PETROVIETNAM
) D l i u KIEN VA CAC YEU l6 A N H Hl/ONG DEN SLJ HINH THANH, PHAN B 6 HYDRATE KHI TRONG TL/ NHIEN
TS.Le Van Binh Dai hgc Mo- Dia chdt Email: [email protected]
Hydrate khi Id nguon ndng luang tii nhien sgch rdt cd tiem ndng trong tUang lai. Theo dU bdo trd luang khi hydrocarbon chUa trong hydrate khi tu nhien dgt 7,6 x 10"m\ Do chi duac thdnh tgo trong dieu kiin nhiit dp thdp vd dp sudt cao nin 98% lUcfng khi hydrate ndm dudi ddy them luc dm vd ho, chi 2% d viing bdng vinh cdu trin luc dia.
Trong do, Canada, Bien Den, ho BaikaL.. Id cdc khu viic cd trdluang hydrate khi idn nhdt thi gidi. Bdi bdo gidi thieu cdcyeu to dnh hudng din sii hinh thdnh vdphdn bd hydrate khi trong tU nhiin; trdlUang vdphdn botrdlugng khi hydrate trin thi gidi.
Tdkhda: Hydrate khi, suphdn bo hydrate khi, trdluang khi hydrate trong tu nhien.
1. Dieu kien va cac y^u t o cinh hadng den sU hinh thanh, phan bo hydrate khi
1.1. Biiu kiin hinh thdnh hydrate khi 1.1.1. Nudc ehda khi hda tan dmUc dp nhdt dinh
Ket q u i nghien cdu ly hda phan t d chc thay: elc nguyen t d hydro va oxy trong p h i n t d nUde ket hgp va phan bd g i n nhu nam d dinh eiia tam giac can. Gde tai dinh ed nguyen t d oxy la 109,5°, hai gde edn lai la 37,5°
(Hinh 1). Ddi dien tCr diing chung cua nguyen t d hydro v l oxy (trong lien ket dong hda trj) bi hut lech ve phia nguyen t d oxy tao nen tinh phan cUc eho phan td. Cue am ve phia nguy§n t d oxy, cOc dUOng ve phia nguyen tCr hydro. Hydro trong cae phan t d nude cd sU "gin bd"
chat ehe vdi eac nguyen t d oxy tao ra mdi lien ket khdng chi vdi nguyen t d oxy trong phan t d (lien ket ddng hda trj) ma eon tao mdi lien ket tam thdi vdi eae nguyen t d oxy cua elc phan t d nudc khac, tham ehi nd ed the lien ket vdi oxy trcng p h i n t d khoang chat tac da. Do vay, cIcphantLf nUde trcng t u nhien luon "xoo/'trong khdng gian, sao chc moi nguydn tCf hydro n i m gida 2 nguyen t d oxy. Lien ket gida 2 nguyen t d oxy cija 2 phan t d nude g i n k l , thdng qua nguyen t d hydro trung gian tac ra mdi lien k i t hydro giOp cho HjO tdn tai trong trang thai ldng d d i l u kien tieu chuan, tao ra Idp nUde lien ket bao quanh mat d l . Do dac diem tren, nUdc cd cae tinh chat v i t ly khac so vdi hydrua khic ndi rieng va cic c h i t Idng ndi chung nhU: sde cang mat ngoii Idn, nhiet dung cao nhat d d i l u kien tieu chuan, k h i nang truyen nhiet ldn n h i t , k h i nang hoa tan r l t ldn, h i n g so di&n mdi Idn, nhiet hda hoi cao.
Trong hda hpc, lien k i t gida elc nguyen t d c d 2 thong sd dac trung I I chilu d i i lien k i t I v l gdc a gida hai lien k i t . Trong li^n k i t chuin, chilu d i i lien k i t hydro va gdc gida chung cd gia trj chuan: I ~ 2,7A° va a ~ 109,5° phan t d se b i n vdng nhat. Do dai I va gdc lien k i t a eang khae vdi gia trj ehuan thi eang hao phi nang lugng de tao nen c l u true va eau true eang kem ben vdng. Tuy nhien, lien k i t hydro la "Hen k i t mem" (dp dai va goc lien ket co the thay doi 6 mde do tuong ddi) nen khi ket tinh cae phan t d nude CO the ket hap vdi nhau de tao thanh elc tmh the la nhdng khoi da dien khic nhau ve sd mat, hinh dang mat, so canh va tUOng dng se ehda cic khoang trdng khic nhau ve kfch thude (Hinh 2). D i y I I nguyen nhan chinh dan den sU da dang ve c l u true tinh t h i ndi ri^ng eung nhu to hap elc tmh t h i tao nen cau triic hydrate khi ndi chung [9].
