332 Xac djnh dac trung chiia bg tram tich Phii Khanh, Thgm luc dja Viet Nam bang mdj^juing^^ XAC DINH DAC TRUNG CHlTA BE T R A M TICH PHU KHANH, THEM LUC DIA VIET NAM BANG MO PHONG MONTE CARLO VA HE T[.]
332 Xac djnh dac trung chiia bg tram tich Phii Khanh, Thgm luc dja Viet Nam bang mdj^juing^^ XAC DINH DAC TRUNG CHlTA BE TRAM TICH PHU KHANH, THEM LUC DIA VIET NAM BANG MO PHONG MONTE-CARLO VA HE THONG THAN KINH NHAN TAO Nguyin Thu Huyen Viin Ddu Khi Kazuo Nakayama, Hou Jianyong Viin Khoa hoc Dia chdt Nhdt Bdn TOM TAT Md phdng Monte-Carlo vd Hi thdng thdn kinh nhdn tgo (ANN) da dugc dp dung de xdc dinh su phdn bd ciia dd chua cho nhieu vung tren thi gi&i Cdng cu ndy gdp phdn to l&n giiip ta xdc dinh sir phdn bd ciia dd chira v&i mirc chinh xdc hon v&i gid thdnh hg han Tru&c day de xdc dinh sir phdn bd ciia da chira ngu&i ta thu&ng diing phuong phdp dia thdng ke, song phuang phdp ndy thu&ng bi hgn che nhimg vimg m&i chua cd nhiiu giing khoan Vi vdy, mdt cdng cu m&i rdt huu hieu cd ten la "Geology Driven Integration - GDI" cd the giiip ta khdc phuc dugc hgn che tren, dd la giiip ta xdc dinh dugc su phdn bd ciia da chua diiu kien vitng nghien ciru chi cd mdt vdi giing khoan V&i GDI, bdng md phdng Monte-Carlo, hdng logt cdc gieng khoan gid dinh dugc tgo dua tren mdt vdi giing khoan thuc da cd cdng v&i cdc thdng tin dia chdt ciia vung nghien ciru, tif dd viec hgn che vi cd qud it giing khoan se dugc khdc phuc Hon nira, bdng dia chdn tdng hgp dugc tgo tii nhung gieng khoan gid dinh cdng gdp phdn bii dap lgi hgn che thieu thdng tin giing khoan Cdc thudc tinh dia chdn thich hgp vd cdc ddc trung chua dugc lua chon vd dugc dua vdo Hi thdng thdn kinh nhdn tgo (ANN) de xdc dinh cdc hi sd cd lien quan den cdc ddc trung chua dd Cudi cung hi thdng thdn kinh nhdn tgo dugc luyen bdng cdch dd se dugc irng dung cho todn bd cdc tuyen dia chdn cd vimg nghien ciru nhdm ddnh gid su phdn bd ciia dd chica viing Trong bdi bdo ndy, tdc gid da ung dung phuong phdp GDI de xdc dinh su phdn bd cdc ddc trung chira cho tap da vdi Miocen giua: su phdn bd ciia chieu ddy vd rdng ciia tap chira Miocen giira ciia be Phii Khdnh Theo ket qud nghien ciru thi vung Ddng Bde ciia be Phil Khdnh dugc cho la viing cd trien vong v&i chieu ddy thay ddi tu 70 -100m vd rdng thay ddi tu 15-30% Tuygn tap bao cao Hoi nghj KHCN "30 nam Phu Viet Nam: Co hoi moi, thach thiic moi" 333 GIOI THIEU CHUNG L Muc dich nghien ciiu Tir trudc din bl trim tich Phii Khanh dugc danh gia la be tram tich cd tnen \ gng dau vdi hai ddi tugng chiia chinh la da chira cat ket va da vdi Dua vao tai lieu dia chin da cd vimg, cac dang cau tao trien vgng cua be Phii Khanh chii yeu la cac dang cau tao vdm, khdi ke ap dirt gay va cac dang phi cau tao each day khdng lau, Vien Dau Khi va Vien Khoa hgc Dia chat Nhat Ban da cd hgp tac nghien cim danh gia tiem nang be tram tieh Phii Khanh va da dua ket luan la dau da duge sinh va thoat tir Miocen va van cdn tiep tuc den tan Nhung be tram tich Phii Khanh van cdn dang d giai doan dau ciia qua trinh tim kiem tham dd, chua cd gieng khoan nao dugc dat tai day vi vay nhirng ket qua nghien cim trudc day cdn mang tinh gia dinh viec nghien cini chi