NGUON GOC VA Diu KIEN SINH T H A N H DAU, CONDENSATE, KHi 6 BE' CIJU LONG VA NAM C O N SON
PGS.TSKH. Hohng Oinh TIJn KS. Hoing Thi Xuin Huong bin doanh Viit - Nga "Vietiovpetrd"
T6m t i t
Nghiin cUu dugc thuc hien dUa trin cdc kit qud phdn tich nhCmg miu ddu, condensate, khi d hai bi Cihi Long vd Nam Cdn San bdng cdc ddu tich sinh vdt dugc phdt hiin bdng cdc bd phdn tich OC, GC-MS vd GC-MS-MS. Tuy nhitn, di tdi chl tdp trung vdo mdt sdcdc ddu tich sinh vdt cd khd ndng phdn dnh mdi trUdng tich luy vdt liiu hCfU ca, logl vdt liiu fiihi ca vd qud trinh chuyin hda chung sang ddu khi cung nhUthdl gian vd dd idu diin ra qud trinh ndy.
Kit qud nghiin cUu cho thdy ddu khi, condensate d bi Cdu Long cd ngudn g6c tifrong tdo (rang xanh cd Uu thi C,^ igi dugc tdi tgo bdi vi khudn thudc kerogen chu yiu loai 11, trong mdi trUdng ddm hd, cda sdng. Cdn dbiNam Cdn San ddu, condensate, khicd ngudn gdc tifthUc vdt vd thUc vdt bdc cao thudc kerogen logl III trong mdi trUdng trin can (luc dja, tam gidc chdu tren cgn), it dugc vi khudn tdi tgo.
d bi Cdu Long ddu khi dugc sinh ra ddo sdu nhd han, nhung Igi d diiu kien nhiet dd cao han so vdi ddu khi trong be Nam Cdn Son. Thdi gian sinh ddu khi d hai be deu bdt ddu tU cudi fAiocen sdm, nhUng sinh mgnh vdo Miocen trung - mudn vd PHocen - De tU, khi chi do nhiet cao dugc thiit Idp sau khi cdc tdng dd me dd bi nhdn chim xudngsdu.
I.IVIddau
Dau, condensate, khi ludn la ddi tUong nghien cifu true tiep v i chinh xic ve ngudn gdc, mdi trudng tich luy vat lieu hdu co v i q u i trinh chuyen hda eua chung. Ngiy nay, cdng eu nghien cdu hydrocarbon dugc cli tien nhieu, cd the cho phep xic dinh van de tren thdng qua cic d i u tich sinh vat tdn tai trong d i u , condensate. Cie d i u tich dugc xic dinh b I n g sic ky chat Idng (GC), g i n vdi khdi phd (MS) de goi ra cic c l u t d c d h i m lugng nhd nhung lai ed gia trj thdng tin cao.
Nguyen ly ciia chijng l i mdt sd c l u t d trong sinh vat tdn tai l l u trong mdi trUdng dja chit, dau, khi v i condensate.Vidu [1,2,3]:
Pristane, phytane I I cic c l u t d ed trong diep luc td ciia thuc vat va trong hemoglobile ciia ddng v l t .
Khi vat lieu hdu co chuyen hda sang d i u cung mang theo chung v i o dau khi. Mdt sd cau t d lai ddt vd theo quy l u i t cho ra cic cau t d nhe hOn mdi khi thay dot che dp nhiet theo xu hudng tang len. Vi du; MPI-1 I I methylphenantrene Index p h i n anh qua trinh ddt vd cau t d phenantrene cho ra ele cau t d nhd hon nhU: 1-MP, 2-MP,3-MPva9-MP.
Cau t d 16 demethyl - botryococcane sinh ra td rong xanh sdng trong d i m hd nude nggt.
Oleananes duac p h i n huy t d hat kin ciia thuc vat v l thuc v l t b l e cao.
