PETROVIETNAM
NGHIEN CUU CHE TAO HE GEL POLYMER SLT DUNG CHO DONG GIENG TAM THOI TRONG C O N G TAC SUA CHUA GIENG
KHAI THAC CO AP SUAT THAP KHONG ON DINH
V
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ThS. Ta Quang Minh', ThS. Vu An', KS. Cao Huy Hiep' ThS. Tran Hiing Sdn', ThS. Phan Trong Hieu', TS. Nguyen Tuan Anh' KS. Vu Van Himg', KS. Nguyen Cong ManhS ThS. Vu Thi^t Thach^
'Viin Dau khiViitNam
'bin doanh Viet - Nga "Vietsovpetro"
'Dai hgc fVId - Dia chat Email: [email protected]
Co nhieu phifang phdp dengdn chdn hien tUctng mdt dung djch khi dong gieng tam thdi trong qud trinh sCta chda ido difdng cac gieng khai thdc cd dp sudt thap khong on djnh. Trong do, he gel polymer ditpc sCr dung nhieu trong :dng tdc xd I'y gieng, cd tdc dung trdm kin cde kenb ddn vd cac lo bdn via, dong gieng cdch ly via sdn xudt, dong thdi igdn chdn dung djch xdm nhgp td gieng vdo via chda. Gidi phdp cdng nghe ndy giup kiem sodt gieng khoan cd dp
•udt via thap [1,2}; dong thdi cd th^ndng thd cac thiet bj, ong khai thdc, cdn khoan vdi tdc dd Idn.
He gel polymer gdm nhiiu thdnh phdn tiiy vdo muc dich sddung nhit cdch ly via tam thdi khong cho dung djch rong giing xdm nhdp vdo trong via chda vd de gidm toi da ton hgi lin thdnh he. Bdi bdo gidi thieu ket qud nghien :Cfu he gel polymer sddung cho ddng gieng tam thdi trong cong tdc svta chvfa gieng khai thdc co dp sudt thap khong jn djnh.
rifkhoa: Dau khi, sCfa chQa gieng khai thac, gel, polymer, vh ap sudt thap khong on dinh.
I. Gioi thieu
f. 1. Phuang phdp sddung he gel polymer tgo nut gel He gel polymer (hay nut gel) la dung dieh goc nude :6 dp nhdt cao, thdi gian on dinh gel (dp ben gel) Idu hPn io vdi gel polymer sfl dung trong chit Idng nflt via thCiy Uc. So vdi nut ddng co khi, he gel polymer cho phep ong (hai thdc (CT) di chuyen linh hoat hon; de dang loai bd chi khdng can thiet bang each sfl dung acid [3]... He gel 3olymer thudng ed chda mdt polymer, chdt dieu chinh pH /d mpt tac nhan khau mach. Cde polymer gdm polymer polysaccharide, nhd guar gum, cde dan xuat guar gum, Jan xuat cua cellulose. Cac chat dieu chinh pH la acid yeu He gidm dp pH va tac nhdn khau mach, Cde dung dieh cd 36 pH thap Idm cham thdi gian tao gel vd keo ddi thdi
;ian dat he gel polymer. Thdi gian dat he gel polymer gidm di nhi^t dp tang len va ngUpe lai. Dd pH cao giup hdi gian ddt he gel polymer va lien ket khau mach xdy ra ihanh hOn.
Cac he gel polymer lien ket cau sCf dung mot ion phflc gom cac ion borate, zircon...) de li^n ket cau vdi polymer jolysaccharide vd tao thdnh gel cflng. Khi lya chpn mot le gel polymer can Idu y cde thdng s6: cau hinh dng khai hdc, chieu sau, tinh dn dinh cua nut gel, nhiet do day
I. He gel polymer phdi ddp gieng - BHT va thdi gian tao g
flng cac dae tinh sau:
Chat Idng gel polymer cd the bPm de ddng;
Khdng can cac thiet bj dac biet de pha trdn;
Cd the chju dfloc dudi ap suat via va ap suat thCiy tinh;
Cae polymer phan tan tdt trong nUdc ngpt va nfldc bien;
Ttnh ehat eCia he gel polymer dang tin cay va cd the dli bao;
Bt pha vd trd lai dang chat long ed dp nhdt tflpng duong chit Idng khi khuay trdn;
De lai it can nhat sau khi sfl dyng cac chat pha gel (acid, chat oxy hda va enzyme) de giam thieu ton hat via chfla.
Tren co sd khd ndng tao gel cCia polymer fla nfldc vdi cac tac nhdn khdu mach, he gel polymer dflpc nghien cflu cd khd nang phan hijy de ddng gieng tam thdi trong qua trinh sfla chfla gieng dp suat thap, dap flng thdi gian tao gel du de bom ede thanh phan cua he xuong vj trivia chfla trong it nhat 30 phut trudc khi tao gel. Dp ben gel cd the
DAU KHI - s6 2. 17 1
THAM DO - KHAI THAC DAU KHI
keo dat trong 15 ngay. He gel polymer co the phdn hCiy bdi cac tae nhdn pha gel de gidm dp nhdt nhdm bom rfla he gel polymer ra khdi cde edc kenh dan va 16 ban via trfldc khi dfla gieng trd lai sdn xuat.
1,2.Guargum
He gel polymer gom nhieu thanh phan tuy vao mue dieh sfl dung.
Cac loai polymer dflpc sfldung de each ly via tam thdi khong cho dung dieh trong gieng xam nhap vdo trong via chfla va de gidm thap nhat tdn hai len thdnh he, gom: cellulose carboxymethyl (CMC), hydroxyl ethyl cellulose (HEC) vd cacboxymethyl hydroxylethyl cellulose
(CMHEC), guar gum (GG), xanthan gum, (>
va polyacrylamite (PAM). Trong nghien c nay, guar gum dflpc Ifla chpn Id polymer cl ehe tao he gel polymer ddng gieng tam tl trong cdng tdc sfla chfla gieng.
Guar gum la mot polysaccaride ty nhii chiet xuat t f l cay dau guar gum (Cyamop:
tetragonoloba), dflpc sfl dung rdng rai troi cac flng dung cdng nghi&p. Phan tfl guargu bao gom mot chuoi mach thang cua cac nho p-1,4 mannose va nhanh ben gom cac nho a-1,6 galactose dflpc gdn ngau nhien vi chudi mach chinh. Ty le trung binh cija nhoi mannose va edc nhom galactose la 1,6:1.Ty chinh xdc cua galactose va mannose thay &
theo mua. Guar gum r i t de phdn tan tron nfldc lanh, nfldc ndng vd nfldc mudi. Mi Iflpng nhd guar gum khi dflpc hoa tan tron nfldc se tao ra dung djch co d6 nhdt ldn d phdn t f l Iflpng Idn cua guar gum (len 66 6 trieu don vi) va t f l cac lien ket hydro hin thdnh gifla cac phan t f l [4].
