DO THAM COA TANG MONG M 6 BACH H 6 VA VAI TRO COA N 6 TRONG
B I E N LUANGlAl
P H A P N A N GCAO H^ S6 THU
H 6 | D A UTruang Cong Tai, Nguyen Chu Chuyen XNLD Vietsovpetro
ABSTRACT
Permeability is basic parameter of oil and gas reservoir. Final oil recovery factor is strongly depended on
distribution of permeability and characteristics of relative permeability cun/es. Base on available studies of permeability and numerical model of resen/oir we can estimate adequate value of final oil recovery factor Analysing EOR methods have been used versus characteristics of permeability. Method consists of changing hydrodynamic working parameters of production and injection wells to adjust water - oil contact movement is considerable the most efficiency. This paper also includes some proposals for next stage of resen/oir development.
MdoAu
op thim la thdng sd ca sd cua cac vi'a dau khi, gia tri tuyet ddi, dac diem phan bd dp tham trong khdng gian va cac thdng sd cua dudng dp thim tuang ddi cd lien he mat thie't vdi he sd thu hdi dau (HSTHD). Theo mdt sd tac gia [1], HSTHD (ri) eua mdt via cd the tinh bing quan he:
n = nd-nq Trong do: r i ^ : he sd day d i u , q^: he sd quet.
He sd day dau cua mpt via trong md hinh sd dugc dac trung bdi cac dudng dp tham tuang ddi. He sd quet phu thudc vao vi tri, dac diem he thdng gie'ng khoan, tinh bat ddng nhit ve dp tham va che dp lam viec eua eae gie'ng.
Tren ca sd nghien cuu dac diem dp tham eua tang mdng va md hinh hinh sd khai thac eua tang mdng, npi dung bao cao phan tich vai trd phan bd dp thim trong nhumg giai phap nang cao HSTHD da ap dung cho tang mdng: Dieu chinh he thdng mang ludi gie'ng khoan, thie't ke cac gieng khoan ngang - a ngang, tao cac ddi khai thac bam ep nude., va kien nghi dau tu nghien cuu xay dyng md hinh dd tham phuc vu cho bien luan giai phap nang cao HSTHD cho ddi tuang nay,
I. oO THAM CUA TANG MONG M6 BACH H 6
Ket qua nghien cUu trong phdng thi nghiem cho thiy dp thim bien ddi rat manh, tu khdng thim (k = 0) d eae m i u da chat xit den thim rit tdt (vai ngan mD) d cac m i u ed cac nUt ne Idn. Dp rdng chung eua miu thudng rat nhd, tap trung trong khoang 1-5 % va quan he vdi dp thim khdng rd rang.
Cac gia tri dp thim trung binh theo m i u Idi, nghien cUu dia vat ly va nhiet thuy ddng gie'ng khoan ed xu hudng chung la giam theo chieu sau (Hinh 1, 2). 0 phia tren cua via, g i n vdi nde mdng la vung cd dp thim tdt va phan Idn khoang cho ddng cua eae gie'ng khai thac thupe khu vyc nay (Hinh 3), xudng sau dp thim giam din. He sd san pham cua cac gie'ng khai thac ed khoang lam viec dudi dp sau 4000m thudng rat nhd. Tinh tham cua mdng md Bach Hd phu thupe vao sy hien dien eua he thdng nut ne - hang hde, chit luu dich chuyen trong mdng chu yeu thdng qua he thdng cac nUt ne - tap trung trong nhung ddi da bi dap vd. Cac ddi dap vd phan bd theo hudng ed gdc dd Idn, cudng dp dap vd nhin chung giam dan theo chieu sau [6].
Tinh bit ddng nhit cao ve dp thim cd anh hudng tieu eye den he sd thu hdi diu thdng qua cac tac ddng lam giam he sd quet. Anh hudng nay ed y nghla quan trpng trong cac trudng hgp khai thac ed giu ap suit via bing bam nude hoae khi do sy dich chuyen khdng ddng deu va khd kiem soat cua mat tiep xCic diu-nude hoae khi-dau.
Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bach Hd"
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Hinh 1. Phan bd dp thim theo chieu sau (Sd lieu miu Idi [5,45])
Hinh 2. Phan bd mat dp nCrt ne theo chieu sau (Sd lieu FMS/FMI [5,35])
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Hinh 3: Phan bd mat cat ddng theo mdt mat eat hudng Bae-Nam
Ket qua nghien cUu thyc nghiem tren miu Idi eua ting mdng md Bach Hd [5] cho thiy dudng dp thim tuang ddi diu - nude (Hinh 4) khdng cd dang thang va bien ddi trong khoang rdng. Phan tich ket qua cho thiy dac trung cua chung phu thudc vao dp rdng, dp thim cu? mau va bi anh hudng bdi hudng thay the diu nude.
Vdi dp hPa diu tan du (Sor) dao dpng trong khoang tU 0.30 den 0.42, chip nhan dp bao hda nude la 0.15, he
Cac dutog thSm pha dSu nude tuomg doi Via : mong - mo Bach Ho
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60 70 80 90 100 DO bao h6a nadc qui chuin (Swn),
>-• Din (Miu thuc nghidm) -— D^u ( Trung binh thuc nghiem)
Nude ( MSu thuc nghiem) - Nude { Trung cho thuc nghifim)
Hinh 4. Dp tham tudng ddi theo sd lieu mau sd day dau eudi cung theo nghien cuu thyc nghiem
cao nhat cd the dat duac la tU 0.505 den 0.64.
Trong thyc te d mUe via, he sd nay se ed gia tri nhd han do gidi han kinh te va dac diem bit ddng nhat ve dp thim.
II. GIAI PHAP NANG CAO HSTHD CHO TANG MONG
M6 BACH H6
1. Danh gia kha nang ap dung cac giai phap nang cao HSTHD cho tang mong mo Bach Ho
Phan tich nhung giai phap nang cao HSTHD hien cd tren the gidi va sa bd danh gia kha nang ap dung cho tang mdng md Bach Hd cho thiy:
- Do nhiet dp via cao (~137°C d -3650m) eae phuang phap nhiet cd hieu qua han che.
- Phuang phap bam khi (CO2 hoae hidro- earbon) ddi hdi thie't bi may bam cd edng suit cao va phai giai quyet vin de ngudn khi bam vao. Nhung tinh toan sa bd dya tren md hinh thanh phin diu eua mdng md Bach Hd cho thiy de dam bao che dp
hda tan (miscible) cua khi bam vao, ap suit via phai duy tri rit cao (>400 atm) hoae ham lugng LPG trong khi phai lan (>40%). Giai phap bam khi trong dieu kien khdng hda tan se tao ra mu khi d phan nde mdng (ddi khai thac chu yeu) se lam cho phan Idn eae gie'ng khai thac cd luu lugng Idn sdm ngUng hoat ddng, HSTHD khdng cao, hieu qua thip han so vdi bam nude. Vi vay kha nang ap dung giai phap bam khi de nang cao HSTHD cho ting mdng la rit thip.
- Cac phuang phap hda hpc (hoat chit be mat, polymer), phuang phap vi sinh nhim tac dpng thay ddi dac diem he thdng da chUa - chit luu (thay ddi tinh chit eua chit luu va nhung thdng sd eua cac dudng dp thim tuang ddi) theo hudng lam tang he sd day dau eudi cung ed gia thanh rat cao, dac biet trong dieu kien nhiet dp cao cua tang mdng va khai thac ngoai bien. Ngoai ra, do dac diem phan bd dp thim - dp rdng phCre tap, hieu qua kinh te eua nhung giai phap nay chua the khang dinh dugc.
- Cac giai phap nang cao he sd quet cua ting mdng thdng qua thiet ke cac gie'ng khoan ngang - a ngang, chuyen ddi cac khoang lam viec, thay ddi thdng sd thuy lye eua cac gieng khai thac, bam ep... da va dang dugc ap dung hien nay tiep tuc la eae giai phap kha thi trong thai gian tdi.
2. Cac giai phap nang cao HSTHD ap dung cho tang mdng mo Bach Ho
- Khoan bd sung de phan bd san lugng khai thac va bam ep: Sau khi phin Idn cac gie'ng khoan thang dCrng vao phin dudi lam viec kem, dp tiep nhan nhd, cac gie'ng md vao trong mdng ed gdc nghieng Idn dugc thie't ke theo hugng a ngang va da ca ban khae phuc dugc nhugc diem tren. Phin ign cac gie'ng deu cho dp tiep nhan cao, trong dd cd nhieu gie'ng rit cao (gie'ng: 465, 452, 427, 464, 435). Thanh edng cua giai phap nay da cho phep thyc hien duac che dp giu ap suit via vdi he sd bu khai thac bang bam ep la 100% vdi qui gie'ng bam khdng ddi hdi Idn d ngay nhung phuang an ed nhip dp kha cao va lam tang dang ke he sd quet eua qua trinh day dau.
