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Lun vn tt nghip Li cm n ____________________________________________________________________________

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LI CM N Li u tin em xin trn trng by t lng bit n su sc n thy Mai Cao

Ln. Thy truyn t cho em nhng kin thc l thuyt c s qu bu, ch dn

cho em phng php hc tp hiu qu, cch phn tch v gii quyt vn , gip

em ngun ti liu tham kho quan trng, cng nh to iu kin cho em c thc

tp, v Thy l ngi tn tnh hng dn em trong sut thi gian thc hin lun vn.

Em xin chn thnh cm n anh Nguyn Vit Vn, ngi hng dn v gip

em tng bc hon thnh lun vn tt nghip, gip em lin h kin thc gia l

thuyt v thc tin. Em tht s cm n v nhng kin thc thc t rt hu ch m anh

ch dn trong sut qu trnh thc tp. Bn cnh , em cng xin c gi li cm

n su sc n cc anh ch phng Khai Thc Hong Long Hon V JOC nhit

tnh gip v sn sng gii p nhng thc mc ca em trong sut qu trnh thc

tp.

Em mun c by t lng bit n trn trng n cc thy c trng i hc

Bch Khoa HQG Tp.HCM, c bit l cc thy c khoa KT a cht v Du kh,

cc thy b mn Khoan v Khai Thc Du Kh tn tnh ging dy, ch bo v

gip em trong sut thi gian trn ging ng i hc.

Em cng xin gi li cm n n Ban lnh o Cng ty iu hnh chung du

kh Hong Long Hon V JOC, Ts. Ng Hu Hi, ng V Vn Cng, to iu

kin cho em thc tp v hon thnh tt lun vn ny.

Con xin gi li tri n su sc n Ba M, cm n Ba M sinh thnh, nui

dng v dy d con nn ngi. Ba M lun l ngun ng vin ln nht v to

cho con nhng iu kin tt nht trn bc ng hc tp v trng thnh. i vi

con, gia nh lun l ch da ln lao trong cuc i ny.

Sau cng, ti mun cm n cc anh ch sinh vin khoa K Thut a Cht &

Du Kh, cc bn cng kha v cc em sinh vin kha sau cng ti ng hnh trn

bc ng hc tp.

XUN HA

Lun vn tt nghip Tm tt lun vn ____________________________________________________________________________

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TM TT LUN VN

Ngy nay, vic kt ni h thng cc ng ng vn chuyn du kh ni m hoc

m cn bin l mt trong nhng phng n pht trin c nh gi cao v hiu qu

kinh t t c. Tuy nhin, bn cnh , nhiu ri ro lun tn n trong qu trnh vn

hnh h thng ng ng ny, c bit i vi nhng ng ng ngm di hng chc

kilomet di y bin. Do , trong lun vn ny, gii php ti u ha qu trnh vn

chuyn hn hp du kh trong ng ng ngm di bin nhm m bo tnh n nh

dng chy trong ng, gim thiu ri ro v chi ph vn hnh c thc hin.

Trong phn u ca lun vn, c s l thuyt v ti u ha s c trnh by

mt cch tng quan nhm xc nh mc ch, i tng v cc phng php s dng

cho vic ti u. Tip , c s l thuyt v tnh ton nhm xy dng m hnh dng

chy a pha trong ng ng vn chuyn c trnh by. C s xy dng m hnh

dng chy a pha l cc phng trnh vi phn c thit lp cho tng pha ca cht lu.

i tng nghin cu c th ca lun vn l ti u ha qu trnh vn chuyn

hn hp du kh bng ng ng ngm di bin t m C Ng Vng n gin x l

trung tm s 3 ca m Bch H. Da trn c s l thuyt trnh by nhng phn

u, cc thnh phn, tnh cht cht lu v hin trng lm vic thc t trong ng ng

vn chuyn ny c tin hnh phn tch v a ra nhn xt. Sau qu trnh phn tch

ny, cc quy trnh ti u ha c xy dng chi tit bao gm thu thp v x l cc s

liu u vo cn thit phc v cho vic xy dng m hnh, hiu chnh m hnh, s dng

m hnh m phng bi ton.

