MOT s6 GlAl PHAP GIA TANG Hf s6 THU H6I DAU M 6 BACH H 6
Nguyen Ouoe Thap, Le Van Truang, Nguyen Quoc Thang Cong ty Dau tu'd Phat trien Dau khi
ABSTRACT
Bach Ho oil field was discovered m 1974 by Mobil and put on production in 1986 by Vietsovpetro. Since that time, a total of app. 100 million ton of oil was produced from the field. According to the latest production forecast, the field life is soon going to be in the decline phase. Therefore, enhance oil recovery (EOR) is most important method to maintain the filed life and maximize value of the filed. Water injection has been applied to maintain resen/oir pressure successfully. However, at some stage water injection management has experienced many difficulties & water breakthrough has occurred abnormally due to the key reservoir (fractured granite basement) of the field is very complex and heterogeneous in term of physical properties as well as the unceriainty of the aquifer. In this paper, the authors will highlight some ideas on how we might be able to improve our
exploitation skills to optimize & increase the oil recovery of the Bach Ho field. We will look closer at what needs to be done to optimize the reservoir data and the exploitation tools, and what are the needs of the Bach Ho reservoir management.
I. CAC PHLTONG P H A P GIA T A N G H $ S6 THU H 6 | D A U T R E N T H ^ GICJI
Van de gia tang he sd thu hdi dau da dugc dat ra tU rat lau trong cdng nghiep khai thac dau khi. Theo thdi gian va cung vgi sy phat trien cua nganh dau khi, cung nhu yeu cau khai thac tan thu cac md dau cu cac nha nghien cUu da gidi* thieu va ap dung thanh edng rat nhieu phuang phap gia tang he sd thu hdi dau. Theo cac dinh nghla mdi nhat cua hiep hdi dau khi the gidi SPE thi giai phap thu hdi dau bang bam ep nude thdng thudng khdng phai la phuang phap gia tang hay nang cao he sd thu hdi dau va ehi ed cac nhdm phuang phap trong Hinh 1 dudi day dugc gpi la cac phuang phap gia tang he sd thu hdi dau.
Nhin chung lai, cd 7 phuang phap gia tang he sd thu hdi dau, bao gdm: Phuang phap bam ep nita Idng hay khi (ed the la COj), phuang phap bam ep polymer, phuang phap ddt tai via, phuang phap bam ep nude nong, phuang phap bam ep ddng thdi chat hpat tinh va polymer hoae kiem, phuang phap bam ep khi CO2 va phuang phap bam khi hydrocarbon Idng.
Khi kho
hydro carbou CO, Cac chat
ho^t tfuh
Bom uirdc uoug
Dot
Hoi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bach Ho'
Cac phuang phap deu cd chung mdt nguyen ly la dya vao C3c phan Ung ly hda cua qua trinh tiep xuc giua nude hay hdn hgp bam ep ed chCra hda pham lam tang he sd quet va day dau, giam he sd dp nhdt cua dau hay giam ty trpng eua dau trong dng khai thac, hoae gia tang kich thudc vCing cung cap ddng xung quanh thanh gieng khoan. Mdi phuang phap se ehi thich Ung vdi tUng dieu kien ky thuat md, dieu kien cung cap vat tu hda pham va cung nhu kha nang cho phep cua he thdng thiet bi hien da cd trudc dd tai md. Do dd, de xem xet kha nang ap dung cac phuang phap ndi tren cho mdi mpt mdt ddi tugng hay md dau, trudc het can tien hanh eae nghien eUu kha thi ve ky thuat va kinh te eua mdi phuang phap. Cac tdng ket dya tren cac kinh nghiem ap dung thanh cdng viec gia tang he sd thu hdi dau cho cac ddi tugng khai thac dau khae nhau tren the gigi dugc tdm tat trong Bang 1 va Hinh 2.
TU cac tdng ket trong Bang 1 va Hinh 2 cd the de dang danh gia lya chpn cac phudng phap mdt each thich hgp ve cac dieu kien ap dung. Vi vay, cac ddi tugng ehUa eua md Bach Hd can phai dugc nghien cuu hien trang ky thuat de tU dd cd ca sd de xuat eae giai phap cdng nghe phu hgp nham gia tang he sd thu hdi dau.
