Hệ thống theo dõi đáy giếng PMS trong công nghệ khai thác dầu khí

Hpi nghi KHCN 2000 "Nganh Dau khi Viet Nam trifdc them theky 21'''' HE THONG THEO DOI DAY GIENG PMS TRONG CONG NGHE KHAI THAC DAU KHI Le Ngoc San Phan Ngge Trung Tong cong ty Dau khi Viet Nam TOM TAT Ddi[.]

HE THONG THEO DOI D A Y GIENG PMS TRONG CONG NGHE KHAI T H A C D A U KHI

Le Ngoc San Phan Ngge Trung

Tong cong ty Dau khi Viet Nam

TOM TAT

Ddi vdi cac gieng khai thae dau khi, sau mdt thdi gian khai thac nhat dinh can phai tien hanh eae cdng tac thir

va khao sat gieng de cd the nam ro tinh trang hoat ddng eiia gieng va tu dd de ra giai phap xd ly thich hgp cung nhu thu thap cac thdng sd can thiet phue vu eho viec nghien ciru ehinh xac hoa md hinh md/via Vi vay qui che khai thac tai nguyen dau khi ciia nude ta yeu cau tien hanh cdng viee nay toi thieu 2 lan mdi nam Tuy nhien, khi tien hanh khao sat gieng theo dinh ky bat bugc phai dung khai thac gieng lam cho san lugng khai thac giam do ddng gieng, mat khae

ed the gay ra nhurng riii ro anh hudng den cau true gieng cung nhu cac yeu cau khae ve an toan Chinh vi mong mudn giam thieu ean thiep vao gieng dang khai thac cang nhieu cang tdt, tai nhieu nude tren the gidi trong dd cd Viet Nam

da va dang sir dung he thdng cd dinh theo ddi lien tue eae thdng so Idng gieng khai thac

MO TA HE THONG

He thd'ng (Hinh 1) theo ddi khai thae cd djnh PMS dugc thiet ke de thay the eho edng doan khao sat

gieng djnh ky bing phuang phap thdng thudng He thdng duge sir dung de ghi lai lien tue eae thdng sd day

gieng nhu ap suit, nhiet do, luu lugng, mat do chit Idng, do ngap nude "we" nham muc dieh tdi uu khai

thae, dy bao khai thae cung nhu phat hien tire thdi eae nguy ca tiem tang nhu khi san lugng gie'ng giam, thdi

diem ap suit day gieng giam tdi gia trj ap suit bao hoa, van Idng gieng bj hdng hay rd ri, v.v

He thd'ng PMS bao gdm hai loai chii yeu sau:

• He thd'ng PDG (Pemianent Downhole Pressure Gauge) dugc sir dung de do ap suit va nhiet do day gieng

• He thd'ng PDF (Permanent Downhole Flowmeter) duge sir dung de do eae thdng sd chit luu day gieng

Ngoai tinh nang tuang duang vdi he thd'ng PDG (do ap suit va nhiet do), he thd'ng nay cdn cd kha

nang do do ngap nude "we", mat do chit Idng va dae biet la do luu lugng chit luu tai day gieng

Mdt sd cdng ty djch vu chuyen cung cap loai thiet bi nay nhu Expro, Geoserviees, Schlumberger,

Smedvig, v.v Tuy nhien, cae ket qua khao sat cho thay he thd'ng PDF khdng dugc cac Nha thiu ua

chudng do tinh khdng dn djnh, hay hdng hde d bd phan do luu lugng (de bj an mdn do ma sat vdi ddng chit

luu) Hien nay, he thd'ng nay dang dugc nghien ciru, tim bien phap khic phue nhugc diem dd Rieng ddi vdi

he thdng PDG, nhung nam g i n day da ed nhung bude tien dai trong cdng nghe che tao thiet bj do dac biet

la bd phan cam bien dien tir lam cho do dn djnh va do ben ciia thiet bj kha tdt Trong pham vi bai viet nay,

chiing tdi mudn di sau han ve uu diem va tinh hieu qua ciia viee sir dung he thdng PDG ddng thdi trich din

mdt sd ket qua khao sat ve tinh trang hoat ddng eiia he thdng nay d mdt sd nai tren the gidi

LAJ DIEM

• Giam thdi gian ngung khai thac khi phai khao sat gieng;

• Giam sd lin c i n tien hanh khao sat gieng;

