662 Thay ddi quy trinh minh giai dut gay trong md cd c§u true dja chat phdcj£P^
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THAY DOI QUY TRINH MINH GIAI DlTX GAY TRONG MO CO CAU TRUC DIA
C H A TPHlTC TAP
Jim Lingley, Nguyin Minh Tuan Schlumberger
TOM T A T
Ngdy nay, nin cdng nghiep ddu khi dang ddi mat v&i nhiiu thdch thirc m&i. Mdt sd thdch thuc liin quan din yiu td thi tru&ng, sd cdn lgi liin quan t&i do phuc tgp cua diiu kiin dia chdt md vd mdi tru&ng thdm do, khai thde. Trong khi do, nhu cdu gia tdng ty le thu hdi ddu, khi ddi v&i cdc md khai thac dugc xem Id vdn di thiit yiu. Thuc ti thi trir lugng ddu md trin thi gi&i dang gidm, gid ddu vd nhu cdu tieu thu lgi tdng.
Mdt vdi ndm gdn day, cdc chuyen gia sir dung nhiiu cdng cu, mdy mdc thiit bi hiin dgi trong viec cdi tiin cdc quy trinh tim kiim, thdm dd ddu khi. V&i cdc tiin bd trong cdng nghi mdy tinh, ngdy cdng nhiiu cdng ty ddu khi trang bi mdy tinh PC cho viec minh gidi, phdn tich tdi lieu. Mdy tinh PC dap ung dugc cdc yeu cdu da dgng cua ngdnh cdng nghiep ddu khi, khdng nhirng trong viec tim kiim, thdm dd md cdn giup lap bdo cdo, hdi hop qua mgng vd han thi nda la cd thi xach tay. Cung v&i su thay ddi nhanh chdng ve cdu hinh phdn cirng cua mdy tinh PC, cdc gidi phdp, phdn mim irng dung di kem ciing phdt triin nhanh chdng vd dugc dung di thuc hiin cdc phdn tich, tinh todn trir lugng. Nhiing yiu td trin giup cdc chuyin gia cd thi phdn tich, nghiin ciru md ky cdng han, chinh xdc hon, gidm thiiu rui ro, bdt dinh, vd hiiu ro han vi md hinh trdi ddt & cd hai trgng thdi tinh vd ddng.
Viec hiiu ro vi cdc kiiu dirt gdy trong md cua mink se giup cae ehuyin gia cd cdi nhin todn diin hem vi cdu true dia chdt trong long ddt. Diiu ndy giup cho viec ra quyit dinh liin quan t&i viec dgt vi tri giing khoan, gidn khoan vd tinh todn tinh kinh ti cua timg gieng khoan mdt.
Y tw&ng m&i + Cong nghi m&i = Gia tdng trir Iwgng (thim md)
Vi sao irng dung cdc y tu&ng m&i lgi quan trong? Chung ta ciing nhin lgi birc tranh todn cdnh ciia quy trinh phdt triin md. Nin tdng cua viec phdt triin md dugc hiep hdi cdc nhd dia chdt - dia vgt ly lap ra vd nay la nhdn td co bdn di phdt triin them.
Tuygn tap bao cao Hdi nghj KHCN "30 nam D^u khi Viet Nam: Co- hdi mdi, thach thuc mdi' 663
Hinh 1: Birc tranh toan canh cua quy trinh phat trien mo
(Lap duai ciing: lap dia chat - dia vat ly, cac chuyen gia dia chat, dia vat ly co the thay kich thuac m6, vi tri, cac loai da va cac chat luu trong mo. Lap giira, \&p c6ng nghe mo, cho chiing ta th6ng tin ve su chuyen dong cua chat luu, va cac du doan ve kha nang thu h6i dau, khi. LcDp tren ciing, lap c6ng nghe khai thac, tap trung vao viec t6i uu hoa qua trinh thu h6i dau).