Hinh 1. Sado phdn bd cdc bi trdm tich thim luc dia Viet Nam trong phdng kien tao Ddng Nam A (theo dnh vi tinh cua CCOPndm 19821
26 DiUKHi-S01/2013 i'^^Qf^'^Bi
PETROVIETNAM
Chi tieu Cj^-homohopane Index chi ra ngudn vi khuan hoat dpng, vi hopanes duoc sinh ra t d m i n g nhly ciiavikhuan...
De g i i i quyet van de nay, nhdm t i e g i i da thu t h I p sd lieu cua cic cau t d HCsat. va Hcarom, trong dd die biet quan t i m den cic steranes v i hopanes. Sd mau dau, condensate dugc nghien cdu la 64 mau d be Cdu Long v i 22 mau d be Nam Cdn Son (Hlnh 1, 2, 3).
Cic ket q u i p h i n tich cho phep nghien cdu nhieu khia canh khac nhau, nhung nhdm t i c g i l chi liAi y tdi cic ddi tugng thudng dUOc quan t i m , dd I I : mdi trudng tich luy vat lieu hdu cO, do trUdng t h i n h , thdi diem v l do siu sinh d i u khi.
2. Mdi trUdng tich luy va loai vat lieu hCTu cd 2.1. Cdc chl tiiu Pr/Ph - T / C
Da tien h i n h x l y dung do thi mdi quan h& gida ehi tieu Pr/Ph ddi vdi H,, (Tricyclic steranes/hopanes) (H,,=
T/G) [6]. Tren Hinh 4 cho thIy cic mau dau, condensate d be Cdu Long phan bo rat tap trung trong khoing g i l trj ciia Pr/Ph t d 1,25 - 2,2, phd bien la 1,8 - 2,1 phu hgp vdi kerogen loai II trong mdi trUdng dam hd, cda sdng. Thanh phan chii yeu la rong t l o nen g i i tri tysdT^/G thudng cao (td 60 - 250 don vj), mdt sd mau cdn cd gia tn cao han va dat tdi 400 - 850 don vj [5].
Ddi vdi cic mau dau, condensate d be Nam Cdn San thi ty sd Pr/Ph thudng cd g i i trj rat cao (tU4,6 - 9 don vj) va bj phan t i n nhieu han.Thinh phan rong t l o rat it ma chii yeu la tren can (tham cd) v i cay than gd (thi/c vat bac cao) phu hgp vdi kerogen loai III.
2.2. Tuang quan gi&a C „ - C^,- C „
Hinh 5 cho thay rd cae mau dau, condensate d be Cdu Long p h i n idn phan bd d khu viic sd 4 (mdi trUdng dam hd) tdc l i Uu the ciia C^^ cd tU rong t l o . Con mot sd mau nam d khu 3 (eda song), rIt it mau d khu 2 (bien md) [5].
Trong khi do, cic mau d i u , condensate d be Nam Cdn Son tap trung nhieu d khu 5 (tren can), mdt it mau d khu 6 (thuc vat bic cao). Hai khu nay p h i n i n h Uu the ciia C „ ciia rong nau chi ra mdi trUdng phat trien thiic vlt. Chi cd hai mau n i m d khu 2 (bien md), mdt mau nam d khu 3 (cda sdng) va mot mau n i m d khu 4 (dam hd).
2.3. Cdc chi tieu 0/G - S,
Tren Hinh 6, ty sd 0 / G ciia cic mau dau, condensate d be Nam Cdn San thudng cd gia tri eao (td40 - 88 don vj)
Hinh 3. Sa do cau true be mat mdng be Nam Con San [5j phan i n h gia trj cao ciia cau t d oleananes. Cau t d nay rIt phong phu trong thuc v l t (thim cd va than gd). Cdn dau, condensate ciia be Cdu Long cd ty sd 0,/G g i i tri t h I p (< 23 don vi); chi cd 2 mau condensate cd g i i trj cao I I 4 6 v l 77 don vj [5].
