khae la mUc dp hoan thien eua eae gieng ndi tren thap (2, 417, 801, 802 va 803) khoang md via vao mdng thap, Cdng them nhip dp khai thac cao lam tang gradient ap suat can gieng tao dieu kien hinh ludi nude sdm tai cac gieng ndi tren Do tinh bat ddng nhat cao ca khoang dp sau dudi mye nude trung binh kha nang tdn tai nhieu vung chUa dau ed dp tham thap bi nude bam ep bd qua khdng quet tdi Tai cac vung dd ca che thu hdi dau chu yeu nhdhien tugng mao din V D^ X U A T AP DUNG CAC GlAl PHAP N A N G THU CAO H | MONG BACH H6 Viec lya chpn phuang phap gia tang thu hdi EOR phai dugc tien hanh tren ca sd nghien cuu day du ve md; dac diem dia chat, thach hpc, tinh chat via, ap suat, nhiet dp, da chira, luu the, che dd nang lugng md ,Lya chpn phuang phap nao cung phai tuan thu eae nguyen tac ehinh: Kha thi ve mat ky thuat, thu hdi tdi da dau khi, hieu qua kinh te, khdng gay tac hai mdi trudng 35 Hoi thdo khoa hoc "Ndng cao he sd thu hoi ddu md Bach Ho" Vdi nhung hieu biet sa bd ve ddi tugng mdng Bach Hd cd the thay rang gia tang he sd thu hdi dau se tap trung chu yeu vao nang cao hieu qua bao quet Ey mdng tuc la chu yeu vao dieu chinh sa dd cdng nghe, cai thien bam ep va khai thac nham khai thac them phan dau linh ddng sd 97.5 trieu tan cdn lai via Bien phap khdng ddi hdi thay ddi Idn ve cdng nghe va tan dung dugc tdi da sa dd edng nghe hien tai dd nim d dien uu tien thU nhat Do dieu kien phuc tap cua mdng cac bien phap gia tang thu hdi cai thien he sd day dau E^ nhu bam ep polymer dieu khien dp linh ddng, HDBM, bam ep khi, vi sinh nham khai thac them phan nao sd 43.8 trieu tan dau du khd cd the thyc hien neu xem xet toan dien ve mat kinh te d thdi diem hien tai Do vay cai thien he sd day dau ehi dung lai d muc xu ly tdi uu nude bdm ep va nam d mire uu tien thir hai * Cai thien lie so bao quet mong E^ De tang kha nang bao quet eua nude bdm ep mdng Ey ean dieu chinh ddng deu tien dp ranh gidi dau/nude tren toan md Trudc mat can chan va triet tieu cac ludi nude phat trien sdm d bdn vung da ndi d tren Cac bien phap trudc mat cd the la: - Han che tdc dd khai thac thac hoae ddng cac gieng khai thac tai eae vung xuat hien ludi nude: Gieng 2,417, 430, 801, 802 va 803; - Khai thac theo chu ky ddng md cac gieng khai thac nay; - Xem xet lai nhip dp bam ep, khoang bam ep nude tai cac gieng cd kha nang anh hudng true tiep tdi sy hinh cac ludi nude ndi tren Cac phuang phap ndi tren gdp phan cai thien he sd bao quet Ey mdng, dieu chinh ddng deu gidi han dau nude Tuy nhien han che chinh cua chung la lam giam dang ke nhip dp khai thac md, keo dai thdi gian thu hdi dau va lam xau di cac chi tieu kinh te khai thac md De han che nhuac diem tren va quan triet nguyen tac gia tang va tri san lugng d muc dinh cho phep can cd cac phuang an khai thac bu phan dau thieu hut ddng/han che khai thac cac gieng vung ludi nude ndi tren Mpt phuang an toan dien han ed the xem xet den nhu sau: - Cach ly cac luai nude ehinh gay ngap nuac da noi tren bang each bam dung dich polymer v6 ca tao g Mo Bnch H6 061 luong ni6ng, V6m Trung lam 430 - N6c mdng Fihlpc 41.-* J(U 410 -6ng ch