II. OAC OI^M VA H I E N TRANG KHAI THAC M 6 BACH H 6
Md Bach Hd nim trong Id 09.1, them luc dia Nam Viet Nam each thanh phd Vung Tau 120 km ve phia Ddng Nam, dugc Cdng ty dau khi Mobil phat hien dau tien vao thang 3 nam 1975 thdng qua gieng khoan tham dd BH-1, Md ed dien tich khoang 120-130 km^vdi chieu sau nude bien khoang 50 m, Cac ddi tugng chCra chinh eua md bao gdm: Cat ket Miocene dudi, Oligocene tren, Oligocene dudi va tang da mdng granite nut ne &
phong hda, Tdng tru lugng dau tai ehd eua md tinh den thgi diem 01.01.2002 khoang 630 trieu tan, trong dd, rieng tru lugng eua tang mdng granite nut ne & phong hda chiem -80%,
Dac tinh eua dau thd va eae thdng sd ca ban eua eae ddi tugng ehUa ehinh md Bach Hd dugc tdm tat trong Bang 2.
Nhin chung, dau cua cac via thupe Ipai dau cd ty trpng trung binh, dp nhdt thap va thanh phan nhe cd trong dau tU trung binh den cao; via cd chieu sau Idn (3000-5000m), nhiet dp cao (90-170°C), dp rdng thap den trung binh (da cat) va thap 0,5-4,0% (da mdng granite nut ne phong hda).
0)
(0
3
o
10 20 30 40 50 60
Ty trpng cua dau (API)
Hinh 2. Khoang cliieu sau va ty trong cua dau ap dung cac phu'ong phap gia tang he so thu hoi dau
Bang 2: Cac tham sd ehinh eua cac ddi tugng chua md Bach Hd Cac dac tinh
ly hoa
Ty trpng dau (g/cm') Dp nhdt (cp)
Thanh phan eua dau Dp bao hda dau (%) Lpai da chua
Chieu day via OP tham (mD) Chieu sau via (m) Nhiet dd via (°C)
Miocene dUdi 0.86
<2 CdTPnhe
>40 Cat ket Mdng -trung binh,
gdcnghieng nhd
>10
<3000
<90
Cac ddi tUdng Oligocene tren
0.85-0.88 1.4-3.5 Cd TP nhe
>40 Cat ket Mdng-trung binh,
gdc nghieng nhd
>10
<3500 100-130
chinh cua mo Bach Ho Oligocene dUdl
0.82-0,83
<1 Nhieu TP nhe
>50 Cat ket
Trung binh - Idn, gdc nghieng nhd den trung binh
>10
<4200 120-150
Mong phong hoa nirt ne
0.82-0.84
<1 Nhieu TP nhe
>70
Granite phong hda, nut ne
>500m
>100 3100-5000
120-170 Md da dugc Xi nghiep lien doanh dau khi Vietsovpetro tiep tuc tham dd tham lugng tU nam 1983 va den thang 6 nam 1986 da dua md vao khai thac. TU dd den nay san lugng khai thac dau trung binh hang nam da khdng ngung dugc tang len tU 40 ngan tan nam 1986 tang len gan 1 trieu tan nam 2001. Tinh den thdi diem 01,01,2002 tren md da xay dung 10 gian eddinh, 1 gian xuly trung tam, 7 gian nhe va he thdng dudng dng npi md, cung cac edng trinh nha may nen khi, bam ep nuac va tram rdt dau [6],
Tren md da tien hanh khoan 210 gieng, trong sd dd cd 134 gieng khai thac, 44 gieng bam ep nude, 12 gieng quan sat va 6 gieng tam ngUng khai thac. Tdng san lugng dau khai thac dau cua md tinh den 01,01,2002 la 99,174 trieu tan, trong dd:
" Ddi tugng Miocene dugi: Da khai thac dugc 3,44 trieu tan dau, 1,96 trieu m' nude va bam ep vao via 3,4 trieu m' nugc, tuang ung vdi he sd thu hdi dau 24% va muc dp bu dap dau bang nude bam dat -50%,
• Ddi tugng Oligocene tren: Mgi khai thac dugc 20 ngan tan dau, 0.36 ngan m' nugc, tuang ung vai he sd thu hdi dau -0,004%.