Cdng thdc chung ciia hydrate khi la:
M.nHp
Trong dd:
M: Phan t d khi tham gia tao hydrate;
n: Chi sd hydrate khi (so phan t d nude tuong Cfng vdi 1 phan t d khi, thudng dao dpng trong khoing n = 5,75 - 17). Vi du: quan sat thUc t l chi ra cac khi hydrocarbon tao hydrate khi vdi ty le: CH^ x 7Hp: C^H^ x 12Hp; C^H^ x
MHplM
Td cdng thifc ehung ed the nhan thay de tac thanh hydrate khf p h l i can mdt lugng ldn nddc. Theo V.I.Ermcnkin, khi trcng khoang trdng cua da khong du lupng nude c i n t h i l t , ehi mot phan khi n i m trong eau true hydrate, phan edn lai van ton tai trong trang thai k h i " t u
iU KHl - sO 3raoi5 67
do". Trong khoang trdng ton tai ddng thdi 2 pha: pha ran la hydrate khf nam bao quanh, pha khi nam gida khoang trdng [5]. Khi luong nUde trcng tich tu vda dii, toan bp khi tham gia vac thanh phan hydrate khi, khi nUde thda se ed mdt sd ngan trong khdng dilcjc lap day bdi phan tu" khf.
Neu eae khoang trong trong tinh the hydrate khong duac lap day bdi cac phan t d khi thi tinh t h i hydrate khdng b i n v l nhiet dpng, de bj p h i huy. D i l u kien tdi thieu de cau trije dn djnh la > 70% tdng sd ngan p h l i dUOe lap day (ty le eae ngan trdng dugc l i p day eang cao thi he hydrate khf eang ben vijfng). Dilu nay giai thfeh vi sao mdt trong
Hinh I. Cdu true phan tim/dc Phan ti> methane
cac dieu kien hinh thanh hydrate khi ben vdng la nudc phai cd ehda lugng khi hda tan nhat djnh.
1.1.2. Nhiit dp thdp
Nudc chi k i t tinh d nhiet dp t h i p . 0 dieu kifn ap suat tieu chuan tren mat dat (P = 1 at) nddc ket tinh d nhiet dfl 4''C song trong dieu kien ap suit cao, khi ehda nhieu khi hoa tan, nddc cd the k i t tinh d nhiet dp cao hcfnnCfa. Tuy nhien, p h i n Idn khi t u nhien cd nhiet do tdi ban (Hmh 3).
Nhiit do tdi hgn tgo hydrate cua mdt logi khi- Id nhiit dp cao nhdt cdn cd thi tgo ra hydrate cda khi do. Niu nhiet dp mdi trUdng vUdt qud gid trj tdi bgn thi du cd tdng dp suat lin mdc rdt cao cung khdng the tgo ra hydrate khi.
Cac khi cd kich thudc phan t d nhd CH^, O^ N^, Ar, Kr, Xe (d < 0,4n.m) thudng khdng cd nhiet dp tdi han va gin nhi/
chi tham gia l i p day eac khoing trdng nhd tao hydrate khf he eau true CS-I (ben vCfng nhat la he c l u true ehda khoang trdng cd kich thude tuong ddng vdi kfch thudc phan t d khi nam trong do). Trong t u nhien, khf ehda trong hydrate khf he eau tnic CS-1 chu y l u la khi methane.
Cac khf cd kich thude Idn tham gia tao hydrate khf eae he cau triic CS-il;TS va HS deu cd nhiet do tdi han:
CjHg -T,^^ = 8,8°C dudi I p suat P = 4at;
CjHg - T^^=14,8°C dudi ap suat P = 80at, HjS - T ^ = 29,5''C dudi I p suat P = 21at.
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0 5 0 > 10 15 20 Nhiet dfl T t
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Wnft 2.7/nft tfte hydriRe methane
iuirt-sOMois
Hinh 3. edlhinhiel^ too hydrate mdt id logi idil
PETROVIETNAM
Tddo thj nhiet I p tao hydrate khi (Hinh 3) ed t h i thay vai trd eua nhiet do la quan trpng nhat, khi nhiet dp tang len theo t u y l n tinh thi ap suat tang theo t^ le logarite (ham so mu).