7.3. Cde tdc nhdn khdu mach Cac polymer sinh hpc nhfl xanthan gun hoae guar gum, cd the dflpc khdu mach bh cac tdc nhdn khac nhau (nhuTi, Zr, AI hoa Cr...) thdng qua kha nang tao phflc cua cii nhdm hydroxyl trong phan tfl polymer.Troiv sd cac tac nhan tao gel polymer, phan flngge hoa gifla guar gum va borate khd dac bieti diem dp nhdt cfla he gel polymer nay c6 thi thay ddi nhd tac ddng cua luc cd hpc. Phar flng tao gel cua guar gum va borate la phir flng thuan nghjch. Co che phd bien nhat cho phdn flng nay la SLftao thanh phflcgifla borate va guar gum, trong do nguyen tfl Bo lien ke:
2 mach phdn tfl guar vdi nhau thdng qua dit nhom cis-hydroxyl trong vdng mannose [4^
Acid boric cung ed the dflpc sfl dyng^
lam chat khau mach thay cho edc muoi borate Tuy nhien, trong trfldng hop nay can phdi cf ion hydroxyl (OH") de lam chuyen djch df bang nhfltrong phdn flng (Hinh 2).
H^BO^ + OH- ^ B(OH)^
MqX tdc nhdn khau mach khdc thudni dupe sfl dung ddi vdi edc gel polymer tr&n <?
18 DAU KHi-so 2/2016
PETROVIETNAM
id cac polymer sinh hpc Id zircon [5]. Zircon cd the :dc dung vdi rat nhieu he polymer, trong khoang pH 'png (ti^ 1 den 12) vd khoang nhiet do tCf 37 - 205°C.
Cac chat khau mach zircon cd the la cde phflc chat khdc nhau, vi du nhfl lactate hoac citrate, nhflng dang khau mach chinh xdc nhat van chfla dflpc xac djnh. Qud trinh khau mach sfl dyng zircon xdy ra thdng qua cde nhdm OH eo tren cac mach polymer sinh hpc, hoac thdng qua edc nhdm chflc carboxyl hoac dan xuat carboxyl tren cac dan xuat cCia guar gum 15]. Co 3 co che dflpc de x u l t doi vdi qud trinh gel hda sfl dung zircon. CO che thfl nhat la lien ket gifla zircon va cac polymer sinh hpc nhfl guar gum hoac hydroxypropyl guar gum (HPG) ed bdn chat Id lien ket hydro gifla cac nhom OH tren mach phan tfl polymer va nguyen t f l zircon.
Lien ket h y d r o t h f l d n g x u l t hien trong khodng pH - 4 - 10. Dang ll^n ket ndy thfldng bi pha vd bdi tac dpng cfla Iflc eO hpc (trflcft) vd cd the tdi tao sau mptthdi gian dai.
Co che t h f l hai dflOe dfla ra Id zircon tao lien ket cpng hda trj vdi polymer. Cac lien ket cdng hda tri ndy CO the xuat hien dot vdi cde polymer ion nhfl carboxyl methyl guar (CMG) hoac carboxyl methyl hydroxy propul guar (CMHPG). Nguyen t f l zircon eo thetao lien k^tcdnghoatrivdi cac nhdm carboxylate tren phan t f l cua cac polymer. Dang lien ket nay se .tao ra gel ben vflng hOn so vdi gel polymer dfloc tao
thanh nhd co che tao lien ket hydro.
Co ehe thfl ba Id he gel polymer dflOc tao ra ithdng qua sfl tflOng tdc gifla cac hat keo dflpc tao :thanh bang each thuy phan mdt phan ddi vdi cac : phflc c h i t kim loai (zircon) tai pH cao (khoang 11) ';vdi cac phdn t f l guar gum.
1.4. Cde tdc nhdn phd gel
Cde tac nhan phd gel Idm giam dd nhdt cCia 'gel polymer sau khi tao gel ben trong khdng gian [Xop g i n be mat cfla via chfla. Cde tdc nhan phd igel (thfldng dflpc sfl dung gom: tdc nhan oxy hda ,vd enzyme [6]) se t i n cong vdo mach chinh cua . polymer vd phan chia chdng thdnh cac phan ed khoi Iflpng phan t f l nhd hOn, t f l do giup gidm dp nhdt.
7.4.1. Tdc nhan oxy hoa
' Tac nhdn oxy hda tao ra cac gde tfl do, phdn flng
•vao cac vj tri nhat djnh tren mach chinh cfla polymer
Hinh 3. Cache too gel cua guar gum vd 2i(tV}
^ Nhom Galactose
H J a H J o ° NJ\OH HO/\ ^'NJVPM MO/1
Lien ket beta (1,4] , ^ _
^ ^ Khung Manr Hinh 4. Cde vi tried khd ndng phdn 6ng v6i goctudo cuamdtmonome
tren mach polymer guar gum
de phd vd edc chuoi polymer. Cde goc tiJ do cd boat tinh phan flng manh dflpc tao ra thdng qua sfl phdn huy nhiet cfla cac c h i t oxy hda. Col 8 vi tri tren mdt monome eua guar gum ma cac gde tfl do cd the phdn flng (Hinh 4).
Cac mudi persulfate thfldng dUcjc sfldung lam tdc nhan oxy hda gdm: ammonium persulfate ((NHJ^Sp^), sodium persulfate (Na^SjOg). Cac mudi persulfate co the phan hfly bdt nhiet vd sinh ra cac gdc t f l do dflpc md td theo phflpng trinh:
0^-0 : 0-SO^ -^ .S0;'+ .SO,;'
Hai gde t f l do nay cd the tan cdng vdo 18 vi tri cua mdt monome cua guar gum.
