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7/23/2019 DAMH Chau Phuoc Tho

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Mc lc

SVTH: Chu Phc Th Pagei

MC LC

MC LC ..................................................................................................................................................... i

DANH SCH BNG BIU ........................................................................................................................ iii

DANH SCH HNH V ............................................................................................................................. iv

MU ...................................................................................................................................................... 1

1. Tnh cp thit ca ti .................................................................................................................... 1

2. Mc tiu v nhim vca ti ....................................................................................................... 2

3. Phng php nghin cu................................................................................................................... 2

4. Tng quan vtnh hnh nghin cu................................................................................................... 2

5. Cu trc n ................................................................................................................................... 7

Chng 1....................................................................................................................................................... 9

TNG QUAN VKHAI THC DU BNG PHNG PHP GASLIFT............................................. 9

1.1 Kho st tnh cht vt l ca ging 5P thuc mBch H................................................................. 9

1.1.1 Tnh cht vt l ca va sn phm ................................................................................................ 9

1.1.2 Tnh cht ca cht lu trong iu kin va ................................................................................. 10

1.1.3 Nhit v gradient a nhit .................................................................................................... 121.2 C sl lun chn phng php khai thc gaslift lin tc cho ging thit k.................................. 13

1.3 Khai thc du bng phng php Gaslift.......................................................................................... 14

1.3.1 Gii thiu chung vphng php gaslift:.................................................................................. 14

1.3.2 Cc phng php khai thc du bng gaslift ............................................................................. 16

1.4 C sl thuyt vphng php khai thc gaslift............................................................................. 18

1.4.1 Nguyn l lm vic: ................................................................................................................... 18

1.4.2 Nguyn l hot ng .................................................................................................................. 19

1.4.3 Cc yu t nh hng n hiu quca phng php gaslift................................................... 201.4.4 Hthng van gaslift ................................................................................................................... 21

Chng 2 ..................................................................................................................................................... 24

C SL THUYT TNH TON CHO GING GASLIFT ................................................................... 24

2.1 Xc nh ng knh ti u ca ng khai thc ................................................................................. 24

2.1.1 Tnh ton ct ng nng khi khng chlu lng khai thc:.................................................... 25


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Mc lc

SVTH: Chu Phc Th Pageii

2.1.2 Tnh ton ct ng nng khi khng khng chlu lng khai thc:.......................................... 26

2.2 Xc nh p sut khi ng ging khai thc bng gaslift: ............................................................... 28

2.3 Tnh ton chiu su t van gaslift khi ng ................................................................................. 31

2.4 Cc yu tnh hng n hiu sut ca ging gaslift ...................................................................... 33

2.4.1 Lu lng kh nn: ..................................................................................................................... 33

2.4.2 ng knh ng nng: ............................................................................................................... 34

2.4.3Lu lng ring ca kh: ........................................................................................................... 35

Chng 3..................................................................................................................................................... 37

TNH TON V THIT KGING KHAI THC GASLIFT BNG PHN MM PIPESIM ............. 37

3.1 Gii thiu phn mm Pipesim ........................................................................................................... 37

3.2 Thit kging khai thc Gaslift ........................................................................................................ 39

3.2.1 Cc thng skhai thc ca ging 5P thuc mBch H.......................................................... 39

3.2.2 Dng excel tnh ton lu lng khai thc v lu lng bm p ca ging 5P thuc mBchH ........................................................................................................................................................ 39

3.2.3 Xy dng m hnh v cc bc nhp thng svo m hnh:.................................................... 45

3.2.4 Phn tch khnng cho dng ca ging.................................................................................... 48

3.2.5 Xc nh su ti a bm p kh............................................................................................. 51

3.2.6 Thit kvtr t van Gaslift ..................................................................................................... 52

3.2.7Lu lng kh bm p ti u...................................................................................................... 57

3.2.8 Hiu qukhai thc ging khi p dng phng php gaslift...................................................... 59

KT LUN V KIN NGH .................................................................................................................... 65

TI LIU THAM KHO .......................................................................................................................... 67


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Danh sch bng biu

SVTH: Chu Phc Th Pageiii

DANH SCH BNG BIU

Bng 1: Cc thng skhai thc ca ging 5P............................................................................................ 39

Bng 2: Thng sban u ca va tng ng cho Flowline...................................................................... 40Bng 3: p sut theo su tng ng vi GLR ca Flowline................................................................. 40Bng 4: Thng sban u ca va tng ng cho Tubing......................................................................... 42Bng 5: p sut theo su tng ng vi GLR ca Tubing.................................................................... 42Bng 6: Lu lng inflow tng ng p sut va....................................................................................... 44Bng 7: GLR githit tng ng vi lu lng bm p cn thit............................................................. 44Bng 8: Lu lng cht lng (STB/d) khai thc tphun............................................................................ 51Bng 9: Kt quvtr t Mandrel............................................................................................................. 56Bng 10: Lu lng khai thc vi lu lng kh nn v hm lng nc khc nhau............................... 58


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Danh sch hnh v

SVTH: Chu Phc Th Pageiv

DANH SCH HNH V

Hnh 1:Nguyn l hot ng ca phng php gaslift............................................................................... 20

Hnh 2: Van Gaslift ..................................................................................................................................... 22Hnh 3: S ging khai thc gaslift .......................................................................................................... 28Hnh 4: S xc nh su t van Gaslift ........................................................................................... 32Hnh 5: thgia lu lng khai thc vi lu lng kh nn................................................................. 34Hnh 6: thbiu din mi quan hgia lu lng kh bm p, lu lng du khai thc vi ng knhng nng ..................................................................................................................................................... 35Hnh 7: thmi quan hca lu lng khai thc Ql= f(Vk), lu lng ring ca kh nn R = f(Vk), psut kh nn Pk= f(Vk) ................................................................................................................................. 35Hnh 8: thtra p sut theo su ....................................................................................................... 41Hnh 9: thIPR v GLR tng ng cho Flowline................................................................................. 41Hnh 10: thIPR v GLR tng ng cho Tubing.................................................................................. 43Hnh 11: thmi quan hgia lu lng khai thc v lu lng bm p ca ging 5P...................... 44Hnh 12: Giao din chnh ca m hnh ging 5P ....................................................................................... 45Hnh 13: Giao din thit lp dliu cho Black Oil.................................................................................... 46Hnh 14: Giao din thit lp dliu cho Vertical Completion................................................................... 46Hnh 15: (A),(B),(C):Giao din thit lp dliu cho Tubing..................................................................... 48Hnh 16: Giao din ca Nodal Analysis ..................................................................................................... 49Hnh 17: thphn tch ng dng vo v ra trong trng hp water cut khc nhau khi ging tphun ............................................................................................................................................................ 49Hnh 18: thphn tch ng dng vo v ra trong trng hp water cut khc nhau khi ging khaithc bng gaslift .......................................................................................................................................... 50

Hnh 19: Giao din tnh ton su ti a bm p kh.............................................................................. 51Hnh 20: Giao din thit lp thng scho Design Control........................................................................ 52Hnh 21: Giao din thit lp thng scho Design Parameters.................................................................. 53Hnh 22: Giao din nhp thng sSafety Factors...................................................................................... 55Hnh 23: Kt quchy phn mm PipeSim vtr t Mandrel................................................................... 55Hnh 24: thkt quvtr t Mandrel................................................................................................. 56Hnh 25: Giao din thit lp thng scho Artificial Lift Performance...................................................... 57Hnh 26: ththhin mi quan hgia lu lng khai thc i vi lu lng kh nn v hm lngnc khc nhau ........................................................................................................................................... 58Hnh 27: Giao din ca Downhole Equipment........................................................................................... 59Hnh 28: Giao din thit lp lu lng kh bm p cho ton hthng...................................................... 60Hnh 29: Giao din ca Nodal Analysis .................................................................................................... 60Hnh 30: thphn tch ng dng vo v ra trong trng hp lu lng kh nn 0.3mmscf/d.......... 61Hnh 31: thphn tch ng dng vo v ra trong trng hp lu lng kh nn 0.4mmscf/d.......... 61Hnh 32: thphn tch ng dng vo v ra trong trng hp lu lng kh nn 0.5mmscf/d.......... 62Hnh 33: thphn tch ng dng vo v ra trong trng hp lu lng kh nn 1mmscf/d............. 62Hnh 34: thphn tch ng dng vo v ra trong trng hp lu lng kh nn 2mmscf/d............. 63Hnh 35: thphn tch ng dng vo v ra trong trng hp lu lng kh nn 2.5mmscf/d.......... 63


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Mu

SVTH: Chu Phc Th Page1

MU

1. Tnh cp thit ca ti

Du kh l ngnh cng nghip cn rt non trnhng l ngnh kinh tminhn v c nhiu tim nng, trin vng trong tng lai.Sau hn 25 nm phn u

xy dng v trng thnh, ngnh du kh t c nhiu thnh tu rt to ln,

ng gp nhiu cho snghip cng nghip ha, hin i ha t nc.

