Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bqch Hd" TfNH BAT O6NG NHAT COA CAC TANG SAN PHAM TRONG OA TRAM TfCH M 6 BACH H 6 VA KHA NANG THU H6| DAU Tran Le Dong, Tran Van Hoi Pham Tuan Dung, Phu[.]
Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bqch Hd" TfNH BAT O N G NHAT COA CAC TANG SAN PHAM TRONG OA TRAM TfCH M BACH H VA K H A N A N G THU H6| DAU Tran Le Dong, Tran Van Hoi Pham Tuan Dung, Phung Dac Hai XNLD Vietsovpetro ABSTRACT In this article heterogeneity of lower hMocene and Oligocene terrigenous deposits has been described that is due to the depositional environment, tectonics In turn, it affects the efficiency of the development, namely oil recovery from the mentioned above producing objects To enhance oil recovery as a target, it is important to geologically characterize sand bodies and their hydrodynamic connectivity At the time being in the clastic section in the White Tiger oil field productive horizons 23 (lower Miocene) and Vl^Xl (lower Oligocene) have been developed whose oil discovenes were made in 1975 and 1985 and commercial production commenced in 1986 and 1987 respectively The mentioned objects consist of numerous sand bodies formed in the shallow marine and continental (alluvial fans, lagoon and fluvial) environments As obsen/ed in wells, sand bodies cut in each other and form thic stacks Laterally, single sands developed locally, sealed with fault planes or lithological boundaries Resen/oir rocks developed irregularly, their properties change laterally as well as with depth Besides, oil properties greatly differ from one tectonic block to another Furthermore, the geologic heterogeneity of the objects has been also obsen/ed on pressure graphics or on maps of current formation pressure At this time lower Miocene has been developed in two parts within the Northern and Central Domes, lower Oligocene - just in the Northern Dome According to the numerical simulation, the current oil recovery factors are 0.28 and 0.24 for Miocene and Oligocene correspondingly Thus, it is necessary to investigate the geological heterogeneity of the objects in details with output of technic solutions to enhance their oil recovery in order to reach the highest economic effectiveness Tren md Bach Hd, dau lin dau tien dugc phat hien eat ket tudi Mioxen sdm vao nam 1975, sau la cat ket tudi Oligoxen vao nam 1985 Nhung ddi tugng tram tich lan lugt dugc dua vao khai thac tuang Ung tU nam 1986 va 1987 vdi tdng lugng dau khai thac dugc cho tdi la han trieu tan bang mang ludi gie'ng khoan caeh deu, bay diem nghich dao vdi khoang each giu'a cac gieng khoan cho tUng ddi tugng tuang Crng la 400 va 600m Nhung ddi tugng khai thac gdm nhieu via cat ket cd ngudn gdc khae tU bien ndng ven bd nhu ddi vdi tang san pham 23 Mioxen dudi tdi luc dia ddi vdi cac ting san pham Oligoxen dudi nam d chieu sau tuang Ung la 2718-2913m va 3200-4350m dudi mye nude bien Trong ting 23 cd via cat ket dugc nhan dang va lien ket, chung dugc danh sd tU tren xudng dudi 23_0, 23_1, 23_2, 23_3 