904 Sa ling mudi Co'''' chg, du bao va bien phap phdng tranh cho khai thac dau mdng md Bach Hd SA LANG MUOI CO CHE, DlT BAO VA BIEN PHAP PHONG TRANH CHO KHAI THAC D A U MONG M O BACH HO Nguyen Hiiu Trung[.]
904 Sa ling mudi: Co' chg, du bao va bien phap phdng tranh cho khai thac dau mdng md Bach Hd SA LANG M U O I : CO CHE, DlT B A O VA BIEN P H A P P H O N G T R A N H C H O KHAI T H A C D A U M O N G M O B A C H H O Nguyen Hiiu Trung, Hoang Van Tham, Pham Xuan Toan Nguyin Xuan Hda, Duong Diic Quang, Ngd Xuan Vinh Viin Ddu Khi TOM T A T Bdi bdo tap trung vdo cdc vdn di sa ldng mudi vd biin phdp ngdn ngira & quy md phdng thi nghiem vd thuc ti khai thde md Mdt logt cdc phucmg phdp thdm dinh vi sa ldng mudi da dugc thuc hiin tgi cdc phdng thi nghiim ciia Viin Ddu Khi (VPI) bdng cdc phuong phdp hiin dgi nhu XRD, SEM, sdc ky, phdn tich hod hgc, v.v Co chi sa ldng mudi tgi mdng Bgch Hd dugc ldm rd Sa ldng mudi calcium carbonat vd calcium sulfate diin phd biin qud trinh khai thac thu cdp bom ep nu&c tgi mdng Bgch Hd Rd rdng, su cd mat cua cdc khodng vgt thu sinh dugc tgo thdnh bcri cdc hogt ddng kiin tgo, thuy nhiet vd phong hod qud trinh hinh thdnh mdng Bgch Hd Id nguyin nhdn chinh gdy su bdo hod cdc khodng vdt hod tan cua nu&c biin bom ip Cdc khodng vdt thu sinh lap day khdng gian rdng nut ne dd chu yiu la cdc logi zeolite, calcite vd cdc khodng vdt sit Sir thay ddi ciia cdc diiu kiin thuy nhiet mdng gdy trgng thdi qud bdo hod mudi cua nu&c khai thac vdn dugc bam ip vdo via vd qud trinh sa ldng mudi xudt hiin Bdo cdo Cling tdm luge du bdo quy md sa ldng mudi cung nhu cdc biin phdp dieu hdnh chdng sa ldng mudi cho mdng md ddu Bgch Hd Cdc biin phdp phdng chdng vd xir ly via dugc ddnh gid tgi cdc phdng thi nghiim VPI Mdt vdi chdt chdng sa ldng vd td hgp hod hgc cho xu ly vung can day gieng mdng Bgch Hd dd dugc VPI thir nghiim vd di xudt Di phdng chdng sa ldng mudi mdt nhung vdn di quan trgng la du bdo nguy ca sa ldng mudi tgi mdng Bgch Hd, tu trgm xu ly bam ip nu&c, via m&ng vd hi thiit bi khai thde GIOI THIEU CHUNG Md dau Bach Hd nam d bl Ciiu Long Vietsovpetro la nha dilu hanh md, khai thac dau tir ddi tugng: mdng mit ne, eat kit Oligocen va Miocen Ddi tugng khai thac chinh la mdng mit ne vdi ty trgng san lugng hon 90% toan md Nham muc dich tri ap suat via, tu nam 1993 nude da dugc bom ep vao mdng Nude biin dugc sii dung cho bom ep, khai thac thii cap Sau vai nam nude xuat hien d mdt vai gilng khai thac Theo bao cao ciia XNLD Vietsovpetro [1] chi nam 2003 nude khai thac da dugc ghi nhan d 17 gieng khai thac Do ngap nude thay ddi tii dudi 10% din 60 - 70%) Cdng tac dilu hanh khai thac tap trung chu yeu vao each ly nude tai cac gilng khai thac Khi nude xuat hien cung bat dau xuit hien cac vin dl sa lang mudi gay cdng tac dieu hanh khai thac tai mdng Bach Hd.Tich tu sa lang mudi dau tien tai van tuin hoan bom ngam F.A Kirieev phat hien nam 1994 Theo bao cao cua XNLD Vietsovpetro [2], den hien tugng sa lang cac mudi huu co da xay tai rit nhilu dja Tuygn tap bao cao HQi nghj KHCN "30 nSm Phu