Tuygn tap bao cao Hdi nghj KHCN "30 nam DIU khi Viet Nam Cff hdi mdi, thach thuc mdi" 937 KET QUA AP DUNG CAC PHU ONG PHAP TAC D Q N G LEN VUNG CAN DAY GIENG TAI MO BACH HO VA PHÛ OHVG H U ^ 6 N G HO[.]
Tuygn tap bao cao Hdi nghj KHCN "30 nam DIU Viet Nam: Cff hdi mdi, thach thuc mdi" 937 KET QUA AP DUNG CAC PHU-ONG PHAP TAC D Q N G LEN VUNG CAN DAY GIENG TAI MO BACH HO VA PHU^OHVG H U ^ N G HOAN THlisN CONG NGHE CUA CHUNG • • Duong Danh Lam XNLD Vietsovpetro N224 (77) TOM TAT Bdo cdo neu kit qua nghiin ciru thi nghiim vd kit qud thu dugc ngodi thuc ti vi hodn thiin cdng nghi xir ly vung can day giing (CDG) tgi md Bgch Hd & thim luc dia Viet Nam, giai dogn 1991 - 2004 Hiin nay, tgi md Bgch Hd, ddu dugc khai thde tir cdc giing thudc ddi tugng Miocen du&i, Oligocen trin, Oligocen du&i vd tdng mdng dgng khdi (da granit nirt ni) Do viing CDG bi nhiim bdn qud trinh khoan, hodn thiin vd sua ehda giing, nin hdu hit cdc giing khai thde & muc thdp hon tiim ndng cua chung Trin co s& nghiin ciru, lua chgn vd dp dung nhiiu phuong phdp khdc di xu ly vung CDG nhdng diiu kiin dp sudt via thdp (trong mdt sd gieng, dp sudt via thdp hon dp sudt thuy tinh vd cd giing, dp sudt via thdp han dp sudt bdo hda), nhiet via cao (^ 150 C) vd ddc biit, tdng mdng cd nhiiu logi khodng vdt thu sinh, cdc tdc gid chi nhirng cdng nghi tdng hgp xu ly viing CDG kit hgp v&i khai thdng vd ggi ddng cdc giing sau chung dugc xu ly Din nay, cdng nghi xir ly vung CDG ciia cdc giing thudc ddi tugng tdng mdng vd Oligocen du&i ddn dugc hodn thiin tdi uu nhdm tdng hi sd thu hdi sdn phdm & nhirng giing hiin cd vd de dgt dugc hi sd thu hdi ddu cao & md Bgch Hd G l l THIEU CHUNG Mo Bach Ho dugc dua vao khai thac tu nam 1986, nhung den nam 1991 moi tien hanh xii ly vung CDG nham gia tang he so san pham gieng khai thac Tai mo Bach Ho hien dang tien hanh khai thac dau tir doi tugng chu yeu: Mioeen duai, Oligocen duoi va tang mong dang khoi (da granit nut ne) Khi nghien cuu cae dae tinh cua tung doi tugng khai thac, nhan thay rang, doi voi Miocen duoi va Oligocen duoi: tham thau nho va trung binh (0,08D va 0,03ID tuong ling); CO nhieu tap via (3 va 10 tap tuong ung) va khong dong nhat (do eat ket ciia Miocen duoi khoang 0,34 - 0.32 va ciia Oligocen duoi -0,18); hau bet cac gieng co cot ong chong khai thac den tan day va phan via san pham dugc due 16 Ing ching; nhiet via cao (90°C - 130°C via Miocen duoi va 130°C - 150°C Oligocen duoi) Tinh den 1/1/2005, & ddi twgng Miocen dw&i vd Oligocen dw&i cd 65 giing khai thde (trong dd 51 giing khai thde bdng gaslift) vd 18 gieng bom ep Tdng Iwu Iwgng dau khai thde trung binh dat 3000 tdn/ng.d 938 Ket qua ap dung cdc phuong phap tac ddng Ign viing can dav gieng tai md Bachjtd Tang mong la dang khoi chiia collector granit nut ne co hang ble va 16 r6ng, cac khe nut va vi khe niit la nhung b6n chiia diu Cac khe niit va vi khe niit co chieu day 0,3 - 3mm Do r6ng ciia collector khoang - 5%o va thim thiu thay dii pham vi rong tu 0,004 din 464D (trung binh la 0,135D) Nhiet via khoang 130 - 155°C va ap suit via thay dii tu 200 din 320at (do o sau 3650m) Theo kit qua nghien ciiu, da mong mo Bach H6 dugc tao chii yeu tir da granit, monsonit thach anh, granodiorit, monsodiorit thach anh, diorit, diorit thach anh [1] Thanh phin khoang vat da mong mo Bach H6 dugc chi Bang Cac da ting mong mo Bach H6 da