Cng tc khoan v khai thc cc ging du l mt cng vic ht sc kh

khn, phc tp v l cng vic sng cn ca ngnh cng nghip du kh.Hin nay

cc nh khoa hc trn th gii lun khng ngng nghin cu nhm tm ra ccphng php khai thc mi t hiu qucao.Mc tiu quan trng nht ca ngi

k s du kh l bit p dng cc k thut v cng nghmi khai thc ngy

cng hiu qungun ti nguyn thin nhin v gi ny.

Trong thc tkhai thc du kh, sau mt thi gian khai thc, nng lng va

suy gim dn, khng cn ln a dng sn phm ln ming ging.Lc ny

cn phi sdng phng php khai thc c hc thch hp.Vo cui thkXIX,ngi ta nn khng kh vo khong khng vnh xuyn hoc trong cn nng lu

cht. Nm 1920, bt u dng kh ng hnh thu c tqu trnh khai thc du

p tr li ging. Phng php bm kh cao p vo ging ha trn vi cht lng

trong ging lm gim ttrng v a chng ln bmt c tn gi chung l phng

php gaslift.

Vn ti u phng php gaslift trong khai thc du kh c tranh lunv nghin cu. Nhng im chung l ti u lu lng du khai thc cao nht,

li nhun thu c l ln nht.


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Mu


2. Mc tiu v nhim vca ti

T vic nghin cu tnh hiu qu trong khai thc du kh, mc ch

nghin cu ca n l lm sao dng phng php gaslift lu lng dukhai thc cao nht, li nhun thu c l ln nht cho ging cn c khai

thc.Nhim vti l dngphng php gaslift lin tc thit ktnh ton nh

thno khai thc ging mt cch c hiu qu.

3. Phng php nghin cu

ti tp trung nghin cu c s l thuyt cng nghkhai thc, nh gi

kh nng khai thc,ng dng v xut gii php khai thc ph hp cho vngnghin cu.

Nghin cu cc phng php trong khai thc, c bit l nghin cu c sl thuyt ca phng php khai thc du bng Gaslift.

Thng k, phn tch cc s liu lin quan n ging tngun khc xut gii php khai thc bng phng php gaslift lin tc mt cch hp l choging cn c khai thc .

4. Tng quan vtnh hnh nghin cu

Thit ksvan,chiu su t van hp l cho ging Gaslift lin tc, ng dng

thc tMBch H, (ip, V Tn)

t vn :

Tm nhng thng s cn thit cho vic thit k khai thc bng

gaslift. Xy dng c cc phng trnh dng chy trong ng thng ng.

Tnh ton cc thng sv thit khthng khai thc gaslift.

Phng php nghin cu:


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a ra c s l thuyt v Gaslift v gii thiu cc thit b trong

phng php gaslift.

Tin hnh tm hiu cc thng slin quan n cc thit b

Sau ,tin hnh xy dng ng phn bp sut trong ng ng

Ri n vic tnh ton cc thng s lin quan v ng dng n vo

trong thc t

Kt qu:

Tnh ton cc thng sv thit kc chiu su t van ca ging

gaslift mt cch hp l.

p dng c phng php tnh ton v xy dng c ng

phn bp sut r rng v chnh xc.

ng dng phng php ny vo thc tcthl: MBch H

Tnh ton thit kkhai thc Gaslift lin tc (Tin, L Quyt)

t vn :

Gii thiu chung v c sl thuyt vphng php GasliftTnh ton thit kcho mt ging Gaslift cth

Ti u ha bm p cho ging Gaslift

Cch xc nh p sut khi ng ging khai thc bng gaslift

M phng phng php kim tra bng sliu cth

Phng php nghin cu:

a ra c s l thuyt vP.P Gaslift v gii thiu v P.P gasliftlin tc

a ra bi ton gii quyt vn tnh ton v thit k

Kt qu:


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Mu


Tnh ton c cc thng sv la chn chkhai thc ti u

S dng c phn mm gii quyt bi ton hiu qu-v ng

dng thc tphong ph

Thit lp c ca sm phng p sut trong qu trnh khi ngging gaslift

ng dng PIPE SIM thit kging khai thc du bng Gaslift lin tc

(Trm, Hong Triu Thy)

t vn :

Gii quyt bi ton thit kcho ging gaslift mt cch hiu qu

bng phng php th v phn mm PIPE SIM-i chiu 2

phng php

Lp phng n thit kging gaslift c hiu qukinh tnht

Phi nm bt c c s l thuyt ca phng php gaslift v

phn mm PIPE SIM

Phng php nghin cu:

Gii thiu cc phng php gaslift c p dng (u-nhc-kh

nng p dng)

Gii thiu phng trnh dng chy trong ging p dng cho

gaslift

Sau ,thit kging gaslift bng thi phn bp sut v phn

mm PIPESIM

Kt qu:

Nhvo cc phng trnh dng chy,xc nh cc thng sca

ging gaslift,cng nh thit kcc Mandrel bng phn mm v

th


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Mu


Bit ng dng v p dng phn mm PIPESIM v thgii

bi ton mt cch r rng v chnh xc

Nghin cu phng php l ha nhm nng cao hiu quging khai thc

Gaslift trong iu kin khai thc ti Vit Nam (Nhn, Nguyn Hu; Kabirov,

M. M; Dng, Nguyn Thnh, 2009)

t vn :

Phn tch nh gi chn phng php khai thc hp l trong

iu kin khai thc bin ti Vit Nam

Phn tch v gii quyt cc yu tph thuc v nh hng n

phng php gaslift:cu trc dng chy,vn tc tng i,lng

ng paraffin

La chn cc ha phm gii quyt nhng vn trn gip

nng cao hiu qukhnng khai thc ging gaslift

Phng php nghin cu:

a ra nhng yu t nh hng n vic khai thc du bngphng php gaslift

Phn tch snh hng cc yu t v tm ra hng gii quyt

vn

Sau ,tnh ton v th nghim cc phng php gim bt

hoc loi bnh hng ca nhng yu t n vic khai thc

ging gaslift bng cch dng ha phm,th nghim a ra cc

phng php gii quyt khc

Kt qu:

Vic p dng hn hp ha phm: cht hot tnh bmt v cht

c ch lng ng paraffin lm gim vn tc chuyn ng ca


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pha kh, lm chm qu trnh pht trin ca bt kh khi chuyn

ng trong ng khai thc v tng khnng to bt ca hn hp

du-kh nc

Vic p dng hn hp ha phm lm tng lu lng ging khaithc gasliftlm tng hiu qu sdng kh nn v hiu sut lm

vic ca ging gaslift

Xc nh c nng ti u ca hn hp ha phm, tuy nhin

ty iu kin, tnh cht l ha du - kh nc tng mnn hiu

chnh nng ca hn hp cho ph hp vi iu kin tng m

ti Vit NamSau khi tham kho mt s ti liu nh trn,cho thy vn khai thc du

bng phng php gaslift rt phbin.c bit l trong bi cnh nn kinh t th

gii ang pht trin nn cn nhiu nng lng: quan trng l du v yu cu s

dng cao nn phng php khai thc bng gaslift cng ang trthnh ti nng

bng cn phi c nghin cu gip tnghiu qukhai thc hn.V c bit

hn na, l thng qua vic s dng ngun kh ti ch khai thc du bng

phng php gaslift lin tc l ti cng cn c quan tm.Ngy nay, vi vic

kt hp nhng cng cv phn mm (PIPESIM) vo trong phng php khai thc

gaslift cng rt phong ph.V l do m ti Thit kkhai thc du bng

phng php gaslift lin tc c chn lm ti nghin cu n tt

nghip. Ni dung chnh l nu ln tm quan trng ca phng php khai thc

Gaslift, cc bc tnh ton thit kkhai thc Gaslift, cc thit bdng trong khai

thc Gaslift

ngha thc tin

n nghin cu v a ra gii php cng ngh khai thc bng phng

php gaslift lin tc thc hin trc skhng nh tm quan trng v tnh


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Mu


hiu qucao ca vic p dng phng php khai thc bng gaslift. Mrng nghin

cu v ng dng,gip k s du kh c th tip cn v p dng cc phng

php,k thut v cng ngh khai thc mi.Thnh cng ca gii php cho ging

khai thc ny cng vi cc ging khai thc cc gii php khai thc bng phngphp Gaslift mi ph hp vi mc tiu v iu kin ca ging khai thc cthhn.

5. Cu trc n

Ni dung chnh ca n bao gm 3 chng:

Chng 1:Tng quan vkhai thc du bng phng php gaslift

Trong chng ny em gii thiu s lc vcc phng php khai thc c

hc, u nhc im ca tng phng php v c schn la phng php khai

thc c hc ph hp vi hon cnh khai thc ti Vit Nam l phng php gaslift.

Phn loi c cc hthng khai thc bng gaslift v gii thiu cc thit b

khai thc bmt v lng ging.

Chng 2:C sl thuyt tnh ton cho ging gaslift

Trnh by cc c sl thuyt tnh ton bng thut ton cc thng snh:

Kch ctubing.

p sut khi ng van gaslift

su lp van gaslift

p sut ti van lm vic.

