Ap sudt cao, nhiet do cao HPHT tiem dn nhieu rdi ro vd phdc tgp trong qud trinh khoan vd trdm xi mdng gieng khoan - mdt trong nhdng cdng dogn cd tinh chdt quyet djnh din chdt lugng thi
Trang 1CAC TINH CHAT CO HOC CUA OA XI M A N G TRAM GIE'NG KHOAN
TRONG DIEU KIEN AP SUAT CAO, NHIET DO CAO BE NAM C O N SON
T h S T r U t f n g H o a i N a m
Tdp dodn Ddu khi Viit Nam Email: rjamth@pvn.vn
Tom tSt
Be trdm tich Nam Cdn San cd dieu kien dia chdt rdt phdc tgp, ddc biet nhiet do cao den 200'C vd gradient dp sudt
via len den 2MPa/100m Ap sudt cao, nhiet do cao (HPHT) tiem dn nhieu rdi ro vd phdc tgp trong qud trinh khoan vd
trdm xi mdng gieng khoan - mdt trong nhdng cdng dogn cd tinh chdt quyet djnh din chdt lugng thi cdng vd an todn,
Ket qud nghien cdu dnh hudng cua HTHP den cdc tinh chdt cahgc cua dd xi mdng Id casd quan trgng de thiet kedan
pha che vda xi mdng trdm cde gieng khoan dgt hieu qud cao vd an todn
TUkhda: VCfa xi mang trdm, dp sudt cao nhiet do cao, silica 55A-i
1 Gidi thieu
Be Nam Cdn Sdn gdm cae dang ddi tUdng chda d i u
va khi r l t da dang trong mdng ndt n l trude DeTam, trong
c i t k i t Oligoeene tren va Miocene dUdl, trong c i t ket va
ddi tuong carbonate tudi Miocene gida Ngoai ra, be Nam
Cdn Son edn g i p cic he thdng dau v i khf trong cac dj
thudng ap sua't eao, nhiet dp cao v i nam d viing nUde
sau [11] Hien tupng HPHT dUpc p h i t hien trong khu vUe
t r i m tich Cenozole thay doi tUTay sang Ddng cd be d i y
5.000-14.000m
D i n nay, d be Nam Cdn Son da ed gan 100 gieng
khoan tham dd, tham lupng va p h i t tnen khai thac Tai
mdt sd g i l n g khoan, gradient ap suit dat 1,6MPa/100m
(04-3A-1X, 04-3-MC-2X ); tham ehi cd gieng khoan
gradient i p suit dat 1,9 - 2,04MPa/100m (04-1-ST-lX,
04-SDN-1X,05-2-HT-lX ).Tdchilu siu 2.500m trd xudng
x u l t hl^n khoang ap suit tang cad,
ngay ben dudi c i c ddl dat d i tuoi o » « »
Pliocene Khoang chinh gida ap suit
via v l ap suit ndt via rat nhd (chi 1 ppg)
trong t i n g Miocene g i y khd khan cho
cdng tac khoan va hoan thien gieng g
Tai b l Nam Cdn Sdn, da p h i t §
hien nhiet dp eao tai 25 gieng, trong |
do tap trung trong dia t i n g cd tuoi , g
Miocene giufa va Miocene sdm Tai eic
gieng 04-2-SB-1X va 04-2-NB-lX, nhiet
dd tren d i y gieng dao ddng t d 135
-l y c C d chieu sau tCf 3.800 - 4.000m
Hien tUdng i p suit cao, nhiet dp cao
xuat hien tai gieng khoan 05-2-HT-2X,
d chieu sau 3.740m nhiet do tren d i y
g i l n g l i 172°C v i ap suit via 74MPa; tai gieng 05-1c-DN-2X-ST2, d chieu sau 4.245m gap nhiet dd 185''C, i p suat via 98,7MPa; tai g i l n g 04'2-HT-1X d chieu sau 4.548in nhiet dp tren day gieng la 210°C va I p s u i t via 91 MPa [8, 9] Hinh 1 the hien sU p h i n bd nhiet dp eie gieng khoan
md Hal Thach v i i p suit day tai khu md MdcTinh
Trong dieu kien ap suat cao va nhiet dp cao, viec thi edng gieng khoan tiem an n h i l u rdi ro eho q u i trinh khoan va tram xi m i n g gieng khoan Trong gieng khoan
cd ap suit va nhiet dp b i l n ddi Idn se lam tang Ung suit
p h i vd dp dn djnh eda vanh da xi m i n g , lam bien dang cot dng chdng anh hadng den sU Hen ket cdt dng chdng vdl v i n h da xi m i n g va kha nang each ly eda d i xi mang
K i t qua khoan tai be Nam Cdn Sdn cho thay viec