bi tac dong boi nhiing qua trinh kien tao, thuy nhiet, phong boa, v.v hinh cac 16 h6ng, khe niit va vi khe nut, co chua nhilu khoang vat thii sinh chu yeu la seolit, felfan dugc bien d6i tu plagiocla HIU hit o cac gilng, phin tang mong deu than tran Hien co 83 gieng khai thac thuoc dii tugng (trong do, 27 gieng khai thac bang gaslift) va 31 gieng bom ep T6ng luu lugng diu khai thac dat khoang 30000 tin/ng.d voi 6,4% ngap nuac san pham khai thac Bang Khodng vdt, % Plagiocla Fensfat kali Thach anh Biotit Muscovit Amfibol Loai plagiocla Granit 20-47 20-50 25-40 - 10 0-3 0-2 Oligocla den Andezin Monsonit thgch anh Granodiorit 30-40 30-45 5- 18 5- 13 40-54 16-28 18-24 6- 10 Monsodiorit thgch anh 43-62 10-28 10- 17 - 13 - - 0-3 Oligocla andenzin 0-3 Oligocla andenzin Diorit Diorit thgch anh 13- 15 62-80 2-7 7- 17 - 10 - - - 0-18 Oligocla andenzin - 10 Andezin - 10 Andezin 62-68 3-5 80 C) tao mot kh6i lugng Ion tro N2 [2] Phuong trinh phan iing ciia h6n hgp h6a chat xay nhu sau: NaN02 + NH4Cl => NaCI + 2H2O + N2t Nhan thay rang, san pham sau phan ung eo mot kh6i lugng Ion tro N2 (uoc tinh Im^ dung dich hoa pham nhiet > 95°C thu dugc 150m"^ N2) Sau tao su chenh ap Ion giua day gieng va via (P(j > Pv) cot chat long - bi nen gieng nho hon hgp boa pham bi phan giai, gieng dugc mo nhanh tao nen chenh ap tiic thai giQa via va day gieng (Py > Pd) lam cho cac san pham phan ung sau xii ly axit viing CDG dugc day thao day gieng va dua len be mat qua trinh goi dong gieng Xii ly axit vung CDG theo eong nghe da dugc ap dung ph6 bien a cae gieng khai thac thuoc doi tugng Oligocen duoi va tang mong mo Bach H6 va he s6 c6ng xu ly dat 62% (Bang 2) Tuy nhien, hieu qua kinh te chua eao, phai chi phi nhieu cho hoa pham Ke tu nam 1997, sau he th6ng gaslift dugc dua vao khai thac, c6ng nghe xu ly axit ket hgp khoi thong, goi dong gieng bang gaslift duge ap dung rong rai va mang lai hieu qua cao b Gidi phdp nhd twong khi- ddu - axit Trong dilu kien nhiet via cao, be mat tilp xiic giua axit hon hgp nhii tuong dau - axit va dat da giam thi h6n hgp se di vao via sau ban so voi bin hgp axit binh thuong, d6ng thoi giam kha nang an mon kim loai ciia dung dich axit Pha h6n hgp nhu tuong - dau - axit lam tang nhanh kha nang goi dong, th6ng via sau gieng da dugc xu ly Giai phap sii dung nhu tuong - dau - axit [3] nh6m tac gia a XNLD Vietsovpetro de xuat xu ly mot s6 gieng thuoc tang mong Giai phap dugc tien hanh bang each bom d6ng thoi hoae ke tiep cac phan nhu tuong dau - axit (axit, dau diezel hoae dau tach va dau) vao cot 6ng khai thac (OKT) cua gieng xu ly Ty le the tieh ciia cac phan va trinh tu bom chiing dugc lira ebon cho dat dugc kha nang boa Ion nhat hon hgp dung dich nhu tuong diu - axit va dam bao chac chan h6n hgp nhu tuong - dau - axit xam nhap sau vao cac khe niit ciia via Nhu vay, a nhung d6i tugng xu ly c6 ap suat via thap thi sau xu ly, vung CDG dugc khoi th6ng manh va ting thao nhung chat gay ban va cac san pham phan ung tir via day gieng va theo san pham khai thac di len Tuy nhien, ban cbl vl ap suit Tuygn tap bao cao Hdi nghj KHCN "30 nam Phu Viet Nam: Cff hdi mdi, thach thuc mdi" 943 nen va lugng diu tach tu cac gilng tu phun ian can, nen giai phap kh6ng dugc tiep tuc ap dung tai mo Bach Ho c Xu- ly axit dw&i dp sudt cao Khi xu ly vung CDG bing axit duai ap suit cao, mot kh6i lugng Ion dung