• Tang tinh toan ven ciia gieng, dam bao an toan gieng;

• Tdi uu hoa viec quan ly md va ke hoach khai thae;

Hpi nghj KHCN 2000 "Nganh Dau khi Viet Nam trifdc them the ky 21'

0 \ ^ Nghi len cLRj via

Phan tich khai thac May chu

Bo truyen tin hieu ti/xa

Pin mat trdi

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P, T, Q mieng, P, T, Q day gieng

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hoae va Q

H i n h l Sadd he thd'ng PMS Cung cip sd lieu gieng tU cac gieng khoan ngang hoae ed do xien Idn ma khdng the thyc hien bing eae phuang phap khae tuang duang;

Cung cap sd lieu Idng gie'ng trye tiep khi tien hanh nirt via thuy lye hoae kfch thfch via;

Ty ddng luu giu cac thdng sd khai thac Idng gieng trong eae trudng hgp ddng gie'ng theo ke hoach hoae ngoai ke hoach (khdng cin sir dung phuang phap cap dien "wireline");

Tdi uu hoa thdi gian thir gieng, khdng phu thudc vao eae hoat dgng khae;

Sir dung ket hgp trong cac gieng gaslift cung nhu gieng dung bam dien ngim de tdi uu khai thae (do ap suit, nhiet do dau ra va dau vao may bam, nhiet do may bam, luu lugng bam, do ap suit dau ra van gaslift, v.v );

Theo ddi mUc do duy tri ap suit via khi sir dung ket hgp he thdng PDG cho gieng khai thac va gieng bam ep trong ciing 1 via cd the xac dinh duac mure dd duy tri ap suit via tU cac gieng bam ep nude (Hinh 2);

Cung c i p them thdng tin cho edng tac md phdng via/md (Hinh 3):

> Xac djnh mUc do lien thdng giua cac gieng va cae khu vyc khai thac trong md

> Cung cap diy du sd lieu eho edng tac chfnh xac hoa md hinh md bing phuang phap phuc hdi Ijch sir

> Kiem soat ddng chit luu vao ra trong tUng khd'i de duy tri trang thai can bang via

Gieng khai thac Gie'ng bam ep

5000

P, psi

4000

2000 Khoang thLT gieng djnh ky

4 0 0 0 Thai gian, h

Hinh 2 Ap suit do tai cac gieng

• Gie'ng khai thac/ PG

• Gieng khai thac

• Giena bom eo/ PG Fault

Partial fault

Hinh 3 Lien thdng gieng - md nhieu dUt gay

HIEU QUA KINH TE-KY THUAT

Sau day la mdt sd vi du chi rd hieu qua kinh te khi sir dung he thd'ng PDG trong edng nghe khai thac

Sd lieu trong vi du duge sd dung eho he thd'ng dau gieng dat tren gian ngoai khai, cd san lugng khai thac diu trung binh 3000 thiing/ngay, gia diu tam tfnh 20 USD/thung, gia thanh djch vu va thiet bj lay theo thai gia d thai diem hien tai va eae tinh toan chi mang tinh so sanh

1 Giam thieu chi phi khi sufdung he thong PDG

Trudng hgp khong sir dung he thong PDG: Hang nam cin phai tien hanh khao sat ap suat day gieng

djnh ky 2 lin vdi chi phf eho edng tac djch vu nay khoang 90 ngan USD/gieng/nam Tham hut doanh thu do

Hpi nghj KHCN 2000 "Nganh Dau khi Viet Nam trifdc them theky 21'

hut giam lugng d i u khdng khai thac vi phai dUng khai thac trong qua trinh khao sat gie'ng la 780 ngan USD/gieng/nam

Trudng hgp sir dung he thdng PDG: Tdng ehi phi cho mua va lap dat mdt bd PDG tai mdi gieng la

150 ngan USD/gieng

So sanh 2 trudng hgp tren ta thiy rang phuang an sir dung he thd'ng PDG la hoan toan hieu qua, tiet kiem chi phi (tudi thg trung binh eiia he thd'ng khoang 5 nam) Mdt diem ndi bat nO'a khi sir dung he thdng PDG la giam thieu nguy ea mit an toan eho ngudi cung nhu eau true gieng trong qua trinh do va khao sat gieng Theo kinh nghiem lau nay, phuang phap khao sat gieng dung cap ludn ludn cd nguy ca xay ra sy ed, lam rai cae thiet bj chuyen dung xud'ng gieng cGng nhu gay anh hudng den san lugng khai thae