sd dung cac phu gia vda xi m i n g chaa phu hdp vdl mdi trudng trong gieng, dan den dp t h i m eua da xi mang tang
Ap sua't (EMW-ppg)
-j 1 a Z
° F ' , 2 »
(a) (b) Hinh 1 Bieu do phdn lid nhiet do (a) vd dp sudt (b) I8j
Trang 2Phan cSp
HP/HT
_Ex-HP/HT_
"ultra HP/HT"
Bang 1 Bdi
Nhiet d o t r e n d a y gieng
] ^ SOCF OSO'-C) - BSO'F ( 1 7 5 X 7
> SSO^F (175°C) - 400°F (200''C )"
>"400''F (200°C)
in cap HPHT[71
A p suat trSn diy gieng
> 1 O^OOpsi (69MPa) - 1 S.OOOpsi (103MPa) _
^ IS^OOpsi (103MPa)^20.qoOpsiJ138MPa)
> 20.000psi (138MPa)
n h a n h t h e o t h d i g i a n , d p b i n eua da g i i m , sU lien ket gida
da va cdt dng kem, gay ra ap suit trong cot dng; tai mdt sd
gieng x u l t hien hien tupng vanh da xi mang bj b i l n dang,
CO ngdt, nut vd
Hiln nay trong nganh dau khf chUa cd loai xi mang
dupe tieu chuIn hda de tram xi mang cie g i l n g khoan
HTHP Do dd, xi mang Portland G-APi van la loai xi mang
dupe sd dung phd b i l n de tram gieng khoan sau Vi vay,
nhat thiet p h i i bd sung phu gia ben nhiet, de duy tri v i
n i n g cao dp ben v i g l i m do tham cua da xi mang
Cic k i t q u i nghien cdu va tdng hpp kinh nghiem
ve i n h hudng eua HPHT den cae tfnh c h i t co hpc eda
da xi mang eho phep thiet ke he vda xi mang phu hpp,
gdp p h i n nang cao c h i t lupng va hieu q u i thi cdng
cic gieng khoan tham dd, khai thac d i u khf tai be Nam
Con Son
2 Anh hUomg cua HPHT den do ben nen cua he xi mang
tram gieng khoan
2.1 Phdn cap dp sud't cao nhiet do cao be Nam Con San
Cie g i l n g HPHT dupe quy Udc la cic gieng ed nhiet
dd ttnh tren d i y t d 1SCC v i ap suit via t d 46MPa trd len
Halliburton phan chia HPHT thanh 3 c l p (Bang 1)
Cie dau hieu HTHP tai be Nam Cdn Son phan Idn tap
trung trong dia t i n g tuoi Miocene sdm va Miocene gida,
cd the p h i n loai thanh 2 cap (Hinh 2):
Cap HP/HT: nhiet do t d 150 - 175''C v i i p suit ti^
69-103MPa;
Cap ex-HP/HT: nhiet do tU 175 - 200°C v i i p s u i t
tren 103-138MPa
2.2 Anh hudng eda nhiit dd cao den dd xi mdng
2.2.1 Xi mang trdm giing khoan dau khi
Xi mang Portland mac G la loai xi mang dUOc sd
dung chu y l u de t r i m c i c g i l n g khoan s i u ed phdi hpp
vdi cac phu gia khac Thanh phan eua xi mang Portland
gdm: 3CaO.S10j (C^S) c h i l m 50 - 70%; 2CaO.SiO^ (C^S)
chiem 15 - 30%; SCaO-AI^O^ ( C / ) chiem 5 - 10%;
4CaO-Alj03-Fej03 ( C / F ) c h i l m 5 - 15%; CaS0^2H,0
(CSH^) chiem 4 - 6 % [1,4, 5]
Reservoir ConditiDn
Hinh 2 Bdng phdn cap HPHT cdc mo be Nam Con San [9]
CjS ed van tdc thuy hda cao nhlt, tao ra dd b i n va tang nhanh do ben trong thdi han ddng r i n sdm Thanh phan C^S ddng ran cham hdn se keo dai ddng r i n eda da
xi mang C^A quyet djnh sU ngUng k i t ban d i u va tang nhanh dd ben trong thdi han ddng rIn sdm do hoat tfnh thuy hda cao hdn Vai trd eua C^AF trong qua trinh ngUng ket gidng C^A, nhung phy thude nhieu vao nhiet dp va ehlt lupng phu gia
0 nhiet do dudi lOO^C sin pham thuy hda cua xi
m i n g Portland la gel calcium silicate hydrate (C-S-H (ll) hoac CjSHj) va calcium hydroxide Ca(OH)^ Vda xi mang dat dp ben trong thdi gian tUdng ddi lau (tdvai ngay den
v i i nam) cho d i n khi dat dupe dp ben tdi han