Viet Nam: Cff hdi mdi, thach thiic mdi" 905^ dilm ciia he thing khai thac: viing ban via, bom ngam ESP, cin dng khai thac, van tuin hoan va van an toan, mieng gilng, van tilt luu, he thing xii ly, thu gom va xuit dau nhu minh hoa d Hinh - Can muli ciing xuit hien d mdt sd vi tri cua he thdng bom ep Sa lang muoi lam giam kha nang cho ddng ciia via hu hdng he tai gieng khai thac hoae bom ep va kit qua la giam san lugng khai thac dau Sa lang mudi cdn la mdt nhiing nguyen nhan hu hdng thiet bi bom ngam ESP, thiet bi ldng gieng va can trd ddng chay Sd lieu khai thac ciia XNLD Vietsovpetro da chi rang, rat nhieu gieng da giam san lugng van de sa lang mudi he va thiet bi dudi gieng Thiet hai sa lang mudi gay la ldn suy giam san lugng khai thac va gia tang tan suat cdng tac riit thiet bi ldng gieng cho sua chiia, ban lai gieng ciing nhu kich thich via, khoi thdng ddng chay va cac cdng tac siia chiia gieng khae Rat nhieu trudng hgp sa lang cac loai mudi calcium carbonat, calcium sulfate, strontium sulfate va barium sulfate da dugc bao cao [ ^ ] Nham muc dich dua cac giai phap phdng chdng sa lang mudi tai mdng Bach Hd mdt each hieu qua, Vien Dau Khi da nghien ciiu tdng the ve van de vdi muc dich lam rd co che sa lang mudi, danh gia anh hudng ciia nd len cac gieng bom ep va khai thac, du bao xu the sa lang mudi tai mdng Bach Hd Ket qua nghien ciiu da xuat dugc mdt don pha che ngan ngira va tang cudng xii ly day gieng tai mdng Bach Hd Hinh 1: Sa l^ng tai mi^ng gieng 440 Hinh 3: Sa I^ng ldng gieng 902 Hinh 2: Sa ling 16ng gieng 817 Hinh 4: Sa l^ng trin thiet bj be m^t 906 Sa lang mudi: Co chg, dy bao va bien phap phdng tranh cho khai thac dau mdng md Bach Ho^ CO CHE SA LANG MUOI TAI MONG BACH HO Kit qua cac phan tich tdng hgp (XRD, SEM, sic ky, phan tich kich thudc hat boa hoc, v.v.) cac mau can sa lang thu hdi tir ban 20 gieng tai mdng Bach Hd da chi cac luan diem nhu sau: Can sa lang vd co tai mdng Bach Hd cd phan chu yeu la mudi calcium carbonat CaCOs and calcium sulfate CaS04 (cac loai thach cao sulfates) Ham lugng ciia chiing thay ddi tir mdt vai % din ban 90% Cac muoi vd co kbac nhu carbonat magnesium MgCOs, strontium sulfate (Celestine) SrS04, barium sulfate (barite) BaS04, siderite FeCOs, halite NaCI, v.v dugc tim thay d ty le nhd hon • Cac tap chat co hoc nhu manh da, zeolite, khoang vat set, chat ri sat, v.v cd mat phd biin can sa lang mot vai gieng cdn phat hien cac hydroxit nhdm va sat cd the la cac san pham xu ly gieng • cac vat chat hiiu co tim thay phd bien can sa lang vdi phan thay ddi tir mdt vai % din ban 80% Can sa lang calcium sulfates cd cau triic cac tinh the dugc sinh va phat trien tir ldng mdt dung dich ddng nhat qua bao hoa Do cd kich thudc rat chiing thudng dugc tai di va phat hien d vi tri each xa noi bat dau hinh mam tinh the (Hinh 5) Can sa lang calcium carbonat thudng cd cau triic tinh the dang kim, phat trien hudng tam tu tren be mat kim loai ciia thiet bi (Hinh 6, 7) Loai cau tnic chiing td qua trinh tao mam va phat trien tinh the mang tinh di the tir dung dich