Nguoc lai, ehi tieu B, = 8P(H) drimane/C^^ hopanes lai ed gia tri rIt eao (td 120 - 930 don vi) ehdng td rang v l t lieu hdu co d be Cdu Long da dugc tai tao rat nhieu bdi vi khuan.Trong khi dd, chi tieu nay d be Nam Cdn Son lai cd g i i trj rat thap (phin Idn nhd hOn 100 dan vi) chl ra rang v l t lieu hdu ca d be Nam Cdn Son it dugc t i i tao lai bdi vi khuan.
Xi.^C^^lo/J OAU KHi-S01/2013 2 7
Qua dd cho thIy d i u , condensate d hai bd t r i m tich CO ngudn gdc rIt khic nhau:
6 be Cdu Long d i u khi dugc sinh ra t d v i t Hdu hdu CO rong t l o I I chinh, thudc kerogen loai II, lai duge t i l t^o chii yeu bdi vi khuin trong mdi trudng d i m hd v i vdi m6t it t d cda sdng, vung nddclo, bidn md.
Cdn dau, condensate d bd Nam Cdn Son dUge sinh ra t d ngudn thUe v l t l i chinh thudc kerogen loai III; nhung bj p h i n t i n rdng chdng td d i bi phan bd lai do cic hoat ddng kidn tao dien ra nhidu pha. Cie ehi ti^u % Ro v l H^
e d g i i tri thap.
3. Do trudng t h i n h 3.1. Phdn xg vitrinite
% Ro duoc tinh theo MPI-1 v i = 0.6(MPI-1) -i- 0,4 [6]
Theo Hinh 7, d e l hai bd t r i m tich dau, condensate phan Idn duge sinh ra trong dieu kien nhiet dd trung binh va cao (td 0,72 -1,2% Ro), Rit it mau ed g i l tri vUat ra khdi cacgia trjnay [5].
+ d be Cdu Long, phan Idn cac mau dau dugc sinh ra trong dieu kien nhiet dd cao, t d 0,78 -1,15% Ro. Chied cae mau dau dugc di cU xa mdi ed cic g i i trj % Ro thap do tang eac t h i n h phan nhe. Rieng 2 mau condensate mdi duge sinh ra d ddi sinh condensate, lai duge tich luy d cic bay gan viing sinh condensate nen dat gia tri % Ro r l t Idn (1.41-1,43% Ro) [5].
+ 6 be Nam Cdn Son, cic mau dau va dau nhe chii yeu duge sinh ra trong dieu kien nhiet dd thap hOn, khoang 0,72 - 1,05% Ro. Cac mau condensate cd gia trj thap han so vdi dau va chi dat 0,71 - 0,98% Ro. Dieu do chdng td cac tich Jiiy nay I I ket q u i eiia q u i trinh phan bd lai cac c l u t d hydrocarbon tdc la d l duge t i c h ra t d cic via dau [5].
3.2. Chi tiiu H^
Trong cic m l u d i u d bd Cifu Long, chi ti^u Hg(Ts/Ts+
Tm) cd g i l trj cao tU 0,5 - 0,95 dOn v|. Cdn d bd Nam Cdn Son, ehi tidu n i y chi dat 0,44 - 0,62 dan vi. Ri^ng cic mk condensate cdn ed g i i trj t h I p han v l chi dat 0,28 - 0,37 dan vi. Cic sd li^u tr^n cho t h I y d bd Nam Cdn San da dien ra q u i trinh p h i n bd l^i cic hydrocarbon t d e i c via diu [5].
3.3. Nhiit dd mdi trUdng
Ndu d i u 6 bd Cdu Long dugc sinh ra khi trudng nhiftt dat 0,78 - 1,2% Ro (tuong duung 115-154''C), phd bien 0,83 - 1,15% Ro (120 - 150"C), thi condensate dugc sinh ra trong didu kidn nhidt dd eao khoing 1,41 - 1,43% Ro (168-170-0 [5].