d nhiet do tren 100 - 1 2 0 ° ^ gel C-S-H b i l n doi thanh dicalcium silicate hydrate (a-C^S {C^SH(A) v i xi m i n g dat den dp ben cue dai trong vai t u l n d i u tien v i sau dd dp ben g i i m dan D i y la hien tuong do b i l n ddl hinh thai cau true tinh the cua xi mang va dupc gpi la sU suy giam dp ben (strength retrogression)
Khi nhiet dp > leO^C, C-H-S chuyen thanh y-hydrate C^SH (C^SH(C)) va khi nhiet dp < 202''C, C-S-H tao thanh CjS cd edng thde day du la Cag{Sip,)(OH)^ thay ddl cac tinh ehlt ly - hda va cP hpc [3]
Nhiet dp tang khien dp t h i i nude tang, sdc ben nen cua xi m i n g giam va dp tham tang, I n h hddng den chat lapng t r i m gieng, g i i m tuoi thp, de gay ra phdc tap trong qua trinh khai thac
Trang 32.2.2 Bien phdp ehong suy thoai do ben
Viec bd sung silica vao xi mang cho phep tao ra pha xi
m i n g g i i u silica gidng nhU tobermorite va xonollte, tang
dp ben nhiet, duy tri chat lUpng cua xi mang va n g i n ehan
suy giam dp ben Giii p h i p nay dUPe ap dyng t d nam 1950
va den nay da trd thanh tieu chuIn cdng nghiep [3,10]
Silica la phy gia ben nhiet dupe sd dung trong he
vda xi mang tram gieng khoan gdm: cat thach anh, dupe
nghien dat ed hat t d 175 - 200mm; bdt silica (silica flour) ed
cd hat 200-300 mesh; silica sieu min (silica fume) - phu gia
sieu phan t i n t d pha khi khi nung hop kim silica, cd ham
lUdng eao cic silica vd dinh hinh; nanoslllca cd kich thUde
nhd hdn cie hat xi m i n g trung binh 1.000 l i n , thudng sd
dung cd hat loai t d 5 - 50nm v i loai tU 5 - 30nm [5]
De tram gilng khoan ed nhiet do cao tren t h i m lyc
dja Viet Nam mdt sd nha thau khoan nhU: Now/sco, Dow/ell/
Schlumberger, Demitsu/Schlumberger, BJ, Halliburton da
sd dyng silica vdi ham luong 35% trong hdn hop tram
gieng.Theo nghien cdu [4, 5], viec bo sung 40% oxide silic
l i chua du de b i o d i m dat dp ben eda d i xi m i n g trong
cie gieng khoan ed nhiet dp tren 500°F hoic cao hdn
De xac dinh ham lUpng silica tdi Uu d i n cae tfnh ehat
cP hpc eda vinh d i xi mang gieng khoan trong dieu kien ap
suit cao, nhiet do eao tai be Nam Cdn Son, t i e g i i da tien
hanh nghien cdu i n h hudng nhiet dp eac cap khae nhau
Ket q u i cho thay viec sddung silica nhan hieu SSA-1 ™ de bo
sung cho hdn hpp xi m i n g tram dem lai hieu q u i cao [8,9]
SSA-1™ (silica flour) la loai oxide silie ket tinh, mdt
loai phy gia b i n nhiet do Halliburton sin suit SSA-1™ ed
khdl lupng rieng: 2,60 - 2,63g/em^; cd hat 200 - 300 mesh
(35%), 100 - 200 mesh (8%) va > 100 (0,2%), va ehpn t^ le
35% theo khdi lupng eda xl mang nen
2.3 Anh hudng eua HPHT den dd ben nen
2.3.1 D6 bin n4n
Trong thi edng tram xi mang g i l n g khoan dau khf, gia
trj dp ben nen l i ehi tieu duy nhat de d i n h gia tinh chat
cua v i n h d i xl mang, d i m b i o k h i nang gia cd va dp kfn khoing khdng vanh xuyen Trong d i l u kien binh thUdng,
xi mang cd dp ben nen 3,5MPa cd t h i xem nhd thda man eho edng t i e tram xi mang.Trong eic g i l n g khoan HPHT, cac dng suit ludn b i l n ddi do cic t i c ddng co hoc, do ap suat va nhl&t dp thay ddi theo ehe dp khai t h i c SUthay ddi cac dieu kien trong gieng khoan lam phat sinh cac
Ung s u i t p h i vd sUdn djnh cua vanh da xi mang ngoai cot
