Tap chiKHKTMo - Bia chdt, sd30, 4/2010, tr.1-3
DAU KHI (trang 1-3) DONG CHAY CUA
C H A T L U UTRONG ONG KHAI THAC DAU
LE DLTC VINH, Tnrdng Dgi hoe Md - Dia chdt
Tom tat: Sau khi khoan vd hodn thien, gieng duoc dua vdo khai thdc. Chuyin ddng eiia hdn hop chdt long trong giing ddi hdi phdi cd ndng luong thdng duoc sire cdn do ma sdt giira hdn hop vdi thdnh dng, ma sdt giira cdc lop chdt long, giira chdt long vd khi. di ndng diroc hdn hop tir ddy gieng lin miing giing qua dng khai thdc vd din hi thdng thu gom xir ly.
1. Mddau that do thuc hien cdng cd ich (dua chat luu len Ddng chay trong dng khai thac la ddng mieng gieng); tdn that do su chuyen dgng tuong chay ciia hdn hop khi hoa tan trong pha long. ddi ciia hon hop so vdi thanh dng va do sir Lugng khi hoa tan trong mot don vi the tich pha chuyen dong tuong ddi ciia cac pha khac nhau Idng phu thudc vao dieu kien nhiet do va ap (long - khi) trong hdn hgp.
suat. Khi chuyen ddng dgc theo dng khai thac Tdn hao ap suit dgc theo dng khai thac phu til' day len den mieng gieng, nhiet do va ap suat thudc vao cac yiu td:
thay ddi theo chieu hudng giam dan nen the tich - Luu lugng ciia ch§t ldng chuyin ddng pha khi va pha Idng cd su thay ddi. trong ong;
2. Sy tach pha trong ong khai thac va anh - Luu lugng khi chuyen ddng trong dng;
hudng cua nd din ddng chay . Duong kinh dng;
Trong khai thac dSu, chSt luu chuyen dgng . ji^h chk vat ly (ty trgng. do nhdt) ciia trong dng khai thac nhd hai dang nang lugng chk Idng chuyin ddng trong dng;
chinh: nang lugng khi va nang lugng ap suat . ^uc ciing bi'mat gida chit long va chit thuy tTnh. Dgc theo than gieng, ap suat giam |^|.,i
diin tir dudi len tren. Khi ap suit cua chdt luu Coi van tdc cua chit long trong dng khai Ion hon ap suat bao hoa thi loan bg khi hoa tan j^ac la v,; van tdc cua thanh phln khi trony dnu trong dau; ddng chay trong dng khai thac la ^h^j ^^^^ ,^ ^^^ ^5,^ t^^t ,^^ ^^^ j o s^. ^h^.^.g^
dong mot pha va nang lugng de nang chat luu ^g^g tuong ddi ciia hdn hgp so vdi thanh dng la len mieng gieng den he thdng thu gom xir ly la ^
nang lugng ap suit thuy tTnh. Khi ap suit chit '"^^ ^^ ^j^g ^^^-^ ^l^^^g^ ^~^g ^-,^ ^^^^ 1^,.^, luu trong dng khai thac nhd hon ap suat bao ^j^g^ ^^^.^ l^^g . ,.,^[) ^^.^^„ g^g j^,^^; ^,^.^ j , ^ . ^ , ^ 3 hoa, cd mdt lugng khi tach ra, ddng chay tro truing hgp chii yiir
thanh ddng hai pha (Idng - khi). Nang lugng khi _ ^y tudng: v, = v^ va h„, = 0;
Iro thimh nang luong cd ich gdp phan nang chat D • 1 - , - ^ • 1 n ... .i' - t r - K ^ - Ban ly tuong: V| < Vk va hms = 0;
luu len mieng gieng. -^, . • 1 .^ A ,^, . , • i , , i , , : iX , . , , - Thuc: V| ^ V|, va h^s > 0.