1.1.3.Apsudtcao
Dp ben vuYig eua tinh the hydrate khi q u y l t dinh bdi luc tuang tac Van der Waais giQa cae phan t d nudc "chii"
va eae phan t d k h i " k h l e h " n l m ben trong khudn tinh the.
d dieu kien nhiet do thap, nude ddng bang tao tinh t h i cd ehda ngan trdng, song rat "xdp" va ngan trdng khdng ehda p h i n t d khi, khdng tao hydrate khi. Khi ap suat tang cao ep elc p h i n t d lai gan nhau, vdi khoing each nhd hon b i n kfnh Van der Waals cda mpt nguydn t d hay p h i n t d ( b i n kinh cOa mdt hinh c l u tudng tugng, duac diing de md hinh hda cho nguyen tCf hay phan t d d d , la khoing cich gida cac cap nguyen t d hay phan tCr khi gida ehung khdng cdn tUOng tac) - lire tUOng t i c Van der Waals gida cic phan t d nude va cae phan t d khf gia tang d i n g k l ,
"nhot" eae phan t d khi vao trong ngan trdng dan den hinh thanh hydrate khf.TrUdc day, khi nghien cdu sU hinh thanh hydrate khi trong d i l u kien ap suat khdng eao (P
< 2kbar) ngudi ta nhan thay: trong mdt ngan trdng chi ehda khdng qua mdt phan t d khi va cac khi eo ban kinh Van der Waals nhd nhd hydro, helium, neon khdng the tao hydrate khi. Hien nay, khi nghien edu sU hinh thanh hydrate khi trcng d i l u ki^n ap suat cao thi thay khong nhCtng elc khi cd b i n kinh Van der Waals nhd cd t h i tham gia tao hydrate khf ma trong mpt ngan trdng ed t h i "nhdt" 2 phan t d khf vdi kfch thude khdng Idn. Nhdng d i l m tren ehdng td vai trd quan trpng eua l p suat trong hinh thanh hydrate khf.
1.2. Cdc yiu tddnh huAng din sUhinh thdnh vdphdn bd hydrate khi
1.2.1. Thdnh phdn kh!
Cd nhieu loai tinh the hydrate khf va tuang dng cd nhieu loai khoang trong ehda trong cae tinh the, elc tinh the khic nhau k i t hgp tao n6n cac he eau true tinh the eO b i n CS-I; CS-ll; HS v l TS [10], Trong moi he eau true cd t d 2 - 3 loai tinh t h i ed ehda elc ngan trdng vdi kich thudc khie nhau. Cic he c l u true chi thuc su ben vOmg khi cac ngan trdng p h l i d\iac l i p day bdi elc phan t d khf (> 70%).
NhUvly, de tao he c l u true hydrate khi b i n vdng nhit, khi p h l i da dang v l t h i n h phan.
Phin Idn khi t d nhien (CH^, C^H,, C,Hg, CO^, N^, H^S, iC H ...) tao dupe hydrate khf, song chu y l u t l hydrate methane va dioxide carbon.
d cung dieu kien ap suat, khi kfch thddc phan tCf khf tang nhiet dp tao hydrate khi cung tang, vi du: dudi l p suat P = 0,1 at nhiet do tao hydrate cua CH^ la T = -78,6°C, C,H J a T =-31,4°C, CjHg la T =-11,5°C.
Trong sd cac khi hydrocarbon, do dd dan hdi cua khf methane cao (khi nang va xu hudng quay trd lai tdn tai d trang thai khi khi bj hda tan hay hda Idng dudi l p suat eao) nen khi ty'phan khi methane trong hdn hap khi eang eao, dieu kien hinh thanh hydrate khi yeu cau nhiet dd c i n g thap va I p suit cang cao.
Nghien edu thuc t l eho thay khi hydrocarbon tham gia vao qua trinh tao hydrate khi chu y l u la khi methane sinh hda do: (i) eae tich tu hydrate khi chi cd the hinh thanh va tdn tai trcng dieu kien nhiet dp va l p suit d nda phan tren cua ddi biln doi sinh hda cua vat chit hufu co (H < 1.500m;T
< 55 - 60°C), nai hinh thanh chii y l u khf methane sinh hda va dioxide carbon t d phin hiiy vat chat hiiu cado t i c dong cua vi khuin va men vi sinh; (ii) khf nhiet (chCi yeu la methane, hinh thanh do cracking kerogen trong ddi biln ddi dia hda v i t chat hilu co) chi ed the di ehuyin t d dudi len tren vcfi lugng han chl, tap trung trcng cac ddi dCft gay, khe ndt).
1.2.2. Op khodng hda vd thdnh phdn hda hqc cua nddc via Nude tinh khilt ed t h i k i t tinh d nhiet ddT = 4''C dudi I p suat khf quyln, song khi nude cd ehda cac chat hda hpe ndi chung va eae mudi vd co (dp khoang hda) ndi rieng thi nhiet dp k i t tmh ciia nude ddi hdi t h i p hon. D i l u nay dan den: trcng d i l u kien tUOng tU, dd khoang hda eua nUde tang thi nhiet dd tac thanh hydrate khi can g i l m hon nda.