Trong so 18 vj tri nay, 2 vj tritot nhat de phd huy edc polymer la cae mdi lien ket acetal p-1,4 gifla eae nhdm mannose. Hai vi tri nay co tinh acid yeu hon so vdi phan edn lai, do do xu hUdng phdn flng vdi edc gdc tfl do thap hon. Qud trinh phd vd ly tfldng se dflpc thfle hien neu cac goc tfl do phd vd cde chudi polymer d gifla 2 phan chuoi polymer bang nhau; sau dd, cac gde tfl do lai tiep tue phd vd vi tri gifla cac manh polymer nay. Neu chuoi dflpc phd vd tai vi tri gan dau cua chuoi polymer thay cho vj tri DHUKHI-so 2/2016 19
THAM DO - KHAI THAC D A U KHI
d gifla, se tao ra mdt mdnh vd nhd va mpt manh vd ldn hpn. Nhfl vay, viec giam khdi Iflpng phan tfl cda polymer se kem hieu qua.
Nhiet dd cao (> 60°C) la dieu kien d ^ tdc nhan oxy hda phdn flng manh. Khi nhiet dp tang len, chung trd nen hoat tinh hOn, tdc dp phdn flng gifla cde gdc tfl do vd polymer tang len, dp nhdt cua gel gidm rat nhanh. Persulfate d nhiet dd 93°C cd chu k^ ban ra khoang 20 phut va d nhiet dp 225°C gidm xudng dfldi 5 phut. Vi vdy, can phdi sfl dyng can than tac nhan oxy hoa d nhiet dp cao, viec tdng nong dp qud cao co the gay ra sfl pha vd sdm va lam mat kha nang tao gel.
Cde tac nhan pha vd dang vien bpc (chit oxy hda nhfl;
persulfate dflOe bpc bdi mdt Idp nhfla PVC, nylon...) cd the dflpc sfl dyng d nhiet do rat cao de kim ham tdc dp phd gel, ngan ngfla cde nguy cP gel sdm bi pha vd trfldc khi dflng bom.
} Theri gian (phut) Guar gum
0,3%
Hinh S. Pho hong ngoai cua phan t6 guar gum
1. Khda sdt dnh hudng cua nong do guar gum den do nhdt cua he gel polymer GG-Zr(IV) Do nhdt bieu kien * nhiet do 25oC (cP)
theo nong 36 guar gum
Guargum Guargum Guargum 0,42% 0,5% 1%
23 28 56 124 25 33 60 129 38 47 71 _ 136 46 55 79 158 53 65 88 179 61 76 92 185 j g 2. hh hudng ciia nong do tdc nhdn khdu mach Zr(IV} vd thdi grnn Sen 36 nhdt
cua he gel polymer : Thdi gian
(phut)
25 30 "
Do nhdrt cua he gel polymer trong moi trUcrng nudc ky thuat d nhiet do 25°C (cP) Zr(IV) 25ppm Zr(IV) 40ppm ZrjlV) 60ppm
28 32 34 29 35 "" 38
2. Che tao he gel polymer cho dong gieng tai thdi trong c6ng tac sijfa gieng co ap su^t thS khong on dinh
2.7. Ode triing cdu trOc bdng pho hong ngoai ci guargum
Phd hong ngoai dflpc diing de danh gia cS nhdm chflc (C-0, 0-H, C=C...) trong phdn t polymer. Sau khi phdn flng vdi cac tac nhan liei ket, sd sdng ddc trflng cua cac nhdm chflc ni se cd sfl thay ddi ve efldng dp. Dfla vao dd c6 thi danh gid hi$u qua cfla phdn flng tao gel gifla c^i ion trong phdn t f l cfla tdc nhan lien ket vdi ca nhdm chflc trong phdn t f l polymer. Ket qud fli phd hdng ngoai cCia phdn t f l guar gum the hiei
6 Hinh 5. ' Cac nhdm chflc, nhdm nguyen tflva lien kfi
trong phdn t f l cfla cde dam phd hdng ngoai dai trflng {Hinh 5) cho thdy, cau true phdn tfl guai gum cd nhieu nhdm 0-H, C=0 vd lien ket C-H i eac bdc khdc nhau la co sd eho sy tao lien ket v6 tac nhan tao cau.
2.2. Anh hudng nong do guar gum den dp nhdl cda he gel polymer GG-Zr(IV)
Ket qud nghien cflu dnh hfldng cfla ndng 3t guar gum den dd nhdt cfla he gel polymer QG-
Zr{IV) dupe the hien d Bdng 1. i Tfl ket qud d Bang 1 cho thay, ndng dp guffl
gum tang dan den khd nang tao gel cfla he polyml GG-Zr(IV) tang (thdng qua thay ddi do nhdt). 1
Ve mat ky thuat, dd nhdt ban dau cua he gel polymer eho ngan cdch via cang cao thi khd nang tao gel cang thuan Ipi, song khd nang bom cang khd khan. Vi vay, can gidi han dd nhdt ban dau sao cho he gel polymer cd the bom dflOc. Theo do, d^
nhdt bieu kien dflpc gidi han khi do tren may do do nhdt Model 800 vd tflong dflong (mdy do d$
nhdt FANN 35) khong cao hon 30eP. Do dd, ndng dp guar gum cCia he gel polymer duac Ifla chpn Id 0,42%.
2.3. Anh ht/dng cda nong dp khdu mach Zrffl^
den khd ndng tgo gel f Hoa chat nghien cflu: nfldc ky thuat, guar giM
0,42 %, Zr(IV) 25ppm, 40ppm va 60ppm. Do n h i eua he gel polymer dflpc thd hien tren Bdng 2.
[ 2 0 nlinf-s02/2oi6
PETROVIETNAM
Khi tang ndng dd tac nhan khau mach Zr(IV) va thdi gian phan flng se Idm tang khd nang tiep xuc cCia Zr(IV} vdi phan t f l guar gum, dan den tang khd nang phan flng lien ket khau mach va tdng dp nhdt cua he gel polymer.
Sau 2 gid d ndng do Zr(IV) 60ppm, he gel polymer cd hien tflong tdch nfldc. Khi ndng dp tdc nhdn khau mach tdng, mat do edc mdi lien ket tang theo, do nhdt tang len theo ndng dp Zr(IV) nhflng chi tdng den mot mfle dp nhat djnh.
Neu tiep tyc tang ndng dp tac nhan khau mach, khd nang tao gel xdy ra nhanh hon, ddng thdi xay ra hien tflpng tach nfldc do mdt dp lien ket khau mach chiem ehd trong khdng gian d mang gifla edc phan t f l polymer, kem theo sfl co ngdt cfla khdi gel lam gidm dp ben gel. Vi vdy, ndng dd Zr(lV) 25ppm dflpc Ifla chpn eho nghien cflu tiep theo.