dua vao ngudn tai lieu dia chan da cd vimg De khae phuc ban che tren, GDI la mdt ky thuat mdi rat hiiu hieu giup ta xac dinh su phan bd ciia tang chan mdt each true tiep tir cac thudc tinh dia chan va tii' se gdp phan danh gia lai trir lugng mdt each ddc lap tir ket qua minh giai cau triic Trong bai bao nay, cae tac gia da img dung phuong phap GDI cho tuyen dia chan qua be Phii Khanh nham xac dinh su phan bd ciia dac tru-ng chii'a cho tap chua da vdi Miocen gitra Co' SO' du' lieu Tam tuyen dia chin thudc khao sat NOPEC VOR-93 dugc sir dung (Hinh 1): Tuyen VOR 93-101, Tuyin VOR 93-102, Tuyin VOR 93-104, Tuyin VOR 93-106, Tuyin VOR 93-108, Tuyin VOR 93-110, Tuyin VOR 93-112, Tuyin VOR 93-301 Cae tai lieu carota ciia hai gieng khoan dugc sir dung nghien cii'u la 120-CS-lX: Sonic, Gama ray va 121-CM-lX: Some, Gama ray (Hinh 2, 3) DAC DIEM DIA CHAT VA CAC KET QUA MINH GIAI TAI LIEU DIA CHAN BE PHU KHANH L Dac diem dia chat chung be Phii Khanh Be tram tieh Phii Khanh la be tram tich hep, keo dai dge them luc dia mien Trung Viet Nam vdi chieu dai cd 250km va chieu rdng cd 50km Be phii Khanh dugc phan each vdi be tram tich Sdng Hdng bdi ddi trugt Da Nang va dugc phan each vdi be tram tich Cii'u Long bdi ddi trugt Tuy Hda (Hinh 4) Be tram tich Phu Khanh la mdt be tram tich tach gian (Hinh 5) vdi cac dac trung chinh nhu: mdng dugc phan eat manh bdi cac diit gay, phu tren mdng la cac tap tram tich ddng tach gian, xuat hien cac bat chinh hgp va cac tap tram tich sau tach gian Hoat dgng tach gian va nang trdi xay sudt Oligocen - Miocen sdm Giai doan sau be dugc dac trung bdi boat ddng lim chim 334 Xac djnh dac trung chiia bl tr^m tich Phii Khanh, Thgm luc dja Viet Nam bang mdj^hdng^^ Kit qua minh giai tai lieu dia chan Nhu da dl cap d phan tren, pham vi bai bao nay, tac gia da sir dung tuyen dia chin ciia khao sat NOPEC (Hinh 1) Viec minh giai tai lieu dia chan be Phu Khanh chii yeu dua vao cac marker tir cac giing khoan ian can bl Phu Khanh va dya vao ly thuyet dia chan - dia tang (Hinh 7, 8) cac ting dia chin da minh giai dugc the hien tren Hinh Nde mdng chinh la mat bit chinh hgp cd nhat - SHI Day la ranh gidi ngan each giira mdng trudc De tam va trim tich De tam Bit ehinh hgp SH2 tuang iing vdi nde tap Oligocen Noc tap Miocen dudi ehinh la bit chinh hgp SH3, day cung chinh la ranh gidi phan each giira lat cit trim tich ddng tach gian va sau tach gian SH4 la bat chinh hgp tuong irng vdi nde tap Miocen giira va day eiing chinh la nde tap carbonat phat triln bl Phii Khanh Bit ehinh hgp SH5 tuong irng vdi nde tap Miocen tren SH4 va SH5 rat triing kbit vdi cac marker tir cac gieng khoan d phia Nam be Song Hdng Tai be tram tich Phu Khanh, tang dia chan da duge minh giai dd la: nde mdng, noc Oligocen, noc Miocen dudi, nde Miocen giira, nde Miocen tren Tren mat cat dia chan, nde mdng (Hinh 8) tuong ddi de xac dinh, cd the quan sat thay ranh gidi mdng nhu la cac phan xa bien manh d phan dudi ciing ciia Mt cat dia chan (mau dd) Viec lien ket mdng dugc dua vao cac dau hieu phii day, ga day, d mdt so noi cd dau hieu chdng nde Dac biet mdng d day cdn duge xac dinh dua tren dau hieu bat chinh hgp gdc - day la bieu hien ciia su