1.2.3. Yeu to dia chdt
Trong tU nhien, dUdi Idp tram tieh hydrate khi chi tdn tai b i n vCrng d khoing do sau nhat dmh. Trang t h i i tdn tai dn dinh (trang thai pha) eiia hydrate khi phu thugc nhiet do va I p suat. Ddi tram tieh cd nhiet dp, ap suat thuan tien cho thanh tao hydrate khf ben vdng trcng vd trai d i t dUOc gpi I I "ddi hydrate khi on dinh".
Ddi hydrate khi on dmh thudng dugc xae dinh trong mat cat bang phuong phap p h i n tieh do hinh {chong do thi dudng cong thanh tao hydrate len dudng eong phan bd nhiet dd va l p suat theo do sau (Hinh 4).
Do ddi hydrate khi on dinh ehi tdn tai trcng khoing nhiet dd va ap suit tUOng thieh nen ehieu day eua ddi nay trong t u nhien phy thude vao cac dae diem dia chat:
Do dac diem hinh thanh hydrate khi eCia methane, nen khi ham lugng methane tang se lam giam do day ciia dcri dn djnh hydrate khi.
DAU KHl-sd 3/2015 69
Gradient dia nhiet tang cao dan den 'su nang" len cda day ddi on dinh hydrate khi va lam giam chilu day ddi dn ^ n h hydrate khi. Ngugc lai, khi gradient dia nhiet gilm, d i y ddi dn i^nh hydrate khi'ha"xudng va chieu day ddi dn dinh hydrate khf tang len.
Tren d i t liln, khi nhiet dd b l mat tang, dp day ddi tao bang vfnh edu tren b l mat giam (nhiet dp tang va I p suat g i l m trong ddi d i t da be mat) lam g i l m ehilu day ddi on dinh hydrate khf.
Khi gradient nhiet trong nUde b i l n va gradient dja nhiet khdng thay ddi, dp sau day nude tang, se Um giam nhiet dd d i y nudc, gia tang ap suit trong ddi dat da be mat dan d i n sii°nang° cao ciia ndc ddi dn dinh hydrate khi, i l m tang chieu d i y cua den' nay va ngUgc lai. D i l u nay CO y nghia Idn khi den' dn djnh hydrate khi hoan toan nam trong pham vi tram tfeh dudi day nude ed ehda nhieu khi hda tan.
Dp khoang hda tang ddi hdi nhiet dp ddng bang eua nude gilm, lam giam dp day ddi on djnh hydrate khi.
Khi di siu v i e Idng d i t nhiet dd tang len, vuot qua g i l tri tdi ban ve nhiet dp lam cho hydrate khi khdng the tdn tai.
Nghien edu thuc t l cho thay phan ldn cac tich tu hydrate khi t u nhien n i m trong khu vue tram tfeh dugc Ilng dong vdi tdc dp eao. Dieu nay hoan tcan hpp ly. Mac dii theo Simeus va Trimonis, do anh hUdng eua "hieu dng lam loang' eua ngudn vat lieu tram tieh ham luang vat chit hdu eo cung nhU ham lUpng carbonate trong tram tich ty le nghjeh vdi tde dp lang dpng eae t r i m tieh luc
ll''>l>*-Saddl?iadienddii6nta,dndinhcwhydmiekhimngtrdmiid,b-ien
nguyen, song nhilu nha khoa hpc khic lai cho ring quan diem tren chi cd tinh ly t h u y l t cdn kinh nghiem quan sat thue te lai nhan thay ham lugng vat c h i t hdu co ty le thuan vdi tde dd tram tfch va "hieu dng lam loang" ehi c6 t i e dung khi tde dp tram tieh qua cao [6]. Khi tram tich luc nguyen giau vat chat hdu co n i m trcng ddi b i l n ddi sinh hda (Sedimentogenes v l Diagenes), dudi t i e dgng ciia vi khuan va men vi sinh tao ra lugng Idn khf hydrocarbon, ehu yeu la methane, nguon vat lieu thiet y l u d l tao hydrate methane.