Kt qu t c sau qu trnh m phng l s biu din p sut, nhit , t

phn lng, tc ng s hnh thnh cc nt kh trong h thng ng ng vn chuyn

vi cc ch lm vic khc nhau. Trn c s phn tch v nh gi cc kt qu ny,

vic xut phng n hp l nhm ci thin hiu sut vn chuyn cng nh gim

thiu ri ro v tit kim chi ph x l c thc hin.

Lun vn tt nghip Mc lc ____________________________________________________________________________

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MC LC

MC LC ...................................................................................................................... iii

DANH SCH HNH NH .............................................................................................. v

DANH SCH BNG BIU ........................................................................................ viii

CH VIT TT ............................................................................................................. ix

M U .......................................................................................................................... x

CHNG 1: TNG QUAN V TI U HA VN CHUYN DU KH BNG NG NG KT NI ................................................................................................. 1

1.1. Tng quan v ti u ha vn chuyn du kh bng ng ng kt ni .............. 1

1.2. Mc ch ca vic ti u ha vn chuyn du kh trong ng ng ................. 2

1.3. Phng php ti u ha ...................................................................................... 3

1.3.1. Mc tiu ti u ha ................................................................................... 3

1.3.2. Cc thng s kim sot qu trnh ti u ha ............................................ 3

1.3.3. Cc phng php s dng cho qu trnh ti u ha ................................. 3

CHNG 2: C S L THUYT DNG CHY A PHA TRONG NG NG VN CHUYN ............................................................................................................... 8

2.1. Tng quan v dng chy a pha ......................................................................... 8

2.1.1 Cc ch dng chy trong ng ng nm ngang .................................... 8

2.1.2 Cc ch dng chy trong ng ng thng ng ................................ 10

2.1.3 Biu ch dng chy (Flow regime maps) ........................................ 11

2.2 C s tnh ton v xy dng m hnh dng chy hai pha ................................ 15

2.2.1. Phng trnh bo ton khi lng .......................................................... 15

2.2.2. Phng trnh bo ton ng lng ......................................................... 16

2.2.3. Phng trnh bo ton nng lng ......................................................... 17

2.2.4. Phng trnh p sut ............................................................................... 18

2.2.5. S truyn khi gia b mt phn cch cc pha ...................................... 18

2.3. Cc tnh cht c bn ca cht lu vn chuyn trong ng ng ...................... 19

Lun vn tt nghip Mc lc ____________________________________________________________________________

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2.3.1. Tnh lu bin .......................................................................................... 19

2.3.2. Nhit kt tinh ..................................................................................... 24

2.3.3. Nhit ng c ................................................................................... 24

2.3.4. nh hng ha phm gim nhit ng c n cc tnh cht ca cht lu ................................................................................................................ 25

CHNG 3: M PHNG QU TRNH NHIT THY NG DNG CHY TRONG NG NG KT NI M C NG VNG N M BCH H V XUT PHNG N TI U HA QU TRNH VN CHUYN HN HP DU KH ....................................................................................................................... 30

3.1. Tng quan h thng kt ni m C Ng Vng m Bch H ........................ 30

3.1.1. Gii thiu chung m C Ng Vng ........................................................ 30

3.1.2. H thng ng ng kt ni CNV CPP3 ............................................ 31

3.1.3. Thnh phn v tnh cht du th CNV ................................................... 33

3.1.4. Hin trng lm vic thc t trong ng ng vn chuyn du kh CNV CPP3 ................................................................................................................ 41