- Thay ddi he thdng khai thac: Giai phap thay ddi che dd mang ludi gie'ng khai thac va bam ep, chuyen dac diem lam viec eua via theo 2 ddi (khai thac va bam ep) sang 3 ddi (khai thac - trung gian - bam ep) da tan
Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bach Hd"
dung hieu qua tac ddng cua lye trpng trudng lam cham lai qua trinh ngap nude eua cac gieng khai thac d phia tren va tang hieu qua cua he sd day diu d mUc dd via.
- Chuyen ddi khoang lam viec eua cac gie'ng: Gieng khai thac bi ngap nude d vi tri sau chuyen len khai thac tren cao, eae gie'ng bam ep chuyen sang khai thac phia tren, each ly cac khoang ngap nude trong gie'ng khai thac gdp phin dieu ehinh ranh gidi diu nude giam dp ngap nude trong ddng san pham.
- Thay ddi che dp lam viec eua eae gie'ng (luu lugng khai thac va bam ep) de dieu chinh sy dich chuyen cua ranh gigi diu - nuge nhan tao nhim han che dp ngap nude d cac gie'ng khai thac. Hieu qua eua phuang phap nay dugc danh gia qua tinh toan mdt sd phuang an giu ap suit via bing bam ep nude vdi he sd bu 100% va dam bao khai thac dau d mUe cao trong nam 2001, 2002 [4,145]. Cac ket qua lien quan tdi HSTHD cua tang mdng theo cac phuang an nay dugc trinh bay d Bang 1. Trong dd, ten cac phuang an mang y nghla nhu sau:
- Cac phuang an ed ki hieu 1, 2, 3, 4 la eae phuang an ma luu lugng thay ddi tuang Crng 10%, 20%, -10%, -20% gia tri hien thgi nhung trong gigi han kha nang cho phep cua eae gie'ng.
Nhdm phuang an cd ki hieu A la nhdm ma viec tang giam dugc thyc hien ddng deu d tit ca cac gie'ng.
- Nhdm phuang an cd ki hieu B la nhdm cd them hieu chinh dya dan thuin tren ed sd phan tich ket qua thu dugc tU md hinh sau mdi lin tinh.
- Nhdm C tuang ty nhdm B, nhung viec hieu chinh dya theo mpt thuat toan tim kiem tdi uu cua Vien Ca hpc Ha Ndi.
Bang 1. Chi sd khai thac cd ban eua eae phuang an tinh toan
Phi/dng an Casd
A1 A2 A3 A4 BI B2 B3 B4 CI C2 C3 C4
MLTC bdm ep ZQwi, tr.m^ • He sd thu hoi dau, % Ngap nUcfc, % ni/dc, tr.m^ (cud! nam 2020) (cud! nam 2020) (nam 2020)
20.615 384.5 22.420 398.1 23.845 407.6 19.845 381.4 18.430 369.9 22.135 396.2 22.135
20.235
403.9 382.2
19.845 363.7 22.977
24.506
386,1 404.8
20.933 366.7 20.934 345.3
36.03 78.92 35.97 80.79 36.08 80.45 35.58 79.47 35.30 77.66 36.21 79.13 36.88 79.48 35.66 79.09 35.5 77.20 36.56 78.00 36.97 77.68 36.37 74.94 36.30 70.72 TU Bang 1 cho thay, viec dieu ehinh nhip dp khai thac dau va bdm ep nude ed the thu dugc sy gia tang he dang ke sd thu hdi diu va han che dp ngap nude cua ting mdng. De dam bao hieu qua va dp tin cay cua giai phap, thdng sd dupe thay ddi phai dugc lya chpn mpt each ed khoa hpc dya tren md hinh sd thuy ddng lye tiem can thyc te va thudng xuyen dugc cap nhat, hieu chinh theo sd lieu lich su khai thac.