Cd y kien eho rang tich tu hydrate khi t u nhien cd t h i hinh thanh khi khdng cd t i n g ehSn v l bin than hydrate khi I I tang ehan rat tdt. Song, theo t i c g i l tang ehan la d i l u kien khdng the t h i l u cho hinh thanh tieh tu hydrate khf trong t u nhien vl di tao hydrate khi ngoai nhiet dp thap ddi hdi nudc ehda lugng khf hda tan nhat dinh, trong dieu kien nhiet dp thap khi chl ed t h i hda tan nhilu vao trong nUde chi khi I p suat dat g i l trj cao nhat
^ n h , trong dieu kien do n l u khdng cd tang chin khi se di thoat h i t ma khdng hda tan nhieu vao nudc. Tang chin tac dieu kien cho khf va nudc tfch tu, la nhuTig ngudn vSt lieu thiet yeu ban d i u cho thanh tao tfch ty hydrate khi t u nhien.
Khoang the hydrate khi tao ra trong phan mat cit tram tfch ed the t i l p xdc: phfa tren vdi tfch ty khf hoac tang da chan, ben dudi vdi nudc via, d i u , khi hoac khi condensate.
1J.4.Yeut6dialy
Trong t u nhien nhiet dp tren be mat t r i i d i t phu thuoe vao vT do, nhdng dieu kien phii hop eho sU hinh thanh vl bao ton hydrate khf thudng tdn tai trong cae tap tram tich nong hole nam ngay ben dddi Idp bang vinh edu thuoc eae viing cue, d day hd hole bien (Hinh 5) cd dp sau day nudc hon 500m d cac viing cd vT dp trung binh hole thap va d chieu sau t d 150 - 200m tai eae viing vT dp eao.
Vung b i l n Bac Cue ton tai 2 ddi thanh tao hydrate khi:
(i) vung nudc ndng gan bd, noi phan bd eae tram tich dddi Ic^ bang vinh edu ehda it hydrate kht; (ii) vung nUde sau (tren sUdn doe lyc dia) la ncri cd d i l u kien ly tudng cho sU h'inh thanh hydrate.
2. TrCr liTgrng va phan bo trii' (Utfng k h i hydrate tren t h e g i d i
Theo danh g i l cua cae n h i khoa hgc, lupng khi hydrocarbon (chu y l u la khf methane) ehda trong hydrate k h i t d n h i e n d a t l , 8 x l O ' * - 7 , 6 x l O ' W n i ] . T h e o l u . A D i a i n va A.L Gusin - Dai hoc Tdng hgp Novoxibirxk, trd lugng
PETROVIETNAM
hydrocarbon nay tao nang lugng Idn gap 2 lan nang luong duge tao ra tir tong trd luong nhien li&u hda thach ed tren hanh tinh [4]. Neu khai t h i c dupc, chi 10% lugng khi tren cung da g i p 2 lan lugng khf khai thae t d cac ngudn truyin thdng.
Co quan tai nguyen thien nhien Canada cho r i n g trd luong hydrate khi cd the dap dng 100% nhu cau nang lUgng cCia t h i gidi trong 2.000 nam.
Trd luong ciia hydrate khi d Canada ducjc xem la nhieu nhat the gidi, t i l p theo la Lien bang Nga, My, An Dp, Nhat Bin, Trung Qude [2,4]. Tinh the khi hydrate tfch tu tai bien chau A duge d i n h gia cd chit lugng tdt nhat vdi ham lUOng khi methane tdi 99%.
Gilm ddc Vien bang quyen (Criosfera) Triumen Vladimir Menhieov tong hpp ket qua nghi§n cdu hydrate khi cua cae nha khoa hpc the gidi da neu: cd 98% luang khi hydrate nam dudi day hd sau va biln, chi 2% n i m trong t r i m tich ben dudi bang vTnh cCfu tren lye dja.
Theo d u bao eOa eac nha khoa hpe, elc tieh ty hydrate khi phan bd hau nhu khap noi dpe theo bd elc bien sau, dai duong (Hinh 5). Nhifng noi hydrate khi phong phu nhat tren the gidl la Siberia, cac viing b i l n Ddng Bic A, bien Trung Qude, them lyc dja Nhat Bin (die biet la phia Ddng), Bae b i l n Ddng, viing luc dja phfa Bic My, Bie Alaska, New Zealand... [2,4].
Dda vao dieu kien thanh tao va b l o tdn cua hydrate khf, phan tfeh che do nhiet ddng khu vUc va tdng hop elc phat hien tren t h i gidi, elc nha khoa hpc cho rang trong mat eit dia chat cac mo hydrate khi t u nhi^n ch? cd t h i tdn tai d phan tren cCia v6 trai dat.