bat dau ciia hien tugng tach gian viing Lien ket mdng gap khd khan anh hudng ciia nhieu phan xa nhieu ian d phan phia Tay Bae be, lien ket thuc su tin tudng qua nhirng viing mdng nang cao, cdn qua nhirng viing trung sau thi viec lien ket kem tin tudng ban Nde Oligocen (Hinh 8) dugc lien ket nhu la nde tap phan xa manh tuong img vdi mat bat chinh hgp khu vuc khu vuc phia Ddng Nam be trim tieh Sdng Hdng, bit chinh hgp cd dang bao mdn rd net Nde Miocen dudi duge xac dinh tuong img vdi bat ehinh hgp khu vue lien quan tdi thdi ky cudi cua pha tach gian Bien Ddng Nde Miocen dudi ciing chinh la day eiia tap tram tich nem ian Bao mdn eat cut ciing rat phd bien d phan ria them ciia be Nde Miocen giira cd dac trung nhu la nde tap phan xa bien trung binh, lien tuc tir trung binh den tdt d phia BIC bl, din phin phia Nam be thi bien phan xa manh ban Day eiing la mat bit chinh hgp khu vuc, dugc xac dinh bdi cac dau hieu ga day, phii day Mat bit chinh hgp cung chinh la noc tap carbonat phd biin vimg Noc Miocen tren dugc lien kit nhu la nde tap phan xa bien tir thap din trung binh lien tuc tir trung binh din cao Lien kit dge theo cac tuyen dia chan hudng Tay - Tuygn tap bao cao Hdi nghj KHCN "30 nam Phu Viet Nam: Co hdi mdi, thach thiic mdi" 33^ Ddng quan sat rd diu hieu ga day cdn diu hieu mat bao mdn kenh dao khoet quan sat rd dge theo cac tuyin dja chin d phia Nam be Phii Khanh KHAI NIEM VA LY THUYET GDI GDI dugc tiln hanh dua tren bude chinh (Hinh 10), dd la: co cau tich hgp (integration framework), md phdng Monte-Carlo (Monte-Carlo simulation), he thdng than kinh nhan tao (Artificial Neural Network - ANN) Co'cau tich hop GDI dugc thiet lap nham xac dinh cac dac tinh chiia va phan tich cac thudc tinh dia chan Mdt nhirng img dung ciia GDI la xac dinh su phan bd theo khdng gian ciia cac tap da chira nhu chieu day, rdng, cdt dau va khi, v.v bang viec lien ket tai lieu dia vat ly gieng khoan va cac thdng tin dia chat vdi cae thude tinh dia chan Thdng thudng, de xay dung mdi quan he giira cac thudc tinh dia chan va cac dac tinh chira can phai tham khao tai lieu ciia nhieu gieng khoan Trong trudng hgp ma tai lieu gieng khoan cd it hoae khdng cd dii thi GDI la mdt phuang phap hieu qua giup ta giai quyet van de khd khan Mae dii khdng cd dii tai lieu nhung eae nha dja chat lai ed rat nhieu cac thdng tin dja chat lien quan kbac Vdi phuang phap GDI, cac tai lieu dja vat ly gieng khoan da cd va eae thdng tin dja chat lien quan se duge tich hgp lai nhd co eau tieh hgp (Hinh 11), sau dd hang loat cac gieng khoan gia djnh va bieu dd dja chan tdng hgp tuong img se dugc tao bang md phdng Monte-Carlo (Hinh 12), va nhiing gieng khoan gia djnh se ddng vai trd nhu nhtrng gieng khoan thue viing nghien cim, bang each nhimg han che vi thieu tai lieu se dugc giai quyet Mo phong Monte-Carlo Vdi phuang phap GDI, cac tai lieu dja vat ly gieng khoan, cac thdng tin dja chat lien quan dugc tdng hgp co eau tich hgp Sau dd hang loat cac gieng khoan gia djnh dugc tao Nhtrng gieng khoan gia djnh vdi hang loat cac phan dja tang va cac dudng cong carota tuong img se dugc coi nhu la nhting dau hieu thuc ciia ddi tugng chira can nghien ciru mac dii ta ehua