2.4. Anh hudng cua pH den khd ndng tao gel Sfl dyng acid citric va Na^CO^ la chat dieu chinh pH de khao sdt dnh hfldng eija dp pH den dd nhdt cua he gel polymer (Bdng 3).
Acid citric cd the dieu ehinh pH xudng den 3 - 4. Khi dieu chinh pH cfla nfldc xudng thap, acid citric giup keo dai thdi gian hydrate hda cCia guar gum, vi vdy dp nhdt cua dung dich guar gum tang chdm theo thdi gian. Khi tao gel dung djch guar gum dflpc cho Zr(IV) vdo trfldc, sau dd cho Na^CO^
de dieu chinh pH cua dung djch den pH = 10. Tai gid trj pH nay, gel cd dd nhdt dat gid tri cao nhat sau 30 phut.
2.5. Anh hudng cua tdc nhdn kim hdm gel den sU hinh thdnh va dp ben cda gel polymer [7]
Tac nhdn lam kim ham gel la cde chat dupe dfla vdo de kiem soat thdi gian tao gel, dam bdo h^ gel polymer dflpc bom den dflPc vj tri via san xuat trfldc khi tao gel. Cae tac nhan kim ham gel dfla tren khd nang tao phflc tdt vdi cac tac nhan khau mach, ban ehe phdn flng ngay lap tfle gifla cac tde nhan khdu mach vdi cac nhdm chflc ed tren mach phan tfl cua polymer. Khi cd mat cac tac nhdn kim ham gel, phdn flng khau mach se phai canh tranh thdng qua phan flng tao phflc, do dd keo ddi thdt gian tao gel.
Cactdc nhdn kim hdmgel thfldng dflpcsfldyng gdm: acid citric, sodium lactase, ethylendiamine
Bdng 3. Anh hudng cua pH den he gelpolyniei GG-ZiOV) 6 nhiet do phong thi nghiem Do nhtirt cua he gel polymer (cP) d nhiet do
phong thi nghiem
10 15 20 30
phut ' phdt phdt 23"
26 26 37 32
phut 23 26 26 37 40
phut 2~3 26 26 37 51
phut
" "23 26 26 37 65
phdt ' 23 26 26 37 77 Bdng 4. Anh htidng cua ndng do tnelhanolamine den thdi gian tgo gel cda hi gel polymer GG-ir!IVj I Thanh ph^n cua :
' he gel polymer Thai gian tao gel (phut) Trong mol trUdng nUdckythuatd nhiet do 25''C
• -Guargum,0,42% f^^^;^ j - Ti^^:^irrTiM,i^
- Na CO oH =10 - Trong m o i t r u a n g nUOc m u o i NaCI 4 % o 25°C
25 70
Bang 5. Anh hiring cua nhiet do den khd ndng tao gel cua he gel polymer GG-Zr(IV)-TEA trong mditntdng mldcky thudt
T h d i g i a n ( p h u t )
D o n h a t ciJa h e g e l p o l y m e r GG-Zr(IV)-TEA t r o n g m o i t r U d n g n f l d c k y t h u a t (cP)_
250C ~
\ 10
I 15 20 j 25 I 30
45<'C 31 40 44 48 59 78 83 8 5
" " 8S"C" J 40 4 4 [ 48 * 59 [ 78 1 83" -- 1 85
1 90 i i 100 1 ' 110 1
120 i 125 !
130
F" 140 !"
-- J- .- L... .^-. .J
tetraacetic acid (EDTA) va triethanolamine (TEA). Hieu qua keo dai thdt gian tao gel dflpc ddnh gia thdng qua thang bang ma gel. Ket qua danh gia hieu qua kim ham gel cua TEA ddi vdi he gel polymer GG-Zr(IV) tren dupe the hien d Bang 4.
TEA Id tac nhdn keo dat thdi gian tao gel cua he gel polymer GG-Zr(IV);
Khi tang ndng dd TEA tfl 0,3% den 0,9%, trong cd 2 mdi trfldng nfldc ky thuat va nUde muoi NaCI 4%, thdi gian tao gel cang duac keo dai hon.
6 cung ndng dp TEA, thdt gian tao gel trong mdi trUdng DAUHHI-: J 2/2016 21
nudc ky thuat keo dai hOn trong mdi trfldng nfldc mudi NaCI 4%.
Thdi gian tao gel cd the keo dai den 240 phut (4 gid), do dd cd the dieu chinh khd nang tao gel trong khodng thdi gian dai, dfl de bPm he gel polymer den vi tri cua via cin ddng d bat cfl dp sdu nao.
2.6. Anh hudng cua nhiet dp den khd ndng tgo gel cda he gel polymer GG-Zr(IV)-TEA 0,6%
Kdt q u d n g h i e n c f l u k h d o sdt h e g e l p o l y m e r GG-Zr(IV)-TEA d 3 d i e u k i e n n h i e t d p k h a c n h a u d f l p c t h e h i e n d B d n g 5.
Hinh 6. Anh hodng cua Na^p^SHp den khd nang chiu nhiet cua cua he gel polymer
Khi tdng nhiet dp eua he gel polymer GG-Zr(IV)-TEA 0,6%.thi thdi gian tao gel cang rut ngan. d nhiet dp phdng thi nghiem 25%
sau 130 phut, he gel polymer mdi dat dp nhdt cao nhat la 85cP. 6 nhiet do 45°C, thdi gian nay la 35 phut va d 85''C chi cdn 30 phiit 2.7. Ndng cao dp ben nhiet cua he gel polymer vdi tdc nhin khUoxy
Oxy hda tan trong nfldc dnh hfldng ddn sfl phan hijy nhi^
cfla polymer do qua trinh phdn flng oxy hda khflvacaramenhm {dfldng chdy) d nhiet dp 120''C.
Cde chat khfl oxy dflpc sfl dung trong linh vflc dau khid!
ndng cao dp ben nhiet cua polymer. Nhdm tdc gid tien hdnh tfi nghi§m nang cao khd nang chju nhi&t cCia he gel polymer dig 120°C vdi tac nhdn sodium thiosulfate (NajSjOj.SHjO):
Quy trinh pha che: Chuan bj 2 mau d 2 cde mau. Do vaO*
edc gan 1000ml nfldc may sau do eho mdi cdc4,2g (0,42%) guar gtjl vao. Khuly deu trong 30 phut. Cho them 1,2g (0,12%) NajS^OjJl vao mpt cde mau va khuay cho den tan het. Cho 0,28m! dung d j ^ phflc zircon ndng dd quy ve ion Zr (IV) 90g/l (25ppm Zr(IV) vdo d ^ 2 edc mau, khuay deu sau do de yen cho tao gel. Lay 200ml mau he gel trong moi edc mau cho vao Id nung d nhiet dp 120''C trong thcS gian 4 gid. Quan sdt mau sau khi nung fl Hinh 6.