dng chdng Cie dng suit k i l n tao va sU b i l n ddi ve i p suit hoic nhiet dp trong g i l n g khoan cd the lam ran ndt vinh
da va sut lun DUdng kinh cdt dng chdng bj b i l n dang do
t i c ddng eda sU b i l n ddi nhiet dp va i p suit ed the pha vd
sU dfnh k i t eua vanh d i xi mang vdi cdt dng chdng hoac tangehUa, t a o t h a n h c a c k h e h d v i m d [ 1 , 2 , 6 ]
2.3.2 Thiet kehi vda xi mdng trdm giing khoan
Thanh phan chd y l u eua he vda xi mang cho gilng khoan trong dieu kien HPHT be Nam Cdn Son gdm: xi
m i n g nen, chat tang trong, phu gia ben nhiet, nude trdn
va eic phu gia cham ddng ket, g i i m dp t h i l nude, cac thdng sd lUu bien, chdng t h i m , phy gia gia cudng cotinh
eua da xi mang Tren eP sd tdng k i t he vijfa xl mang sii
dung cho eie gieng da khoan tai Ld 05-2 va 05-3 [8], tac
g i l de xuat edng thde, thanh p h i n , h i m luong vat lieu, phu gia eho he vda xi m i n g t r i m g i l n g khoan HPHT be Nam Cdn Son {Bing 2)
2.3.3 Thiet bl do do ben dd xi mang bdng sieu am (UCA) Tie gia xie djnh 66 b i n cua d l xi mang b i n g thiet bj
sieu am - UCA {Hinh 3) Nguyen ly hoat ddng eua UCA dUa tren sU Hen ket gida thdi gian tin hieu sieu i m xuyen qua
v i dp ben nen eua mau d i xi m i n g do bang sU pha hCiy dudi t i c ddng eda t i l trpng eo hpe (Hinh 4) Trong dd,"d6 ben I m hpc" la mde dp phat t r i l n dd ben cua mau da xl mang va do trUc tiep van tdc I m xuyen qua miu."Op ben nen"dupc do trdc tiep va xie djnh bdi lgc can t h i l t de pha huy mau d l xi mang Hai trj sd dope xie djnh trong cCing dieu kien, nhung vdi phuong phap khac nhau, trj sd tuyft ddi khdng n h i t t h i l t gidng nhau l/u diem cua UCA l i c6
Bdng 2 Bon pho chebexi mdng gieng ichoan HPHT be Nom Con Sm
ThUcmg pham
Holcim Class G
Silica SSA-1, SSA-2
! HiDENSE K4 (FeTiOj
WellLife987(PB)
Microbond HT
SCR-25L "
Halad-431L
Nudc ky thuat
Dofn vj
%kL
%kL
%kL""
%kL
%kL gps _ gps
Ham lutfng
100
35 "
' 40 "" _
7
3 0,25 : 0,50 16"
Cong dung
Xi mang nln Phygia ben nhiet P^y-Q'^^sng trpng Phu gia tang do ben Phyjiagiannd ~ Cham ngirng ket Phu gia giim do thii nudc Nudctron
Trang 4the quan s i t sU phat tnen dd ben theo thdi gian, da b i o
thdi gian chd ddng ran xi m i n g , xae djnh dp ben trong
dieu kien HPHT
2.3.4 Ket qud thi nghiem
Bing 3 tong hpp cae k i t q u i thf nghiem ve I n h
hudng cua HPHT den do quanh eda vda xi m i n g vdi ham
luong 35% silica SSA-1 A™ [8]
Bd sung phu gia HR-25L v i CFR-3L la g l i i phap ehd
y l u v i hieu q u i de duy tri va ell thien cae tfnh ehlt cdng
nghe eua xi mang: tang thdi gian q u i n h cua viJfa xi mang
dat trj sd lOOBc (dp q u i n h Bearden) trong khoing 6 - 8
gid, dam b i o an toan trong thdi gian bom ep; lam cham
thdi gian ngUng ket cua vda xl mang; ngan ngda sU suy
thoai dp b i n cCia xi mang va nang cao cic tfnh c h i t co
hpe eda vanh d i xi mang d nhiet dp tren day gieng khoan
(140-180°C)
Phy gia tang trpng Hi-Dense dUdc sin x u l t t d
nguyen lieu khoang hematite, khong nhiem td, khdng
chda phdng xa dap dng cac yeu cau c h i t lam nang nhd
dp p h i n tan cao, bao d i m dp dn dinh (khdng lang dpng)
cua vUa.Trong phu gia chda cic oxide sat cd t h i tao ra cac
hydration ferret v i alumoferit dd ben eao, on djnh trong Hinf} 4 Sado nguyin if ldm viiccua UCA