3.2. Xy dng m hnh dng chy a pha trong ng ng vn chuyn ................ 50

3.2.1. Cc d liu thc t cn thit cho vic xy dng m hnh ...................... 51

3.2.2. Xy dng m hnh nhit thy ng dng chy trong ng ng vn chuyn ................................................................................................................ 53

3.2.3. Hiu chnh m hnh nhit thy ng dng chy trong ng ng vn chuyn ................................................................................................................ 54

3.3. M phng qu trnh nhit thy ng dng chy trong ng ng v xut phng n ti u ha vn chuyn hn hp du kh ................................................... 57

3.3.1. M phng qu trnh nhit thy ng dng chy trong ng ng vn chuyn vi ch lu lng hot ng hin thi.................................................. 57

3.3.2. M phng qu trnh nhit thy ng dng chy trong ng ng vn chuyn vi cc ch lu lng khc nhau .......................................................... 59

KT LUN V KIN NGH........................................................................................ 84

TI LIU THAM KHO .............................................................................................. 87

Lun vn tt nghip Danh sch hnh nh ____________________________________________________________________________

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DANH SCH HNH NH

Hnh 1.1 Mc ch ti u ha vn chuyn du kh trong ng ng ........................... 2 Hnh 1.2 Cc lp bc cch nhit ng ng vn chuyn CNV CPP3 [9] .................. 4 Hnh 1.3 Hnh dng con thoi 8.5" ................................................................................. 7 Hnh 1.4 Hnh dng con thoi 9.25" ............................................................................... 7

Hnh 2.1 Cc ch dng chy trong ng ng nm ngang [3] ............................... 10 Hnh 2.2 Cc ch dng chy trong ng ng thng ng [3] .............................. 10 Hnh 2.3 Biu ch dng chy Beggs & Brill (1973) cho ng ngang [3] ............ 13 Hnh 2.4 Biu ch dng chy Taitel v Dukler (1976) cho ng ngang [3] ........ 15 Hnh 2.5 Cc m hnh cht lng Newton v phi Newton [2] ....................................... 20 Hnh 2.6 Hnh v biu din ng sut trt ca cht lng Newton [2] ......................... 21 Hnh 2.7 Cc tinh th paraffin trc (tri) v sau (phi) khi s dng ha phm [16] . 26 Hnh 2.8 Kt qu th nghim cc cht lm gim nhit ng c khc nhau vi cc liu lng khc nhau ...................................................................................................... 27 Hnh 2.9 nh hng ca cc cht PPD vi liu lng 1000ppm n cn ban u ........................................................................................................................................ 28 Hnh 2.10 nh hng ca cc cht PPD vi liu lng 1000ppm n nht ng hc du ca CNV ........................................................................................................... 28

Hnh 3.1 S v tr m C Ng Vng [9] ................................................................... 30 Hnh 3.2 S vn chuyn du kh t CNV WHP [9] ................................................. 31 Hnh 3.3 th biu din s thay i tc lng ng paraffin khi gim nhit .. 35 Hnh 3.4 th biu din hm lng % paraffin ha tan trong du theo nhit ... 36 Hnh 3.5 th biu din bin thin nht ng hc STO theo nhit ................ 38 Hnh 3.6 th biu din bin thin nht ng hc Live Crude theo nhit ..... 39 Hnh 3.7 th so snh nht ng hc bin thin theo nhit ca STO & Live crude ............................................................................................................................... 40 Hnh 3.8 th biu din lu lng v p sut lm vic trn CNV & CPP-3 ........... 43 Hnh 3.9 th biu din lu lng v nhit lm vic trn CNV & CPP-3 ......... 44 Hnh 3.10 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 1st ..... 45 Hnh 3.11 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 2nd .... 45 Hnh 3.12 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 3rd .... 46