Khu vuc bang gia vTnh cdu d dp sau 100 - 1.100m dudi mdc nddc bien (130 - 2.000m tinh t d be mat), thudng I I h > 300m
D i y t h i m va sUdn lyc dia vdi T^s/mwc" ^ ' 4°C vi dd Bic, dp s i u day bien h > 300m, vi do Nam h > 600m, tham chf cd the tdn tai d d i y dai duong t h i gidi
Den nay, cac n h i khoa hpc da phat hien 3 d i l m p h i t Id cua hydrate khi tren d i y nudc d: vmh Mexico; ven bien Vanecver va tai d i l m nui Ida phun biin Saint-Petersburg dudi d i y hd Baikal.
Tai hd Baikal vdi do sau day nude tdi 1.640m
Hinh 5. Cdc phdt hien hydrate lihitren thegidi [71
Hinh 7. Hydrate khi imng trdm lich ddy ho Baikal - Nga [3}
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Hiah10.BeNankaiOdngNomtlhdtBdn,nc^limihdyhydmtekhf 72 Diu KHl-SO 3/2015
va nhiet do tUOng iing khoing 3,3°C, hydrate khi nam d d6 s i u 350m, ddi chd phat Id tr^n day hd (Hinh 6,7) [4]. Theo du bao hydrate khf ed the chiem 70% dien tich day hd. Nam 2009, tau lan "mir" p h i t hien c l hydrate khi tren mat trim tieh day ho va da lay dUac m l u hydrate khi tir dd sau 150m, Theo cisoilgas.com ngay 8/4/2012, b i n g elc phUOng p h i p tham dd dia ehan va khoan tim k i l m trdn elc viing bang vinh cdu va ven ria lue dia da p h i t hien tren 200 ^em ed p h i t hien hydrate khi.Tuy nhien, phan Idn elc p h i t hien chl can cd vac d i u hieu tren mat eat dja chan, tai lieu do dja vat ly gieng khoan hole mau Idi duge bao tdn nhiet Ip. Cac p h i t hien quan trpng (xae dinh so lugng, dien tich phan bo cung nhu chilu d i y vfa ehda hydrate khf; da khai thae thCf hole khai t h i e cdng nghiep) khdng nhilu: md Malliktren ddng bang Mackenzie dTay Bic Canada; md PrudoBeltrS^
sudn Bae Alaska, My; md Nankai d sUdn Ddng Nam Nhat Bin; md Messhoyakha d Tly Bic Siberia va d i y ho Baikal cCia Lien bang Nga.
Canada la qudc gia cd trd lugng hydrate khi ldn nhit the gidi. Cae chuyen gia dau khi d i n h gia m i l n ddng bang sdng Mackenzie (Tay Bae Canada) la khu vUe dUOc dau ti/
nhieu nhat de tim kilm, tham dd hydrate khi. Trong giai doan 1998 - 2002, Tap doan khoa hpc sin xuat Canada khoan g i l n g khoan khao sat Mallik va 3 gieng khoan tham dd d ddng b i n g sdng Mackenzie (Hinh 8) da phit hien ddi phan bd hydrate khLTren CO sd nghien cdu dja vat ly gieng khoan va mau Idi da phan djnh 3 via ehda hydrate khi A, B va C vdi tdng chilu day 130m trong khoing dp sau 890 - 1.108m. Chuang trinh hop t i c qudc te ldn nhat tren t h i gidl ve hydrate khi dugc thUe hien theo eae giai doan tai ddng b i n g sdng Mackenzie - Bae Canada [3].
Lien bang Nga ed t i l m nang Idn ve dau md v l dac bi§t la khf. Vien Nghien cdu Khoa hoe ve khi Lien bang Nga dinh g i l it nhat ed 30% dien tieh lanh thd Lien bang Nga cd dilu kien thuan Igi cho viec hinh t h i n h hydrate khi. Tdng trij' lugng khi ehda trcng hydrate tr^n luc dia va t h i m lue dja thudc chu quyen eua Lien bang Nga dat 10'^m^ rieng vung them lyc dja Siberia cd khoing 540 ty m^Trd lugng khi dot t u nhien cua Lien bang Nga cdn dCi diing trong 200 - 250 nam nda.
Theo thdng tin cua RIA Novosti, khi khio sit diy biln Okhot va bien Nhat Ban eac nha khoa hpc qude te Nga, Nhat Ban va Han Qudc d l phat hien 2 md hydrate khi mdi: 1 md nam tren sudn trung Kurin, mien Nam b i l n Okhot; 1 md n i m tren sUdn ddc d i o Sakhalin, eo Tatar ciia b i l n Nhat Bin.