Bdng 3 Tong hap edcketgud thi nghiem vesu dnh hudng cua HPtiJden thai gian quanh eda he vSa trdm gieng khoan
Dien g i i i Don vi
Xi mang Holcim G % kL
Chat on djnh do ben-SSA-1 %kL
jChat tSng trpng - Hidense-4 % kL
Chat tSng trong MicroMax FF % kL
,g Chat gian nd Microbond HT , % kL
E 'ChattangcOtfnh-WellLife897 %J(L
,g SA-1015(PB) _ _'^^^
c iTang do ben k4o F^P-C765_ r %kL
•c^ Chat chdng tao bot - D-A|r 4000L gps
•= , Chat giam dp thai nUdc Halad-413 gps
t Ic 'Phu gia cham ngiing ket-HR-25L
Phy gia cham ngUng ket SCR-100
j I Phu gia pha loang-CFR-3L
Nudc trdri
Mat d6 vQa
.5 Nhiet dp thi nghiem
„g Ap suit thf nghi#m
£ Dp quinh ban dau
gps gps gps_
gps pgp
"F _ psi _
Mau vCa xi mang
A B _ C _ D(6P)_ E(6P) F G H I , 1100,00 1100,00 100,00' 100,00 100,00' 100,00' 100,00' 100,00 ' 100,00 '
35,00 35,00 35,00
3 jDpqu^nh30Bc
g |Pp quinh 50Bc
l£ Dd quinh lOOBc^
0,05^
0,50
10,05
I 13,50
190
5,382
8
I 7h55'
35,00 35,00
3,00 7,00 0,70 0,05 0,40 0,29 0.70 0,20 4,46 17,00 i
239 5,482 7,005 , 8,601
0,05 0,55
0,10 0,25 ' 5,19_
15,80_'
190
I gid, phut I
! gid, phut ' 7h57' gid, phut 8h7'
I gid, phut ! 8h15'
0,05 0,50
0,20 0,30 5,35 15,80
6h56'
7 h "
7h7'
15 , 8h29' 8h43' 8h50'
8 h 5 4
52
5h59' 8h00'
35,00 35,00 •
3,00 7,00
0,70 0,05 0,04
0.02 0,30 5,18 16,00
230 7,324
3 4
7h43' 8h05' 8h08'
35,00 40,00 25,00 3,00 7,00 0,15 1,00 0,10 0,50
7,97 17,00
27 8h48' 8h52' _8h53' 8h53'
35,00 40,00 25,00 3,00 7,00 0,10 1,00 I 0,10 0,50
0,26 0,90 7,97
17,00
257
9,624
27
8h48' 8h52-8h53'
35,00 40,00
^5,00 3,00 7,00
0,10 1,00 0,10 0,50 ' 0,27 _0,22 0,90
481 18,50
302 12,900 12,900 12,900,
35,00 40,00
^5,00 3,00 7,00 0,10 1,00 0,10 0,50 0,27 0,26 0,90 4,81 18,50
100,00 35,00 40,00 25,00 _3,00 ' 7,00 0,10 I' 1,00 '' 0,10
0,50 ^ 0,27 0,26 • 0,90
481 18,50
302
7h37' 7h39' 5h38' 7h46' 5h42' 8h30' 8h35'
Trang 5THAM DO - KHAI THAC DAU KHI
"^' P
ehat lUu via, eho phep n i n g eao dp ben nen eda
da xi mang, g i l m ham lupng the tfch, nhd dd g i i m
dupc trj sd dp nhdt
Dp ben nen cua da xi mang trong eic dieu kien
ap suit va nhiet do khac nhau dupe the hien trong
Hinh 5 - 9 DUdng mau lam - the h i l n sU phat trien
dp ben nen; dudng mau xanh - nhiet do va dudng
mau dd - thdi gian truyen sdng i m tren mdt don vj
khoing each.Trj soap suit d i t trong UCA va khdng
the hien tren bieu do
Trong Bieu dd sa p h i t trien dp ben nen cua d i
xi mang cd mat do vda 15,80ppg (Hinh 5), nhiet do
tang tU80 - 237''F {26,7 -114=0 va ap suit 20,67MPa
Dp ben tdi thieu cua gel bang SOpsi (0,34MPa) trong
thdi gian 6 gid 49 phut; lOOpsi - 6 gid 56 phut;
I.OOOpsi - 8 gid 12 phut; 916psi - 8 gid v i 1.698psi
- 1 2 gid; do ben nen cue dai b i n g 1.780psi -13 gid,
sau dd g i l m dan dat 1 SOOpsi trong khoang 22 gid
Hinh 6 the hien do ben nen theo thdi gian cCia
d i XI m i n g cd mat dp vda 15,8ppg, nhiet dp t d 80
- 266''F (26,7 - ISO^C) v i i p suit 3.000psi Quan sit
cho thay dp ben nen tang d i n : SOpsi trong 5 gid 4
phut; 100psi-5gid 10 phut; SOOpsi - 5 gid 59 phut;
859psi - 12 gid; 860psl - 24 gid; 1 OOOpsi - 29 gid 35
phut; 2,681 psi-48 gid
Bleu dd dp ben nen cua xl mang cd mat dd vda
17ppg, nhiet do t d 80 - 275''F v i i p suit 3.000psi