Khi ap suat cua chat luu bat dau nho hon ap , , , ' , x , , . , , , ., . , , , i^ , . . . I . , , i, ,x ., , . , u * • -^et mot ong khai thac co duong kinh trong suat bao hoa, khi bat dau tach ra o' dana bot va ,, , , .x ' ... f , x , . , . ^1
, :, j ^ , . , ; , , . ; " ; ' la d. chieu dai 1, ap suat tuong imu tai hai dau chu\en doni' voi van toe Ion hon van toe cua ; ,, „ . r, • • , t i-
, ; ' . . •«,'-, I . . ' - -;., - ' lu -.u- oris la P| va PJ, luu luong cua chat long chay chat long. Mat khac, ap suat trong ong khai thac ^ ^ ,~ ^ ' i , , , - , . , , -r- • "~ •/
,, ' , .. ,x ^1 - 5 1 - - u » trong ong la Q, luu luong khi la V. Tai mot tiet caim len cao cang mam dan, the tich cua cac bot ... ,, . ^ .i ;., , 5 ,.' ', , , . , .- , ,, ,~" ^x , , ;. , .- - u-' dien r cua ong, tiet dien cua chat long va khi khi cang Ion. dan den khoi luo'ng neng cua hon ' , ,, ,- . ^ ,r ' ,• ,-
I . " ^ r 1 • .1 - •' > " " tuong ung la 1| va f|, (f = f| + tk ):
hop trong oiig khai thac giam dan. e »
Chat luu chuyen dgng dugc tir day len den f 1 = - (I) mieng gieng la nhd cd su chenh lech ap suat ^1
giua da> vii mieng gieng. Thanh phan lam tieu r 2VP hao nang lugng trong dng khai thac gdm tdn '' (Pi+P,)v|^
Tai cac tiet dien khac nhau thi ap suat khac nhau nen fi. f^, V|. v^ cung cd cac gia tri khac nhau. Khdi lugng rieng cua hdn hgp tai tiet dien f dugc xac dinh:
_f,.p,+f;.p^
f (3)
trong do pk la khdi lugng rieng cua khi d gia tri ap suat trung binh Pib:
" . - ' - ^ (4) 3. Can true ciia ddng chay trong dng khai thac
Cau tnic cua ddng chay trong dng khai thac
dgc tir da> den mieng gieng rat khac nhab phu thudc vao ty le long - khi, dudng kinh dng- van tdc trung binh cua hdn hgp
Niu t\ le khi trong ddng cha\ la nhd thi chirng chuyin ddng theo dang cac bgt khi rieng biet. khi ap suit giam. ty le khi tach ra tang len.
kich thudc cac bgt khi Idn din va chuyen dgng theo tirng chuoi. chit Idng din trd thanh cac gigt nhd^chu} in dgng theo. Khi ty le khi tiip tuc tang thi chit long chi chuyen ddng^ xung quanh t^hanh dng. d tam ong la khi cd lan cac giot chat long.
^•^
°'^Oo
mQ
0 n 0 00
o°O0Ol
I
r<D\ rOi
m
L>o
. t
k •
Hinh 1. Cac dang ddng chay ciia hdn hgp Idng - khi trong dng khai thac
Cd nhiiu trang thai ddng chay khac nhau trong dng khai thac nhung thirdng quy vi bdn loai nhu hinh 1:
a: Ddng chay dang bgt khi hay suong mil (Bubble flow);
b: Ddng chay dang nut khi hay chudi (Slug flow);
c: Ddng chay dang sdng khi (Churn flow);
d: Ddng chay dang vanh khuyen (Annular flow).
Trong thuc te. cd the tdn tai ddng thdi hai. ba. tham chi ca bdn dang ddng chay trong mdt dng khai thac nhu tren hinh 1 .e. Ci phan dudi ciia dng khai thac cd ap suit Idn nen kich thudc cac bot khi cdn nhd tuong irng vdi trang thai ddng chay bgt khf. Dgc len tren theo chieu dai 6n<', ap suit tiip tuc giam. kich thudc ciia bgt khi tang len, trang thai cua ddng chay thay ddi sang chuc"^ sdng va vanh khu\en.
Hinh 2. Hinh anh cua hon hgp trong dng khi the tich khi tang dan (tii' a den c) 4. Ket luan
C) trang thai ddng chay nhu hinh I .a, ta thay mat do cua chat luu chuyen dgng len mieng gieng la tuong ddi Idn va lien tuc, thudng cd trong dng khai thac ciia cac gieng tu phun va gaslift lien tuc (continuous gaslift). 0 hinh l.b, trang thai ddng chay gdm cac nut khi xen ke vdi cac nut chat Idng, thudng cd trong dng khai thac ciia cac gieng gaslift dinh ky (intermittent gaslift). Khi ddng chay trong dng khai thac d trang thai nhu hinh 1 .c va 1 .d thi dau hau nhu khdng len dugc mieng gieng; neu cir tiep tuc nen khi xudng se xay ra hien tugng trugt khi.
can phai chuyen sang phuong phap khai thac khac hieu qua hon.
Nhu vay, mudn lua chgn dugc phuong phap khai thac phii hgp, xac dinh dugc che do
lam viec tdi uu ciia gieng va lua chgn dugc td hgp thiet bj tuong thich de dam bao su chuyen dgng ciia ddng san pham len be mat mdt each cd hieu qua, nhat thiet phai xac dinh dugc tinh trang pha. cau tnic cua ddng chay trong dng khai thac ciia gieng.
TAI LIEU THAM KHAO
[1]. Phiing Dinh Thuc, Duong Danh Lam, Le Ba Tuan, Nguyen Van Canh, 1999. Cdng nghe va ky thuat khai thac dau khi. NXB Giao due.
[2]. Christopher Earls Brennen, December 2003. Fundamentals of Multiphase Flow.
California Institute of Technology.
[3]. Franz Durst, March 2008. Fluid Mechanics - An Introduction to the Theory of Fluid Flovvs.Germany.
SUMMARY
The flow of fluid in production tubing Le Due y'lnh. University of Mining and Geology
After drilling and completion, the well was put into operation. Motion of the liquid mi.xture in a well requires power to be won by the frictional resistance between the mixture with the pipe, the friction between fluid layers, between liquid and gas, to raise the mixture from the bottom hole through production tubing to wellhead and surface production system.
Ngudi phan bien: Hodng Dung