Cdn d bd Nam Cdn Son, d i u duge sinh ra d ch^ do nhi^t t h I p hon tdO,71 -1,05% Ro (105 - HO-C). Khi nghien cdu trudng nhi^t d c l u tao Thanh Long, nhdm t i c gii thay ring n h i ^ t d d h i ^ n tai r l t cao t d 25-198''C d d p siu tifO- 4.950m, dat 3,5''C/1 OOm, Trong khi dd mau kerogen trong d i ehi dat d nhidt dd 35 - 152"C, tdc I I ch! dat gradient 2,56°C/1 OOm thap hon nhidu so vdi hien tai.
Cd le sau khi ngung nghi hoat ddng cua dj thudng nhi^t v i true t i c h gian d l y bien Ddng t d cich dly 15,5 tri^u nam, khoi magma d dUdi sau b i t dau lanh ngufii trong giai doan Miocen trung - mudn, song p h i i den giai doan Plioeen - De t d mdi lanh ngudi nhanh v l giii phdng nhiet manh. Td dd eac loai khi va hcri nUdc mdi di cU len d at v i sudi I m Idp tram tich phia tren l i m t i n g nhiet do mdi trudng dja c h i t mdt cich nhanh chdng nhUvly. Be Nam Cdn Son lai 6 g i n dudi Tly Nam ciia dj thudng nhi&t n i n cang thu nap nhieu nhidt g i l i phdng ra r l t nhanh va manh me. Vi vay, gradient dja nhiet d gan trung tim da dat 3,5''C thi d cie ddi n i n g p h i i dat tdi 4,0, tham chitcii 4,2=C/100m.
2- Biin m ^ open marine) 3- C ^ sOng, vflnc v|nh
(Estuarine, Bay) 4-Dlmh&(tocustrirM)
5- Trtn Cf n (terrettrlal) 6- Thirt vtt b|c CM)
(higher plant)
Hinh 5. Tuang quan giUa cdc cdu tCt C^, C^^ C^, cua steranes
Bin KHi - sd 1/2013 P&^C^T^zo/j
• - Mlu diu i'MUu Unit A •MludluA'M MmCAnSm
I I I l l l l l l 'l I H I l l
m
Hinh 6. Tuang quan gida H vd B,
PETROVIETNAM
• - MiudluJrbfC^
\
^ «iis~
\ - ' v
/'^V.
Hinh 8. Gidn d6 phdn b6 nhi^t d^ (do trUc tiip vd theo phdn xa vitrinite d TL- IX. TL-2X)
Hinh 9. Llch sd chdn vdi tram tich vd sinh ddu khidtrung sdu be Cdu Long
Hinh 10. Lich sUchdn vui tram tich vd sinh ddu khi d trung sdu bi Nam Cdn San Hinh 8 cho thay sUcach biet nhidu gida nhiet do hien tai vdi nhiet dp co ma vat lieu hdu coda trai qua. SUchenh lech d vung ria va ddi nang dat 1.500-2.000m, cdn d gan trung t i m dat 2.000 - 3.100m va d trung siu nhat cd the dat tdi 3.400m. SU chenh lech n i y eung chinh la be day ciia tram tich Plioeen - Be td. SU sut lun nhanh va lap day tram tich dly, cdng vdi sU gia tang nhiet dp nhanh eiia mdi trudng nen vat lieu hdu ca chUa kip e l m nhan chd do nhiet mdi.
Chd dd nhiet cao neu tren tao dieu kien chuyen hda v l t lieu hud cosang dau, condensate t d t r i m tich Eocen v l Oligocen d be Cdu Long, t d tram tich Oligocen va Miocen dudi d be Nam Cdn Son chl dien ra khi c i c tram tich tren bi nhan chim sau bdi c i c t r i m tich cudi Miocen sdm, Miocen trung - mudn va Plioeen - Be tU.