(Hinh 7) eho t h i y dp ben gel dat 50psl trong 9 gid
9 phut; 1 OOpsi - 9 gid 15 phut; do b i n nen tdi thieu
bang theo tieu chuIn API SOOpsi trong 10 gid 6
phut; I.OOOpsi - 11 gid 30 phijt; 1.104,04psi - 12
gid Dp ben nen eye dai 1.595psi dat dupc trong
24 gid
Hinh 8 t h i hien dd ben nen eda xi mang cd
mat dp vda 17ppg, nhiet dp t d 75 - 310°F va ap suat
3.000psl Dd ben cua gel dat SOpsi trong 6 gid 42
phut; 10Opsi 7 gid 23 phut; 123psi 8 gid; 285psl
-12 gid; dp ben nen tdi thieu SOOpsi dat dupe trong
12 gid 54 phut; 1 OOOpsl -15 gid; 1.941 - 24 gid; do
nen cUc dai 2.101 psi trong 48 gid
Trong Bieu dd dd ben nen cua xi mang cd mat
dp vda 18ppg, nhiet do tU 180 - seCF va i p suit
3.000psi (Hinh 9), dp ben gel SOpsi trong 14 gid 3
phut; lOOpsi - 14 gid 16 phut; dp ben nen tdi thieu
theo API SOOpsi - 15 gid 21 phut; I.OOOpsi - 16 gid
4 phut; dp ben nen cue dai dat 3.395psi - 24 gid va
tiep tuc t i n g
Hinh 6 Bieu dodo ben nen cdo ddxi mang dudi dp sudi 3 OOOpsi
vd nhiet do 266'F(13<fC)
Hinh 8.8ieu do do ben nen cua ddxi mdng, duai dp sudt3.000psi
vd nhiet do 310'F
Trang 6Hinh 9 Bieu do do ben nen cua dd xi mdng dudi dp suat 3.0i
vd nhiet do WF
Bdc tinh icy ttiudt
Bo cdc thong so: He so Poisson, module Young, module gidn nd the lich
d6 ben nen
Ni^iit do toi da: 204''C (400'F)
Ap suat toi da: 52MPa (?.500psi) Phdn mem hien thi do rhi cdc thong so
thi nghiem vd cdc thdng so tinh chat cohoc trong che do thdi gian thi/c
Hinh W Thiet bi MPPO - Model 626S Chandler Engineering
Hinh 11 Anh huang cua nhiet do den he so Poisson, module Young vd do ben nin
Ket qua Hinh 5 - 9 cho thay dp ben nen cua da
xi mang tang dan v i dat cie g i i tr; cUc dai dUdi t i c ddng cua i p suit cao va gia t i n g cua nhiet dp ddi vdi loai vCfa ed ty trpng khic nhau Trong dieu kien binh thuOng, xi mang ed dp ben nen 3,5MPa dat yeu cau cho edng t i e tram xl mang Cic m i u da xi mang trong d i l u kien nhiet dp cao dat tren lOMPa, dap dng yeu c l u tram gilng khoan
Sd dyng xi m i n g m i e G lam xi mang nen, cd
bd sung 35% silica SSA-1 va mdt sd chat phu trp khae,
dp ben nen cua vanh d i xi mang d i p dng eie yeu cau v l ehlt lUpng t r i m xi mang gieng khoan trong
d i l u kien i p suit eao nhiet dp cao eua be Nam Cdn Son, cap HPHT vaex-HPHT
Khi sd dung xi m i n g Portland d l tram gieng khoan trong dieu kien nhiet dd > lOO^C can sd dung silica
Thuc t l eho thay hPn 90% tdng dp ben nen cija
xi mang trong g i l n g khoan thadng phat t r i l n trong
48 gid sau thdi gian khuiy trdn, nen cd the xac djnh
do ben nen trong khoing 48 gid D i y cung la thdi gian tdi thieu trade khi do dja vat ly gieng khoan
3 Anh hudng cua HPHT den tinh chat dan hoi cua
da xi mang
3.7 Tinh chdt bien dgng cua dd xi mdng
Da xl mang bj b i l n dang nhu vat the dan hdi
- gidn va bj pha hdy khi dng s u i t dat den gidl han dan hdi
De b i o d i m dp kfn eua khoing khdng trong viJng tiep xue "di xi m i n g - cdt dng chdng" c i n p h i i tao ra i p suit nhat dinh t d da xl mang Dp kin eua
g i l n g khoan phu thudc nhieu vao sU thay ddi the tfch da xi mang khi ddng r i n De dat dupe dieu do can sddung hon hpp tram, ed the nd trong qua trinh tao c l u true Vi vay, trj sd nd can phai ldn hon so vdi