Bong 6. Khodng bien thien cua cac yeu to dnh hadng len thdi gian tgo gel cda he gel polymer MUc
MUc tren (+) Mtfc CO sd (0) MiJc^di (-) Khoang bien thien
Nhiet do CC) 50,0 37,5 _ 25,0 12,5
Cac y e u to dnh hUo^g
T^ 14 GG/Zr(IV) Nong do TEA (%)
Cacyeu to dnh hudng Ty le Nong do
+
+
+
!
0j 0
0 +
0 0 0
0 0
'liem cha qua trinh che tao gel polymer
=. _ =^^^ .- —.
D o nhdt cao nhat (cP)85 83 84 80 85.5
79 81 75 85 81 85 81 85 80 84 84 84
-=-
Thdi gian tao, =- ..
gel (phut) 180 150 75 30 80 28 80 30 25 80 27 29 40 33 40 40 40
- „.— ;. ..__.__
D d nhdt t h e o phiftfng trinh
84,29 83,79 82,49 81,24 83,74 79,99 79,69 80,27 77,77 85,67 82,37 82,63 85,17 81,37 82,63 82,63 82,63
P E T R O V I E T N A M
M a u g e l p o l y m e r k h d n g c d N a ^ S ^ O j . S H j O c h u y e n m a u n a u v a n g , c h f l n g t d d a b i o x y h d a { c a r a m e n h o a ) . M a u g e l p o l y m e r c d N a j S j O ^ . S H p h a u n h f l k h d n g c h u y e n m a u c d t r a n g t h a i g e l t o t h o n , c h f l n g t d c d k h d n d n g c h i u n h i e t t d t h o n .
2.8. Toi Uu hda che tao he gel
M d h i n h q u y h o a c h t r f l e g i a o d f l p c s f l d y n g d d g i d i b d i i t o a n t d i flu e h e t a o h e g e l p o l y m e r . V d i t y le G G / Z r ( I V ) b i e n t h i ^ n t r o n g m o t k h o d n g n h d , cac t h a n h p h a n g d m n f l d c k y t h u d t , g u a r g u m , z i r c o n v a cac y e u t d ( n h i e t d p , p H ) d n h , h f l d n g d e n q u a t r i n h t a o g e l .
Tdi flu c h e t a o h | g e l p o l y m e r :
Y d u t d X I la t:y' le G G / Z r ( I V ) , b i e n t h i e n t r o n g k h o a n g i l , 2 - 2 ;
Y e u t d X 2 la n d n g d p t r i e t h a n o l a m i n e (TEA), b i e n ' • t h i e n t r o n g k h o a n g 0,3 - 0 , 9 % ;
. Y e u t o X 3 la n h i e t d d , b i e n t h i e n t f l 2 5 - 5 0 ° C ;
ii H a m m u c t i e u la d p n h d t e u a d u n g d j c h GG-Zr(IV) 5(cP) d a t c a o n h a t Y l ;
H d m m u c t i e u Id t h d i g i a n t a o g e l c u a h e g e l p o l y m e r Y 2 .
P h a n t i c h p h f l o n g sai cde k e t q u a t h U c n g h i e m , r u t ra K d U p c m d h i n h t h d n g k e d o n h d t g e l t h e o p h u o n g t r i n h h d t
^ q u y b a c h a i n h u s a u :
D p n h d t (cP) = 5 0 , 6 9 3 3 1 + 2,02239x^ - 19,4731 Sx^ +
" 0 , 0 9 2 4 7 X 3 " 0 ' 0 3 7 5 x , X 3 - 2 , 1 6 6 6 7 x l O ^ x . x ^ - 0 , 0 4 6 8 7 5 x ^ X 3 ' 0 , 0 2 3 0 9 9 x , ' + 8,69278x^^ + 9 , 8 9 8 2 8 x 1 0 ^ /
B i e u d i e n d u d i d a n g d o t h i 3 c h i e u n h f l H i n h 7.
* P h a n t i c h p h f l O n g sai cac k e t q u d t h f l e n g h i e m , r u t ra 5 : s s - *
¥ m d h i n h t h d n g k e t h d i g i a n t a o g e l t h e o p h f l p n g t r i n h h o i ? = ; = _ .
• q u y b a c h a i n h f l s a u :
T h d i g i a n - 5 0 1 , 5 3 4 5 1 - 4 , 6 6 3 7 2 x , - 3 8 3 , 5 9 2 4 3 X j '.?- 5,89353X3 - 0,325x,x^ - 9 X l O ' x ^ X j + 2,36458x^X3 + i ? 0 , 0 9 5 7 3 x ' + 9 6 , 6 1 0 9 2 x / + 0 , 0 2 6 6 2 x =
T f l p h d n t i c h g i a t r i c u a cd h a i h a m Y^ m a x v d Y^ m i n , x d c d i n h d i e u k i e n t d i flu la: n h i e t d o 3 7 , 5 ° C ; t y le G G / Z r ( I V )
= 1,6; n d n g d p TEA 0 , 6 % ; t h d i g i a n t a o g e l : 4 0 p h u t .
T f l k e t q u a d a n h g i a t i n h n a n g c f l a h e g e l p o l y m e r t h a n h p h a n v a d a c t i n h c u a h e g e l p o l y m e r GG-Zr(IV)-TEA d f l p c d e x u a t n h f l B a n g 8.