va 23_4 Trong lat cat Oligoxen dudi eae ting san pham dugc phan chia va gpi ten tUtren xudng dudi la VI, VII, VIII, IX, X va XI (Hinh 1) Viec nghien cUu lam rd tinh bit ddng nhit eua cac ddi tugng neu tren la mdt nhung ndi dung ca ban nham nang cao hieu qua cdng tac thu hdi dau Tinh bit ddng nhat cua eae ddi tugng trugc het lien quan tdi dac diem mdi trudng tram tich ma he qua eua nd la sy phan bd khdng deu cac than eat dan le vung vdi sy thay ddi gia tri eae tham sd thim ehUa khdng gian Han the nua, sy tdn tai lat cat eua chung nhung dCrt gay kien tao - ket qua t i t yeu cua hoat ddng kien tao lich sir phat trien dia chit eua vung md ddng vai trd man chan cac chat luu Yeu td cung cac man chan thach hpc nhu ket qua eua cac dieu kien mdi trudng tram tich da pha vd sy dang hudng eua cac tinh chit di dudng eua cac via cat ket nhung ddi 137 Hoi thdo khoa hoc "Ndng cao he sd thu hdi ddu md Bqch Ho" tugng vUa neu Ngoai ra, sy chenh lech qua ign ve chieu sau the nam cua cat ket cung mdt ddi tugng, vi du nhu eua Oligoxen dCrai, thudc cac khdi kien tao khae cung din den sy suy giam tinh di dudng cua da chua nhu he qua cua qua trinh nen ep d chieu sau Idn va cac qua trinh bien ddi thCr sinh Theo ket qua nghien eCru cd dia ly va tudng da tac gia Trin Nghi va nhurng ngudi khae thyc hien [2] tren ca sd mdt khdi lugng tai lieu dia chin, carota, khoang vat set, dp hat, tai lieu dia hoa va hoa thach-bao tCr phin hoa han che da phan chia cac tudng da dien hinh cua Oligoxen dudi va Mioxen dudi va dua nhurng chi din chung ve sy phan bd va quy md phat trien cua chung Theo tac gia, tram tich Oligoxen dudi, gidi han bdi tang phan xa dia chin mat mdng va SH11, dugc tao dieu kien luc dia va mdi trudng.chuyen tiep giQfa luc dia va bien Di len phia tren cua lat cat, cac tudng da cang cd bieu hien gin bien han Nhung tudng dien hinh cua tram tich Oligoxen dudi la eudi tang phat trien vdi quy md rit han hep d chan nhung khdi nang mdng, eudi san va cat san aluvi-proluvi, tudng cat, cat san ndn quat cua sdng va cat Idng sdng Cac ndn quat eCra sdng phat trien cue bd bi bien Ting TirdTig da dam lay vung \inh d^m l^y va bien nong - 3400" • 3500- — Trim tich thuc>c tudmg delta, song ngoi, ho, dam lay va bien nong Cat ket, set ket va cat bpt ket xen ke \II-VIII< C Mong granil Da ket tinh va mil ne Hinh Cpt dia tang tdng hgp md Bach Hd, phan lat cat chCra san pham tudng theo hudng dpc theo dudng bd cung nhu vudng gdc vdi nd Tudng eat Idng sdng chu yeu phat trien d phin ddng bang TU dudng bd ve phia bien cat ket delta dudi mat nude chuyen sang cat-bpt ket bien ndng hat dudi dang via ed dien tich phat trien rdng rai Ldp phu tren cung cua nhung tram tich la set vung vinh Tuy nhien, theo ket qua nghien eCru khoang vat set eua Vietsovpetro, khae vdi ket qua tac gia Trin Nghi dua ra, set dac trung cua trim tich Oligoxen dudi la kaolinit va khdng thay sy ed mat eua montmorillonit - dac trung cho tap set phu tren tang san pham 23, Mioxen dudi (Kiriev Ph A) Diem khae biet nua la quy md phat trien cua cat Idng sdng