QUY TRINH MINH GlAl DLTT GAY
Su hieu biet cua chiing ta d6i vai cac d6i tugng trong long dat phu thuoc nhieu theo kinh nghiem, c6ng nghe, y tuong va tai lieu chiing ta dang co. Do chat lugng, loai va s6 lugng tai lieu thay d6i tuy theo vimg mo, nen chiing ta can phai co cac c6ng cu de c6 the hieu sau ban ve cac doi tugng tren. Hinh 2 cho chiing ta mot cai nhin ting quan vl qua trinh minh giai cac diit gay. Mot s6 phin viec co thi dugc thuc hien bing phuong phap truyin thong la minh giai theo timg tuyin dia chin mot. Dilu nay phu thuoc vao tai lieu va phuong phap nghien cuu.
664 Thay ddi quy trinh minh giai dut gay trong mo cd cau true dja chatj^hdcjgp^
Input Seismic
1 r Traditional Interpr^ador
r
w rreconai tioning
i r
Attribi
^--^'^^^^^
1
ites
RIter or afnoothing
Edge Bihancanent
Hinh 2: Quy trinh minh giai diit gay (truyen th6ng)
Tai lieu dia chan thuong di kem vai tin hieu nhieu (noise) lien quan tai viec thu n6, xir ly, van t6c, hoae moc (datum). Nhieu gay nhieu kho khan cho viec minh giai tai lieu dia chan. Neu trong qua trinh minh giai, chiing ta nhan ro dugc nhieu thi co the nhan dang dugc ngu6n g6c ciia nhieu va co the ra soat lai cac th6ng s6 xir ly.
Bang viec tien hanh cac buac tien xir ly (precondition) tai lieu dia chan, chiing ta c6 the nhan dang dugc cau tnic dia chat tir tai lieu dia chan. Th6ng tin nay c6 the dugc diing de kiem chimg lai cac minh giai diit gay va co the tim kiem them th6ng tin ve mo. Vai tinh chat rieng ciia minh, tai lieu dia chan cung cap mgt s6 th6ng tin lien quan den cau tnic dia chat, dieu ma tai lieu carota kh6ng the lam dugc (vi du nhu cac diit gay xien). Hinh 3 se cung cap them cho cac chuyen gia mot quy trinh moi dimg de xay dung ban d6 cau tnic mo.
^Seismic. -^ Precondition
I
Filtering
Attributes "•"
i
Dip Coherency
Chaos
Manual
Interpretation "TaulTl^
Volune
Recondition ig
Ants
L,L... .dU..\ .,,.,.MllJi„l,l^,.
Area!
Filtering
Structure Editot,
Hinh 3: Quy trinh minh giai dirt gay moi
Tuygn tap bao cao H^i nghj KHCN "30 nam DIU khi Viet Nam: Co' hdi mdi, thach thuc mdi 665 CHINH LY T A I LIEU DIA C H A N
Sa d l tren bilu diln cac buac lien quan tai viec chinh ly tai lieu dia chan. Cac buac nay bao gIm cac thuoc tinh nhu loc Gaussian (Gaussian Filter), Gain, hoae cae c6ng cu loai b6, hieu chinh tin sl. Cac hinh sau day cho ta thay ro hon viec ap dung cac thuoc tinh len tai lieu dia chin.
Ori^nal Filtering
Hinh 4: Mat cat dia chan chira diro'c conditioning (ben trai) va mat cat da diro'c filter (ben phai)
Co rat nhieu thuoc tinh chan dugc sir dung trong viec nghien ciru cau true dia chat cua mo. Chung co the dugc sir dung rieng le hoae ket hgp vai nhau de cho ra ket qua tot ban. Hinh 4 cho ta thay mat cat dia chan da dugc loc tan s6 cao, sau do se dugc lam smoothing va edge enhancement. Khi thuc hien chay thuoc tinh dia chan, chung ta nen xac dinh ro muc tieu cua minh va tranh viec bo di cac th6ng tin ve dia chat ma tai lieu dang c6. Muc tieu sau ciing ciia cac viec nay la cung d p mot biic tranh ro rang ban v l he thing dirt gay tren cac mat cit dia chin.
666 Thay ddi quy trinh minh giai diit gay trong md cd cau true dja chat phuc tap
THUOC TINH LAM RO BIEN
Cac chuyen gia mu6n co mgt hinh anh ro ban ve sir phan b l va huong cua cau tnic ben duai mat dat.