dich axit dugc bom ep true tilp vao gilng qua thiet bi long gieng (TBLG), tren da lap dat san van gaslift Dl tiln hanh xu ly vung CDG theo c6ng nghe [4], cac thiet bi va dung dich axit diing dl xu ly dugc dat tren tau dieh vu Trong qua trinh xu ly, dung dich axit dugc bom toi mieng gilng qua 6ng mem chiu ap, n6i tu tau toi gian khoan Nhung uu diem chii yeu ciia cong nghe xu ly axit duoi ap suat cao so voi c6ng nghe nut via thuy lire (NVTL) la: qua trinh xu ly don gian, giam bot nhieu c6ng doan siia chua gieng (trong co qua trinh dap gieng) gay nhiem ban viing CDG, giam thai gian va chi phi cho chuan bi gieng truoc tien hanh xii ly So voi xu ly axit th6ng thuang, c6ng nghe xii ly axit duoi ap suat cao c6 mot so uu diem sau: khoi lugng dung dich axit bom ep co the dat toi 120m (d6i voi xii ly axit th6ng thuang, kh6i lugng axit trung binh la 24m^) va ap suat bom ep dat toi 350at (so voi 250at tien hanh xii ly axit thong thuong) De nang cao cac chi tieu kinh te - ky thuat xii ly axit duoi ap suat eao nhiing gieng CO khoang mo via san pham Ion, XNLD Vietsovpetro dang nghien ciiu, hoan thien va dua vao sii dung thiet bi mai (cac may bom, binh chiia va duong 6ng bom ep axit, v.v.) dugc lap dat tren gian khoan nham dam bao kh6i lugng va ap suat bom ep axit di sau vao via d Xii: ly axit dw&i dp sudt cao co chen ep proppant v&i nong thdp Trong qua trinh khoan, sua cbQa va khai thae nhiing gieng thuoc tang mong, dung dich set va cac tap chat lang dong tao nhQng mang bao boc tren be mat khe niit va vi khe nut Ngoai ra, d6i voi cac gieng khai thac, qua trinh lam viec cua chiing, ap suat via giam dan theo thai gian lam cho cac khe nut a vung CDG co xu huong khep lai bien dang dan h6i ciia dat da Doi vai cac gieng bom ep, cac phan tu ciing chat long bom ep co the lam bit cac kenh dan hoae nhQng lop set cac khe niit bi truang no tac dung voi nuoc Cac nguyen nhan ke tren lam giam chay tham ciia dong chay a viing CDG Trong truong hgp nay, xii ly axit duoi ap suat eao co chen ep proppant voi ham lugng thap da mang lai ket qua dang ke [4] Sau xii ly axit, chuyen dong ciia chat long mang cat voi van toe Ion lam be mat ciia cac khe niit va vi khe nurt bi bao mon va riia xoi manh Cac vi khe niit va khe nut (ehu yeu phan du6i) dugc kh6i phuc hoae dugc mo rong them Sau do, cac khe nut va vi khe nut dugc chen ep boi propant de chiing khoi bi khep lai Phuong phap xii ly axit duoi ap suit cao co chen ep proppant voi n6ng thap kh6ng dugc tiep tuc ap dung tai m6 Bach H6 cong nghe xii ly phiic tap va chi phi Ion cho c6ng viec chuan bi, xii ly gieng va bom riia proppant sau xii ly Tuy nhien, c6ng nghe dang dugc tiep tuc nghien ciiu hoan thien nham nang cao hieu qua kinh te ky thuat xu ly vung CDG ting mong 944 Ket qua ap dung cac phuong phap tac ddng len vung can day gigng tai md_BgchJj^^^^ Cong nghe xij ly gieng bang dan chay nl PGD-42T tao cao ap, ket hop voi chat long hoat tinh Nhu chiing ta da biet, d6i tugng Oligocen duai tao boi nhilu tap via nam xen ke va khong d6ng nhat, tang mong dugc ma co day via san pham rat Ion De tang hieu qua xu ly vung CDG nhung dieu kien dia - ky thuat nay, tai mo Bach H6 da filn hanh thu nghiem phuong phap xii ly t6ng hgp nha dan chay n6 PGD-42T tao cao ap, kit hgp \6i xu ly axit C6ng nghe xii ly dugc tien hanh bing each tha mot so ian xulng gilng nhung bang dan PGD-42T co