2.9. Ket qud ddnh gid ddc tinh cua hi gel polymer GG- Zr(IV)-TEA
2.9.1. Pho hong ngoai cua mSu gel polymer che tgo
N h d m d a o d d n g d v u n g c d s d s d n g t f l 3 . 3 0 0 - 3 . 4 0 0 c m " ' t f l P n g flng v d i d a o d d n g c u a n h d m O H t r o n g p h a n t f l g u a r g u m v a G G - Z r ( I V ) ;
N h d m d a o d o n g d v u n g c d s d s d n g t f l 2 . 9 0 0 - 2 . 9 2 0 c m " ' t f l O n g flng v d i d a o d d n g c u a n h d m C - H ;
N h d m d a o d o n g d v f l n g c d s d s d n g 1.700 - 1 . 7 2 0 c m " ' t f l O n g flng v d i d a o d d n g c u a n h d m C - 0 t r o n g n h d m c h f l c c a r b o x y l ;
Hisr-
Hinh 8. Do thi t6i i/u thOi gian tao gel cdo hi gel polymer GG-Zr(IVI-TEA
! . Tong hap dexuat thdnh phon i/a ddc tinh he gel GG-Zr(IV)-TEA che lao
> , Chat d i e t k h u a n T h a n h p h a n _ NUdc Polymer
: Nudc ky t h u a t
D & m p H
Guar g u m bien t i n h cua An D 6 0,42%
Na;COi Biosafe JTac^nhdn o n d i n h nhi&t Thiosulfate - N a ^ S A
Tdc n h a n khau mach Zirconium s o d i u m lactate t r i e t h a n o l a m i n e Tac n h a n k i m h a m t a o gel 1 JTriethanoiamine (TEA)
T » l e G G / Z r ( I V ) 7
0,1 - 0,5%
^ 0 , 0 5 - 0 , 1 % ! _ 0 J - 0 , 4 % j
2 5 p p m a 6 % _ !
1,6 " " ;
I 0 6 n h d t d nhiet d p p h o n g , cP pH_ ; j Thdi gian tao gel j Nhiet d o pha che
--t
9 ^ 1 0 4 0 p h u t 25 - 38=C_ I
D A U K H I - S P 2/2016
THAM DO - KHAI THAC D A U KHI
Nhdm dao ddng d vung cd so song t f l 1.000 - 1.010cm' tflpng flng vdi dao dpng cua nhom -C-0-;
Nhdm dao ddng d vung co sd sdng tfl 1.010 - 1.020cm"' dac trflng cho dao ddng cfla lien ket Zr-O (phflc 6 ZrOH). Day la minh chflng cho thay cd sfl tao lien ket (lien ket cpng hda tri hoac li^n ket hydro) gifla cde phan t f l guar gum vd zircon bdng chflng cho sfl khau mach gifla cde dai phdn tfl guar gum bdng tac nhan khau mach zircon de tao gel.
2.9.2. Nghien c((u cdu true hinh thdi cua he gel che tgo bang phuang phdp 5EIVI
Qua dnh chup hien vi dien tfl quet, cau true cua gel polymer Id cac khdi lien ket vdi nhau (cd cac tdm la Zr) cd kich thfldc khodng 50 - 100pm, phan bd ddng deu tren cac mat ph§ng lien ket, tao thanh khdng gian da Idp xep chdng len nhau.
2.10. Ddnh gid dp bit nhet vd ngdn cdch via cua he gel CG-Zr(IV) len mdu loixop
So do nghien cflu mau Idi xdp {Hinh 11) gdm: (1) Bom mini, (2) cdt phan chia, (3) cdt hoan xung, (4) gia nhiet, (5a, b) cdt xdp ddi tU tao, (6) cdt do dau/nfldc thodt, (7) bom khitao dp, (8) bom khi ddi ap.
2.W.I. Quy tnnh thi nghiem
Chuan bj mdu Idi xdp: Mau 161 xdp dflpc che tao tfl mun khoan d dia tang Miocene, gieng khoan 507 RC - Lien doanh Viet - Nga "Vietsovpetro". Dp sau lay mau la 2.450m, thanh phan chu yeu la cat ket lan dau tho. Sau khi Ipc rfla bun va dat set, Ily phan cac hat cdt tflong ddi ddng deu cd kich thfldc tfl 0,5 -1 mm. Cac hat nay dflpc cho vao dng thCiy tinh hflu cotao hinh try ed dfldng kinh 4,5cm vd chieu ddi 6cm.
r-
-.^. MSU SP ^ . ^\ V / MSunirSj/
\ - - ' ' ^ Y .OM -CH A/
-0-0 Zr-O
J m
1 1
•C-0.
Hinh 9. Phd hdng ngoai cua mdu gel polymer
• 24 DAUKHI-SP 2/2016
A p suat (bar) ,1 The tich t r e n b e m a t m a u loi x d p (ml)
\ T h j j i c h g i f l lai t r o n g m a u lot x d p (ml)
•i The tich di qua mau lot x o p (ml)
Bdng 9. Xdc dinh dac tinh mau Idi xdp
^ J I 0,3
T h e t i e h c f l a m a u Idi x d p h i n h t r y d f l p c t i n h t h e o c d n g flc
V= hnr" = 6x3,14x2,25' ^ 95.4(cm') T r o n g d d :
V : T h e t i c h c f l a m a u l o i h i n h t r y ; h: C h i e u c a o cCia m a u Idi;
r: b a n k i n h c u a m a u I d i .
T i e n h a n h t h i n g h i e m : B d m e p 1 0 0 m l d u n g d i c h g e l p o l y m e r GG-Zr{lV)-TEA q u a m a u Idi x d p d a p s u a t k h d c n h a u . T h d i g i a n b O m e p n h a n h d d h e g e l p o l y m e r c h f l a c d t h d t a o g e l d e n k h i d i h e t v a o k h d n g g i a n r d n g c u a m a u Idi x d p .
Ban d a u d U a d u n g d i c h h e g e l c h o c h a y v d o d n g m l u p h i a t r e n m a u l d i x d p c a t . D u n g d j c h g e l c d d p n h d t t f l P n g ' d d i I d n n e n g a n n h f l k h d n g c h d y v a o k h d n g g i a n r d n g cfla . m a u Idi x d p . T d n g d p s u a t t f l t f l l e n h e t h d n g d e h e g e l x a m n h a p v a o m a u x d p . T r o n g q u a t r i n h e p h e g e l v d o m a u l d i x d p , q u a n s a t v a d i e u e h i n h d p s u a t sao c h o h e g e l x a m
• n h d p h o a n t o d n v a o m d u 161 x d p t h i d f l n g e u n g e l p d p
^suat. G h i lai d p s u i t t f l O - 0,7bar.
T f l B d n g 9 , x a c d j n h t h e t i c h r d n g c u a m a u l d i x d p la 3 8 c m l T y l e d p r d n g eua m a u x d p : 3 8 x 1 0 0 / 9 5 , 4 = 3 9 , 8 % . 2.10.2. 5u thay doi ap sudt bam he gel vao mau loixop theo thdi gian tgo gel
Bom he gel polymerGG-Zr(IV)vaotodnbd khdng gian I cua mau Idi xdp, nghien cflu khd nang tao gel trong mau , Idi xdp thdng qua sfl thay ddi dp s u i t (Bdng 10).