Tren cd sd ket qua nghien eCru tudng da theo miu Idi d mdt vai gie'ng khoan dan le (Snip O.A) ket hgp vdi viec phan chia nhip trim tich va nhan dang theo td hgp dugng cong dia vat ly gieng khoan, ket qua lien ket chi tiet cac via san pham cua Oligoxen dudi d tit ea cac gieng khoan hien cd theo cac hudng song song, vudng gdc vdi dudng bd va tuyen kiem tra theo da giao khep kin (tuyen vdng) cho thiy lat cat Oligoxen dudi tudng eat Idng sdng phat trien theo hai chu ky Neu khdng tinh tudng eudi, sdi hay quat bdi tich chu ky thCf nhat bat diu tu mat mdng d nhung gieng khoan sau nhu GK.4, 715 va ket thue bing tap set ddng bing ngap lut day ngan each giu'a tang san pham sd IX va VIII, chu ky thU hai tU ting VIII trd len Hudng cua ddng chay dudc vach theo true eae dai hep ed chieu day Idn nhit so vdi phan nam ke vdi chung tU phia ngudn cip vat lieu tdi dudng bd tren cd sd ban dd dang day eua khoang giua mdt via tya chinh hgp phia tren va mat bao mdn 138 Hdi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bqch Hd" Idng sdng eat xe vao trim tich nam phia dudi [3] Trong thyc te via tya chinh la mdt via bdt-set nam d nde tang VI cd dien tich phat trien rdng tren md Viec ddng danh via cung nhu eae ting san pham gieng khoan dugc thyc hien theo nguyen tac tu biet tdi khdng biet theo tuyen hay theo cac hudng xuit phat ti; mdt gieng khoan chuan nao dd Viec phat trien rpng rai eua tudng eat Idng sdng ed the dupe giai thich bang sy dich chuyen ngang eua ddng chay [6] ed the' dat 15 lan chieu rdng cua nd Cung theo tai lieu tren, sy tdn tai va phat trien chu ky thU hai eua tudng phat trien mang tinh thua ke Nhu da trinh bay, ddng chay dich chuyen ngang lich sCr tdn tai eua minh, nen thdng thudng lat cat bat gap d gieng khoan ddi mdt via cat ed chieu day dang ke dd chinh la ket qua eua viec nhieu than eat eat xe va nim chdng len Chinh vi vay ma mpt ting san pham se gdm nhung than cat dan va nhung than cat hgp vai nhung a tudng khae (Hinh 2a) Dieu din tdi sy bit ddng nhit ve chieu day hieu dung phan chia cac than eat bat gap d cac gie'ng khoan, sy phan bd cua chung lat cat ed dang ma tran va tinh di dudng eua chung bien ddi theo eae hudng cung khae Vi du minh ehCrng cho trudng hgp vua neu cd the dugc dua la ket qua khao sat ddng theo thdi gian d cac GK.14, 64,107 MNTK Nefteotdatra thyc hien Theo ket qua ddng, mdt sd via lam viec theo thdi gian thuy thudc vao tinh thim ehUa cua chung va che dp edng nghe ap dung qua trinh khai thac Sa dd lien ket eae ting san pham Oligoxen dUai dugc trinh bay tren Hinh 3a, ban theo nde da chua eua cac ting san pham - tren Hinh a) Oligoxen dudi b) Mioxen dudi Hinh Ban dd cac tudng da ehinh trim tich Oligoxen dudi va Mioxen dudi {theo Tran Nghi va nnk) Trim tich Mioxen dudi, nam khoang SH-8 va SH-5, cd cac tudng dac trung la cac flisd eua eae tram tich delta, bien ndng ven bd va eua bien ndng - delta - dim liy Cac manh than dugc bat gap d mau Idi va mau vun nhdm eae GK.1, 22, 24, 28 thudc vdm Trung tam Ngoai ra, sy cd mat cua set bien montmorillonit, chie'm