kich thuoc be, tren cap dia vat ly qua cot OKT tai cac khoang xii ly xac dinh Sau m6i ian tha, bang dan dugc kich chay n6, tao cao ap o day gilng vugt qua ap suat niit via, chat long ciia gieng cung vai mot phan eo kha nang ep sau vao via lam mo rong cac khe niit san co va tao them he th6ng khe nut moi Cac khe mit sau dugc tao dan chay no, tiep tue dugc xu ly bang axit lam tang them tham thau viing CDG xii ly U'u diem ap dung c6ng nghe ke tren la qua trinh xii ly, kh6ng can phai tien hanh dap gieng va nang - tha cot OKT Tuy nhien, xii ly, xung ap suat o day gieng CO the dat toi 1800at lam anh huong chat lugng vanh xi mang tram va cot 6ng ch6ng khai thac dan toi xuat hien ap suat giua cac cot ong chong hoae lam mop 6ng chong khai thac Ngoai ra, cac khe niit tao sau xu ly kh6ng dugc chen ep boi proppant nen sau xii ly mot thai gian, cac khe niit dong khep lai, dan den he s6 san pham ciia gieng giam nhanh (th6ng thuang thai gian hieu qua khoang - thang) [5] Do nhQng nguyen nhan nay, phuong phap xii ly t6ng hgp nho dan chay n6 PGD-42T tao cao ap, ket hgp \oi xu ly axit dugc ap dung rat ban che Nut via thiiy lyc co chen khe nut tao boi proppant Trong nhung nam gan day, phuong phap NVTL eo chen proppant dugc tiln hanh nhieu gieng thuoc Oligocen duai tai mo Bach H6 Day la phuong phap mang lai hieu qua cong nghe nhat d6i voi d6i tugng khai thac Ket qua NVTL phu thuoc rat nhieu vao trang thai va dac tinh dia - ky thuat ciia gilng (ap suat \ia s6 lugng va day cac tap via san phim, day ciia cac tap via ngan each giua cac via san pham, tinh trang cot Ing ching khai thac, chit lugng bom tram xi mang, miic ngap nuoc ciia chat long khai thac, v.v.) Nhin chung, cac gilng da dugc thuc hien NVTL c6ng deu co lugng dau gia tang Ion va thoi gian dat hieu qua keo dai khoang - nam Tuy nhien, cac gieng xu ly khong c6ng hoae dat kit qua kh6ng tit la mot so ngu}en nhan chii yeu sau: - Theo thiet ke, can phai tiln hanh NVTL hoae ting gilng, nhung tien hanh a tang duoi thi xay hien tugng thong via len tren (chit long di len tang tren qua phia ngoai cot ong ch6ng khai thac chat lugng tram xi mang ngoai cot 6ng chong kh6ng bao dam), nen phai tien hanh hoae ting nhap mot - Khi tien hanh NVTL kh6ng ep hit proppant vao via va proppant lai nhilu cot OKT De giai phong packer gieng da phai tien hanh bom rua proppant OKT nha sii dung ong mem - Sau kit thiic N'VTL, kh6ng dua packer len dugc cot 6ng ch6ng khai thac bi mop Khi tiln hanh NVTL a ting tren bi thong via xu6ng tang duoi luygn^tap bao cao Hdi nghj KHCN "30 nSm Phu Viet Nam: Cff hdi mdi, thach thuc mdi" 945 Khi tiln hanh NVTL ting duoi bi th6ng via, chit long mang proppant di len ting tren qua phia ngoai cot Ing ching khai thac Sau ngung bom, proppant dong lai tren packer gay nen su c l (kh6ng keo packer len dugc) Voi muc dich de phong ket packer, co thi diing "sum packer" thay thi packer th6ng thuong de tien hanh NVTL nhieu tang cac gilng thuoc dii tugng Oligocen duoi U'u diem eua viec sii dung packer la proppant ling dong tren packer, cot OKT dugc keo len de dang va de lai "sum packer" gilng, sau packer dugc giai phong nho khoan pha Cong nghe NVTL co chen proppant cung dugc tien hanh thii nghiem mot s6 gieng tang mong mo Bach H6, nhung he s6 c6ng dat kh6ng cao Den nay, cac hang dau n6i tieng tren the gioi chua c6 mo hinh chuan de thiet ke NVTL cho tang