nude qua bao boa Hinh chi rd dau vet giai phdng CO2 qua trinh tao loai can Hinh 5: Cau true can anhydrite Hinh 7: Tinh the calcite dang kim huong tam Hinh 6: Cau true tia can calcite Hinh 8: Thoat CO2 kem theo Tuygn tap bao cao H^i nghj KHCN "30 nam Dau Viet Nam: Cff hdi mdi, thach thiic mdi" 907 Hiln nhien qua trinh tao mam va trudng ciia tinh thi xuit phat tir dung dich nude mudi qua bao boa Phan tich hoa hgc nude biin bom ep chi rang, nude bien bom ep vao mdng cdn d trang thai dudi bao hoa Tuy nhien, nude ddng hanh thu dugc d gilng khai thac thudng dat trang thai qua bao boa Nhu vay, trang thai qua bao hoa cua nude bom ep la kit qua tuong tac ly - boa cua chiing vdi mdi trudng thuy dia chat khdng gian nut ne ciia mdng Bach Hd Phan tich thach hoc da via mdng Bach Hd cho thay su cd mat ciia cac khoang vat thii sinh, dugc tao bdi cac hoat ddng kien tao, thuy nhiet va phong boa qua trinh hinh mdng Bach Hd Phd bien ban ca sd cac khoang vat thii sinh la zeolite, calcite va cac khoang vat set khdng gian niit ne nhu minh boa d Hinh 10 Hinh - 10: Khoang vat zeolite khong gian niit ne mong Bach Ho Cac khoang vat thii sinh rat khdng ben va la ngudn chinh gay bao hoa nude bom ep bdi cac khoang vat hoa tan Qua trinh bao hoa nude bom ep dien dudi dang tuong tac ly - hoa hgc giiia nude bien bom ep va cac khoang vat thii sinh Cac tuong tac bao gdm cac qua trinh hoa tan cac khoang vat zeolite, calcite, feldspar, v.v va trao ddi ion ciia cac khoang vat set Do miic hoa tan cua cac khoang vat thay ddi theo dieu kien thuy ddng luc nen de dang gay nen tinh trang qua bao hoa va dien hien tugng sa lang mudi tii pha nude Mdng Bach Hd dac trung bdi miic bat ddng nhat cao ve thuy ddng lire: vdi chieu cao mdng ban 1600m chenh lech nhiet giira phan day va noc mdng len tdi 30 - 35°C va giam ap tai cac gieng khai thac thay ddi tir 0,5 - 20 MPa Chinh dac trung thuy ddng luc da tao dieu kien thuan lgi cho sa lang mudi d vimg can day gieng khai thac Vdi can sa lang calcite, su sa lang cua chiing cdn phu thudc manh vao qua trinh giai phdng CO2 Khi ap suat giam dudi ap suat diem hot boa tan thoat khdi he dung dich dau/nirdc mudi Ket qua la sa lang mudi calcite dien theo phan iing hoa hoc sau: Ca^^ +2 HCOj- -^ CaCOji + COjt + H2O Qua trinh tach dien chii yeu dng khai thac gieng va thilt bi tren mat Dieu giai thich tai can sa lang calcite hay dugc phat hien thudng xuyen qua trinh siia chiia gieng tai mdng Bach Hd Sa ling mudi: Co' che, du b^o va bien phap phdng tranh cho khai thac dau mdng md Bach Ho 908 Nude he mdng Bach Hd van chua dugc phat hien Chi phat hien dugc nude via cue bd tai mot gilng vdi ham lugng mudi rat thap, khoang 7g/l Dieu cho phep du doan su tuong tac cua nude via va nude bom ep khdng ddng vai trd gay nen sa lang mudi tai mdng Bach Hd Thi nghiem bom ep nude qua miu mdng Bach Hd da dugc thuc hien de kiem nghiem gia thuyit tren Nude biin dugc bom ep qua mau tdng hgp dugc ghep ndi tir nhieu miu ldi d cac gilng khae Nude bom ep dugc thu hdi va phan tich dinh ky Cac ket qua phan tich phin nude thu