Khi he gel polymer chfla tao gel, dp s u i t g i n nhfl khdng doi dat gia trj thap d 0,2 - 0,3bar. Khi gel dflpc hinh thanh sau khodng thdi gian 60 phflt d nhiet dd phong va sau khodng 40 phut d nhiet dd 38°C, dp suat bdm dau vao tang nhanh ddn 0,7bar. Qua dd, xac dinh dflpc dac tinh gel cfla he gel thong qua dac tinh thay ddi dp suit.
' 2.10.3. Xdy dung dudng dgc tinh dp sudt tgo gel cOa he gel polymer GQ-Zr(IV) tren mau loi
Xac d j n h d p b i t n h e t c u a m a u l o i x d p c d c h f l a g e l p o l y m e r : M a u d u n g d j c h g e l p o l y m e r d f l p c b O m v d o m l u Idi x d p . Sau k h o d n g 3 0 p h f l t , g e l - p o l y m e r h i n h t h a n h . D o
38 62
36 j 64
Bdng 10. Thay doi dp sudt theo thoi gian tao gel tren mau ldi I T h d i g i a n
1 0 5
i ''
1 15 20 1 30
! 4 0 [ 50
! 6 0
\ 70 j _ 80
p h u t )
d n h i e t d o 25'>C
"o"
0,1 0,1 0,1 0,2
" 0,2 0,3 0,3 0,7 2 4
1 d n h i 4 t d o 3 8 < - C 0 0,1
T - '
j
-r
0,2 1 0,2 ! 0,3 j 0,3 1 0,7
2 1 4 1 6
7 1
•02 50c 638''C
Hinh 13. Budng ddc tinh thay doi dp suot theo thdi gian tao gel trang khdng gian xop Bdng 11. Ket qud do tham nudc qua mau loi xdp chda he get polymer GG-Zr(IV}
T h d i j i a n (gid) I 1 ; 2 I 3 ' 4 ' J_\ 6 ! 7 ^ 8 L u p n g n u d c " j Q | 0 0 i 0 i 0 I 0 I 0 ' 0 I truyen qua (ml) ' | 1 ' | ^ [
Bdng 12. Xdc dmh phuc hot do tham sau khi phd gel trong mdu ldi xop '« A j p ^ a t ( b a r ) 0 0,1 0,3 I 0,5 ! 0,6 0,7 t The tich tren be mat
I m a u Idi x d p (mi) i The tich g i f l lai t r o n g
i mdu^loi_xop (rnl)_ 15 ' 36 3 7 37 ' 37
' T h ^ t i c h d i q u a mau ioi x o p (ml)
I 100 . 100 100 i 100 100 • 100
d d t h a m c u a m a u Idi x d p b a n g c d c h : C h o 1 0 0 m l n f l d c l e n b e m a t m a u Idi x d p , t a n g d a n d p s u a t n e n d f l p c c u n g c a p t f l b i n h k h i n i t o d e n d p s u a t 9bar, sau d o g i a m x u d n g 5 b a r v a g i f l n g u y e n t r o n g t h d i g i a n 8 g i d . K e t q u d d u o c g h i lai t r o n g B a n g 1 1 .
DflUKHI SO2/20ie
THAM DO - KHAI THAC D A U KHI
Tfl ket qua thi nghiem cho thay:
Mau gel polymer sau khi hinh thanh trong khodng thdi gian hon 30 phut da bit kin hodn toan edc 16 rdng cua mau loixop.
He gel polymer danh gid tren mau loi xdp cho thay kha nang tao gel trong khdng gian rdng cua mau Idi va bit nhet hoan toan mau Idi xdp cd dp rong rat Idn gan 40%.
- Dp ben gel duy tri trong 8 gid dUdi ap suat 5bar khdng cd hien tUdng tham nUdc truyen qua khdi gel va khdng gian xdp cua mau Idi.
2.10.4. Nghiin c(Su kha ndng phuc hoi dp thdm cua he gel polymer sau khi sCfdung chat phd gel
Ddnh gia kha nang phyc hdi dp tham eua mau Idi xop tfle la danh gid khd nang Iflu thdng trd lai cfla via sau khi pha gel.
Mau Idi xdp chfla he gel d tren dfloc bom len be mat dung djch chat phd gel ammonium persulfate nong dp 0,36%, de yen mau Idi nay trong thdi gian 60 phut, 120 phut, 12 gid va 24 gid cho phdn flng pha gel trong khong gian xdp. Sau khi hi&n tflpng pha gel xay ra hoan toan, bom nfldc vdo mau Idi xdp rfla vdi Iflpng nfldc bang 2 lan the tich cua mau Idi, khoang 200ml (tfle 5PV). Sau do, tien hanh do ap suit khi bom 100ml dung djch gel polymer cham qua mau xdp tUOng tU nhu quy trinh d myc 2.10.1.
Xdc dmh lupng mau gel con lai trong mdu dem so sanh vdi lupng gel trong mau ban dau. Sd lieu dUpc dUa ra d Bdng 12.
Tinh toan kha nang phuc hdi dp tham cfla mau Idi xdp sau khi phd gel:
R = 37x100/38 =97,4%
Khd nang phuc hdi do tham sau khi pha gel tren mau lot xdp dat 97,4%. Cdn 2,6% dp tham chfla dflpc phyc hdi do dung djch persulfate tham khdng deu vao toan bp khdi gel trong khdng gian rdng cua mau loi xop, vi vay, mdt phan nhd he gel khdng dfloc tiep xuc vdt dung dieh persulfate nen khdng bi oxy hoa phan buy eae polymer guar gum. Ddy Id xac suit chip nhdn dflOc trong nghien cflu phuc hdi do t h i m trong dieu kien phong thi nghiem.
Trong dieu kien thuc te dupe trang bi cac thiet bi hien dat ed the bom rfla dfldi dp Iflc Idn (den vdi tram bar) hay gpi dong tao ra sfl chenh dp trong gieng khoan vd dp suit via, cac thanh phan dfl ciia he gel polymer cd the dflOc thdt rfla mpt each de dang.
^ 2 6 DAU KHt-SO 2/2016
3. Ket luan va kien nghj
Qua qua trinh nghien cflfu, nhdm tdc gid dd lua ehgn dflpc guar gum bien tinh la loai polymer cd kha nang phdn huy sinh hpc de che tao he gel polymer ddng gieng tam thdi. LUa chpn dflpc tdc nhan lien ket cau thich hop Id phflc chat zlcpn sodium lactate cd hda trj 4 - Zr(IV),tao lien ket khdng gian vdi phan t f l polymer guar gum tai cac vj tri cis-hydroxyl, mat dp lien ket thich hpp tao gel tflOng ddi bdn 6 didu kien nhiet dp phdng va nhiet dp eao trong thdi gian sfla gieng. Lfla chpn dfloe tac nhar triethanolamine thich hpp lam chdm thdi gian tao gel cfla he polymer GG-Zr(IV) tfl 30 - 240 phut vdi nong d?