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Hnh 3.13 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 4th ..... 46 Hnh 3.14 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 5th ..... 47 Hnh 3.15 S quy trnh m phng chung cho bi ton ti u ha qu trnh vn chuyn du kh trong thc t .......................................................................................... 49 Hnh 3.16 S m t cc bc chung trong qu trnh xy dng m hnh ............... 50 Hnh 3.17 th m phng mt ct tuyn ng CNV-CPP3 trn OLGA 7.0 .............. 52 Hnh 3.18 M hnh h thng ng ng vn chuyn hn hp du kh CNV CPP3 53 Hnh 3.19 Kt qu m phng p sut trn CNV & CPP3 trong 24h (start-up) sau khi chy m hnh. ................................................................................................................. 53 Hnh 3.20 Kt qu m phng nhit trn CNV & CPP-3 trong 24h (start-up) sau khi chy m hnh ............................................................................................................ 54 Hnh 3.21 Kt qu p sut o thc th trn CNV v CPP-3 trong 24h ...................... 55 Hnh 3.22 Kt qu nhit o thc t trn CNV & CPP-3 trong 24h ....................... 55 Hnh 3.23 Kt qu hiu chnh p sut thc t v m phng trn CNV & CPP3 ........ 56 Hnh 3.24 Kt qu hiu chnh nhit thc t v m phng trn CNV & CPP3 ....... 56 Hnh 3.25 th biu din mi quan h gia nhit v p sut sau cn tit lu ... 57 Hnh 3.26 Kt qu m phng bin thin p sut trong ng ng vn chuyn CNV - CPP3 .............................................................................................................................. 58 Hnh 3.27 Kt qu m phng bin thin nhit trong ng ng vn chuyn CNV - CPP3 .............................................................................................................................. 59 Hnh 3.28 Kt qu m phng p sut v nhit trong ng ng sau 24h (6000STB/d) ................................................................................................................... 60 Hnh 3.29 Kt qu m phng vn tc v t phn lng trong ng ng sau 24h ...... 61 Hnh 3.30 Kt qu m phng lu lng dng chy ti CPP-3 ................................... 61 Hnh 3.31 Kt qu m phng p sut v nhit trong ng ng sau 24h (5000STB/d) ................................................................................................................... 62 Hnh 3.32 Kt qu m phng vn tc v t phn lng trong ng ng sau 24h ...... 63 Hnh 3.33 Kt qu m phng lu lng dng chy ti CPP-3 ................................... 63 Hnh 3.34 Kt qu m phng p sut v nhit trong ng ng sau 24h (3000STB/d 40bar) ...................................................................................................... 64 Hnh 3.35 Kt qu m phng vn tc v t phn lng trong ng ng sau 24h ...... 65 Hnh 3.36 Kt qu m phng lu lng dng chy ti CPP-3 ................................... 65 Hnh 3.37 Kt qu m phng p sut v nhit trong ng ng sau 24h (3000STB/d 17bar) ...................................................................................................... 66 Hnh 3.38 Kt qu m phng vn tc v t phn lng trong ng ng sau 24h ...... 67 Hnh 3.39 Kt qu m phng lu lng dng chy ti CPP-3 ................................... 67