Mo hydrate khi Messhoyakha n i m d vung phfa Bie ciia Tly Siberia (Hinh 9) ddcjc p h i t hidn nam 1968 va bat d i u
PETROVIETNAM
Hinh 11. Cdc Stem dd phdt hien co iim nong hydrate khi a Bien Dong[S, 9]
khai thae t d nam 1969. Day la md dau tien tren the gidi khai thae khi t d hydrate mang tinh thuong mai. Theo Ude tinh ban dau md ehda xap xi 10*m^ khi, nhung d i n nay lupng khi khai thae t d hydrate da dat tren 5 x lO'm' khi (36% tdng lugng khi khai thae t d md). Trong khu vUc tren da phat hien hOn 60 md khi hydrate, ehda khoing 22 x lO^^m^khi.
Bd Nang lugng My da phdi hgp vdi Chevron Texaco Corp. da tim ra nhilu md khi methane hydrate d vinh Mexico va Alaska. Theo danh gia ciia elc nha dja chat My, trCf lugng khi trong hydrate tai vimg Alaska la 66,6 x 10'^m^;
vinh Mexico 1,03 x 10"m^T^#n vung Prudo Bel - Kyparue River sudn Bie Alaska da ed 50 gilng khoan p h i t hien 6 via cit ehda hydrate khi d do sau t d 210 - 950m [2].
Bien Den dUpe xem la"md"hydrate Idn nhat hanh tlnh vdi trd lugng CH^ tdi 20.000 - 25.000 tJ- m\ Tai d i y d l xlc dinh duoc tpa do eCia hon 150"ngpn dude khi"ddd sau 60 - 650m, trudng phun khi d mdt sd noi eao tdi 2km, phan bd d vung b i l n cua Romania, Gruzia, Bulgaria, Ukraine va Lien bang Nga. Cd noi d day bien Gruzia lugng khi phun ra do dupe 170.000mVmVngay d^m. Bien Den la ngudn nang lugng g i n nhU khdng can, du dung cho 64.000 nam.
Vi vay cac qudc gia d gan Bien Den (Lien bang Nga, Ddc, Phap va Hy Lap) rat quan tam tdi ddi tugng niy.
Trong giai doan 1999 - 2004, Nhat Ban khoan 38 g i l n g khoan tim k i l m - t h i m dd tren pham vi be tram tich Nankai trong khoing dp s i u day bien 720 - 2.033m (290m dudi d i y biln) va khing dinh su ton tai cua 3 Idp hydrate khi vdi tdng chilu day 16m trong cat d i y b i l n {Hinh 10). Giai doan tiep theo I I nghien cdu, khai thae thd
va d u k i l n dUa vac khai t h i e cdng nghieptCrnam 2017 [12; 13].Thing 2/2007, Nhat Bin edng bd da phat hien hydrate khi trcng tram tich d i y bien viing Nigata. Khio sat dd tim b i n g sieu am cho thay cd khoang 7.000 t^ m^ methane hydrate dudi Idng bien quanh Nhat Ban [8].
Lugng methane hydrate nay cd the dii de eung eip mot lugng khi ddt chc Nhat Bin diing trong 100 nam.
Trd lugng hydrate khf d vimg b i l n phfa Ddng HIn Qude dupe udc tinh khoing 600 trieu tan, cd the dap OTig nhu cau khf ddt tU nhien ciia nude nay trong khoing 30 nam.
Han Qude da phat hien va chilt tieh duoc hydrate khi d vimg lanh thd dai duong phfa Ddng, phia Ddng Bic Tp. Pohang. Seoul hy vong ngudn nhien lieu thay the nay se giup lam g i l m dugc sU phu thudc cua nudc nay vao d i u md nhap khau.
N i m 2007,Trung Qude lan dau tien phat hi^n hydrate khf d Nam bdn trung Chau Giang, noi dp sau nUde bien 1.500m, trong tram tich dUdi day bien 200 - 250m tdn tai ddi hydrate day d i n 25m. Cudi t h i n g 9/2009, Trung Qudc d l p h i t hien trd luang Idn bang chay (methane hydrate) trong long d i t tinh Thanh H l i v l cao nguyen Tay Tang, cd the cung cap n i n g lugng cho Trung Qude trong vdng 90 nam.
Philippines da phit hien dupc dau hieu hydrate khi trong trung sau nam dpe ddi hut chim Tay Manila [8, 9].
Indcnesia xae dinh dien tich rdng Idn cd t r i l n vpng v l hydrate khi doc eae ddi hut chim Sumatra va Borneo [8,9].
Malaysia phat hien duoe hai khu vuc rat cd t i l m nang v l hydrate khi la Andeman va Sabah [8,9].