0,3 - 0,9%. J Khao sat he gel trong mdi trfldng nfldc mudi NaCI
4% (nfldc bien) vd thdi gian tao gel khi hdm Iflpng triethanolamine tfl 0,3 - 0,9% la khoang 25 - 130 phut nhanh hon so vdi trong mdi trfldng nfldc ky thuat. Lya chon tdc nhan pha gel cfla he GG-Zr(IV)-TEA la ammonium persulfate (APS) cd dac tinh: thdi gian phd gel tang khi tang ndng do APS; thdi gian phd gel tang khi nhiet dp tdng; thdi gian phd gel dat 120 phut d ndng dp APS 0,3 - 0,4%.
Che tao he gel polymer GG-Zr(IV) cho ddng gieng tam thdi, gdm cac thdnh phin: nfldc ky thuat; guargum 0,42%;
tac nhan khau mach Zr(iV) 25ppm; ty le GG/Zr(IV} = 1,6;
tac nhan kim ham gel triethanolamine 0,6%; chat dieu chinh pH: citric vd Na^CO^; chit diet khuan - biosafe 0,5%;
tdc nhdn dn dinh nhiet thiosulfate 0,12%; tac nhdn pha gel ammonium persulfate 0,3 - 0,5%.
He gel polymer che tao ddp flng cde yeu cau: thdi gian tao gel khoang 40 phut; nhiet dp 37,5''C; thdi gian pha gel tdi thieu 120 phut; dd nhdt cfla dung djch guar gum ban dau 28cR He gel polymer ndy cd the de ddng bom vaovi tri ban via vd de dang ep vdo khdng gian rdng d be mat cfla via sdn pham; dp dn djnh d dieu kien thfldng cd thi dat 3 thang; cd khd nang chju nhiet den 120°C khi co tac nhan nang cao dn djnh nhiet thiosulfate.
Ket qud thfl nghiem he gel polymer ehe tao d nhift dp phdng va nhiet dp 45''C tren mau loi xdp eho thay: Khi nang bOm ^p mau d l dang vao khdng gian xdp ciia m^u cat ket; cd kha nang tao gel trong khdng gian xdp ci!ia mau cat ket cilia gieng 507 RC; xac djnh dflpc dfldng dac tinh dp suat thay doi theo thdi gian tao gel eua gel polymer trong khdng gian cfla mau xdp cdt; nghien cflu phuc hoi dd tham cfla mau xdp sau khi pha gel bang APS Iflu trong thdi gian tao gel 15 ngdy, dat 97,4%.
PETROVIETNAM
Tfl ket qua nghien cflu, nhdm tac gid de xuat kien
; nghj tidp tue trien khai cde nghien cflu: nghien cflu he gel 5 polymer GG-Zr(lV) eho nflt gel tai vi tri lo ban via va ep gel fVao khe rong phia ngoai be mat via trong dieu kien cu the
via sdn ph^m cfla gieng khai thac dfloe dfla vao sfla chfla ,, nhdm thay the cac thiet bt Idng gieng vd ban via de dieu j^ehinh lai vj tri khai thdc nang cao hieu qua khai thac cCia ,.gieng; nghien cflu phd gel 6 dieu kien via va ky thudt phd
gel phu hop cd the kiem soat kha ndng pha gel trong ndt gel va trong khdng gian rong cfla via chfla; nghien cflu khd nang bit nhet vd phuc hoi do t h i m via cua he gel polymer
"tren thiet bj thi nghiem mo hinh mau ldi via.
Tai lieu tham khao
"• 1. Ta Quang Minh. Wg/iien cflu ^exudf(?onp/)o c/ie 'idling dich khoan goc ddu tong hap cho tdng mdng md Bgch '^ Ho vd cde gieng khoan thupc Dong bang Song Hong. 2002.
2. Hoang Hdng Linh. Dgc diim ndt ne cua da mong
"md Bgch Ho vd nghien cUu dieu che tampon thich hap de
chdng mdt dung dich trong ddi nCft ne di thudng dp sudt thap. 200^.
3. Le Phudc Hdo. Bdi gidng cong nghe khai thdc dau khi. Dai hpc Bdch khoa Tp. Hd Chi Mmh. 2006.
4. Aqualon. Guar and guar derivatives oil and gas field applications. 2007.
5. Ralph Moorhouse, Lester E.Matthevi/s. Aqueous based zirconium (IV) crosslinked guar fracturing fluid and method of making and use therefor. Patent US 6737386 Bl.
2004.
6. Aung Kyaw, Bibi Syabila Binti Nor Azahar, Saleem Qsd\rJ\sri\o. Fracturing fluid (guar polymer gel) degradation study by using oxidative and enzyme breaker. Research Journal of Applied Sciences, Engineering and Technology.
2012; 4(12); p.1667-1671.
7. Kathryn L.Payne. Control of crosslinking reaction rate of aqueous fracturing fluids. Patent US 4579670A. 1986.
^:- Study of gelled polymer system used for temporary plugging of oil well in workover operation for low pressure and unstable I production wells
Ta Quang Minh', Vu An', Cao Huy Hiep' Tran Hung Son', Phan Trong Hieu', Nguyen Tuan Anii' Vu Van Hung^ Nguyen Cong Manh^ Vu Thiet Thach^
'Vietnam Petroleum Institute 'Vietsovpetro
^Hanoi University of Mining and Geology Email [email protected] ' Summary
Many methods are used to prevent fluid losses in low pressure and unstable production wells during temporary shut-in for well workovers. Among these, polymer gels are usually used in stimulation and workover operation. They , can plug channels and perforated entrance holes, block producing intervals as well as prevent fluid movement into reservoirs. This technological solution allows control of wells with low reservoir pressure 11,2] and rapid movement ofdownhole equipment, tubing and drilling pipes within well bores.
Multi-component polymer gel system can be flexible to fit each purpose such as temporary plugging of selected producing intervals and reducing formation damages. This article presents the study results of using polymer gel
°" system to temporarily shut-in low pressure and unstable production wells during workovers.
..Key words: Petroleum, workover of production well, gel, polymer, low pressure and unstable reservoir.
DAU KHi s o 2/2016