4, Mo hinh sinh dau, condensate
Cac didu kien tr^n p h i n bd trong khdng gian eCia be Nam Cdn Son v i bd Cdu Long can dUOc lam sing td. Da tidn h l n h xay dung cac mat c l t , lap lai mat cat cd kidn tao, x l y dung mo hinh sinh dau 6 c i c trung sau, vl d noi d l y khdng cd cac gieng khoan, nen p h i i tinh chi sd thdi nhiet (TTI). Cdn d cac ddi n i n g d l cd cic gieng khoan, tdc la cd
mau Ioi, mau vyn, m l u sUdn, nen ed the do duoc g i l trj p h i n xa vitrinite (% Ro) p h i n i n h dp trudng t h i n h eiia v l t lieu hdu cO.
4.1. Che dd nhiit
Trong mdt be t r i m tich, cic ddi n i n g hay gd n i n g la eic vung ndng, vi dugc tich luy nhidt eao. Noi d l y nhiet dp thudng l^n cao do duge cic khi, hai nUdc v l hydrocarbon mang nhidt tdi. Cdn d cic trung sSu, b i n dia h l o thudng I I vung lanh, noi sinh ra nhi#t (nhiit t d Idng trai dat tda ra, t d ele Id magma d dudi sau dUa len, t d cic p h i n dng hda hoe trong t r i m tich, t d cae p h i n dng ciia nhiet djch vdi cic khoing vat kem ben vdng, t d cic p h i n dng hinh t h i n h khoing vat thdsinh. I d cic p h i n dng ddt vd ciia cic nguyen td phdng xa,..) nhung lai nhanh ehdng m I t nhiet do cae khi, hoi nUdc di cU len tren va mang nhiet theo vao cic bay chda [7].
Vi vay, de l i p dUOc md hinh sinh dau d cac trung siu thudng c i n cd v i o bien thien nhiet do (hay gradient nhiet do) t d cac phan vdm ra ben sUdn. Tren co sd sU bien thien nhiet do tinh gradient nhiet do d chd sau nhat. Vi du: d vdm Bac c l u tao Bach Hd cd gradient l i 3,6''C/100m, ra ben sUdn noi cd gieng khoan 9-BH gradient chl cdn 3,04''C/1 OOm.
Tren cO sd g i i m dan nhu vay thi gradient nhiet dp chi cdn 2,4''C/100m d cic trung siu (tdc I I cd sau dugc 40m mdi tang len duge r c ) .
d be Nam Cdn Son sd dung che dp nhiet trudc thdi Plioeen nhu da neu d tren, t d dd xay dung md hinh sinh dau d e l e trung sau.
4.2. Md hinh sinh ddudbiCdu Long vd Nam Cdn San d hai be tram tich cd ele thanh he tram tich t d t r e n xudng dudi nhu sau: Plioeen - De td, Miocen tren - gida - dudi, Oligocen tren - dudi d be Cdu Long, Oligocen khdng phan chia d be Nam Con San. Rieng tram tich Eocen d be Cdu Long cd gap tai trung €)jnh An (gidng khoan 1-CL) thudc Tay Nam. Cdn d cae trung sau chi dU doan theo tai lieu dia chin. 6 be Nam Cdn Son t r i m tich Eocen cung chl du kidn theo tai lieu dia chan d cic trung siu.
Tren cae b I n g dja chan khu vUc d c i hai be deu phat hien c i c t i p t r i m tich p h i n bd Idn xdn, xien cheo, bien tudng nhanh va thay ddi bd d l y r l t nhanh. Cic d i e diem X^C^-^g^/j BAUKHI-so 1/2013 29
n i y hoan toan khic vdi cie t r i m tich Oligocen d phia tren. Tram tich Oligocen da dupe gap d nhidu gidng khoan, lien he vdi t i i li§u dia c h i n r l t tdt, h o i n t o i n khie vdi cae thanh he tram tich d phia dudi. BIng chdng r l t quan trong ta theo tai lidu eiia ehi nhlnh Sunbure (hing Geochem ciia VUOng qudc Anh) thi trong m l u d i u cda md Bach Hd be Cdu Long v i mau d i u ciia md Dal Hiing be Nam Cdn Son deu cd bao t d p h i n hoa tudi Eocen - Oligocen [4], Didu dd chdng td d hai bd n i y v l t liSu hdu ea trong cic tram tich hat min eiia Eocen da t r i i qua pha chii yeu sinh dau, g i l i phdng iUong d i u n i o dd (tuy it) v i o cic bay chUa-
Hlnh 9 cho thIy d bd Cdu Long cda sd sinh d i u cOa tang d i me Oligocen v i mdt p h i n Eocen chi dien ra v i o cudi Miocen sdm, nhung manh me v i o Miocen trung - mudn, vao giai doan Plioeen - De t d chuydn v i o pha chu yeu sinh condensate. Vi viy, mdt sd c l u tao dgan cic trung sau da va dang ddn nhan cic sin pham ciia condensate (Hlnh 7). Trong giai doan can dai nay phan d i y eiia t r i m tich Oligocen tren mdi n i m trong pha chu yeu sinh dau.