sU g i i m the tfch eua he do hien tUpng co ngdt, ddng thdi khdng dupc vUdt q u i lUe tdi han ep nen hoic
pha vd siJ on djnh eua cdt dng chdng
Trong d i l u kien HPHT, v i n h da xl mang ben
ngoai cdt dng chdng phai cd dd mem deo nhat djnh nen c i n sd dung xi mang cd trj sd module
Young t h i p [2] De da xl m i n g tiep xue tdt vdi cdt
dng chdng va thanh g i l n g xi mang gian nd sau khi ddng ran, can bd sung phu gia gian nd WellLife™ trong ddn pha che vda
Trang 7Khi sd dung mdt trong cac phUdng phap tren day,
vanh da xi mang se cd tinh dan hdi tdt hdn bang cich
g i l m module Young v i ning cao he sd Poisson Trong
d i l u kien t i i trpng tinh va chu ky xl mang cd module cao
va he sd Poisson t h i p lam viec tdt hon Vi vay, ngoai viee
xie djnh dp ben can phai nghien edu die diem b i l n dang
d i n hdi cua xi mang tram dUdi t i c ddng ciia cie t i i trong
ca hpe
3.2 Thiet bi xde dmh cdc tinh chdt ddn hoi trong diiu
kiin HPHT
Thiet bj phan tich cic tfnh ehlt cP hpe Model 6265
(MPRO) lien tuc eho ph^p do cae tinh ehlt co hpc (he sd
Poisson, module Young, module gian nd the tfch) va do
b i n nen cua xi mang trong q u i trinh ddng ran trong eic
d i l u kien HTHP Kit q u i thf nghiem d i m bao tdi Uu hda
thanh phan hda hpc cCia xi mang, nang cao do ben cua
xi ming
\Ju diem cCia t h i l t bj MPRO (Hinh 10) la mdt phUdng
p h i p thi nghiem khdng pha huy, eho phep quan sit qua
trinh thay doi cac tinh c h i t co hoc cua xi mang trong che
dp thdi gian thuc; sd dung de d u b i o thdi gian ddng ran
eua xl mang
3.3 Ket qud thi nghiem
M i u vda xl m i n g dUdc sd dyng trong (Bang 2)
D i l u kien thf nghidm: Nhiet dp 31TF, ap suit 2.117Kps
Hinh 11 l i bieu dd the hien eae thdng sd do: Dadng
mau hdng h& sd Poisson; dadng mau xanh l i ma
-module Young; dadng m i u xanh da trdi - -module the tich;
dudng m i u den - dp ben nen
Module Young dat d i n g i i trj 2.117Kpsl trong 10
gid dau tien va giam dan dat I.SOOKpsi sau 150 gid thi
nghiem;
He sd Poisson dao ddng trong khoang 0,30 - 0,25
4 Ket luan
Trong dieu k i l n HPHT, cac tfnh c h i t hda - ly cCia xi
m i n g bien ddi, lam thay ddl hinh thai eau true tinh the va
chuyin pha, tam giam cic tfnh chat edng nghe eda vQa
va cac tinh chat co hoc eua v i n h da xi m i n g , i n h hudng
den ehlt luong tram xl m i n g gieng khoan Hien nay chua
cd xl mang theo dMc t i l u chuan hoa de t r i m cac gieng
khoan HPHT
Be Nam Cdn Son ed dieu kien dja c h i t phdc tap (thudc
nhdm HPHT v i ex-HPHT), chu yeu dang sd dung xl mang
Portland G-API de tram cie gieng khoan sau Tuy nhien, loai xi mang nay ehUa phu hop vdi mdi tradng trong
g i l n g , dan d i n dp t h i m eua d i xi m i n g t i n g nhanh theo thdi gian, dp ben cua d l g i i m , sU lien k i t giufa d i v i ept dng kem, g i y ra i p suat trong ept dng; tai mpt sd gieng
x u i t hi§n hien tupng vanh da xi m i n g bi b i l n dang, co ngdt, nut vd Do dd, can phai bd sung phu gia ben nhiet
SSA-1™, phy gia tang trong va eic phu gia khac de dieu
chinh thdng sd cua vda