hdi cho thiy xu hudng gia tang rd ret cua ndng Ca^"" S04^' kit qua tuong tac boa hoc giiia nude biin bom ep va khoang vat thii sinh khdng gian mit ne Kit cue la nude bom ep trd nen bao hoa cac mudi de tan Bang 1: Thay ddi phan pha nu'O'c Tinh todn tich ndng Ndng ion (mg/l) T T Ngdy ldy mdu 1 -3 24,46 4-6 HCOs' CO/' so/- pH TCaS04 84,40 6,60 0,20 50,82 1,15 310,0.10"*^ 12,2.10"^ 23,60 90,40 6,60 0,20 52,67 1,1S 310,2.10"^ 18,8.10"^ 7-9 22,90 92,80 6,60 0,20 53,80 7,79 308,0.10'^ 18,3.10"^ Nude bien ban dau 16,00 102,40 7,50 0,20 41,60 7,80 166,4.10"^ 8,0.10'^ Ca^^ Mg'^ TCaCOs Phan tich SEM tren mau ldi mdng sau bom ep nude ciing chi rd biic tranh ket qua boa tan cac khoang vat thii sinh, qua trinh nia lua, cudn trdi va tich tu cac hat va qua trinh ket tiia cac mudi vd co khdng gian rdng Hinh 11: Lomontite bi hoa tan Hinh 12: Sa ldng Lomontite/calcite/halite DU BAO SA LANG MUOI CHO MO BACH HO Nhu da trinh bay d tren sd lieu thuc nghiem va thuc te khai thac mdng cho thiy calcium carbonat CaC03 va calcium sulfate CaS04 la cac mudi sa lang chinh qua trinh dieu hanh khai thac mdng Bach Hd Cdng tac du bao sa lang mudi tap trung chu ylu vao hai ddi tugng Du bao sa lang dugc tien hanh cho viing can day gilng mdng va thilt bi ldng gilng/thilt bi tren mat kem theo Tuyin tap bao cao Hpi nghj KHCN "30 nam Phu Viet Nam: Cff hdi mdi, thach thiic mdi" 909 Nhu da bilt, dl qua trinh sa lang muoi tir dung dich nude da via xay phai hdi tu dugc hai ylu td sau: Pha nude phai dat trang thai qua bao hoa d miic du ldn va mim tinh thi tao muoi phai dat kich thudc tdi ban, xac dinh theo cdng thiic ciia ThomsonKelvin [7] Theo cdng thiic ciia Thomson-Kelvin, kich thudc tdi ban ciia mam tinh the d dilu kien mdng Bach Hd khoang 30|^m Cac dilu kien khai thac dau mdng Bach Hd thoa man cac dilu kien ndi tren: Khai thac d giam ap cao 0,5 - 20Mpa va chay cheo mdng theo nut vd dan din trang thai qua bao hoa d miic cao cua dung dich nude, md ciia cac macro mit ne tir 100 - 500iim hoan toan phu hgp cho qua trinh tao va phat triln mam tinh the tir dung dich nude dieu kien via Mdt vin dk quan trgng la phai du bao nguy co sa lang mudi d viing can day gilng mdng Du bao sa ling mudi mdng dugc bieu dien thdng qua he sd bao hoa S cua calcium carbonat va calcium sulfate pha nude He sd bao hoa dugc tinh toan tir sd lieu hoa tan ciia CaC03 and CaS04, thu dugc phdng thi nghiem qua su tuong tac ciia nude bien bom ep va da mdng tai cac dieu kien nhiet thuy ddng ciia mdng Bach Hd, trinh bay d Hinh 13 D I cho don gian ndng ion dugc sudung thay thi cho boat ddng ion [5] Cac thi nghiem dugc tien hanh khoang ap suat den 23 Mpa, nhiet den 150°C a) b) i Hinhl3: Tich nong ion cua pha nuoc cho a) CaS04 va b) CaCOj o dieu kien nhiet do, ap suat mong Bach Ho He sd bao hoa S dugc tinh cho mdi gilng phii hgp vdi dieu kien thuy ddng lire ciia chiing tai day gilng va via Theo [7], nguy co tao sa ling mudi dien he sd bao hoa S dat din 1,073 Dilu ddng nghla vdi miie qua bao hoa cao ciia pha nude Ket qua du bao trinh bay d Hinh 14 Theo nhu kit qua