Chi cd dien tich rat nho eua tram tich Eocen d cac trung sau bat dau chuyen v i o pha sinh khi khd (> 6,5 - 7km), Nhung trong dau khdng ed cae san pham ciia tram tich
!uc dia hoac chi cd mdt luang rat nhd (Hinh 4),
* ,,
B.
N , » Q
Nj
^.^ Nj ^_^
^ " / 1-101 Mm quin 4tm 1 Hirtft 11. Mat cdt ngang be Cdu Long qua cdc L6 15-2, 16-1.0918,9]
2. Mat cdt dja chdt qua phdn Tdy Bdc - Dong Nam be Nam Con San tuyen 0218,9]
Hinh 10 cho thIy d bd Nam Cdn San cda sd sinh dau eiia ele t r i m tich Eocen - Oligocen didn ra mudn hon {diu Miocen trung), nhdng lai k^o d i i tdi t i n Plioeen. Cdn vao Plioeen - D^ t d t r i m tieh Miocen dudi mdi budc v i o cCfa sd sinh d i u . Trim tich Eocen - Oligocen b i t d i u v i o pha chfl ydu sinh condensate t d cudi Miocen mudn tdi nay
Mac du t r i m tich Eocen - Oligocen v i Miocen dUdI da v i dang n i m d pha ehii ydu sinh d i u , nhung do bin chit v l t li^u hdu CO I I thdc v l t (trong sdt delta, set than v l than delta) ngh^o hydrogen, ndn cd Uu thd sinh condensatevS khi k h d Chinh vl viy cie t r i m tieh n6u trSn cd xu thg sinh mudn v i k6o d l i khi chung dat duge ngudng cudi ciia pha chii ydu sinh d i u v l dat pha chii ydu sinh condensate.
Chi ed mdt p h i n nhd khdi lugng t r i m tieh d cac trung siu chuydn sang pha chii ydu sinh khi khd.
4.2.1 Dd sdu vd thdi diim sinh ddu khi
0 1 tidn h i n h dung hai mat c l t ngang qua mdi be, hai m I t c l t cd kidn tao. Sau dd sd dung cie gia trj phin xa vitrinite d cic gidng khoan tren cic ddi n i n g v l ket qu^
tren eic md hinh d cic trung siu dUa len hai m i t clt hien tai va hai mat c l t ed kidn tao theo thdi gian. Cu the, dau dugc sinh ra trong didu kien nhiet dp cao d hai be (0,78- 1,2% Ro tuang duong nhiet dp 115 -154"^ d be Cdu Long, 0,71 - 1,05% Ro tuong dUOng nhiet dfi 105 - 142''C d be Nam Cdn Son) sedien ra nhu the n l o theo thdi gian va trong khdng gian.
4.2.2. Be CCfu Long
L i p m i t c l t Tly Ble • Ddng Nam qua dja luy Tra Tan (clu tao Hai SiJ Ben) - Te Giic TrIng - Bach Hd - trijng Ddng Bach Hd - Sdi - (dia luy va dOn nghieng Ddng Nam) (Hinh 11) qua cac Ld 15-2, 16-1,09.