Tren ed sd tdng k i t he vQfa xi m i n g sd dung cho cac gieng da khoan tai Ld 05-2 va 05-3 [8], tac g i i de x u l t cdng thde, t h i n h phan, ham lupng vat lieu, phu gia cho he vda XI mang t r i m g i l n g khoan HPHT be Nam Cdn Son Trong dd, viec bd sung 35% khdl lupng phu gia SSA-1™ vao hdn hpp xi mang la gia tri tdi Uu Phy gia SSA-1™ la loai oxide silica k i t tinh, ed khdi lupng rieng 2,60 - 2,63g/ cm^ cd hat 200 - 300 mesh (35%) trong d i l u kien nhiet do cao tren 1OCC se x i y ra phan dng hda hpc vdi xi mang,
giup duy tri dp ben cOa da xi mang, han ehe dp t h i m cOa
d i xi mang Ddng thdi, t i e gia xae djnh I n h hudng HPHT den dp ben nen, h& sd Poisson v i module d i n hdi tren thiet bi UCA, thiet bj MPRO, eho phep md phdng theo cac
d i l u kien trong gieng khoan va thdi gian thuc Tai lieu tham khao
1 Erik B.Nelson Well cementing Schlumberger
Dowell 1990
2 Keelan Adamson, George Birch, Erth Gao, Steve Hand, Colin Macdonald, David Mack, Anver Quadrl
High-pressure, high-temperature well construction Oilfield
Review/ 1998: p 36 - 49
3 Nediljka Gaurina-Medimurec, Davorin Matanovic,
Gracijan Krkalec Cement slurries for geothermal wells cementing Rudarsko Geolosko Naftnl Zbornik 1994; 6:
p 127-134
4 Mojtaba Labibzadeh, Behzad Zahabizadeh, Amin
Khajehdezfuly Early-age compressive strength assessment
of oil well class G cement due to borehole pressure and temperature changes Journal of American Science 2010;
6(7): p 38 - 47
5 U.T.Bezerra, A.E.Martinelli, D.M.A.Melo, M.A.F.Melo,
V.G.OIiveira The strength retrogression of special class Portland oilwell cement Ceramlca 2011; 57(342): p 150
-154
6 Robert Darbe, Chris Gordon, Rickey Morgan Sim design considerations for mechanically enhanced cement
Trang 8systems American Association of Drilling Engineers Paper
AADE-08-DF-HO-06 2008
7 Arash Shadravan, Mahmood Amani HPHT
101-What petroleum engineers and geoscientists should know
about high pressure high temperature wells environment
Energy Science and Technology 2012; 4(2): p 36 - 60
8 BP Vietnam Final Well Report {HT-1X; 2X; 3X) 2003
9 Halliburton Vietnam Cement Post Well Review
(MT-2X, MT-1R MT 6P, MT 3P) 2012
10 Schlumberger Vietnam Cementing End of Well-2013{DN-1X,DN-2X}
11 AraaiMOB O.A., KapHiwoB M.H., L|biL|biiviyiiiKHH
n.O npoexmupoeoHue u pospadomxa mepMocmouKoeo marvinona>KH020 Momepuana BypeHwe M He(|)Tb-/leKa6pb
2011
12 Nguyen Giao, NguyenTrpngTfn Bitrdm tich Nam
Con San va tdi nguyen ddu khi Dja chat v i Til nguyen Diu
khf Viet Nam Nha xuat ban Khoa hoe va Ky thuat 2008: trang319-359
Mechanical properties of cement bond of weilbore in high
pressure Inigh temperature conditions
of Nam Con Son basin
Truong Hoai Nam
Vietnam Oil and Gas Croup
Summary
The Nam Con Son basin has a greatly complicated geology, particularly temperature as high as 200'C and the reservoir pressure gradient up to 2MPa/100m A high pressure high temperature (HPHT) environment contains many potential risks and complexity for drilling and cementing job, which is critical to the v/ell quality and safety The results of studying the effects of HPHT on the mechanical properties of the cement bond will be the important basis to prepare cementing formula with high efficiency and safety for the high pressure high temperature wells in the Nam Con Son basin
Key words: Cementing slurry, high pressure high temperature Silica SSA-1