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Hnh 3.40 Kt qu m phng p sut v nhit trong ng ng sau 24h (2000STB/d) ................................................................................................................... 68 Hnh 3.41 Kt qu m phng vn tc v t phn lng trong ng ng sau 24h ...... 69 Hnh 3.42 Kt qu m phng lu lng dng chy ti CPP-3 ................................... 69 Hnh 3.43 Lu lng th tch ti CPP-3 (2000 bbl/d) ................................................ 70 Hnh 3.44 S nt kh ti CPP-3 (2000 bbl/d) .............................................................. 71 Hnh 3.45 Chiu di nt kh ti CPP-3 (2000 bbl/d) .................................................. 71 Hnh 3.46 Lu lng cng dn ti CPP-3 (2000 bbl/d) ............................................. 72 Hnh 3.47 So snh th tch lng thay i t ngt ti CPP-3 2000 bbl/d & 5000 bbl/d ................................................................................................................................ 72 Hnh 3.48 Kt qu m phng p sut v nhit trong ng ng sau 24h (1000STB/d) ................................................................................................................... 73 Hnh 3.49 Kt qu m phng vn tc v t phn lng trong ng ng sau 24h ...... 74 Hnh 3.50 Kt qu m phng lu lng dng chy ti CPP-3 ................................... 74 Hnh 3.51 Lu lng th tch ti CPP-3 (1000 bbl/d) ................................................ 75 Hnh 3.52 S nt kh ti CPP-3 (1000 bbl/d) .............................................................. 76 Hnh 3.53 Chiu di nt kh ti CPP-3 (1000 bbl/d) .................................................. 76 Hnh 3.54 Lu lng cng dn ti CPP-3 (1000 bbl/d) ............................................. 77 Hnh 3.55 So snh th tch lng thay i t ngt ti CPP-3 1000 bbl/d & 5000 bbl/d ................................................................................................................................ 77 Hnh 3.56 th biu din kt qu phn tch nhit ng c vi cc liu lng cht c ch khc nhau .................................................................................................... 79 Hnh 3.57 th biu din hiu qu ca ha phm PPD n nht ca du CNV 81

Lun vn tt nghip Danh sch bng biu ____________________________________________________________________________

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DANH SCH BNG BIU

Bng 1.1 Cc c tnh c bn ca ng ng vn chuyn CNV CPP3 [9] ................ 5

Bng 2.1 Bng lit k cc cht PPD s dng cho vic sng lc ................................ 26 Bng 2.2 Bng kt qu nh gi hiu qu s dng cc loi PPD khc nhau ............ 29

Bng 3.1 Cc c tnh k thut ca ng ng ngm khai thc [9] ............................ 32 Bng 3.2 Kt qu phn tch cc thnh phn trong du th 9.2-CNV-4XST, DST#1 .. 33 Bng 3.3 Cc thng s c bn ca du th CNV........................................................ 34 Bng 3.4 Kt qu phn tch kh nng lng ng ca du CNV ................................. 35 Bng 3.5 Kt qu phn tch hm lng ha tan paraffin trong du theo nhit ..... 36 Bng 3.6 Cc gi tr nht ng lc du CNV cc nhit khc nhau .............. 37 Bng 3.7 Cc thng s lm vic trong ng ng vn chuyn CNV - CPP-3 ........... 42 Bng 3.8 D liu thnh phn cht lu CNV trn PVTsim 19.0 .................................. 51 Bng 3.9 D liu p sut, nhit v lu lng ........................................................ 51 Bng 3.10 D liu c bn vt liu ca ng ng ..................................................... 52 Bng 3.11 D liu nhit v p sut sau cn tit lu .............................................. 57 Bng 3.12 Cc trng hp m phng ch dng chy n nh trong ng ng .. 58 Bng 3.13 D liu m phng cc ch lu lng khc nhau .................................. 59 Bng 3.14 Kt qu m phng nhit thy ng dng chy trong ng ng vi cc ch lu lng khc nhau ........................................................................................... 78 Bng 3.15 Kt qu phn tch nhit ng c cc liu lng cht c ch khc nhau ................................................................................................................................ 79 Bng 3.16 Kt qu th nghim xc nh nh hng ca ha phm n nht ng hc ca du CNV ........................................................................................................... 80 Bng 3.17 Bng nh lng ha phm cho cc lu lng vn chuyn khc nhau .... 82

Lun vn tt nghip Ch vit tt ____________________________________________________________________________