Smoothing & Dip Guide Edge Enhancement
Hinh 5: Thuoc tinh lam ro bien (edge enhancement)
Trong Hinh 5, chiing ta co the thiy ro han cac dut gay sau khi ap dung cac thuoc tinh dia chan. Cac thuoc tinh dugc ap dung bao gom smoothing va edge/dip enhancement (hinh phia ben tay trai). Trong qua trinh minh giai, chiing ta co thi ap dung them cac thuoc tinh kbac dl hilu ro ban v l clu tnic dja chat. Tuy vao chit lugng tai lieu, tan s6 (frequency) va goc phuang vi (azimuth) co the cung cap them th6ng tin quan trong (Hinh 6).
Tuyen tap bao cdo HQi nghj KHCN "30 nam Dau khi Viet Nam: Co' hdi mdi, thach thuc mdi"
667
Frequency Azimuth
Hinh 6: Ap dung mot s6 thuoc tinh dia chan de hieu ro hon ve m6 hinh dirt gay
Khi ap dung thuoc tinh smoothing, cac diit gay chinh c6 thi se bi ma di, tuy nhien, neu ap dung cimg vai thuoc tinh edge va dip enhancement thi cac dut gay se ro net ban nhieu. Chiing ta c6 the lam ro ban cac dut gay bang each ap dung cac thuoc tinh khae nhu coherency, variance va chaos (thuoc tinh bin don). Hinh 5 cho ta thiy kit qua cua viec ap dung cac thuoc tinh smoothing va edge enhancement. Bang 1 duai day liet ke mot so thuoc tinh co the sir dung trong quy trinh xac dinh cau tnic dia chat cua m6:
Bang 1: Mot so thuoc tinh dia chan co the ap dung trong quy trinh minh giai dut gay Thuoc tinh
Dip Azimuth Chaos Fault Edge Variance Ant tracking
Dirt gdy chinh
X
x
X X XX XX
Dut gdy phu
X
XX XX XX
Dirt gdy
X
X XX
XX
Khong liin tuc
X
X X X
668 Thay ddi quy trinh minh giai dut gay trong md co chu triic dja chiit phiic tap
Nhtrng thuoc tinh dugc liet ke a tren kh6ng phai se dugc ap dung cho tit ca cac m6.
Do sir thay d6i m6i truong tram tich, va cac su kien kem theo, nen co mot miic do ding nhat trong cau tnic cua m6. D6i khi chat lugng tai lieu ciing gay nen nhiing giai ban nhit dinh trong viec ap dung quy trinh minh giai.
Nhin vao cac hinh ben duai, chiing ta co the hieu them vl cac kilu diit gay.
Hmh 7: Cac lat cat dia chan (tune slice) qua cac khoi thuoc tinh migration, dip, variance, chaos THUOC TINH DIA C H A N ANT TRACKING
C6ng nghe ant tracking diing dl minh giai dirt gay tu dong. Khi ap dung ant tracking len khii dtr lieu dia chan, ta co thi co dugc cac kit qua nhu khii thuoc tinh ant tracking (ant tracking cube), cac mang dirt gay (fault patch).
C6n trimg co siic thu hiit dac biet dii vai cae nha khoa hoc, hanh vi ciia c6n tning la nen tang cua viec phat triln khai niem "tri th6ng minh biy dan". Co bao gia ban quan sat cac chu kien di kilm mli chua? Nlu co, ban co ngac nhien kh6ng khi thiy cac chu kiln di chuyen rat trat tu? .
Chiing ta tao ra hang loat cac tac nhan co hanh vi gilng nhu kien ggi la "kiln nhan tao". Khi "kien nhan tao" di chuyin ben trong mot khii thuoc tinh dia chan, chiing se phat ra cac pheromone dien tir danh diu doc theo cac dirt gay. Khi ma co nhieu chu "kiln nhan tao" di tren ciing mot con duang thi con duang do dugc xac dinh nhu la mot dirt gay.