mong Theo chiing t6i, nguyen nhan chii yeu c6 sir kbac biet giQa kh6i lugng proppant theo thiet ke va kh6i lugng proppant thuc te ep dugc vao via la miic mat nuoc tang mong rat manh, ap suat va luu lugng chat long cua he th6ng may bom chua dii kha nang de tao nen khe nut moi tang mong Ngoai nhiing phuong phap xii ly vung CDG chii yeu ke tren, tai mo Bach H6 da nghien ciiu dua vao thii nghiem mot s6 phuong phap xu ly khae nhu: phan rQa set nho boa pham, d6t hon hgp chay oxy hoa (GOS), xii ly nho t6 hgp dan chay n6 va ban via MKAV42 CO kich thuoc be, xii ly nho dung moi ket hgp voi dung dich axit, phuang phap tao xung thuy lire, xii ly bang dien tu, ngan each dong nuoc cac gieng khai thac nho h6n hgp AKOP va GALKA, xii ly bang hgp chat hoat tinh be mat (HTBM) Ket qua xii ly vung CDG nho cac phuong phap dugc ehi cac bao cao [5] Nhan thay rang, kh6i lugng xu ly cua tung phuong phap thu nghiem eon it, viec lira chon gieng de xii ly chua t6t, mgt so phuong phap khong mang lai hieu qua kinh te - ky thuat cao va pham vi ap dung cua chiing eon ban che Hien nay, cac phuong phap dang dugc tiep tuc nghien ciin, lira chon va ap dung eho tung d6i tugng nhiing dieu kien dia - ky thuat thich hgp KET LUAN • Xii ly nhu tuong dau - axit ket hgp voi goi dong bang gaslift la phuong phap tac dong len viing CDG eo hieu qua kinh te - ky thuat nhat cac gieng khai thae mo Bach Hi • Ap dung c6ng nghe xu ly axit duoi ap suat cao (true tiep qua TBLG de kh6ng can phai cac quy trinh nang - tha cot OKT va dap gieng se nang cao hieu qua kinh te - ky thuat De tang hieu qua xu ly axit, can dau tu trang thiet bi chuyen dung (may bom co c6ng suat Ion, he th6ng thiet bi 6ng mem, v.v.) tren cac MSP va BK • Niit via thuy lire co chen ep khe mit tao boi proppant la phuang phap xu ly vung CDG CO hieu qua c6ng nghe nhat a cac gieng khai thac thuoc Oligocen duoi mo Bach H6 Khi tien hanh nut via thiiy luc nhieu tang tach biet, nen sii dung "mit cau" va "sum packer" de ngan each tang duoi va tien hanh niit via tang tren nham giam thieu cac sir c6 co the xay • Tiep tuc hoan thien c6ng cac nghe nut via thiiy lire axit co chen proppant voi nong thip, xii ly gieng bing dan chay n l PGD-42T tao cao ap kit hgp voi chit long 946 Kgt qua ap dung cdc phuong phap tac dgng len viing can d^y gieng tai md Bach Hd boat tinh va mot s6 c6ng nghe khae da dugc thu nghiem tai mo Bach H6 nham xac dinh cong nghe t6i uu cho tung d6i tugng xii ly cu thi, ding thai nghien ciiu lira ebon, dua vao ap dung mot s6 c6ng nghe moi tac dong len via san phim, nhim nang cao he s6 thu h6i dau ciia mo TAI LIEU THAM KHAO Bao cao dl tai NCKH Nhir-21 ciia Vien NCKH & TK D I U biin, XNLD Vietsovpetro, 1997 Duong Danh Lam va n.n.k., 1996 Hodn thiin cdng nghi xir ly bdng axit vung can day gieng thudc tdng mdng md Bgch Hd Tuyen tap Hoi nghi Khoa hoc Dai hoc Mo - Dja chat Ha Noi Duong Danh Lam va n.n.k., 1997 Sdng kiin cdi tiin ky thugt - hgp ly hda sdn xudt "Cdng nghi xir ly bdng nhii tuang - ddu - axit vung can day giing thudc ddi tugng tdng mdng md Bgch Hd diiu kiin dp sudt via thdp" N° 568, XNLD " Vietsovpetro Duong Danh Lam va n.n.k., 1999 Co chi vd cdng nghe nut via thuy luc - xu ly axit ddi v&i cdc giing thudc tdng mdng md Bgch Hd Tap chi Dau khi, S6 Cac bao cao dl tai NCKH, Nhir-16, 21, II1.6, IV.2 cua Vien NCKH va TK DIU biin, XNLD Vietsovpetro, 1994 - 2004