Nghin cu cc yu tnh hng n hiu sut ca ging gaslift:

Lu lng kh nn.

ng knh ng nng.

Lu lng ring ca kh.

Chng 3:Tnh ton v thit kging khai thc gaslift bng phn mm Pipesim


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Mu


Trong chng ny sdng chyu l phn mm pipesim thit kcth

cho mt ging khai thc gaslift.

Don khnng cho dng ca ging qua cc thng s:

p sut va,Pva.

ngp nc (water cut)

Xc nh c hiu qukhi chuyn sang khai thc bng gaslift.

Tip theo da vo cc thng s ca ging ta tin hnh thit k cho ging

khai thc gaslift da vo phn mm pipesim xc nh:

Svan gaslift ti u. su lp t van gaslift.

su ti a bm p kh.


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Chng 1: Tng quan vkhai thc du bng phng php gaslift


Chng 1

TNG QUAN VKHAI THC DU BNG PHNG PHP GASLIFT1.1 Kho st tnh cht vt l ca ging 5P thuc mBch H

1.1.1 Tnh cht vt l ca va sn phm

a.c trng vchiu dy:

Vic phn chia chiu dy hiu dng trong mng rt kh khn do s c

mt ca vi nt nc thtch rt nhnhng li cho php du chy qua vi gi tr

gn ng u tin, gi trti hn ca rng c ly bng 0,6%.

Chiu dy mng c tnh su tuyt i 4046m (chiu su ny ng vi

ging khoan GK 4221 cho dng du khng ln nc). Ti vm Bc chiu dy

chung ca mng thay i t0 375m, trung bnh l 522m, vi hsbin i l

0,40. Trn vm Trung Tm chiu dy chung ca mng nm trong khong t 0

987m, trung bnh l 690m vi hsbin i l 0,30. Chiu dy hiu dng ca

mng nt n theo ti liu a vt l ging khoan l 9,4 91,3% (vm Bc) v41,8 89,2% (vm trung tm) chiu dy ca mng do cc ging khoan mra.

b. Tnh khng ng nht:

MBch Hl mc dng a va, c trng bng mc khc nhau vtnh

khng ng nht ca cc i tng khai thc.

Cc thn du Mioxen di:

ng cht hn c l tng 23 ca vm bc, tnh khng ng nht ca cc

Mioxen cao nht trong scc va ca m.


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Tng Mioxen c phn lm nhiu lp mng, hsphn lp trung bnh

vm Bc l 3,6, vm Trung tm l 5,5, tng ng vi hsct ca vm l 0,45

cho vm Bc v 0,34 cho vm Trung tm.

Ti liu nghin cu a vt l ging khoan v ti liu phn tch mu li trong

phng th nghim ly c tng 3 tng Mioxen di cho thy lt ct cc tp

khng ng nht.

Cc thn du Oligoxen h:

Theo ti liu a vt l v ti liu mu li trong ging khoan thuc tng

Oligoxen hcho thy mt ct cc tng sn phm rt khng ng nht c xen k

bi cc lp ct kt, bt kt cha sn phm v st mng khng cha sn phm. So

snh cc c tnh khng ng nht ca cc i tng khai thc cho thy rng trong

cc i tng c cha rng nh Oligoxen hthng khng ng nht. Hs

phn lp v hsct ca tng Oligoxen hln lt l 10,8 v 0,39.

Ni chung khi nh gi mc khng ng nht ca cc tng sn phm c

thni rng trm tch sn phm Oligoxen l km ng nht hn c. Mc phn

lp ln nht ti 20 va. Hsphn lp trung bnh l 19,8%.

1.1.2 Tnh cht ca cht lu trong iu kin va

a. Cc tnh cht ca du trong iu kin va.

Du tt ccc va trong mBch Hu cha bo ha, h sp (t s

gia p sut va v p sut bo ha) l:

1,43 cho Mioxen hdi vm Bc.1,9 cho Mioxen di vm Trung tm.

3,54 cho Oligoxen thng.

1,94 cho Oligoxen h.

1,76 cho mng.


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Theo cc gi trthng sc bn, cc loi du mBch Hc thchia thnh

3 nhm. Theo chiu tnhm I n nhm III cc thng sgia tng:

Tsut kh du du GOR.

Hsthtch B.

p sut bo ha Ps.

Ttrng du d.

nht ca du d.

Qua phn tch s liu theo tch vi phn ta thy c du c chia thnh 2

nhm:

Du mng v du Oligoxen di.

Du Oligoxen thng v Mioxen.

Vthnh phn cu tdu va, v l do hn chcc sliu vchng ct chn

khng nn sdng du tch c ttrng 833,6kg/m3v phn tlng 251,15g/mol

tnh ton cho tng mng v Mioxen h, cn sdng du c trng lng ring

l 865kg/m3 v phn tlng l 300g/mol cho Oligoxen trn v Mioxen di. S

cho php ktrn da trn c svsging nhau ca cc gi trtrng lng ring

du tch kh ca cc nhm v p ng vi cc c tnh trung bnh.

c. c tnh ha l ca du tch kh.

Theo cc sliu vkhong bin thin v cc gi trtrung bnh ca cc thng

s du tch kh sau qu trnh vi phn cho thn du thuc loi nng, nhiu

parafin, it lu hunh, t nha cho n nhiu nha, tlthu hi sn phm sng muthuc loi trung bnh. Nhit ng c ca cc loi du 29 340C.

d. Cc tnh cht ca nc va.


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Trong cc trm tch ca tng Mioxen di thng gp 2 loi nc chnh l:

nc Canxiclorua (CaCl2) v nc Natrihydrocarbonat (NaHCO3). c im ca

loi nc NaHCO3 l c khong ha thp (6,64g/l) ch nhn bit trong vm

Bc, nc vm Nam thuc loi CaCl2c khong ha cao hn (16g/l), ng thikhong ha gia tng theo hng ty nam. Nc thuc trm tch Oligoxen h

c ly tva lng knh nm trn cc tng sn phm thuc loi NaHCO3c

khong ha thp hn (5,4g/l).

Thnh phn kh ha tan trong nc khc vi thnh phn kh ha tan trong

du chc hm lng Metan (CH4) cao hn. Lng cu tCarbon ca kh ha

tan trong nc l 1,54 3,0% v lng Nit l 1,29 2,8%.

1.1.3 Nhit v gradient a nhit

a. Gradient a nhit (GDN) cc phtrn mng

Mng c phbi cc thnh phn to trm tch st tui Mioxen v Oligoxen,

cc lp phny c h sdn nhit b hn so vi h sdn nhit ca mng.

Dng nhit ny sau khi ra khi mng sbcc lp phpha trn, gradient a

nhit ca cc lp ny ln hn mng.

Nhng o c trong cc ging mvo thn du tui Mioxen h, Oligoxen c

quy lut nh sau:

Cng chiu su nh nhau, ging no nm vng mng nng cao th nhit

cao hn, ngc li ging no nm vng mng h thp th c nhit thp

hn.

b. Gradient a nhit mng

Do nh hng ca lp phMioxen v Oligoxen v do v tr mi vm khc

nhau cho nn nhit cc vng trn mt mng khc nhau.Nhng sau khi i vo


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mng su no (c thchon l 4300m) th nhit vm nam v vm bc

tng ng nhau.

Kt qunghin cu cho php xc nh c gi tri gradient a nhit ca

mng l 2,50C.su 4300m c nhit l 157,50C.

1.2 C sl lun chn phng php khai thc gaslift lin tc cho ging thit k

iu kin khai thc ngoi bin phc tp v kh khn hn rt nhiu so vi t

lin. Do vy thi gian khai thc v pht trin m thng ko di trong khong 20

30 nm. V vy bn cnh vic a nhanh tc khoan v a ging mi vo khai

thc, chng ta cn p dng cc phng php khai thc khc nhau , nhm gia tng

sn lng khai thc v tn dng c ch nng lng ca va sn phm.

Vi iu kin hin ti m Bch H ngoi i t ng mng ang khai thc

theo ch t phun cho sn lng cao v p sut gim khng ng k th hu ht

cc ging khai thc tng Mioxen v Oligoxen thi k cui ca qu trnh t

phun hoc ngng phun v b ngp n c. Do vic a cc ging ny vo giai

on khai thc gaslift l rt cn thit.

c c s la chn phng php kh thi v hiu qu nht i vi iu kin

m Bch H cn phi xt n cc yu t sau:

Tnh cht l u th ca va (du, kh, nc)

Tnh cht colect ca cha .

iu kin a cht ca m tin hnh khai thc .

Tnh trng k thut , cng ngh p dng trn m v thit b hin

c.

iu kin thi tit , kh hu v kinh t x hi .

nh gi hiu qu kinh t k thut thng qua cc th nghim trn

m.