tu 40 den 70% tap set phu tren ting san pham 23, la dac trung cua ddi tugng (Hinh 2b) Cac via eat eua tang 23 ndi rieng ed dien tich phat trien rit khae biet nhau, phat trien rdng nhit la cac via 23_2, 23_3 va 23_1, hep nhit la 23_4 va 23_0 (Hinh 2b, 3b, 5) Trong dieu kien tram tich nhu vay, ed quan sat thay kich thudc dp hat cua cat ket va tinh di dudng cua chung giam di ve phia bie'n 139 Hdi thao khoa hoc 'Wang cao he sdthu hdi ddu md Bach Ho" n" ^M^ n ML \M E 44 %4 •uii.^-g"lljMitiiii-|il g~ T*?ll r t i i , ^ "" »r 1! I ifi rw —-,.-,11" i i Ttc- • -T' •• '•] ] \ ^ 1« ~7i^ il Ip^IB ~?fST' ^1 j r 111 I|^i!:lM| llTLt:^^ a Oligoxen dudi b) Mioxen dudi, ting san pham 23 Hinh Sa dd lien ket eae via va eae tang san pham a)TingVI b)Ting VII+VIII e)Tang IX d)Tang X+XI Hinh Ban dd eiu true nde da chua diu eae tang san pham Oligoxen dudi Tdm lai nhung than eat hinh dieu kien neu tren, dien hinh la eae via cat ket Oligoxen dudi, lam phuc tap them edng tac thu hdi dau vi he sd lien tue eua cac than eat theo dien tich va he sd bao trum eua qua trinh khai thac theo phuang thing dung va nim ngang deu giam di Han the nua, nhung than cat Idng sdng cd mCre dp bit d§ng hudng cao, eae phan khae cua chung thdng thudng luu thdng thuy ddng lye tdt vdi theo hudng true Do vay, nhim nang cao hieu qua khai thac dau nhUng than eat nen ap dung mang ludi gieng khoan khdng deu thay vi mang ludi deu hien dang sir dung 140 Hdi thdo khoa hoc "Ndng cao he sd thu hdi ddu md Bqch Hd" Ngoai cac dieu kien tram tich, thi yeu td kien tao cang lam tang them tinh bit ddng nhit eua cac ddi tugng neu tren bieu hien bing sy gdp mat cua eae man chin kien tao, ben canh nhung man chin thach hpc da cd, ngan each giua cac phan khae eua cac than eat hay tang them sd lugng eae than diu Yeu td kien tao hien dien rd net han ea la trim tich Oligoxen dudi Tai vdm Bae ciu tao, eae dUt gay ehinh chu yeu cd hudng Ddng-Bae Tay-Nam phan chia ddi tugng ba khdi Idn ehinh vdi bien dp dich chuyen theo phuang thang dung tU vai ehue tdi han 250m Trong pham vi mdi khdi bing ket qua khoan va khai thac da ghi nhan dupe sy tdn tai cua mdt vai than dau rieng le neu xem xet d mUe dp ting san pham Tai vdm Nam ghi nhan dugc vd sd eae khdi biet lap eae dUt gay kien tao hinh Theo ket qua nghien eCru kien tao, nhung dut gay la sau tram tich, ed tudi eudi Oligoxen sdm - diu Oligoxen mupn Theo cac nha nghien eUu, hoat ddng kien tao dugc gan vdi qua trinh tao rifta eua bdn trung CCru Long Trong lat eat sy kien dyac ghi nhan bing sy ed mat cua cac via da phun trao nim tren bat chinh hgp Oligoxen dugi-Oligoxen tren cac gie'ng khoan d phin dinh vdm Bae cung nhu d mpt sd gie'ng khoan tren vdm Trung tam - GK.4,14, 64, 65 hay sy gia tang chieu day dang ke d phan dudi lat cat Oligoxen tren nhung gie'ng nam cac khdi sut Vi du, phan tich lat eat va so sanh chieu day d hai gieng khoan lan can la GK.107 va 108 nam d hai khdi ed chieu chuyen dich khae nhau, tap tram tich khoang chieu sau nam tren bit chinh hgp Oligoxen dudiOligoxen tren chi ghi nhan dugc d