2 Tang san JiTdng khai thac hang ngay

• Bing each duy tri ap suit day gieng g i n vdi ap suit bao hoa: Gieng khai thae d i u vdi ap suit bao hoa

4000 psia, ap suit day gieng luc ddng 4600 psia, chi sd khai thac PI = 25 thung/ngdy/psia Trong trudng hgp khdng sir dung he thd'ng PDG, ap suit day gieng luc khai thac = 4100 psia (do khdng the khao sat gieng thudng xuyen nen ngudi ta thuang dat ap suit day gieng luc khai thae khdng qua sat vdi

ap suit bao hoa) Tuy nhien, khi sir dung he thdng PDG, do he thd'ng ed kha nang quan trie ngay tdc

thdi ap suit day gieng, nen ta cd the dieu ehinh cd edn ngay de eho ap suit day gieng - 4020 psia

(gin sat vdi ap suit bao hoa) Chenh ap giua 2 trudng hgp = 80 psia, va do dd trong trudng hgp sir dung he thd'ng PDG san lugng khai thae tang them 80 x 25 = 2000 thiing/ngay Nhu vay, nhg each nay ddng tien mat bd sung /gieng trong trudng hap gieng duge trang bj he thd'ng PDG la 7.3 trieu USD/nira nam

• Quan sat chinh xac sy thay ddi ap suit day gieng ngay lap tUe, tU dd dd dang dieu chinh cd cdn khai thae de tan dung tdi da kha nang khai thac gieng Sau khi dieu chi'nh luu lugng, sin lugng khai thac hang ngay trung binh tang them 600 thiing/ngay/gieng nhu vay ddng tien mat tang them 4.4 trieu USD/gieng/nam (Hinh 4)

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3500 4O00 4-500

Hinh 4 Tuang quan ap suit day gieng va luu lugng

DO TIN CAY CUA HE THONG

TL; khi dugc dua vao sir dung lin diu tien (nhung nam cudi cua thap nien 80) cho den nay, he thdng PDG da dugc cai tien va hoan thien rit nhieu Tuy nhien, van tdn tai mot sd dang hdng hde thudng gap nhu:

• Day cap dien ngim

• Cac loai d i u ndi: d i u ndi cd dinh giu'a ddng hd do vdi day cap hay d i u ndi gii/a 2 day cap vdi nhau, cac diu ndi lien quan khae

Bd cam bien/ddng hd do dat tai day gieng

Cac hdng hde khae trong qua trinh lap dat he thd'ng

Cac hdng hde khdng nhan biet dugc nguyen nhan

Phan tich hong hoc trong giai doan 87-94

Day cap 5%

Thiet bi do

12%'

Khong di/dc nguyen nhan

36%

Phan tich hong hoc trong giai doan 95-99

Thiet bi do

15%

Khong x&s>4inh

dirdc nguyen n

19%

Trong nhdm eae hdng hde tren, hdng hoc nhdm 4J'trong qua trinh lap dat he thdng" kha quan trgng

va phu thuge vao yeu td con ngugi Chang han, khi chuan bj lap dat PDG, c i n phai tuan thii eae quy trinh kiem tra chit lugtig ciia tit ca cae thiet bj, neu qua trinh lip dat dien ra xudi xe (khdng ddt cap, ket cap, v.v ) thi chic chin tudi thg eiia he thd'ng se eao han (dam bao tfnh toan ven he thd'ng) va do dd giam thieu hdng hde d cac nhdm cdn lai Vi vay, cin het sdc ehu trgng den qua trinh chuan bj, lap dat he thd'ng cung nhu viee lya chgn ddi ngu ky thuat vien giau kinh nghiem Rieng hdng hoc nhdm 3, phu thudc vao chit lugng thiet bj, cdng nghe che tao cae bd cam bien, dae biet neu nhu thiet bj lam viee trong mdi trudng.nhiet do via cao thi tudi thg cua thiet bj cang thap So sanh hai bieu dd tren ve ket qua khao sat he thdng PDG duge lip

Hpi nghj KHCN 2000 "Nganh Dau khi Viet Nam trifdc them theky 21'

dat vao nhung nam 87 - 94 va nam 95 - 99 cd the nhan biet nhung thanh phin nao thudng hay bi hdng hde, ddng thdi vdi viec ap dung cdng nghe mdi ty le phin tram cua nhdm "hdng hde khdng nhan biet duge nguyen nhan" da giam rd ret