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Trn c s phn tch u nhc im ca cc phng php khai thc du

bng c hc trn th gii , lin h vi iu kin thc t ca m Bch H , ta thy

rng:phng php khai thc du bng gaslift c th khai thc k tip phng php

t phun.N c nhiu u im hn so vi cc phng php khai thc c hc khckhng nhng v mt k thut cng ngh m cn v mt kinh t. Vi cc trang thit

b hin i rt ph hp phng php khai thc ny ha hn mang li hiu qu

cao hn cc phng php khai thc c hc khc . Vy vic la chn phng php

Gaslift p dng cho ton m Bch H ni chung v cho ging ang thit k ni

ring l hon ton ng n.

i vi ging thit kta chn phng php khai thc gaslift lin tc v gingc lu lng khai thc cao, hssn phm tng i cao v ging c mc nc

thy ng cao.Vy cc iu kin m bo cho ging c th khai thc bng

phng php gaslift lin tc vi hiu qucao.

1.3 Khai thc du bng phng php Gaslift

1.3.1 Gii thiu chung vphng phpgaslift:

Bn cht ca phng php :

Khai thc du bng phng php Gaslift da trn nguyn tc bm kh nn

cao p vo vng khng gian vnh xuyn gia ng khai thc v ng chng khai

thc, nhm a kh cao p i vo trong ng khai thc qua van Gaslift vi mc ch

lm gim t trng ca s n phm khai thc trong ct ng nng , dn n gim p

sut y v to nn chnh p cn thit sn phm chuyn ng t va vo

ging. ng thi do s thay i nhit v p sut trong ng khai thc lm cho khgin n gp phn y du i ln , nh m dng sn phm c nng ln mt t

v vn chuyn n h thng thu gom v x l.

u im:


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C th a ngay ging vo khai thc khi giai on t phun km

hiu qu

Cu trc ct c a ng nng n gin khng c chi tit chng hng .

Phng php ny c th p dng vi ging c su , nghingln.

Khai thc vi ging c yu t kh ln v p sut bo ha cao .

Khai thc lu lng ln v iu chnh l u lng khai thc d dng .

C th khai thc nhng ging c nhit cao v hm lng

Parafin ln , ging c ct v c tnh n mn cao .

Kho st v x l ging thun li , khng cn ko ct ng nng lnv c th a dng c qua n kho st .

S dng trit kh ng hnh .

t gy nhim mi trng .

C th khai thc ng thi cc va trong cng mt ging .

Thit b lng ging tng i r tin v chi ph bo dng thp hn

so vi phng php khai thc c hc khc . Gii hn ng knh ng chng khai thc khng nh hng n

sn lng khai thc khi dng khai thc Gaslift .

C th s dng k thut ti trong dch v sa cha thit b lng

ging. iu ny khng nhng tit kim thi gian m cn lm gim

chi ph sa cha .

Nhc im:

u t c bn ban u rt cao so vi cc phng php khc .

Nng lng s dng khai thc mt tn sn phm cao hn so vi

cc phng php khc.


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Khng to c chnh p ln nht ht du trong va giai

on cui ca qu trnh khai thc .

Ngun cung cp nng lng kh phi ln cho ton b i m .

Chi ph vn hnh v bo dng trm kh nn cao , ihi i ngcng nhn vn hnh v cng nhn c kh lnh ngh .

Phm vi ng dng:

Hin nay gii php khai thc du bng phng php Gaslift ang c p

dng rng ri trn c t lin v c ngoi bin , c bit i vi vng xa dn c v

kh i li . Gii php ny thch hp vi nhng ging c t s kh du cao , c th

khai thc nhng ging c nghing ln v su trung bnh ca va sn phm

trn 3000m. Phng php ny hin ang c p dng rng ri trn m Bch H.

1.3.2 Cc phng php khai thc du bng gaslift

Ty thuc vo phng php bm p kh nn v lu lng khai thc m chia

ra lm 2phng php khai thc Gaslift.

1.3.2.1 Phng php khai thc gaslift lin tc:

Phng php Gaslift lin tc l phng php kh nn a vo khong khng

vnh xuyn gia ng chng khai thc v ct ng nng , cn sn phm theo ng

nng ln mt t lin tc.

Kh nn c th c a vo ging theo khong khng vnh xuyn gia ct

ng chng khai thc v ng khai thc (ng nng), cn hn hp sn phm khai thc

theo ng khai thc ln b mt (hoc ngc li).Phm vi ng dng:khai thc Gaslift lin tc c p dng tt nht i vi cc

ging:

C lu lng khai thc ln .


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Sn phm ct hay b ngp nc .

Sn phm c nht cao , dng chy c nhit ln .

C t sut kh cao mc d sn lng ging c th nh .

u im:

Nng lng ca kh nn v kh ng hnh c tn dng ti ming

ging vn chuyn sn phm i tip n h thng thu gom v x

l.

Lu lng khai thc tng i n nh , hn ch c nhiu phc

tp trong h thng Ga slift.

iu chnh lu lng kh nn thun li bng cn iu khin .

C th iu chnh lu lng khai thc bng vic iu chnh lu

lng kh nn .

Nhc im

Khng hiu qu i vi ging c mc nc ng thp (mc d l u

lng khai thc ln ).

Khng p dng c vi nhng ging c p sut va thp.

1.3.2.2 Phng php khai thc Gaslift nh ky:

Khai thc Gaslift nh k c tin hnh bng cch p kh vo khong

khng vnh xuyn v hn hp sn phm khai thc theo ng khai thc ln mt t

din ra khng lin tc m c nh k c tnh ton da theo cc thng s a cht

k thut ca i tng khai thc .Kh nn tkhong khng vnh xuyn i vo ng

nng, qua mt hay nhiu van Gas-lift vi mt lu lng ln duy tr vn tc

i ln ca cc nt cht lng v gim thiu lng cht lng ri xung.

Phm vi p dng:


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C p sut y thp nhng h s sn phm cao .

C h s sn phm thp .

Ging su v mc cht lng thp .

C lu lng khai thc nh .

u im:

Kinh t v linh hot (gi thnh khai thc v thit b cho cc ging su vi

mc cht lng thp, thp hn so vi cc phng php c hc khc).

Nhc im:

Lu lng c c i b gii hn . Khng thch hp vi cc ging su , ng nng nh c bit l ng

dng m ng o kh nng ti ca ng b gii hn .

p sut dao ng mnh vng cn y ging c th dn n s ph

hu y ging .

Kh iu khin trong h th ng Gaslift khp kn v nh .

1.4 C sl thuyt vphng php khai thc gaslift

1.4.1Nguyn l lm vic:

Yu cu: Khai thc du bng phng php gaslift l phng php khai thc

c hc khi ging du khng thtphun theo lu lng yu cu.

Nguyn tc: bm nn kh cao p vo vng khng gian vnh xuyn (hay

ngc li) nhm a kh cao p vo trong ng khai thc qua van gaslift vi mc

ch lm gim mt ct cht lng trn van (tng yu tkh, gim p sut y).

p sut y gim dn n mt gi trno m chnh lch gia p sut va v

p sut y ln kch thch dng sn phm chy tva vo y ging.Lc ny

kh ng hnh tva vo kt hp vi lng kh nn tbmt cng kh ho ct cht


23/72



lng. Qu trnh ny xy ra n mt lc no p sut y ln thng tn hao

nng lng dc theo ct ng khai thc v y ton bct cht lng kh ho ln

bmt, vn chuyn n hthng thu gom v xl.

Mc ch:lm cho nng lng va thng tng tn hao nng lng a

dng sn phm ln bmt.

1.4.2 Nguyn l hot ng

Kh nn cao p c bm vo vng khng gian vnh xuyn (hay ngc li)

nhm a kh cao p vo trong ng khai thc qua van gaslift vi mc ch lm

gim mt ct cht lng trn van (tng yu tkh, gim p sut y).Ap sut y

gim dn n mt gi trno m chnh lch gia p sut va v p sut y

ln kch thch dng sn phm chy tva vo y ging. Lc ny kh ng

hnh tva vo kt hp vi lng kh nn tbmt cng kh ho ct cht lng.

Qu trnh ny xy ra n mt lc no p sut y ln thng tn hao nng

lng dc theo ct ng khai thc v y ton bct cht lng kh ho ln b

mt, vn chuyn n hthng thu gom v xl.


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Hnh 1:Nguyn l hot ng ca phng php gaslift

1.4.3 Cc yu t nh hng n hiu quca phng php gaslift

Lu lng kh nn: khai thc c hiu quta phi m bo kh nn theo

yu cu. Lu lng ny c tnh bng tng lu lng kh nn c bm vo ttc cc ging trong vng khai thc.Khai thc st hiu qukhi kh bm p t

c lu lng ti u.

Cu trc ng khai thc: khai thc n nh, kch thc ng khai thc l

mt yu tquan trng khi thit k. Kch thc ca ng khai thc qu nhsgy ra

tn tht ma st. Tuy nhin nu qu ln slm cho ng ch y mt n nh. thit

kc ng khai thc ti u cho ng chy hai pha trong ging thng ng cn phic dliu chnh xc.

Tnh cht ca ng ch y khai thc: nht, ngm nc, ngm du,

sc cng trt.