Tuygn tap bao cao Hoi nghj KHCN "30 nam Dau khi Viet Nam: Co hdi mdi, thach thiic mdi" 669 Nhung chu "kiln nhan tao" khae kh6ng kilm ra dugc cac diu hieu eiia dirt gay se bi loai bo ngay. Hinh 8 se minh hoa mot each khai quat khai niem nay.
Hinh 8: Chii kien nao th6ng minh hon? Con duong ngan nhat co nhieu kha nang la diit gay hon nhung con duong khae
ANT TRACKING - PRECONDITIONING T A I LIEU DIA C H A N V A VIEC LUA CHON CAC THONG SO
Neu ban biet tuong d6i ro ve thuoc tinh dia chan va kieu dirt gay, ban eo the dieu chinh hay huong dan hanh vi ciia cac chii kien truac khi chay thuoc tinh. Chung ta co the thuc hien dieu nay bang each sir dung bieu d6 cue (polar plot). Hinh duai day m6 ta viec chon lua goc phuang vi va g6c cam ciia dirt gay de giai ban viec tu dong minh giai dirt gay. Ben canh do, con co nhieu th6ng s6 khae niia ta co the chon de dieu chinh chat lugng s6 lieu dau ra sau khi ap dung ant tracking.
:!• A t t f i b u l i i (•<>[i4.>rtitt(jn
AUiibut*Lkoiy] RHliMSctlinsit SUMonetlMo
Hmh 9: Bieu do cue dimg de prcconditionmg dir lieu dja chan tru'oc khi ap dung ant tracking
670 Thay ddi quy trinh minh giai diit gay trong mo co chu triic dja chat phiic tap
Vi du trong Hinh 9 eho ta thay cac dirt gay co goc phuang \i nim trong da> 60 - 120/240 - 290 va goc elm nh6 hon 15" se kh6ng dugc tfnh. Hinh ben phai the hien kieu dirt gay va huong ma bieu d6 cue de cap den. Sir dung bien phap nay. chiing ta eo the thuc hien ant tracking nhieu lan khae nhau vai eae thuoc tinh dut gay khae nhau de co the minh giai cac kieu dirt gay khae nhau trong mo eiia minh.
Co the ban se rat mu6n minh giai cang nhieu dirt gay cang t6t hoae co the ap dung cac th6ng s6 de giai ban s6 lugng dirt gay theo dung y mu6n eiia minh. Bieu do cue se giup ban thue hien dieu do.
'." Attribute Generation I B B i l t? Attribute Generation
AttAiyte Libiay | Reafcs Se<tfws | Steieonet j Info
1
Stnxtural melhoch
Dip DevTatfon Giadierit Magnitude Local StiiCtualArmjth Local Stiuclijial Dip itructyial Smoothiirig Vatiance (Edge method)
r • ,: (T Reafeed - Inpwt/Outpyt M\nfm
Input jecmc
Output cftirnic
r Set output naivie;
1
P Geneiale Fault Pa!clie:
0
AntT lacking li u:edto end act faults fiom a pte- ptocessed ja:inic volume The preiHocesMig c w i j beVaii.3nceofCha«
combined vjith iliuciufd inwothing.
Cunert^ only leafced
\-oluinei can be calculated
J ^ PoSiiveAnli r AggiemveAnt:
li*3l Ant Boundaiy: ~ j Ant T (ad. Deviation;
AnI Step SE»
ilegol Step.; 1
J Lead! .lepa
1 1 1 1
ik'9 CrteRs pit
1
j / Apply * l ^ Ol' X Cancel
Attrttite Ussy ] Reafce Settings j Steteonet. j Info j
^ SliuctuialmethDds TJ <^ •' (^ Reafced
• lnpy.^Uput dethilion Input setsmc;
DipDewstion Gradient Magnitude Local Staictut3lA2imijth Local St/uctual Dip Siructuial Smoothing Vanance (Edge method)
Output Jaime:
r Set output name:
iv Meige FauS Patches
AniTracl.ng i: used to estiaci (aiJs fiotn a pie- piocessed seemic volume ThepieixocesiingcoMid beVatiaitteofChaK combned with Jtructural OTioothrig.