Tren mat e l t nay phan Idn tap E m i l tap F v l d i y t i p D da v l dang nSm d ddi sinh dau. Phan tren rat Idn ciia tap D van chl n i m 6 ddi trudng thanh, tilc la dang chuan bj sinh d i u . Diy cua tap E va phan tren ciia tap F dang nam^
pha ehii yeu sinh condensate. Mfitso c l u tao d gan cic trung sau ddn nhan cac sin pham cua condensate. Vi vay, cie s i n pham cd mdc bien chat cao{%
Ro = 1,41-1,43).
30 D«UKHf-SOl/2013 ?i^Qif%zoo
PETROVIETNAM
=1L J
Hinh 13. Mat cdt cokien tgo ngang qua be Hinh 14. Mat.
Cdu Long (NW-SE) [8,9] Nam Cdn San 4.2.3. BiNam Con San
Xay dung tuydn 2 cung ed hUdngTIy B i c - D o n g Nam qua dia luy Tay Bic - trung Mang Cau - ddi n i n g M i n g Cau - cau tao Thanh Long - p h i n Ddng Bic ciia trung Trung t i m - d d i nang Tu Chinh (Hlnh 12).
Tren hinh niy t h I y rd vat lieu hdu co trong cic t r i m tich Miocen dudi p h i n Idn dang n i m trong pha ehii ydu sinh dau. V l t lieu hdu co trong cic t r i m tich Oligocen dang n i m d pha chii yeu sinh condensate. Con phan idn tram tich Eocen dang nam d pha chii yeu sinh khi khd.
5. L a p l a i l k h s l i r s i n h d a u d h a i b e t r a m t t ' c h Cin cd vao che do nhiet m i dau, condensate dugc sinh ra (Hinh 7) va md hinh sinh dau khi, condensate d cae trung sau (Hinh 9 v l 10), cae gia trj trUdng nhiet d hai mat eat hien tai (Hinh 11 va 12), da tien h l n h phuc hdi lich sd sinh dau, condensate d hai mat elt ngang, ddng thdi cung p h i n I n h tinh hlnh ehung ciia hai bd tram tieh tren hai mat cat cokien tao (Hlnh 13 va 14) [8].
S.I.BeCihiLong
Hinh 13 cho thay vat lieu hdu ca trong tram tich Eocen - Oligocen dudi v i o thdi gian Miocen sdm bat dau trudng thanh, p h i n day cua chung chuyen v i o pha chii yeu sinh dau. Chl v i o cudi Miocen trung - mugn vat lieu hdu CO ciia cic tap n i y mdi sinh ra dau manh me va tren dien rdng. Vao giai doan Plioeen - Be t d phan day ciia cic
cdt CO kien too tuyen 02 be 9]
tram tich Eocen - Oligocen dudi mdi chuyen v i o pha chii yeu sinh condensate.
Phin day ciia Oligocen tren mdi chuyen vao pha ehii ydu sinh d i u . Tai cie trung siu tren di^n tich han che v l t lieu hdu CO ciia tap t r i m tich F mdi bUdc v i o pha sinh khi khd.
5.2. Be Nam Cdn San Tren Hinh 14 - mat e l t cd kidn tao qua be Nam Con San cung cho hinh i n h gan tuong tu, Vi sau khi bdc bd Idp t r i m tich Plioeen - De tU d hai bd: Nam Cdn Son (500 - 3.400m) va Cdu Long (300 • 750m) thi thay dp sau chdn VUI ciia ele tap tram tich gan nhu nhau. 0 be Cdu Long cdn 4 - 7km, con d be Nam Cdn San chi cdn 4 - 8km.
Vio cudi Miocen sdm v l t lieu hdu ca ciia t r i m tich Eocen - Oligocen mdi bat dau trudng t h i n h . Chi vao giai doan Miocen trung - mudn chung mdi budc v i o pha chii ydu sinh d i u va phan d i y mdi budc vao pha sinh condensate. Vao giai doan Plioeen - Be t d chiing mdi thUc sU budc v i o pha sinh condensate. Cd le do loai vat lieu hdu eo ma trong giai doan nay mdi sinh ra d at eac san pham hydrocarbon.