ed dii thdng tin Xac suat dja chat duge hinh bdi md phdng Monte-Carlo va quan he toan hgc gitra dae tinh chira vdi thudc tinh dia chan se dugc xac djnh bang he thdng than kinh nhan tao He thong than kinh nhan tao (ANN) De tim dugc mdi quan he toan hgc gitra dae trung ehira va thudc tinh dja chan, vdi phuang phap GDI phai sir dung he thdng thin kinh nhan tao Trong he thong thin kinh nhan tao, cd nhieu thuat toan nhung don gian nhit la thuat toan lan truyin liii (back 336 Xac dinh dac trung chiia be tram tich Phii Khanh Thgm luc dja \ iet Nam b^ng mo phong propagation) (Hinh 13) Lan truyen lin bao gdm mdt ldp diu vao vdi mdt vai ndt, mdt ldp dau vdi mgt hoae mgt vai ndt (cd it nhat mdt ldp an) He thdng than kmh nhan tao se tim duge quan he giua nhung nut diu vao va nhting niit dau Thuat toan eo sd dugc dien ta theo phuong trinh: Y (X) = Wi.f(Xi) Trong dd: Y(X): W: X: f(X,): i: Gia trj dau (dac tinh chira) Vecto phu them Vecta dau vao (thudc tinh dja chan) Ham ca ban So lugng nut Khi chay ANN, sai sd dugc tinh bang each so sanh nhiing gia trj da tinh duge bang each img dung he thdng than kinh nhan tao ANN vdi nhung gia trj thuc dugc trich tii' tai lieu gieng khoan Bang each dieu chinh lua chgn tham sd quan he dua tren thuat toan da cd cho sai sd (RMS) giira gia trj tinh toan dau va gia trj mong mudn la nhd nhat Sai sd cang nho thi ket qua dau cang cd tin cay hon Sai sd thudng dao ddng khoang 0,8 - 0,5, neu thap hon 0,5 thi tin cay se cang cao hon AP DUNG PHUONG PHAP GDI VAO BE PHU KHANH Phan tich tai lieu gieng khoan Vi be Phil Khanh chua co gieng khoan tham dd nao nen phai sii' dung tai lieu carota ciia hai giing khoan gan nhit thudc bl Sdng Hdng la: 120-CS-lX va 121-CM-lX (Hinh 2, 3) Hai gieng khoan tren dugc chgn de ap dung phuong phap GDI vi day la hai giing khoan dugc dat d vi tri tdn tai cac dieu kien dia chit tuong tu vdi vdi dilu kien dja chit ciia khu vuc nghien cu'u Dau rang hai gieng khoan khdng thude bl Phii Khanh nhung nhung tap tram tich ma hai gieng khoan da khoan qua cd nhting dac dilm tuong ddng, dac biet la tap Miocen tren va Miocen gitia Su tuong ddng da dugc thi hien tren Hinh qua mat cat dja chan va dja tang giing khoan Tir dd nhung tai lieu se duoc trich dl chay GDI Tram tich Miocen xuat hien d ca hai gieng khoan tren Tudng dja chin diln hinh cho tap tram tich Miocen giiia la dang phan xa bien manh, dac trung cho da vdi phat triln manh vimg 2, Thiet lap co cau tich hop De gan ket cac thdng tm dja chat vdi cac tai lieu gilng khoan da cd, cin thilt phai thiet lap mot co ciu tich hgp Co cau tich hop dugc thiet lap eho vimg nghien cuu bao gdm thdng tin ciia ting cin xac djnh dac trung chiia - Miocen gitra va cac ting tren va dudi nd Trong co ciu tich hgp, ba tang (3 don vi) dugc dat ten la UM, MM va LM (Hinh 14) Moi ting dugc chia cae don vi nhd hon ed ten ggi la Lim, Cls, Vol theo ten goi ciia phin thach hoc chii yeu ton tai mdi dan vj Tuygn tap bao cao Hdi nghj KHCN "30 nam DauJ =0.15-0.30 DT = 200 • 250ms/m Sw = 0.13-0.56 (avg: 0.35) • 1138 o s Q 1155- 1473m: Limestone (^ =0.25-0.32 ae o zft ct o -I DT = 250 - 300ms/m Sw = No oil show I: 1473 a^szzHSs 1475 - 1503.5m: tight limestone low