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CH VIT TT

Ch vit tt M t

API American Petroleum Institute

ASTM American Society of Testing and Materials

BH Bach Ho

CNV WHP Ca Ngu Vang Well Head Platform

CPP JV Vietsovpetros Central Processing Platform at Bach Ho field

CPM Cross Polarized Micoscope

CWC Concrete Weight Coating

DSC Differential Scanning Calorimetry

FSO Floating Storage and Offloading

FPSO Floating Production Storage and Offloading

GOR Gas Oil Ratio

NIR Near infrared

ID Inner Diameter

OD Outside Diameter

PP Polypropylene

PPD Pour Point Depressant

PU Polyurethane

STO Stock Tank Oil

WAT Wax Appearance Temperature

Lun vn tt nghip M u ____________________________________________________________________________

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M U

1. Tnh cp thit ca ti

Du kh l ngun nng lng quan trng pht trin nn kinh t. Ngnh cng

nghip du kh ng gp hn 25% tng ngn sch nh nc. Nhm p ng nhu cu

tiu th du kh ngy cng gia tng ca th trng trong nc cng nh m bo pht

trin kinh t t nc i hi pht trin nhanh v hiu qu cc m du kh, c bit l

cc m c tr lng thu hi nh. Vic nghin cu v a ra cc phng n pht

trin cc m nh ti Vit Nam c ngha quan trng v cp thit trong giai on hin

nay. Mt trong nhng nhng phng n tt nht c ng dng ti cc cng ty iu

hnh du kh l phng n pht trin kt ni. Vi phng n ny, sn phm du kh sau

khi c khai thc ln t cc gin u ging cc m nh s c vn chuyn thng

qua h thng ng ng ngm di bin n h thng x l ti cc gin x l trung

tm hoc cc tu x l v cha FSO.

Vic ti u ha qu trnh vn chuyn hn hp du kh xut pht t nhu cu d

n thc tin gia Hon V JOC kt hp vi Vietsovpetro v ng ng kt ni di

25km t m C Ng Vng ca n gin x l trung tm s 3 m Bch H. Vi mt h

thng ng ng di nh vy, qu trnh vn chuyn lun gp nhiu tim n ri ro cao

nh lng ng paraffin trong ng ng, s hnh thnh cc nt kh, s thay i iu

kin lm vic trong qu trnh vn hnh ng ng,... Tc ng ca nhng vic ny s

lm tc nghn ng ng, gy cn tr s di chuyn ca cht lu, to nn s tch p v

gim nng sut vn chuyn trong ng Cho nn, vic nghin cu, xut cc phng

n cng ngh hp l v lp ra bin php kim sot thch hp nhm m bo tnh n

nh ca dng chy, hn ch ri ro trong qu trnh vn hnh ng ng l mt trong

nhng vn c quan tm hng u hin nay. Chnh v vy, ti lun vn TI U

HA QU TRNH VN CHUYN DU KH TRONG NG NG NGM DI BIN T

M C NG VNG N GIN X L TRUNG TM S 3 M BCH H c nghin

cu.

Lun vn tt nghip M u ____________________________________________________________________________

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2. Tnh hnh nghin cu lin quan n ti

Trn th gii, mt s cng trnh nghin cu v vic ti u ha vn chuyn

hn hp du kh a pha trong h thng ng ng kt ni da trn cc vn xy ra

trong thc t. Trong bi bo (Leksono Mucharam, Septoratno Siregar, Darmadi,

Musyoffi Yahya, Achirul Akbar, 2008), da trn cc phng trnh bo ton nng lng

v phng php Newton-Raphson kt hp vi vic phn tch, nh gi ch dng

chy v cc thnh phn, tnh cht ca cht lu vn chuyn trong ng ng, tc gi

xy dng thnh cng m hnh d bo c qu trnh tn tht p sut v nhit ca

cht lu trong sut qu trnh vn chuyn. M hnh ny c ng dng trong nhiu

bi ton ti u ha vn chuyn hn hp du kh a pha, c bit l du cha nhiu hm

lng paraffin. Bi bo (Jinya Zhang; Hongwu Zhu; Yan Li; Chun Yang, 2009) da

trn thut ton di truyn, tc gi xy dng ln hm a mc tiu cho bi ton ti u

ha qu trnh vn chuyn hn hp du kh a pha trong h thng ng ng vn

chuyn. Thng qua phng php ny, cc yu t v kinh t cng nh hot ng ca

cht lu trong ng ng (ch thy lc, nhit ng) c ci thin kh hiu qu

v gim thiu c nhiu ri ro trong sut qu trnh vn hnh.