Cd thd day cung la ly do vi sao d i u , condensate d be Nam Cdn San dupe sinh ra trong thdi gian d i i hon va mudn hon. Vi vly, dau, condensate d be Nam Cdn San cd do bien chat thap hon so vdi dau, condensate d be Cifu Long.
6. Ket luan
Dau,condensate, khidbeCdu Long duoc sinh ra chii ydu t d ngudn vat lieu hdu cO rong t l o eiia mdi trudng d i m hd, vung vjnh, mot p h i n nhd d eda sdng thudc kerogen loai II duge tai tao lai bdi vi khuan. Cdn d i u , condensate, khi d be Nam Cdn San duge sinh ra t d ngudn vat lieu hdu CO thUe vat va thUc v l t bac cao trong mdi trucmg delta tren can (viing tranh chip nUdc ngot va tren can) thudc kerogen loai III tU set luc dja, set than v l than delta.
Diu, khi d be Cdu Long dUge sinh ra d ehe do nhiet cao (0,78 -1,2% Ro) tUOng dUOng vdi nhiet dd 115 -154''C (phd bidn 120 -150=0; cdn condensate be Cdu Long duoc X^a^7^i60 llAUHli-Sdl/2013 31
MdBachHd sinh ra d che dp cao han (1,41 - 1,43% Ro) tUong dUOng nhiet do 168-170''C. Dau, condensate d be Nam Cdn San duoc sinh ra d ehe dp nhiet t h I p hon v i mudn hon (0,71 - 1,05% Ro) tuong dUong nhiet dp 105 -142°C.
d c i hai be tram tich, dau, condensate, khi duac sinh ra t d cudi Miocen sdm, nhUng manh me nhIt v i o Miocen trung - mudn, tiep tue vao Plioeen - Be td. Do chd dp nhiet cao neu tren dUoe tao lap sau khi eac tang d i me (Eocen + Oligocen dudi + p h i n day eiia Oligocen tren d be Cdu Long, Oligocen + Miocen dUdi d be Nam Cdn Son) da bi nhan chim xudng siu. VI thd, cic pha sinh dau va condensate d be Nam Con Son thudng den mudn hon so vdi be Cdu Long.
Bg siu sinh d i u , condensate va khi khd d be Cdu Long thudng ndng hon so vdi be Nam Cdn Son. VI d be Nam Cdn San co le nhiet dp b\ p h i n tan v l dUOc tao lap mudn hon do hoat ddng kidn tao nhieu pha, trong nhieu giai doan,
Tai l i i u tham k h i o
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2. Kenneth E.Peters. JMiehael Moldowan. TTie biomarker guide. Interpreting Molecular Fossils in petroleum and ancient sediments. New/ Jersey 07632.1993.
3. Al-A. Petrov. Hydrocarbons of crude oils. Publishing
"Nauka". 1984,
4 R.M, Worden and et all. Geochemistry of cnide oils from the Big Bear and Bach Ho fields offshore Vietnam BP- September1989.
5. Tdi liiu phdn tich ddu. condensate, khi thdng quabo GC, GC-MS, GC-MS-MS. LUu t r d d Vietsovpetro va cic don vi khic, cic n i m 1998,1999, 2000 - 2005.
6. Hoing Dinh Tidn, Nguyen Viet Ky, Dia hdadauM Til b i n l l n t h d 2. 2012.
7 Hoang DlnhTien. Dia chdt ddu khivdphuangph^P tim kiim, thdm dd, theo doi md. Tii ban l l n thd 2,2012.
8, Hoing Binh Tien. NhUng ddc diim chinh vedialden tao cOa cdc be trdm tich them luc dia Viit Nam va bien Bdng- Tap chi D I u khi. 2011; 4: p. 16 - 30.
9. Hoing Dinh Tidn. Vdi suy nghJve dia dgng Idcc^'^
true tdch gidn biin Ddng. Tap chi Dau khi. 2009; 7: p. 20 - 25
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