porosity (0.05) DT = 180ms/m Hinh 2: Cot dja tang ting hop GK 120-CS-lX Tuyen tap bao cao Hpi nghj KHCN "30 nam Phu Viet Nam: Co' hoi moi, thach thiic mdi' LOG CHARACTERISTICS LITHOLOGIC DESCRIPTION AND RESERVOIR CHARACTERISTICS AGE FORMATION J] * : NO DATA JH 765 - 1040m: Clay light grey to olive green grey, soft, amorphous, sticky and washable Sometime plastic and smooth in places Occasionally found to contain silt and carbonaceous matter 107S TRITON GROUP 1040 - 1645m: Claystone light to medium grey, soft to firm, homogeneous, slightly a calcareous, occasional fragment of moderately hard silt in part, trace of microcarbonaceous matter In part 1645 - 2200m: Volcanics Mainly with: Low density (2.05-2.3g/cm') High DT (350 - 400ms/m) High CNL (0.35-0.40) Except some tight intervals with low porosity (0.14 - 0.15) No oil shows PAC NEST VOCAUilCS J2K Hinh 3: Cot dia tSng t6ng hop GK 121-CM-MX 341 345 X4ygn tap bao cao Hoi nghj KHCN "30 nam D§u Viet Nam: Co hoi moi, thach thuc moi" •C3 o o o o o o IC! riniiiiif^r I 'i a ^)'\ ;'i( li f-'^''V = ,' :,.\'U':: * ^ r fW I iiifc.^ UI o r^ T ^ ãĐ l:fhlH ' d : t i kmm.!•: ?^^ "S , ,^'^^(-1::: •; 'li,': t;-''v OJ a r^fifc' H ^ ' '-\W>>; •J' '• ••• ' •'- ' ! ' • [ - - ill!.;.-, - - 11 -^.'^ny ^ '-"i'^''' 4) ,:^ u CQ '(/,'.'/ s U u a Mr''c •tm S m o o c o C'2 o c k? ' ^ J ã~T" o o o ô ~~n~ ~' o r o C5 o o U5 -=!• f ohO o o ~ " l s ;^ oC3 a l 6X) C X C s S ia* '2 'oh G o JS JA WD C (ii O •• s c 350 Xac djnh d|c trung chiia bg trSm tich Phii Khanh, Them luc dja Viet Nam bang mo phong >^ C3 J VH -1 +-> zi oo 1) +-> ;« -M O ?3 B _ v1 \ \ A1 K Inp \ s e a z z< o i^ '3 U lU su JS Wei 1\ u o c« >^ DD yer o CJ S fl RO idden \ "O — ' CQ •• i^ rn ^ Hinh 1—^ "^ •fl s • V-( (U (1> : Dangtru yen lui 1o IZ) ecting different layer t4-H w s ctor ^ ? ^ 5* fea • T-H o S -o -a [ O on-1 inear sfor matio • cs Tuygn tap bao cao Hoi nghj KHCN "30 nam DSu Viet Nam: Co hoi moi, thach thiix^moi'^ Well group'R8al_ifell_group' 351 J £bject Display Toggle S^elected Utilities 751- mWell 120 IX b Display Edit t * ^1 f - Sonic \ -m] Toggle "2lv ul] GR* WellJ20J) D^lsplay Edit Toggle t g f\i ^ Wen 120 IX b •^ Smie Integration Frameiiork ^ j MMJim(31) -tt« MMJim(U) Object Edit Display MMJim(M) Utilities MMJIlll|35) MMJim|9l) -ttM A A ,°HMJIIII(37) ~MMJIm(3t) MMJim(3S) -na / MMJiiii(M) / Hai j; il MMJini(t1) -031 MMJini(4I) -c« MMJim(43) MMJiin(44) MMJim(45) IAilJini(4t) MMJJm(«) -o« iMMJiiii(4l) Hinh 14: Cc cau tich hop duffc thiet lap tir tai lieu gieng khoan thuc va cac thong tin dja chat lien quan ... chinh (Hinh 10), dd la: co cau tich hgp (integration framework), md phdng Monte- Carlo (Monte- Carlo simulation), he thdng than kinh nhan tao (Artificial Neural Network - ANN) Co''cau tich hop GDI dugc... chat duge hinh bdi md phdng Monte- Carlo va quan he toan hgc gitra dae tinh chira vdi thudc tinh dia chan se dugc xac djnh bang he thdng than kinh nhan tao He thong than kinh nhan tao (ANN) De tim... phdng Monte- Carlo (Hinh 12), va nhiing gieng khoan gia djnh se ddng vai trd nhu nhtrng gieng khoan thue viing nghien cim, bang each nhimg han che vi thieu tai lieu se dugc giai quyet Mo phong Monte- Carlo