d Hinh 14 nguy co xay sa ling mudi vung can day gieng diln tap trung phin ldn d khu vue khdi nang phia Bae mdng Bach Hd Dd la cac khu vuc cd he sd bao hoa cao chu ylu giam ap suat ldn tai cac gieng khai thac gay nen D I du bao xu the sa ling gilng khai thac va thiet bi tren mat lien quan, nude khai thac ddng hanh d mdi gieng ngap nude dugc thu thap va phan tich phan hoa hgc tai cac phdng thi nghiem cua Vien Dau Khi Nguy co sa lang CaC03 va CaS04 dugc 910 Sa lang mudi: Co chg, dy bao va bi^n phap phdng tranh cho khai thac dau mdng md Bach Ho danh gia qua he sd bao hoa S, chi sd bao boa SI va chi sd dn dinh ISt [7] Ket qua phan tich cho thay cd tat ca 23 gieng khai thac cd nguy co cao sa lang mudi CaS04 va chi cd gieng khai thac cd nguy co sa lang CaC03 Ket qua du bao dac biet ddi vdi CaC03 cdn khae tuong ddi xa so vdi thuc te khai thac mdng Bach Hd Do vay du bao sa lang cho CaC03 neu chi dua vao phan nude khai thac cd the khdng chinh xac va can phai dugc hoan thien tiep tuc a) b) r^.^ ^i«?^- rrr My \ Khu vuc c6 nguy CG _ sa lang mudi cao via Klui vuc c6 nguy ca _ sa l^ng mudi cao (rong via \/N^^&f^ / ^ f\ A /_ KfHl$UQUIUdC S < 1,07: Nguy co sa Ikg Ihip S > 1,07; Nguy ro sa ISng cao \ KlHieuQuiUk: u S < 1,07: Nguy co sa ling tMp S > 1,07; Nguy cosa lang cao Hinh 14: V iing nguy co sa lang muoi via cao a) CaS04 va b) CaCOs GIAI PHAP XLT LY CHO MONG BACH H Mdt vai chat lie che sa lang mudi phd bien da duge danh gia tai cac phdng thi nghiem Thiet bi phan tich hat laser counter dugc su dung nhim danh gia kha nang lie che ciia chiing vao qua trinh hinh va phat triln cac mim tinh thi mudi dung dich nude mudi Cac ket qua phan tich da chi ring cac loai chit lie cbl sa ling mudi kieu axit alkin-phosphor va nitril-trimetil-phosphor cd hieu qua lie cbl tdt hon ea cho dilu kien mdng Bach Hd Ngay nay, xu ly bang axit dugc sii dung rdng rai cdng tac siia chiia gilng tai mdng Bach Hd Cae axit cd tac dung loai bd cac can sa ling d viing can day gilng va eae thiet bi day gieng khai thac mdng Trong trudng hgp mdng Bach Hd hieu qua xii ly cua cac axit bi ban che phan phiic tap ciia cae can sa ling Su cd mat cua cac phan kbac nhu manh da, khoang vat thii sinh va cac phin hiiu co, v.v da ban che sir tiep xiic true tiep cua cac axit vdi can sa lang De khic phuc nhugc dilm nay, Vien Tuygn tap bao cao HQi nghj KHCN "30 nam D5u Viet Nam: Cff hdi mdi, thach thiic mdi" 91J_ DIU Khi da dl xuit td hgp xii ly axit tang cudng tren co sd nhii tuong axit - dau cho mdng Bach Hd Thanh phin td hgp bao gdm vi nhii tuong axit - diu, chat tang cudng chat lam cham phan iing, chit chdng an mdn va td hgp sinh boa VDK-CSL Vien Dau Khi san xuat va pha cbl KET LUAN Bao cao trinh bay tdng quan cac van de sa lang mudi can giai quyet lien quan den qua trinh bom ep nude bien vao mdng md dau Cac luan diem bao cao cd the tdm tat nhu sau: • Sir cd mat ciia cac khoang vat thii sinh nhu zeolite, calcite, set dugc tao cac boat ddng kien tao, thuy nhiet va phong hoa qua trinh hinh mdng, via chiia mit ne Bach Hd la nguyen nhan chinh gay