" Ddi tugng Oligocene dudi: Da khai thac dugc 5,856 trieu tan dau, 222 trieu m' nugc va bam ep vao via 5817 trieu m' nuge, tuang Ung vai he sd thu hdi dau 17% va mUc dp bu dap dau bing nude bam dat -70%, Luu y, trong giai dpan 1997-2000 hau het cac gieng khai thac eua ddi tuang Oliogocene dudi da dugc chuyen sang che dp khai thac bang gas lift.
- Ddi tugng mdng: Da khai thac duac 89,854 tneu tan dau (chiem ty le han 90% toan md), 1,814 trieu m' nude va bam ep vao via 100,968 trieu m' nude, tuang Crng vdi he sd thu hdi dau 21% va mUe dp bu dap dau bang nude bam dat -100%, Khoang 30% sd gieng khai thac tu ddi tugng nay da duac chuyen sang che dp khai thac bing gas lift.
Ket qua nghien eUu thuy dpng lye hpc va dpng thai ngap nuPe cua cac ddi tugng chUa trong qud tnnh khai thac cho thay tat ca cac ddi tuang deu bi chia khdi va tinh lien thdng giua eae khdi la rat han che. Do la nguyen nhan gay ra cac phuc tap va su cd trong qua trinh khai thac va bam ep vao via, dan tdi he sd thu hdi dau va he sd bu khai thac dau bang nude bam ep khae nhau tu khdi nay tdi khdi kia ngay trong cung mot ddi
Hoi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bach Ho'
tugng. Dae biet, ddng thai ngap nude cua than dau mdng didn ra rat phuc tap va eae nghien eCru cua cac tac gia da dugc edng bd trong cac cdng trinh [2,3,5], Theo cac danh gia va tinh toan thi ranh gidi dau nude nhan tao (RGDNNT) da xuat hien va quan sat dugc trong mpt sd gieng khai thac va RGDNNT cd dang nhap nhd.
RGDNNT bi nhd cao d phan phia Bae cua vung Trung tam va thap dan ve phia Ddng Nam va ra hai phan ria, la nai mdi dugc dua vao khai thac sau. Ddng thdi, viec mpt sd cac gieng bi ngap nude cao da phai dUng khai thac de chuyen len khai thac cac ddi tugng phia tren hoae lap lai phan phia duai.
De duy tri san lugng va gia tang hieu qua eua eae gieng khai thac. mpt Ipat cac giai phap ky thuat cdng nghe da dupe nghien cuu va ap dung, trong dd, giai phap bam ep nude ed y nghla ky thuat va kinh te dang ke nhat. Day la nhung thuan lgi can ban va la tien de de tien hanh rieng re hoae ddng thdi cac phuang phap xu ly nham gia tang hieu qua qua trinh bam ep nude va he sd thu hdi dau tU via.
III. CAC PHLTONG PHAP GIA T A N G H $ S 6 THU H 6 | DAU O 6 | VCJI M 6 BACH H 6
Ddi chieu eae tinh chat va chi sd cua cac ddi tugng chUa dau ehinh eua md trong Bang 2 va eae gidi han ap dung thanh edng eae phuang phap gia tang he sd thu hdi dau trong Bang 1 nhan thay ehi cd 2 phuang phap cd the ap dung cho cac ddi tugng eua md Bach Hd, dd la:
- Phuang phap bam ep bang nita Idng hoae nita Idng va khi;
- Phuang phap bam ep hydrocarbon Idng.
Ca hai phuang phap deu khdng khae nhau nhieu ve ban chat va hieu qua, nhung phuang phap bam ep hydrocarbon Idng cd ehi phi rat Idn bdi gia thanh khi hydrocarbon Idng dat han nhieu lan so vdi nita Idng. Nita Idng hien da dugc san xuat d trong nude vdi dan gia khoang 200 US$/m'. Ddng thdi, neu sir dung nita Idng thi edng suat cua may nen cd yeu cau thap han ca do ty trpng eua nita Idng ehi cd g/cm'. Do dd, phuang phap bam ep bang nita Idng cung vdi mpt phan khi tach ra cua md dugc de xuat de tiep tuc nghien cuu su dung de gia tang he sd thu hdi dau cua tang mdng phong hda nut ne. Tuy nhien, can phai luu y den yeu td nUt ne cua tang mdng ed the hinh thanh cac kenh dan, tham thang dUng lam giam hieu qua eua phuang phap. Vi vay, cung tuang ty nhu phuang phap bam ep nude thdng thudng da ap dung ddi vdi ddi tugng mdng nUt ne can phai tien hanh nghien cCnj va thu nghiem tren mdt pham vi hep cua via, sau dd md rdng pham vi qui md cho tdan via hay ddi tugng.