Tuy nhien, khdng phai chit lugng he thd'ng PDG eua cac Nha thau cung c i p thiet bj deu nhu nhau (xem bieu khao sat so sanh tinh trang sir dung he thdng PDG da duge lap dat tai khu vyc Chau A) cung nhu trinh do va kinh nghiem ciia ddi ngu ky thuat vien giu'a cac hang rat khae biet, anh hudng Idn tdi chat lugng lam viec eua he thd'ng PDG

Su dung PDG tai khu vuc Chau A

• Hong hoc

D Hoat dong

Hangl Hang2 Hang3 Hang4

Hang cung cap PDG

TiNH HiNH SCr DUNG HE THONG PDG TAI VIET NAM

He thdng PDG hien dang dugc sir dung d Viet Nam tai nhieu md nhu Lan Tay, Rang Odng, Ruby, Bunga Kekwa, v.v

Md khi Lan Tay tuy chua duge dua vao khai thae nhung do hoan canh ky thuat dae biet nen mdt he thdng PDG da duge lap dat cho gieng quan sat da g i n 4 nam nham muc dieh theo ddi thay ddi ap suit via Hien tai, he thdng vin cung cap kha tdt nhung thdng sd can thiet ve hien trang ciia md

Md dau Rang Odng dang duge khai thae ti/ 2 ddi tugng chfnh la Mioxen va mdng granit nirt ne He thd'ng PDG duge lap dat tai nhieu gieng khdng chi ciia ddi tugng Mioxen ma eua ea ddi tugng mdng granit ndt ne Ke tU ngay bit d i u dua vao sir dung den nay (thang 8/1998) he thdng hoat ddng tdt, hoan toan khdng cd true trac hay hdng hde Mdt dieu dang ghi nhan la ddi tugng mdng md Rang Odng cd ap suit (5700psia@4000m) va nhiet do (khoang 150°C@4000m) kha eao nhung he thd'ng PDG dugc lap dat nay vin dap ung yeu eiu Nha thiu JVPC da sir dung he thd'ng PDG de tien hanh thir mdc do lien thdng md/via Ket qua rat kha quan vdi ting Mioxen ha, tuy nhien vdi tang mdng, h i u nhu khdng cd sy lien thdng giua cac gieng Cac sd lieu thu nhan tU he thd'ng PDG dat tai eae gieng duge theo ddi va che do khai thac eiia timg gieng, tUng ddi tugng dugc dieu chinh eho phu hgp nhit Hdn nO'a nhung du lieu nay cdn dugc sir dung mot each die lye cho cdng tac phue hdi Ijch sir md hinh md

Cac md Ruby, Bunga Kekwa cung duge cac Nha thiu dua he thdng PDG vao sir dung mdt each tieh eye va ehinh cac he thdng nay da giup kjp thdi dieu chinh che do edng nghe khai thae gieng va cung cip sd lieu cho cdng tae hieu chinh md hinh md

KET LUAN

1 Trong cdng nghiep khai thac dau khf hien nay, edng tae thiet ke va quan ly md la mot viee het sdc cin thiet va quan trgng Ap dung edng nghe khai thae thich hgp la mdt trong nhi/ng yeu td ehfnh de dam bao hieu qua kinh te ciia de an, nang cao he sd thu hdi diu khi

2 Vdi tudi thg trung binh 5 nam eiia he thd'ng PDG (theo ket qua khao sat 712 gieng ed sir dung he thdng PDG tren toan the gidi) cung vdi nhi/ng uu diem va do dn dinh ciia he thdng neu tren, han nua qua thyc

te sir dung d Viet Nam ed the ket luan, vdi cdng nghe hien tai, viee sir dung he thd'ng ed djnh theo ddi

ap suit day gie'ng PDG la hieu qua ve mat kinh te cung nhu ky thuat Thiet nghi, viec dua vao sir dung

he thd'ng theo ddi khai thae cd djnh eho cac md diu khi d nuac ta la het sdc cin thiet, dae biet ddi vdi

md Bach Ho, mdt md diu Idn vdi eiu true dja chit phuc tap, v.v

3 Cin cd cdng tac nghien cUu de lya chgn hang cung cap cung nhu nha thiu lap dat de giam thieu anh hudng den hieu qua kinh te ciia de an