Cunent^onlyiealired voiumes can be c^iJated
H
J
Minroum Patch Size Ipomlst Patch Down Sampfcig (voxels):
Maxnwrn Sepeiation (voxelsj Masomum Change m Dip' MajoiMD Change m Azmjth:
• Apply ^ OK
|20 d
|8 J ^.
|5
X c*<«i
Hinh 10: Khoi thuoc tinh diit gay va cac thong so su* dung de tao mat diit gay ANT TRACKING - KET QUA VA POST CONDITIONING
Trong qua trinh tao kh6i thuoc tinh ant tracking, chung ta tao cac mat dut gay, d6ng thai chiing ta cung co the lam smoothing, ket n6i, hay loai bo chiing trong phAn sau ciia quy trinh. Nhijng mat dirt gay nay eo the dugc chuyen d6i thanh tai lieu minh giai dirt gay (fault stick), cac diem dirt gay (fault points), tham ehi la cac mat de sir dung vao viec xay dimg m6 hinh dirt gay. Hinh 11 ben duai the hien sir so sanh giu'a lat cat dia ch4n binh thuang. lat eat dia chan sau khi sir dung edge enhancement va lat eat thupe tinh ant tracking.
Tuy^n tap^ao cao Hoi nghj KHCN "30 nam Phu klii Viet Nam: Co' hoi moi. tiiach tliuc moi" 671
Hinh 11: Lat cat thoi gian (time slice) cua khoi dja chan -hinh ben trai phia ben tren the hien lat cat ciia thuoc tinh migration, hinh ben trai phia duoi the hien ket qua thuoc tinh variance, hinh ben phai the hien ket qua thuoc tinh ant tracking, Chiing ta co the thay
cac ket qua tren co do phan giai cao va chi tiet hon cac thuoc tinh khae
Tir ket qua ciia cac kh6i thuoc tinh, ta c6 the minh giai diit gay, d6ng thai eo the xac dinh cac doi dirt gay trong khu vuc m6 ciia minh.
Hinh 12:Cac mang diit gay (fault patch) duoc tao ra tu- qua trinh ant tracking
672 T h a y 36! quy t r i n h m i n h giai d u l gay t r o n g mo co cau true dja chat phiic tap d SHitirigs for 'diaos fRealizetil*ite»0^
^
] Irito I S!atKtiii:| Histo^am Stewwiel j Cofats . * I
270-
O Setthtos for 'chaos [Redteed] fArvtlracKr?
Irto j Statjslics Hidogfam | Staeoie* | Cobic JJ-IL
^^^_ J— ~] ; ^ [ Min|f S-^g'J^"''*^
r
2 4 S " ~ 8 To
2M)-
103-
-•^tch ConJidsnce
^ Dip
p . Me^an I r p t i Anvlitu.l5 I J ^ F a u t Patch Size
Jj? Inline Extent
^ Dossbie Extent
« ^ VeitiealEiiteni
3
I U H^inpnii
6.364489 U 72898 1409347 i Patd"! ContidefKe chaos [Reared} (AntTiackJ
(/" App^i !(<'' OK I X Car, eel i / ' Applj? I f f OK 3 1 C4nc:el
Hinh 13:Kha nang chinh sira cac mang diit gay bang each su- dung bieu do cue, hoae cac thuoc tinh Hen quan khae cua mang diit gay (goc cam, goc phuo-ng vi, miic do tin tu'6-ng, v.v.,.) KIEM DINH VA MINH GIAI D I T T GAY
Kiem dinh chat lugng ciia dirt gay nham danh gia ket qua ciia ant tracking thuc su co mang y nghTa hay kh6ng, day la mot viec lam rat quan trong. Neu ban dang gap whn dk vai che do khai thac hoae luu lugng d6ng chay trong mo ciia minh, nhung ban kh6ng ro nguyen nhan, ant tracking eo the se cung cap cho ban mot s6 dau moi, th6ng tin quan trong.