Mat khae, do cac than dau ehinh eua md Bach Hd deu ed ap suit cao hdn ap suat bao hda nen giai phap bam ep nude truyen thdng da dugc nghien eUu va ap dung de duy tri ap suat va nang lugng cua via nhim duy tri va dn dinh eua cac gieng khai thac. Mat dp, ty le gieng bam ep nude va khai thac da dugc thiet ke va lya chon tuang Ung vdi dac tinh va qui md eua tUng ddi tuang. Ket qua khai thac va bam ep da thu dugc nhung ket qua rat khich le dudi ca gdc dp ky thuat va kinh te. Tuy nhien, trong tUng trudng hgp cu the vin edn cd rat nhieu van de can tiep tuc nghien cuu va hoan thien nhu da chi ra trong cac edng bd eua Vietsovpetro [1,2,3,5]. Vi vay, song song vdi phuang phap bam ep nina da de xuat d tren, dudi day la mdt sd nhung trao ddi va de xuat tren ca sd cac quan sat tinh huu hieu cua qua trinh bam ep nude trong than dau mdng cua md Bach Hd:
Hien giai phap bam ep nude ddi vdi than dau mdng dugc thyc hien bing each bam ep nude vao vung can day nham tao ranh gidi dau nude nhan tao trong mdng. Ket qua phan tich mdi nhat cho biet ddi chuyen tiep va mat ranh gidi tiep xuc dau nude nim trong khoang ~3600m. Mdt sd cac nghien eCru [2,5] da chi ra kha nang dau chua trong cac vi khe nut eua khung da bi ngap nude va neu khdng ed nhung nghien cuu va giai phap kinh te ky thuat ddng bp de dieu chinh qua trinh khai thac dau va bam ep nude huu hieu thi kha nang thu hdi dugc lugng dau dd. cung nhu he sd thu hdi 38-40% chung cho tdan than dau mdng la rat khd ed the thyc hien dugc. Tren ca sd cac nghien eUu va quan sat hien trang khai thac eua md, tac gia xin de xuat mdt sd eae giai phap tdng hgp dugi day de vUa quan ly, dieu chinh qua trinh khai thac dau cua md cung nhu vUa gia tang he sd thu hdi dau, trong dd dang chu y nhat la tang chUa mdng nUt ne.
Hoan thien md hinh dia chat va hinh hpc eae than dau: Cac sd lieu thu thap trong qua trinh khai thac md da kh^ng dinh tinh chia khdi va eae bat ddng nhat tU khdi nay den khdi kia. Do dd, can phai tien hanh ra sdat hien trang cac gieng khoan va de xuat sd lugng, vi tri, dang gieng khoan khai thac cho tUng khdi cu the. Cdng viec nay se giup hdan thien, bd sung va dieu ehinh dugc mang ludi va ty le gieng bam ep & khai thac mdt each thich hgp.
Lya chpn tdi uu eae giai phap cdng nghe thdng qua nghien cCru md phdng qua trinh khai thac:
Cdng viec nay ddi hdi nang cao dp tin cay eua eae sd lieu quan sat, eae sd lieu dua vao md hinh va ddng thdi nang cap, trang bi mdi mdt sd cac phan mem du manh de cd the tien hanh chia cac d mang theo nhieu phuang an khae nhau va giup tdi uu qua trinh nghien eUu cdng nghe va khai thac md.
Cdng nghe khoan dinh hudng va do dia vat ly gieng khoan: Khoan dinh hudng la mdt trong nhung giai phap huu hieu de gia tang san lugng khai thac cua gieng va nang cao he sd thu hdi dau. Tuy nhien, giai phap nay lai la mpt thu thach rat Idn ddi vdi edng tac nghien cUu khao sat danh gia dac tinh tham chCra eua lat eat thanh gieng khoan, dd la: cdng tac dia vat ly gieng khoan. Hien td hgp do dia vat ly gieng khoan day du (bao gdm phdng xa ty nhien, nhan tao, sieu am va dien trd suat) trong qua trinh khoan da dugc ap dung kha rdng rai va hieu qua tai hau het cac gieng khoan cd gdc nghieng Idn hoae nim ngang. Do dd, can phai ap dung eae edng nghe do dia vat ly tien tien trong qua trinh khoan eae gieng khoan dinh hudng de ed the danh gia day du dac trung lat cat va nghien cuu, dieu chinh md hinh thuy ddng lye hpc cua via dau.