P

Pe= Pmax= Pk

Kh nn

Sn phm


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p sut kh nn: p sut kh nn qu thp skhng khai thc c lu lng

mong mun

Cht lng kh nn: thng thng trc khi bm kh vo ging ngi ta phi

xl chng, bi cc tp cht ln trong kh. Hiu quca hthng khai thc bng

Gaslift phthuc vo p sut cao ca kh c sn.

My nn kh: my nn kh c la chn ph hp vi gi trp sut, kh

nng p dng, cng sut, mi trng hot ng v ngun kinh ph.

1.4.4 Hthng van gaslift

Van gaslift c t vo ti hng su thit knhm a kh vo dng

sn phm khai thc kh ha phn ct cht lng pha trn van.Van c cu to c

bit cho php iu khin qu trnh ng mvan mt cch ddng.Van c cu to

gm:

Bung m(dome): l bung np nit cung cp lc ng

van,hn ch s tng p sut do bung xp b nn li khi van m

hon ton.

Bung xp (bellows): c ni vi bung m cho php gin n

hoc nn p thtch nit v truyn schuyn ng cho xupap.

Cn xupap (stem): l cn ng mvan c gn vi mt vin bi

c tc dng chn dng kh i qua van.Vin bi thng c ng

knh ln hn ng knh ca ca van.

L xo (spring): cung cp lc ng van

chn cn xupap (seat): hn chsdch chuyn ca cn xupap

v to kn khi van ng.

Cn tit lu (choke): c gn vo u ra hoc u vo ca van

iu chnh thtch kh qua van.


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Van mt chiu (check valve): ngn dng chy ngc li ca cht

lng tng khai thc i qua van v vo ng nn kh.Van mt chiu

vtr ng khi van gaslift ng.

Nguyn l hot ng: bm kh cao p vo vng khng gian vnh xuyn

nhm a kh cao p i vo ng khai thc qua van gaslift vi mc ch lm gim

mt ct cht lng trn van,ngha l lm gim p sut y. p sut y sgim

dn n mt gi trno m chnh lch gia p sut va v p sut y ln

kch thch dng sn phm tva vo y ging.Lc ny kh ng hnh tva vo

kt hp vi lng kh nn tbmt cng kh ha ct cht lng. Qu trnh ny xy

ra n mt lc no p sut y ln thng tng tn hao dc theo ct ngkhai thc v y ton bct cht lng kh ha ln bmt. Nh vy nguyn tc

lm vic ca ging gaslift cng ging nh ging tphun,tc l dng sn phm t

y ging c a ln bmt nhnng lng gin nca kh nn. Nhng im

khc bit chnh trong phng php gaslift l kh nn cao p c a t b

mt,cn tphun l kh ng hnh trong va sn phm

Hnh 2: Van Gaslift


27/72



Chng ny trnh by cc phng php khai thc c hc trn th

gii,ng thi phn tch u nhc im ca tng phng php. T a ra c s

la chn mt phng php khai thc c hc khthi vmt kthut ln kinh ti

vi cc mngoi khi ca nc ta, l phng php khai thc bng gaslift

ng thi cng trnh by mt cch chi tit cc phng php khai thc da

vo chgaslift,nu r cc nguyn l hot ng,thnh phn,cu to v cc trang

thit bca phng php ny.

Gaslift cn c xem xt ngay tgiai on u ca cng tc pht trin m.

Phn gii thiu s lc vphng php khai thc gaslift trong chng 1ny chnh

l c stc gitrnh by tnh ton v thit k,hon thin ging gaslift,nng cao

hiu quca phng php nhm duy tr v tng sn lng khai thc ca m.


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Chng 2: C sl thuyt tnh ton cho ging gaslift


Chng 2

C SL THUYT TNH TON CHO GING GASLIFT2.1 Xc nh ng knh ti u ca ng khai thc

Khi khai thc du bng phng php gaslift,nng lng nng dng cht lng

ty ging ln bmt l kh nn p tbmt. Khi chn chlm vic ca ng

nng cn ch n hiu qusdng nng lng ti u.

nng mt lng cht lng nht nh ngi ta phi xc nh:

Chiu di ca ct ng nng.

ng knh ng nng.

Khi lng ti u ca kh lm vic dng bm p.

tnh ton cn c cc sliu ca ging nh sau:

p sut va Pv(atm).

Hssn phm K.

chnh p cho php P (atm).

Lu lng khai thc Q (m3/ng).

Chiu su ging H (m).

ng knh ng chng khai thc D (mm).

Khi lng ring ca cht lng L(g/cm

3).

Yu tkh G0(m

3/T).

Hsha tan ca kh .


29/72



p sut ca hthng phn phi kh PLV(atm).

Khi lng ring ca du d(g/m

3).

2.1.1 Tnh ton ct ng nng khi khng chlu lng khai thc:2.1.1.1 Chiu di ca ct ng nng:

Chiu di ca ct ng nng c tnh theo cng thc:

L=H-10PPhh (2.1)

Trong :

P= PLV 4: p sut ct ng nng,chu tn tht trong qu trnh chuynng ca kh tmy nn kh n y ct ng nng.

hh :trng lng ring trung bnh ca hn hp kh gia y ging v ngnng.

= + 2 (2.2)Theo A.Crlv, cng thc tnh v nh sau:

= /+43,22//43,22/+/+(0)/(+1)

(2.3)

Thay gi trPvo Pcng thc trn, vi:

Qc/l = Q = Q

Q = KP

P = Pv P

2.1.1.2 ng knh ng nng:

ng knh ca ng nng khi lm vic vi chti u c xc nh l:


30/72



= 0,2351 (1)3

(2.4)

Vi l nhng chm tng i ca ct ng nng c xc nh nh sau:

= 10( )/ (2.5)

2.1.1.3 Lu lng kh p:

Tsut kh ring ti u (kckh sn c trong ging)xc nh theo cng

thc:

= 0,77(1)0.5

(2.6)

Tsut ring ca kh p (kn bha tan ca kh)xc nh theo cng thc:

= 2 (2.7)Trong :

G0: yu tkh; m3/T.

: hsha tan ca kh.Vy lu lng kh bm p trong mt ngy m sl:

= (2.8)2.1.2 Tnh ton ct ng nng khi khng khng chlu lng khai thc:

Ngoi cc s liu bit trn,trong trng hp ny cn cn cc s liu

sau:

Chiu dy ca va : a

Lu lng ring ca kh p Roep (m3/T).

2.1.2.1 Chiu di ca ct ng nng:


31/72



thu c lu lng ln nht th p sut ti y phi nhnht. Ta thct

ng nng n chiu su phn mva sn phm. Ti P= P.

Chiu di ca ct ng nng l:

= (2.9)2.1.2.2 ng knh ng nng:

Ta c

= + 0 (2.10)Tgi trRotpv L bit, ta c thtra thxc nh P.

= =( ) =( ) (2.11)ng knh ng nng c xc nh theo cng thc:

= 0,2351 (1)3

(2.12)

Trong :

l nhng chm tng i c xc nh theo cng thc:

= 10( )/

Lu lng kh xc nh theo cng thc:

=


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2.2 Xc nh p sut khi ng ging khai thc bng gaslift:

Hnh 3: S ging khai thc gaslift

Trong hnh trn m ts ging khai thc gaslift c trang bhai dy ng

nng.Khi ging khng lm vic (xem hnh 3a) th mc cht lng trong v ngoi

ng khai thc bng nhau v c gi l mc thy tnh. Vi:

L: di ca ct ng nng gaslift.

h1: nhn chm ca ng di mc thy tnh.

Khi ging lm vic n nh (xem hnh 3b) th mc cht lng trong vngvnh xuyn snhhn mc thy tnh v mc ny c gi l mc thy ng, cn

h- l nhn chm ca ng di mc thy tnh.

p sut yngnng oP cxc nhtheo suthy ngv dicang:

= ( ) = (.)i vi iu kin lu lng khai thc khng i,th di ca ng cng di

th nhn chm ca ng di mc thy ng cng ln,v thp sut y ng cng

cao v lu lng ring ca kh cng gim.

p sut lm vic ca kh nn ti ming ging trong iu kin ging khai thc

n nh khc vi p sut lm vic ti y ng mt gi trbng trng lng ct kh


33/72



v tn hao p sut do ma st trong qu trnh kh chuyn ng trong vng vnh

xuyn, nu c sdng van gaslift lm vic th cn phi tnh n tn hao p sut

qua vanvan

P v c xc nh theo cng thc:

(2.14)

Trong :

lvP - p sut lm vic.

msP - tn hao p sut do ma st.

kn

- tlkhi lng ring ca kh nn so vi khng kh.

Z - hsnn ca kh trong iu kin trung bnh p sut v nhit .

T - nhit , oK.