bao hoa nude bien bom ep Ket qua hoa tan cac khoang vat kem ben vimg va trao ddi ion la cac ddng lire chinh lam bao hoa nude bom ep Cac can mudi sa lang chii yeu la calcium sulfate va calcium carbonat • Trong dieu kien via, su thay ddi dieu kien thuy ddng luc d vung can day gieng la yeu td chu dao gay trang thai qua bao hoa ciia pha nude va ket tiia mudi sa lang tai khu vuc cac gieng khai thac Lugng nude lien ket va nude via cue bd cd vai trd khdng dang ke vao qua trinh qua bao boa • Trong dng khai thac, ap suat giam dudi ap suat bao hoa va ddng hanh dugc giai phdng, vai trd ap suat phan cua CO2 trd nen yeu td quan trgng gay sa lang mudi calcium carbonat Van de du bao sa lang cua loai can trd nen phiic tap ban thieu cac sd lieu ve can bang cac pha khi/dau/nudc dieu kien khai thac mdng Bach Hd • Nguy CO sa lang mudi d viing can day gieng mdng dugc bieu dien qua he sd bao boa CaC03 va CaS04 Theo ket qua khdi nang phia Bae cua mdng Bach Hd cd nguy CO sa lang mudi mdng cao ban ca Dieu ddi hdi phai chii hon cdng tac kich thich via ciing nhu siia chira gieng cho ddi tugng • Nham muc dich cai thien cdng tac xu ly loai bd can sa lang viing can day gieng va kich thich ddng, Vien Dau Khi de xuat td hgp sinh boa VDK-CSL cho don pha che dung djch vi nhii tuong kieu axit - dau cho cdng tac axit hoa via mdng Bach Hd TAI LIEU THAM KHAO Vien NIPI, 2003 So- dd cdng nghi diiu chinh m&i khai thac vd xdy dung md Bgch Hd XNLD Vietsovpetro, Viing Tau Nguyen Hiju Trung, Hoang Van Thim, Nguyin Xuan Hoa va n.n.k., 2004 Ca chi sa ldng mudi, dnh hudng ciia nd lin tinh chdt thdm chua mdng Bgch Hd, he thdng bom ip vd thiet bi cdng nghi, cdc biin phdp khdc phuc Vien DIU Khi, Ha Ndi J Moghadasi, M Jamialahmadi, H Muller-Steinhagen, A Sharif A Ghalambor, M.R Izadpanah, Kerman U., E Motaie, 2003 Scale formation in Iranian oil reservoir and production equipment during water injection SPE 80406 912 Sa lang mudi: Co chg, du bao va bien phap phdng tranh cho khai thac dau mdng md Bach Ho Vetter O.J., Farone W.A., Veith E., Lankford considerations: A practical approach SPE 17009 S Calcium carbonate scale Vetter O.J., Phillips R.C Prediction of deposition of calcium sulfate scale under downhole conditions SPE 2626 Voloshin A.L, Ragulin V.V., Tyabayera N.E., Diakonov 1.1., Mackay E.J., 2002 Scaling problems in Western Siberia SPE 80407 HdparH.MOB Jl.X., MHIUCHKO H.T., HCJIOHHU JX.K., 2000 HnmencurpuKaiiUH dodbmu uecpmu MocKBa, «HayKa» ... sd vi tri cua he thdng bom ep Sa lang muoi lam giam kha nang cho ddng ciia via hu hdng he tai gieng khai thac hoae bom ep va kit qua la giam san lugng khai thac dau Sa lang mudi cdn la mdt nhiing... Sd lieu khai thac ciia XNLD Vietsovpetro da chi rang, rat nhieu gieng da giam san lugng van de sa lang mudi he va thiet bi dudi gieng Thiet hai sa lang mudi gay la ldn suy giam san lugng khai thac... gieng 902 Hinh 2: Sa ling 16ng gieng 817 Hinh 4: Sa l^ng trin thiet bj be m^t 906 Sa lang mudi: Co chg, dy bao va bien phap phdng tranh cho khai thac dau mdng md Bach Ho^ CO CHE SA LANG MUOI TAI