Lya chpn he dung dich: He dung dich ddng mdt vai trd rat quan trpng khdng ehi trong qua trinh khoan ma edn ed vai trd rat Idn lien quan den cac bien ddi vung can thanh gieng khoan va qua tnnh md ddng. Oa cd rat nhieu cac nghien curu eua cac tac gia Vietsovpetro [4] ve he dung dich polymer va polymer it set. Cac he dung dich dich mdi nay cd uu diem rd ret so vdi he dung dich set trudc day su dung. Theo kinh nghiem eua CLJOC va JVPC thi he dung dich gdc dau ed nhung uu viet han rat nhieu so vdi he dung dich mdi (polymer va polymer it set). Do dd, ddi vdi tang da mdng md Bach Hd can thiet phai tien hanh nghien cuu va ap dung he dung dich gdc dau. Tuy nhien, edng tac xu phe thai dung dich va mun khoan can dugc xem xet than trpng de dam bao qui pham ve van de an tdan va bao ve mdi trudng.
Cdng nghe hdan thien gieng: Hau het cac gieng khoan khai thac va bam ep trong tang mdng deu dugc hdan thien dudi dang than tran. uu viet cua kieu hdan thien nay, dd la: dan gian, ehi phi thap va de sCra chua ca hpc. Nhung cung ehinh do kieu hdan thien nay ma mdt Ipat cac van de nhilm ban vung can day gieng, xap Id thanh gieng khoan,... da lam giam san lugng khai thac hoae bam ep nude cua cac gieng khoan. Theo kinh nghiem khai thac dau mdt sd nai tren the gidi, thi mdt dng Ipe hay fin Ipe ed kich thudc phu hgp dat dpc lat cat ting san pham nim dudi packer se cho phep han che nhung anh hudng va tac ddng nhu da ndi d tren.
Sua chua cac gieng khoan cu: Cac gieng khoan cu da ngung lam viec hoae lam viec kem can phai dugc nghien cuu ky va tim hieu nguyen nhan de ty dd ed the dua ra nhOrng giai phap sua chua hCru hieu nhu: He thdng ca hpc (sua chua hoae thay the) hay hda hpc va ty le phan tram hda pham thich hgp, cung nhu chu ky va thgi gian sCra chua.
Nang cao cdng suit xir ly, tach dau khi nude: Viec han che hay gidi han edng suat eua he thdng xir ly, tach dau khi nude cung la mpt trong nhung nguyen nhan lam giam kha nang thu hdi dau eua md, dac biet la trong giai dpan khai thac vet va eudi ddi md. Vi vay, can phai cap nhat dy bao chinh xac san luang dau, khi va nuac de tU dd ed the cd nhung bien phap nang cap kip thdi he thdng xCf ly, tach dau khi nude.
Hoi thdo khoa hoc "Ndng cao he sdthu hdi ddu md Bach Hd"
Bd sung he thdng quan sat thuy ddng lye hoc cua via: Do dac tinh chia khdi cua than dau mdng cung nhu cac than dau phia tren, nen de ed the nghien cuu thuy dpng luc qua trinh khai thac, thi song song vdi viec sir dung eae chat ehi thi ed the lap dat them cac ddng hd do ghi bien thien ap suat nhiet dp theo thdi gian dang cd dinh trong cac gieng khai thac & bam ep va ed the dpc dugc lien tuc tren mat tai cac gian cd dinh hoae phuang tien ndi. Giai phap nay giup khdng can phai ddng gieng de khao sat nhu thdng thudng van lam. Cac cap sd lieu ap suit & nhiet dp cua cac gieng khai thac va bam ep se cung cap nhieu thdng tin ve mdi lien he tUdng tac giua eae gieng khai thac va bam ep trong mpt pham vi khao sat. Phuang phap nay da ap dung rat thanh cdng d cac md khai thac dau d bien Bae, nude Anh & Na Uy va nhieu nai tren the gidi.