L - di ng nng gaslift, m.

p sut lm vic c thln hn hoc nhhn p sut y ng phthuc vo

lu lng kh nn. Khi lu lng kh ln th lng tn hao p sut do ma st c thvt gi trp sut do ct kh to ra,v lc ny p sut lm vic sln hn p sut

y ng.

p sut ti y ng nng trong iu kin ging dng lun ln hn so vi

iu kin ging lm vic chn nh do hh1>

p sut khi ng c xc nh bng gi trcc i ca p sut kh nn khi

khi ng ging,ngha l ti thi im mc cht lng h thp n y ng nng.p sut khi ng nhhn mt t so vi p sut ti y ng nng lc ny,do tc

gim mc cht lng trong qu trnh khi ng ging khng ln v tn hao p sut

do ma st trong qu trnh kh chuyn ng khng nhiu.

vanms

ZT

L

olv PPePP

kn

++=

03415.0


34/72



p sut khi ng kP khng phthuc vo cu trc ng nng gaslift v b

gii hn trong phm vi sau:

1

(2.15)

Trong trng hp mc thy tnh tng i cao v trong qu trnh khi ng

mc cht lng trong ng nng t n ming ging trc khi mc cht lng ngoi

vng vnh xuyn hxung n y ng nng hoc van gaslift,th p sut khi ng

c xc nh bng biu thc sau:

= (2.16)

Trong : L - khong cch tming ging n y ng nng hoc n su t van gaslift lm vic (m).

Nu trong qu trnh khi ng ging m mc cht lng khng t n ming

ging th p sut khi ng phthuc vo cu trc ng nng v xc nh gn ng

bng biu thc sau:

i vi trng hp cu trc ng nng mt dy ng v kh nn a vo

vng vnh xuyn

=1 22 (2.17) i vi trng hp cu trc mt dy ng v kh nn a vo ng nng:

=1 222 (2.18)

i vi trng hp cu trc ng nng hai dy ng v kh nn a vokhng gian gia ng chng khai thc v dy ng nng thhai:

=1 222+2 (2.19)Trong :


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kP - p sut khi ng, Pa.

h1 - khong cch t mc thy tnh n y ng nng hoc van

gaslift, m.

L - khi lng ring cht lng, kg/m3.

g - gia tc ri tdo, m/s2.

D - ng knh danh ngha ca ng chng khai thc, mm.

d - ng knh danh ngha ca ng nng, mm.

dn- ng knh danh ngha ca ng nng dy ngoi (dy thhai),

mm.

2.3 Tnh ton chiu su t van gaslift khi ng

Bng phng php thc thddng v n gin xc nh su t van

khi ng theo htrc thp sut theo su, gm cc bc sau: (xem hnh 4).

Bc 1:Tim c ta (L = 0, mP ) dng ng cong gradient p sut

(ng s1)da trn cc s liu vng ng nng ang xem xt,sn lng,

ngm nc, tspha lng v kh, cc tnh cht vt l ca lu thv nhng thng

scthkhc.

Bc 2:Xy dng ng cong phn bp sut tnh ca ct kh trong vng

vnh xuyn (ng s2) bng vic sdng cng thc sau:

)03415.0

exp()(ZT

LPLPknmkn

= (2.20)

Trong : - ttrng kh nn i vi khng kh;

Z - hsnn ca kh nn;

knmP - p sut kh nn ti ming ging.


36/72



Bc 3:Tim c ta ( P , viaL ) dng ng cong phn bp sut trong

ng nng c tnh n yu tkh nhm xc nh su t van lm vic (ng

s3). Giao im ca hai ng s1 v s3 l su ti thiu t van lm vic.

Bc 4:Tim c ta (L = 0,mP ) dng ng s4 biu din sphn

bp sut trong ng nng ca cht lng tch kh

Hnh 4:S xc nh su t van Gaslift


37/72



Dng ng song song vi ng s2,vi khong cch bng P =0.3 MPa.

Giao im gia ng s2 vi ng s4 sl su t van khi ng thnht.

Giao im ng nm ngang tim1

L vi ng s4 v s2 cho php xc nh

p sut kh nn trong vng vnh xuyn ti su t van khi ng thnht v psut nhnht trong ng nng ti su ny. chnh lch p sut P ti su

t van khi ng thnht cn thit nhm mc ch m bo kh c thi qua van

ny vo ng nng v bng gim p sut ti van khi lng kh theo tnh ton i

qua van.

Bc 5:Tgiao im ca ng nm ngang1

H vi ng cong s1 dng

ng thng 4', song song vi ng thng 4, n khi ct ng thng song songvi ng s2, vi khong cch P = 0,4 MPa (xem hnh 2). Tung ca giao

im ny chnh l su t van khi ng thhai. su t van khi ng cn

li c xc nh tng tnh i vi van khi ng thhai. im khc bit duy

nht y l p sut kh nn trong vng vnh xuyn c gim thm 0,1 MPa cho

tng van

2.4 Cc yu tnh hng n hiu sut ca ging gaslift

2.4.1Lu lng kh nn:

Khi kh nn bm vo ct cht lng cng tng th lu lng du khai thc

cng tng do t trng ca cht lu gim. Tuy nhin,lu lng khai thc du ch

tng n mt gi trQmax. Nu sau tip tc tng lu lng kh nn th lu lng

khai thc li gim. Mi quan hgia lu lng ging khai thc gaslift v kh nn

c biu din bi hm s:

Q(V) = AV2+ BV + C (2.21)

Trong :

Q - lu lng du khai thc.


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V - lu lng kh nn.

A,B,C - cc h s ca hm Q(V), c xc nh trong qu trnh

tnh ton v kho st ging gaslift.

Hnh 5: th gia lu lng khai thc vi lu lng kh nn

Khi Vk Vminth lu lng khai thc bng khng.

Khi Vk= Vgii hnth lu lng khai thc l ln nht.

Khi VkVgii hnth s xy ra hin tng trt kh nn lu lng khai thc

gim.

Khi Vk Vmaxth ch c kh i ln v du khng khai thc c.

Nh vy ta phi tnh ton lu lng kh nn t sn lng khai thc tiu.

2.4.2ng knh ng nng:

ng nng l mt trong nhng thnh phn quan trng nht trong h thng

khai thc. ng knh ng nng cng ln th lu lng khai thc cng tng,tuy

nhin n 1 gi trnht nh th khi tip tc tng ng knh th lu lng li gim

nhng khi li i hi lng kh bmp cao. Do ta phi sdng ng nng c

kch thc thch hp t c hiu qu kinh t nht. Mi quan h gia lu

lng kh nn Vgv lu lng khai thc Qlvi ng knh ng nng c biu

din nh sau:


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Hnh 6: th biu din mi quan h gia lu lng kh bm p, lu lng du

khai thc vi ng knh ng nng

2.4.3Lu lng ring ca kh:

Hnh 7: th mi quan h ca lu lng khai thc Ql= f(Vk), lu lng ring

ca kh nn R = f(Vk), psut kh nn Pk= f(Vk)

Thnh 7 ta nhn thy rng khi tng lu lng kh nn Vk, lu lng khai

thc ging Qlban u tng dn ln, iu ny l do gim p sut y Pd , ko theo p

sut kh nn cng gim theo. Do ng cong Ql= f(Vk) t gi trcc i (ti

im 3 trn hnh 7), ng cong Pk= f(V

k) c gi trcc tiu (ti im 5). Cn sau

khi qua im 3 lu lng khai thc ging gim l do tng lu lng kh nn lm

cho p sut kh nn tng ko theo sgia tng ca p sut y, lm cho chnh p p

gim (p = Pv Pd). Ti im ca ng tip tuyn k tgc ta vi ng

cong Ql= f(Vk) (im 1 trn hnh 7), lu lng ring ca kh nn t gi trcc


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tiu, ngha l ti y chi ph lng kh nn khai thc mt n vsn phm l nh

nht v ng cong Ro= f(Vk) t gi trcc tiu ti im 2. y chnh l ch

ti u c xc nh trn quan im vnng lng.Sn lng cc i m ging c

thkhai thc bng gaslift nu khng bgii hn lng kh nn v hshiu dngca hthng gaslift (im 3).Lu lng ring ca kh nn khi sn lng ging t

gi trcc i sln hn khi ging khai thc ti chti u.Chlm vic ca

ging c chn nm trong min t khong chkhai thc ti u n ch

khai thc cc i.


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Chng 3: Tnh ton v thit kging khai thc gaslift bng phn mm Pipesim


Chng 3

TNH TON V THIT KGING KHAI THC GASLIFT BNGPHN MM PIPESIM

3.1 Gii thiu phn mm Pipesim

Pipesim l phn mm khai thc hng u trn th gii trong ngnh cng

nghip du kh do cng ty Schlumberger pht trin. Cng vi vic pht trin khoa

hc my tnh, ngnh du kh cng pht trin khng ngng v xem my tnh nh l

cng ccn thit tnh ton,thit k, m phng v phn tch hiu quca gingdu kh.

Pipesim l t ghp Pipeline Simulator. Pipesim c vit trn cc phn

mm: Visual Basic, Visual C ++ v MS Excel. Pipesim cng c thkt ni vi cc

phn mm khc nh: Reservoir models (Eclipse Link), Process models (Hysys

Process), Data system (OFM, Fieldview, Finder).