gie'ng khoan nam d khdi sut -GK.108 Ddi vdi Mioxen dudi, hoat ddng kien tao vao thdi ky Mioxen trung khdng ed quy md Idn nhu d Oligoxen sdm, vay bien dp dut gay tram tich thudng khdng Idn, theo ket qua quan sat dugc d 13 gie'ng (GK.10, 28, 35, 43, 67, 72, 79, 81, 86, 94, 108, 504, 810) qua trinh lien ket ty my eae than cat cua tang san pham thay ddi tU tdi 64m Tuy nhien, cac via cat ket eua ting san pham 23 tuang ddi mdng, day tu den 23m, vay bien dp dich chuyen neu tren d nhung ehd xung yeu cung du ddng vai trd cac man chan kien tao Vi du dut gay Idn chay theo hudng Ddng-Bae Tay-Nam chia ddi dien tich phat trie'n cac than cat, phia Tay dCrt gay viing eae gie'ng khoan sd 4, 63, 107 ehUa dau, dd ben canh sut khu vyc GK.116, 117 ehUa nude Phan phia Bae cua khdi cac via eat ket 23_2, 23_3 ed nhung than dau nhd vdi bien dp ehi dat 25m hien dang khai thac bdi cac GK.145 va 708 Ranh gidi dau nude eua chung khae biet vdi ranh gidi eua nhung than dau cac via eat cung ten nam d phia ben eua dCrt gay (Hinh 5) Tdm lai, yeu td kien tao lam tang them tinh bit ddng nhit cho cac ddi tugng, gdp phan lam lam phCre tap them cdng tac khai thac diu a) Via 23 b)Via23_2 c) Via 23_3 Hinh Ban dd eiu true nde cac via cat chUa diu cua tang san pham 23, Mioxen dudi 141 Hdi thdo khoa hoc "Ndng cao he sd thu hdi ddu md Bqch Ho" Ben canh nhung yeu td bat ddng nhit cac yeu td dieu kien trim tich va kien tao, sy chenh lech Idn ve chieu sau the nim cua cung mpt ddi tugng d phan dinh vdm va d phin canh cau tao cung tao nen nhung anh hudng xiu ddi vdi tinh di dudng eua da chCra Vi du, cat ket cua Oligoxen dudi khdi I cd chieu sau the nam khoang 3200-4038m, d cac khdi II la 3211-4214 va d khdi III la 39294348m dudi myc nude bien Theo ket qua minh giai tai lieu dia vat ly gieng khoan thi tai nhung gieng khoan sau nam d phan ria cau tao ty phan cat ket chCra diu dat rat thip tU den 0.2 nhu d GK.9,10, 700, 703, 704 Nguyen nhan eua sy suy giam ty le eat ket chUa diu d nhung gieng khoan sau cd the dugc giai thich bang viec eat ket d dieu kien ap suit va nhiet dp cao bi nen ep chat han va sy xuit hien va phat trie'n nhung khoang vat thU sinh nhu zeolit hay cac khoang vat khae phin xi mang hdn hgp eua cat ket Oligoxen dugi Theo ket qua nghien cUu cua Trudng dai hpc diu GCipkin thupe Lien Xd cu thyc hien tren bp miu Idi cua cac GK.4, 9, 10 [5] hay theo ket qua phan tich miu Idi eua GK.109 tU khoang chieu sau 3941.53952.0/3858.5-3868.0m Vietsovpetro thyc hien (Snip O.A, 1989) thi qua trinh bien ddi thU sinh bat diu xay quan sat dupe tU chieu sau -3800m dudi myc nude bien Tren Hinh la bien thien cua dp rdng eat ket Oligoxen dUai theo chieu sau the nam Quan he giua dp thim va chieu sau the nim cung cd dang tuang ty nhu ddi vdi dp rdng vi giua dp thim va dp rdng giua hat cua eat ket tdn tai mdi quan he tyle thuan Ngoai ra, tinh bit ddng nhit cua eae ddi tugng neu tren edn gdm ea sy khae biet ve tinh chit diu giua cac vung cua cung mdt ddi tuang 0.10 0.12 0.14 0.16 20 0.18 3200 3400 3600 3800 40001 4200 h 4400 J 0Bl0Cl