III. K^TLUANVAO^XUAT 1. Ket luan
- Vdi dac diem eua tang mdng va tren cd sd nghien cUu hien ed, cho den giai doan hien nay nhung giai phap nhiet, hda hpc, vi sinh cung nhu bam khi nham nang cao HSTHD it ed trien vpng ap dung cho ting mdng md Bach Hd.
- Cac giai phap nang cao HSTHD da ap dung deu la nhung giai phap nang cao he sd quet cua tang mdng. Do tinh bat ddng nhit cao ve dp tham, eae giai phap nay da mang lai sy gia tang dang ke he sd thu hdi dau cho tang mdng md Bach Hd va cung la hudng tac ddng nang cao HSTHD chu dao trong tuang lai.
- Phuang phap dieu ehinh cac thdng sd thuy lye eua he thdng khai thac - bam ep nham ed dugc he so quet cao nhit vin la phudng an kha thi va ed hieu qua kinh te. Hien nay, do kha nang khoan gie'ng mdi edn rat it vi he thdng gieng da ca ban hoan thien va sd lugng cac gie'ng cho phep thyc hien cdng viec chuyen ddi ehCfc nang hoae thay ddi khoang lam viec khdng cdn nhieu, phuang phap dieu chinh che dp cdng nghe eua cac gie'ng se la phuang phap chu yeu tac ddng gia tang he sd quet.
- Hieu qua nang cao HSTHD cho pham vi md dupe danh gia tren cac md hinh sd, trong dd do chinh xac cua thdng sd dp thim ed anh hudng quyet dinh. Do vay, trudc tien de cd dugc cac thdng sd thie't ke hgp ly can phai xay dyng dugc md hinh sd tinh toan khai thac ed dp tin cay cao, dac biet sd lieu dp thim phai thudng xuyen dupe cap nhat va chinh xac hda.
2. De xuat
- Chinh xac hda sd lieu dp tham cho md hinh sd tren ca sd ke thi/a md hinh dp thim da dugc sCr dung cho sa dd cdng nghe nam 1998. Tiep tuc cac nghien cuu dia chin, dia vat ly, thach hpc, thuy ddng lye hpc... de hieu ehinh cac thdng sd eua md hinh nay.
- Thiet lap ehuang trinh nghien eUu eiu true Id hdng ben trong ting mdng de chinh xac hoa kieu md hinh thim chUa cua than dau.
- Nghien cuu, ehinh xac hda cac dudng dp thim tuang ddi diu - nude va khi - diu d trong dieu kien phdng thi nghiem va mUe via, nghien cUu cac tac dpng hoa ly anh hudng den dac diem cua cac dudng nay va dac biet phuang phap sir dung sd lieu thyc te upscale cho sd lieu thi nghiem.
- Chinh xac hoa md hinh dau via va xay dyng md hinh sd khai thac phu hgp chi tiet vdi lich sir khai thac cua cac gie'ng tang mdng lam ca sd cho nhung tinh toan nang cao he sd thu hdi diu.
TAI Lieu THAM KHAO
1. A. n . Kpbi.noB, ^^npoeKmupoGcuaie pcnpadoniKU iiecfymmtbix .vecmopo3icdeuuii'\ rocy,i],apcTBeHoe HayMHO-TexHHMecKoe H3AaTe,nbCTB0, MocKBa 1962r.
2. Calvin C. Mattax, "Reservoir Simulation", SPE Monograph Series, Richardson, TX 1990.
3. T. D. Van Golf-Raeht, Fundamental of fractured resen/oir engineering, Elsevier scientific publishing company, Amsterdam - Oxford - New York, 1982.
4. Trung tam KHTN & CN QG - Vien NCKH & TK Dau khi bien, Vietsovpetro, Bao cao "Nghien ciru anh huang
nhip do khai thac dau tang mong nui ne mo Bach Ho doi vdi he so thu hoi dau tren ca sa cac mo hinh tham", Ha Ndi 10/2001.
5. XNLD Vietsovpetro, Vien NCKH & TK Diu khi bien, Hoan thien "Chinh xac hoa sa do cong nghe va khai thac mo Bach Ho", Viing Jau ]998.
6. Vien CHLTD TP HCM - XNLD Vietsovpetro, "Sao cao XLT ly va phat then thong tin ve do tham phuc vu thiet lap mo hinh khai thac dau trong da mdng mo Bach Ho", Tp. Hd Chi Minh 1997.