3. Ket luan
Hydrate khf chl dMc: hinh thanh khi nudc cd ehda khi hda tan d mdc do nhat djnh trong dieu kien nhiet dp t h i p va ap suat cac. Ngoai ra, sU hinh thanh va phan bd hydrate khi trong t u nhien edn phu thude vao nhilu yeu td khae nhU: thanh phan cau t d khf hda tan, dae diem ly hda phan td, ngudn cung cap khi, dac diem dia chat, dae d i l m dia ly, dp khoang hda ciia nUdc, dp siu d i y nude...
Theo d i n h g i l cua elc nha khoa hoc trong va ngoii nude, bien Ddng A ndi ehung va Bien Ddng ndi rieng cd t i l m n i n g hydrate khf rat ldn. Dae biet, hydrate khi d Bien
DAU KHl-SO 3/2015
DAU KHi TH£ G O
Bdng cd chat lugng tdt do ham lugng methane eao. Dieu niy da duac ehdng minh b i n g elc phat hien hydrate khi trong cae trung ven b i l n Philippines, Indonesia va Malaysia...
T l i lieu tham khSo
1. B.A.MaxMax4eB. reoxHMHMecKwe Hcc/ieflOBaHMn u Mercflbi npn nowcKax u paaseflxe He(t)TM u raaa.
MsAaTe/ibCTBO He<^™ M ras PfV He4>™ M rasa MM M.M ry6KMHa. MocKBa. 2002.
2. C.Koji/ier, PJlbioMc, T.VMMfla. Pacrymnii MHiepec K raaoBbiM rMflparaM. JKypnan He(t)Tera3CBoe 06o3peHne.
MocKBa.2001;2.
3. S.R.Dafiimore,T.S.Collett,T.Uchida.Saenfificresu/fs from JAPEX/JNOOGSC fAallik 2L-38 gas hydrate research well, Mackenzie Delta, Northwest Territories, Canada.
Geological Survey of Canada. 1999; 544.
t . fCAJlflflMH, AJl.ryu<MH. raaoBbie rwApaTbi.
CopoeoBCKMM o6pa30BaTenbHbiii xtypHa/i. 1998; 3.
5. A.A.5aK«poB M flpyrwe. recJiorMn M reoxMMWJi He(|)TM M ra3a. MBflaTe/ibCTBO Heflpa. MocKBa. 1993.
u. XaHT fljK. reo/iorMfl M reoxHMwa HQ^TIA M raaa.
Hsflare/ibeTBC Mnp. MocKBa. 1982
7. Keith A.Kvenvolden. Gas hydrates - Geological perspective and global change. Reviews of Geophysics, 1993; 31 (2): p. 173-187.
8. Nguyen Thanh Van, Tran Van Trj. Mpt so thdng tin vedieu tra dia chdt hydrate khi. Tap chi Dia chat. 2007; 30l, 37. Nguyen Ddc Thang, Dd Td Chung, Cao Thj MaL Tiem ndng hydrate khi tren Bien Ddng. Hgi t h i o chuyen di "Hydrate khi - Nguon nang lugng ciia tuang lai va cac phuang p h i p nghien cCfu" 2009.
10. Le V i n Binh. Cau true hydrate khi. Tap chi Dau kW.
2012; 8: trang 31-35.
11. B.A.Co/iaBbeB. npMpoflHbieraaoBbie rMApatbi xaK noreHLiManbHoe no/ieaHoe ncKonaeMce. POCCCHMCKHM xMMMMecKMM ^ypHan. 2003; 3.
12. HideakiTakahashi,YoshihiroTsuji.Jopar?exp/ores for hydrates in the Nankai trough. Oil and Gas Journal.
9/5/2005.
13. Hideaki Takahashi, Yoshlhiro Tsuji. Japan drills, logs gas hydrate wells In the Nankai trough. Oil and Gas Journal. 9/12/2005.
Conditions and other factors affecting gas inydrate generation and distribution in nature
Le Van Binh
Hanoi University of Mining and Geology Summary
Gas hydrate is a greatly promising source of clean natural energy in the future. According to the statistics, the hydro- carbon reserve in gas hydrate reaches 7,6 x 10'^m^. Since gas hydrate forms only in low temperature and high pres- sure environments, 98% of gas hydrate reserves lie on the bottom of continental shelves and lakes. Canada, Black Sea and Lake Baikal are considered the largest hydrate reserve regions in the world. The article presents the factors affecting the formation and distribution of gas hydrate in nature as well as the reserves and distribution of gas hy- drate in the world.
Key words: Gas hydrate, gas hydrate distribution, reserves of gas hydrate in nature.
74 DAUKHI 503/2015