Phn mm ny c nhiu ng dng trong vic m phng qu trnh khai thcbng phng php tphun,phng php nng nhn to cng nh c thnh gi

nhng thay i trong qu trnh khai thc t c thcho ta mt kt qunh gi

vqu trnh khai thc trong tng lai khi cc iu kin ca va thay i. Phn mm

ny khng chm phng cho cc ging n m cn phn tch nh hng trong h

thng mng li cc ging khai thc. Pipesim c 6 phn (modul) phc vm

phng khc nhau, bao gm:

Phn tch hiu quca ging ( Well Performance Analysis ).

Phn tch ng ng dn v cc thit b( Pipeline & Faccilities ).

Phn tch mng li (Network Analysis).

Ti u ha qu trnh khai thc (Production Optimization).


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Thit kging khai thc nhiu tng (Multilateral Hosim).

Cng clp khoch m(Field Planning Tool).

Trong c mt modul rt quan trng l Well Performance Analysis c th

dng thit kging khai thc gaslift. Vi sng dng ca phn mm pipesim

c thtnh ton c:

su lp t van gaslift.

Slng van gaslift.

su bm p ti a cho ging gaslift.

Xc nh lu lng bm p kh ti u.

Ti u ng knh ng nng.


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3.2 Thit kging khai thc Gaslift

3.2.1 Cc thng skhai thc ca ging 5P thuc mBch HBng 1: Cc thng s khai thc ca ging 5P

3.2.2 Dng excel tnh ton lu lng khai thc v lu lng bm p ca ging 5Pthuc mBch H

Tnh ton cho Flowline:


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Bng 2: Thng s ban u ca va tng ng cho Flowline

Da vo nhng thng sban u ca va cho flowline bng 2.Sau , tra

thp sut theo su hnh 8 sc tng gi trp sut y ging (Pwf)

tng ng vi tng gi trlu lng v GLR khc nhau (bng 3) cho flowline.

Bng 3: p sut theo su tng ng vi GLR ca Flowline

Tbng 3, vi gi trp sut va (Pwf), gi trlu lng khai thc v cc gi

trGLR tng ng, svc thlm vic ca flowline (hnh 8).


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Hnh 8: th tra p sut theo su

Hnh 9: th IPR v GLR tng ng cho Flowline


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Tnh ton cho Tubing:

Bng 4: Thng s ban u ca va tng ng cho Tubing

Da vo nhng thng sban u ca va cho tubing bng 4.Sau , tra

thp sut theo su hnh 8 sc tng gi trp sut y ging (Pwf) tng

ng vi tng gi trlu lng v GLR khc nhau (bng 5) cho tubing.

Bng 5: p sut theo su tng ng vi GLR ca Tubing

Tbng 5, vi gi trp sut va (Pwf), gi trlu lng khai thc v cc gi

trGLR tng ng, svc thlm vic ca tubing (hnh 10).


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Hnh 10: th IPR v GLR tng ng cho Tubing

Tthhnh 9-10, th flowline cha c lu lng cht lng c khai

thc cn tubing th c dng vi cc gi trlu lng tng ng vi cc gi tr

GLR khc nhau. Da vo dng chy ca tubing, sc cc gi trlu lng du

khai thc, p sut va v cc gi trGLR tng ng bng 6 v 7:


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Bng 6: Lu lng inflow tng ng p sut va

Bng 7: GLR gi thit tng ng vi lu lng bm p cn thit

Hnh 11: th mi quan h gia lu lng khai thc v lu lng bm p ca ging 5P

Tbng 7, vi cc gi trlu lng kh bm p tng ng v lu lng du

c khnng khai thc c, svc thmi quan hgia lu lng khai

thc v lu lng kh bm p cn thit ca ging 5P ( hnh 11)

Da vo thhnh 11, sxc nh c lu lng khai thc ti a ca

ging khai thc gaslift l: khong 530 (stb/d) tng ng vi lu lng kh bm p

l khong 420 (Mscfd)


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3.2.3Xy dng m hnh v cc bc nhp thng svo m hnh:

Bc 1:M phn mm pipesim bng cch chn Star>Program >

Schlumberger > Pipesim.

Bc 2:MFile > New > Well Performance Analysis.

Bc 3:Da vo Toolbox trn thanh cng c ca phn mm,chng ta xy

dng c m hnh ging khai thc ging nh ngoi thc t(Vertical Completion,

Turbing).

Hnh 12: Giao din chnh ca m hnh ging 5P

Bc 4:Thit lp hn v: MSetup > Units > Eng.

Bc 5:Thit lp cc dliu vtnh cht ca sn phm: MSetup > Black Oil.


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Hnh 13: Giao din thit lp d liu cho Black Oil

Bc 6:Nhp cc gi trcho phn Vertical Completion: Ta nhp vo bng cc

thng sp sut va,nhit va, m hnh tnh ton, chskhai thc.

Hnh 14: Giao din thit lp d liu cho Vertical Completion

Bc 7: Nhp sliu cho Tubing: Ta snhp vo ln lt cc thng sca tubing

nh: Deviation Survey, Geothermal Survey, Tubing Configurations.


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(A)

(B)


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(C)

Hnh 15: (A),(B),(C):Giao din thit lp d liu cho Tubing

3.2.4 Phn tch khnng cho dng ca ging

Ta sdng phng php phn tch im nt trong phn mm PipeSim vi

nhiu ga trhm lng nc khc nhau phn tch nh hng ca hm lng

nc khai thc i vi tng gi trp sut va ca ging.Bc 1:MOperation > Nodal Analysis.

Bc 2: Ta nhp cc thng s: p sut (outlet Pressure),cho p sut va thay

i vi cc gi trkhc nhau(1900 2100),ta cng cho gi trhm lng nc thay

i cc gi tr t (50% - 90%). Sau ta nhn nt Run Model th chng trnh

PipeSim bt u chy v vra c thquan hgia dng vo v dng ra vi

cc hm lng nc khc nhau nh sau:


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Hnh 16: Giao din ca Nodal Analysis

Hnh 17: th phn tch ng dng vo v ra trong trng hp water cut khc nhau

khi ging t phun


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Hnh 18: th phn tch ng dng vo v ra trong trng hp water cut khc nhau

khi ging khai thc bng gaslift

Hnh 17-18 cho thy iu kin khai thc tphun vi p sut va hin nay

(2100psia) ging khng cho dng khi hm lng nc khai thc khong 50% -

80%. M hm lng nc hin nay l 50% v stng theo thi gian,p sut va

gim dn do qu trnh khai thc,khi iu kin khai thc tphun ca ging cng

kh khn.m bo sn lng khai thc v duy tr khnng khai thc ca ging

cn chuyn sang khai thc bng gaslift. Nn chn thi im p sut va gim xung

cn 1900psia th a ging vo khai thc Gaslift c thtng sn lng khai thc

cao hn v ng thi duy tr p sut va.


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Bng 8: Lu lng cht lng (STB/d) khai thc t phun

3.2.5Xc nh su ti a bm p kh

Sau khi nhp cc d liu ca m hnh ging v cc thng s thit k

gaslift. Ta sdng phn mm PipeSim xc nh su ti a c thnn kh

cho ging nh sau:

Bc 1: MArtificial lift > Gaslift > Deepest Injection Point.

Bc 2: Nhp gi tr theo yu cu vo cc trng,sau nhn calculate

th Pipesim stnh ra su thng ng ti a c thbm p xung.

Hnh 19: Giao din tnh ton su ti a bm p kh


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Kt quchy PipeSim cho thy vi p sut nn kh ti bmt l 900 psia th

su ti a thng ng c thbm p xung ging l 2879.7052ft. Vy vi iu

kin khai thc v bm p nh trn,hon ton c thp dng gaslift cho ging 5P

thuc mBch H.

3.2.6Thit kvtr t van Gaslift

Phn mm PipeSim cho php ta xc nh vtr v cc loi van a vo ng

khai thc ca ging. Thit kvtr t van gaslift bao gm hai trng hp:

Trng hp c sn mandrel th chtnh ton thng sti u trong khai

thc bng gaslift (Current spacing)

Trng hp thit kvtr mandrel mi (New spacing).

lun vn ny, s thit k v tr mandrel mi cho ging khai thc bng

gaslift. Cc bc thc hin nh sau:

Bc 1: MArtificial lift > Gaslift > Gaslift Design.

Bc 2: Chn vo tab Design Control,v thit lp cc thng snh sau:

Hnh 20: Giao din thit lp thng s cho Design Control


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Design Spacing: Thit kvtr mandrel mi (New Spacing)

Design Method: Dng phng php IPO Surface Close. Phng php

ny l dng chnh p ng van khng i gia cc van.

Max Allowable Inj.TVD: chiu su thng ng bm p ti a.Top Valve Location: Gi nh cht lng t ging ln b mt (Assume

Liquid to Surface).

Valve Selection Filter: Chn la van trc khi thit k:

+ Manufacturer: Weatherford

+ Type: IPO

+

Size: 1+

Series: R-1

Unloading Temperature: Nhit dti, default

Production Pressure Curve: Ta chn m hnh p sut lm vic l

Production Pressure Model.