Hinh 14: So sanh giua ket qua minh giai dirt gay vol ket qua ant tracking the hien tren khoi dia chan. Hinh ben phai la cac mang diit gay du-ffc tao ra trong qua trinh tao khoi
thuoc tinh ant tracking
Tuygn tap bao cao Hoi nghj KHCN "30 nam Phu khi Viet Nam: Co' hoi moi, thach thtic moi" 673
Hinh 15: Cac mang diit gay duo-c the hien tren mat cat dia chan TREN CA VIEC TAO RA KHOI THUOC TINH ANT TRACKING
• • •
Hinh 16 cho chiing ta thay tinh lien tuc ciia qua trinh phan tieh he th6ng dirt gay.
Hinh nam 6 phan tu ben trai (phia tren) bieu dien dirt gay tao ra do ant tracking vai mot s6 diem huong dan, hinh thir hai a tren cao phia ben phai (ben tren) minh boa lat cat thai gian dugc tao theo m6 hinh mang luai naron (neural network). Cac hinh ben duai minh boa cac kh6i dirt gay co di kem hoae kh6ng di kem vai minh giai ban dau.
Hinh 16: Ap dung cong nghe "neural network", diit gay hoae khoi diit gay co th^ du'oc tao ra khi sii- dung so lieu huong dan va thuoc tinh dia chan
6 7 4 Thay doi quy trinh minh giai diil gay trong mo co c5u triJc dja cli5tjThac_tg£
KET LUAN
Sir thay d6i lien tue va nhanh chong ciia c6ng nghe ma\ tinh. dac biet trong ITnh \irc phhn cimg va phan mem. c6 it nhieu tac dong len cae quy trinh minh giai. Nguon du lieu dia eh4n ngay cang tra nen da dang, neu eo the khai thac nhidu thong tin ve cau lao ben duai mat dat thi chimg ta eo kha nang giam thieu dirge eae riii ro. b^t dinh trong vice \a>' dijng mo hinh.
Chht lugng tai lieu la yeu t6 quan trong quyet dinh gia tri th6ng tin ciia thuoc tinh dia ch4n. Dk c6 duge tai lieu chAt lugng t6t, chung ta phai sir dung cac phirong phap thu no dja chhn mai (dia ch4n co do phan giai eao) va phuong phap xir ly mai. Chiing ta eo the co nhieu c6ng eu moi giup viec minh giai thuan tien han, nhung dieu quan trong ban ca la dir lieu phai e6 chht lugng t6t va nguai sir dung phai e6 kien thire chuyen sau.
Viee hi^u ro cac kieu dirt gay dong vai tr6 rat quan trong bai vi no la nen tang eho tat ca cac c6ng viec khae lien quan den dia chat va dia chan. Neu qua trinh nay dugc lam mot each tu dong vai ket qua tin cay thi dieu nay se giup cac chuyen gia co them thai gian de lam viec vai eae e6ng CIJ cao cap khae dong thai e6 the kiem tra chat lugng ciia ket qua.
Thuoc tinh ant tracking cung cap them nhieu th6ng tin ve cac kieu dirt gay.
Cung can quan tam den c6ng tae xir ly tai lieu dia chan bai vi no anh huong true tiep den ket qua phan tieh thuoc tinh dia chan, tir d6 co the hieu ban ve cau true ben duai long dat. Bat ke ap dung phuang phap nghien eiru gi. cross plot hay neural network, chiing giup chiing ta hieu them ve thuoc tinh dia chan cung chinh la hieu sau ban ve cau triic dia chat. :
Tom lai, kh6ng co mot quy trinh duy nhat nao c6 the diing de hieu ve cac kieu dirt gay ciia cac m6 kbac nhau. Quy trinh minh giai co ban de cap tren co the duge sir dijng de nghien eim ve dirt gay, nhung viec ap dung cac th6ng s6 va thuoc tinh kbac nhau se dan den ket qua khae nhau.
TAI LIEU THAM KHAO
1. S.I. Pedresen, T. Randen, L. Sonneland, O. Steen, 2005. Automatic 3D fault interpretation by artificial ants. Published EAGE in Florence, Italy, May 2002.
2. E. Bonbeau. G. Theraulaz, 2003. Swarm smarts. Scientific American, March 2003.
3. Espen Rodseth Hansen, 2003. Automatic fault extraction workflow. Norwegian University of Science and Technology, Thesis, Spring 2003.