- Hdan thien va nang cao he thdng thdng tin, lien lac: Trong quan ly va van hanh khai thac md, mdt trong nhung yeu cau tdi thieu la he thdng thdng tin, lien lac va bao cao. Mpt he thdng thdng tin, lien lac hien dai va bao cao day du chi tiet se trg giup de sgm ed nhung quyet dinh chinh xac va kip thdi cac tinh hudng lien quan den ke hpach khai thac, bam ep nuac va dieu ehinh cac bien phap cdng nghe chua phu hgp.
- Dao tao va huan luyen: Mdt trong nhung khau tdi quan trpng de ap dung cac giai phap ky thu^t, cdng nghe mdi can thiet phai xay dyng mdt ehuang trinh dao tao, huan luyen va thay the ngan han, cung nhu dai han. Day la mdt trong nhung yeu td quyet dinh den sy thanh cdng ke hpach phat trien khai thac md Bach Hd va Vietsovpetro ndi rieng, va sy phat trien eua nganh dau khi Viet Nam ndi chung.
IV. K^T LUAN VA KI^N NGHI
Mdt sd cac giai phap tdng hgp nhim gia tang he sd thu hdi dau eua md Bach Hd da dugc xem xet va trao ddi. Cac ket luan va kien nghi dugc tdm tat nhu sau:
•:• Cd the tien hanh nghien cUu sCr dung phuang phap bam ep nita de gia tang he sd thu hdi dau cua cac ddi tuang ehUa md Bach Hd
•:• Cd the nghien cuu ap dung ddng bd mdt sd giai phap cdng nghe hd trg edng tac quan ly, van hanh va khai thac mdnhu:
Bd sung he thdng quan sat thuy dpng lye hoc eua via;
- Ap dung cdng nghe do dia vat ly trong qua trinh khoan;
Cai tien he dung dich khoan;
- Dieu ehinh mang ludi gieng khai thac va bam ep phu hgp cho tUng khdi;
Nghien eUu dieu chinh cau true va kieu hdan thien gieng;
- Nghien cuu dieu chinh nhip dp bam ep nude (tang gieng hay tang cdng suit bam);
- Nang cap cdng suit xu ly dau, khi va tach nude;
Nang cap phan cUng va trang bi mdi cac phin mem md phdng via du manh;
- Nang cap he thdng thdng tin, lien lac va bao cao.
<• Song song vdi cac giai phap d tren thi cong cdng tac nghien cUu cap nhat md hinh cua tung via tren ca sd cac sd lieu dia chat - dia vat ly (sd lieu tinh) va eae sd lieu thuy dpng lye hoc & khai thac/bam ep (sd lieu ddng) cung can dugc dat ra de thudng xuyen dieu chinh va tdi uu cac giai phap duy tri gia tang san lugng khai thac md.
TAI Lieu THAM KHAO
[1]. Tran Le Odng va nnk. Qua trinh phat trien he thong duy tri ap suat via va viec nang cao do tin cay eua he thong do trong dieu kien san suat eua XNLD Vietsovpetro. Tap 11, tap san Hdi nghi KHCN
"Nganh Dau KhiViet Nam trudc them the khi 21", Ha Npi 2000.
[2]. Truang Cdng Tai va nnk, Danh gia dac trung ngap nude via dau trong mong mo Bach Ho bSng mo hinh hai do rong, hai do tham. Tap II, tap san Hdi nghi KHCN "Nganh Dau Khi Viet Nam trudc them the khi 21", Ha Ndi 2000,
[3]. Truang Cdng Tai. Dac tinh ngap nuac cac gieng khai thac tang mong Bach Ho. Tap II, tap san Hdi nghi KHCN "Nganh Dau Khi Viet Nam trudc them the khi 21", Ha Ndi 2000.
[4]. Ngd van Ty, Nguydn Trpng Nghiem. Ap dung he dung dich khoan polyme it set de thi cong eae gieng khoan cd goc nghieng idn qua dia tang Oligocene dual va mong mo Bach Ho. Tap II, tap san Hpi nghi KHCN "Nganh Dau Khi Viet Nam trudc them the khi 21", Ha Ndi 2000.
[5]. Pham Quang Ngpc, Van de bom ep nude vao than dau mong mo Bach Ho. Tap II, tap san Hdi nghi KHCN "Nganh Dau Khi Viet Nam trudc them the khi 21", Ha Ndi 2000,
[6]. Tran Van Hdi va nnk. Bao cao tinh lai tru lugng dau va khi hoa tan mo Bach Ho theo trang thai den ngay 01.01.2002. Vung Tau 5-2002.