Bc 3: Chn Design Parameters v thit lp cc thng ssau:

Hnh 21: Giao din thit lp thng s cho Design Parameters


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Kickoff Pressure: L p sut bm p ti a khi ng ging chdng

cho van u tin, 900psia.

Available Injection Pressure: L p sut bm nn sn c tnh ton thit

k, 900psia.Unloading Prod. Pressure: L p sut khai thc ti a trong qu trnh d

ti v chdng cho van u tin, 210psig.

Operating prod. Pressure: L p sut khai thc mong mun v c dng

tnh ng cong p sut khai thc, 210psig.

Target Injection Gas Flowrate: Ch tiu lu lng kh bm p dng

thit k. Dng tnh ng cong p sut khai thc v kch thc van,

0.38 mmscf/d.

Inj Gas Specific Gravity: Ttrng kh bm p, 0.65

Injection gas Surface Temp: Nhit kh bm p ti bmt, 74oF.

Unloading Gradient: Gradient d ti dng tnh ton v tr van,

0.465psi/ft

Min Valve Injection DP: L p sut chnh p ti thiu gia p sut khai

thc v p sut bm p. Van khng tht su hn nu p sut chnh lch

khng ln hn gi trny, 150psi

Click Liquid Production Rate: L lu lng khai thc ti a m ging

du khai thc c bng gaslift, 558stb/d

Bc 4:Chn vo tab Safety Factors v thit lp cc thng ssau:

Surface Close Pressure Drop Between Valves: chnh p ng van

gia cc van,15psi

Locating DP at Valve Location: chnh p ti van, 50psi

Transfer Factor: Hstruyn nhit, 0%


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Bc 5: Sau khi nhp y cc thng strn ta Click Perfrom Design.

Chng trnh schy v truy sut ra kt quvtr t cc mandrel,sau ta Click

Install Design chng trnh stng ci t vtr cc mandrel vo Tubing

m hnh ging 5P thuc mBch H.

Hnh 22: Giao din nhp thng s Safety Factors

Hnh 23: Kt qu chy phn mm PipeSim v tr t Mandrel


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Hnh 24: th kt qu v tr t Mandrel

Tkt quchy Pipesim cho ta thy c tht 7 Mandrel bm p kh cung cp

cho qu trnh khai thc bng phng php Gaslift.

Bng 9: Kt qu v tr t Mandrel


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3.2.7Lu lng kh bm p ti u

Xc nh lu lng kh bm p ti u nhm bit c mt cch chnh

xc lng kh thch hp nht bm p xung ging sao cho t c lu

lng khai thc cao nht.Bc 1: Chn Operrations > Artifical Lift Performance.

Bc 2: Ta tin hnh nhp cc thng sp sut ming ging,thay i cc

gi tr ca hm lng nc v cc gi tr ca lng kh nn bm p xung

ging. Sau ta nhn nt Run Model th chng trnh sxut ra th. T

thny ta c thnh gi c lu lng kh nn bm p ti u.

Hnh 25: Giao din thit lp thng s cho Artificial Lift Performance


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Hnh 26: th th hin mi quan h gia lu lng khai thc i vi lu lng kh nn

v hm lng nc khc nhau

Bng 10: Lu lng khai thc vi lu lng kh nn v hm lng nc khc nhau

Thnh 26 ta thy khi lng kh bm p ln hn 1 mmscf/d th lu lng

khai thc tng ln rt t khng ng kdn n hao ph kh bm p khng cn thit.


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Lng kh bm p ti u cho ging trong khong gi tr l 0.3 mmscf/d 1

mmscf/d va cho lu lng khai thc cao va mang tnh kinh tcao.

3.2.8 Hiu qukhai thc ging khi p dng phng php gaslift

Sau khi hon tt cc dliu thit kcho ging nh su bm p ti a,s

lng v v tr lp t cc mandrel,cng nh lu lng kh bm p ti u,ta tin

hnh tnh ton khnng khai thc gaslift ca ging ng vi cc lu lng kh bm

p l 0.3mmscf/d, 0.4mmscf/d, 0.5mmscf/d, 1mmscf/d, 2mmscf/d, 2.5mmscf/d vi

hm lng nc khai thc thay i t50% => 90%.

Bc 1:Nhp kp chut vo Tubing trn m hnh. Chn Downhold

Equipment > G/L Valve System.

Bc 2: Click chut vo Edit Valve Details, sau ginguyn cc thng

s,chnhp li gi trlng kh bm p cho ton hthng (Injection Gas Rate) l

1mmscf/d.

Hnh 27: Giao din ca Downhole Equipment


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Hnh 28: Giao din thit lp lu lng kh bm p cho ton h thng

Bc 3:MOperations > Nodal Analysis > Run Model. Ta sc c th

phn tch ng dng vo v ra ca ging khai thc gaslift ng vi lu lng kh

nn l 0.3mmscf/d. Sau ta tin hnh cc bc tng t ln lt vi lu lng

kh nn l 0.4mmscf/d, 0.5mmscf/d, 1mmscf/d, 2mmscf/d, 2.5mmscf/d

Hnh 29: Giao din ca Nodal Analysis


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Hnh 30: th phn tch ng dng vo v ra trong trng hp lu lng kh nn

0.3mmscf/d


0.4mmscf/d


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0.5mmscf/d

Hnh 33: th phn tch ng dng vo v ra trong trng hp lu lng khnn 1mmscf/d


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2mmscf/d

Hnh 35: th phn tch ng dng vo v ra trong trng hp lu lng kh nn2.5mmscf/d

T cc kt qucho trong hnh 30 n hnh 35, cho thy khi p dng khai

thc gaslift cho ging,khnng nng du ci thin ng kso vi trng hp khai

thc tphun. Ngoi kt qutng sn lng khai thc,ging cn c khnng khai


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thc khi hm lng nc trn 50%. Trong khi iu kin khai thc tphun vi p

sut va l 2100psia th ging khai thc hu nh khng cn dng sn phm i ln

na khi hm lng nc ln hn 80%. c bit, khi p sut va t 1900psia-

2100psia th ging hon ton khng cn hot ng chtphun c na.Cniu kin khai thc bng gaslift vi hm lng nc khai thc 50% hoc ln

hn th ging vn c khnng cho dng sn phm vi lu lng cao.


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KT LUN V KIN NGH

Khai thc du bng phng php Gaslift chng minh tnh u vit v mt

cng nghip , tnh hiu qu v mt kinh t v c nhiu u im hn so vi ccphng php khai thcc hc khc

n ny nhm mc ch minh ha phng php v cc bc tnh ton

trong qu trnh thit k, c s dng phng php biu Camco xc nh chiu

su t van.

Trong qu trnh khai thc gaslift , khi p sut va khng sc thng c

tn hao nng lng nng sn phm th cn chuyn sang ch khai thc gaslift

nh k.

Thc t lng kh ng hnh c s dng khng nhiu,phn ln vn b t

b do nhiu nguyn nhn . Do vycn y nhanh cng tc xy dng trm nn kh

cng sut ln phc v kp thi vic trin khai m rng khai thc du bng

phng php gaslift v vn chuyn kh vo b . ng thi tng cng nghin cu

nhng tc ng ln dng chy nhiu pha tit kim nng lng va , nng cao snlng khai thc cng nh ti u ha qu trnh thit k lp t h thng gaslift.

Trong n ny,bng phn mm Pipesim,tc gi c bn xy dng c

mt phn ca cng tc thit kh thng khai thc bng phng php gaslift cho

ging nh:

Phn tch khnng khai thc tphun ca ging.

Phn tch khnng khai thc bng gaslift.

Xc nh slng v vtr lp t cc van gaslift cho ging.

Xc nh su bm p kh ti a.

Xc nh lu lng kh bm p ti u cho ging.


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Phn tch hiu qutrc v sau khi ng dng phng php gaslift.

Hu ht vic vn hnh v khai thc ging gaslift theo nhm v gia cc

ging trong nhm c mi tng tc v quan hmt thit vi nhau. Cn tin hnh

nghin cu cc phng php nng cao hiu qukhai thc gaslift: chuyn sang ch

khai thc gaslift nh k, sdng ho phm


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TI LIU THAM KHO

1. Beggs, H. (2003). Production Optimization Using Nodals Analysis.

2. ip, V Tn. Thit ksvan,chiu su t van hp l cho ging Gaslift lin tc, ng dng thc

tMBch H.HCh Minh.

3. E.Brown, K. (1980). The Technology of Artifical Lift Methods.

4. Golan & Whitson. (1995). Well Performance.

5. Nhn, Nguyn Hu; Kabirov, M. M; Dng, Nguyn Thnh. (2009). Nghin cu phng php l

ha nhm nng cao hiu quging khai thc Gaslift trong iu kin khai thc ti Vit Nam.H

Ch Minh.

6.

PIPESIM Training and Exercise Guide.Schlumberger Company.

7. PIPESIM User Guide.Schlumberger Company.

8. Tin, L Quyt. Tnh ton thit kkhai thc Gaslift lin tc.HCh Minh.

9. Trm, Hong Triu Thy. ng dng PIPE SIM thit kging khai thc du bng Gaslift lin

tc.HCh Minh.


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