Ti Vit Nam, mt s cng trnh nghin cu cc gii php cho vic ti u ha

v m bo ch dng chy trong ng ng vn chuyn hn hp du kh. Trong bi

bo ca (Nguyen Thuc Khang, Ha Van Bich, Tong Canh Son, Le Dinh Hoe, JV

Vietsovpetro; Phung Dinh Thuc, PVEP Vietnam, 2004), tc gi xy dng mt

phng php kh hiu qu cho vic qun l ch dng chy a pha trong h thng

ng ng vn chuyn - phng php thng k da trn d liu thc t phn tch s

dao ng p sut v xc nh cc thng s tc thi nh Hausdorff's Dimension D,

Hurst's Index H v Entropies E.

Bn cnh , mt s cng trnh v ang c nghin cu v vic m bo

dng chy trong ng ng vn chuyn cc cng ty iu hnh du kh nh Hon V

JOC kt hp vi Vietsovpetro lin quan n ng ng kt ni t m C Ng Vng v

Lun vn tt nghip M u ____________________________________________________________________________

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gin x l trung tm CPP-3 ca m Bch H, Hong Long JOC kt hp vi Thng

Long JOC lin quan n d n kt ni ng ng t HST/HSD v gin TGT-H1 ca

m T Gic Trng.

3. Mc ch, i tng v phm vi nghin cu

Mc ch ca ti l m phng cc ch lm vic khc nhau trong ng

ng vn chuyn du kh t m C Ng Vng n m Bch H nhm xc nh lu

lng lm vic ti thiu m ti cht lu cn c th di chuyn c trong ng ng

v tm ra phng n hp l gim thiu ri ro nh lng ng paraffin, s hnh thnh nt

kh,... t c mc ch trn, lun vn tp trung vo cc ni dung nghin cu sau :

- Kho st mt cch h thng tng quan v ti u ha qu trnh vn chuyn

du kh trong ng ng.

- Tm hiu cc m hnh dng chy v c s xy dng m hnh dng chy

trong ng ng vn chuyn du kh a pha.

- ng dng phn mm OLGA 7.0 m phng v phn tch cc ch lm vic

khc nhau trong ng ng vn chuyn du kh v xut phng n gim

thiu cc ri ro trong qu trnh vn hnh.

4. Phng php nghin cu

Phng php nghin cu c s dng trong ti bao gm:

- H thng ha c s tnh ton dng chy & l thuyt ti u ha trong ng

ng vn chuyn.

- Phn tch s liu cc th nghim.

- M hnh ha v m phng vi s h tr ca phn mm OLGA 7.0.

- Phng php phn tch nh hng (Sensitivity analysis).

5. Ti liu c s ca lun vn

Lun vn c xy dng trn c s ca cc ti liu v l thuyt dng chy a

pha trong ng ng, l thuyt v thu gom & vn chuyn du kh a pha trong ng

Lun vn tt nghip M u ____________________________________________________________________________

______________________________________________________________________ SVTH: Xun Ha-MSSV: 30800690 xiii

ng v mt s bi bo SPE. Ngoi ra, lun vn cn s dng cc ti liu k thut, ti

liu hng dn s dng phn mm OLGA ca cng ty SPT Group Schlumberger,

mt s bo co v m bo dng chy trong ng ng vn chuyn ca cc cng ty

du kh.

6. Cu trc ca lun vn

Lun vn bao gm cc chng chnh sau:

Chng 1: Tng quan v ti u ha vn chuyn du kh bng ng ng kt ni

Gii thiu mt cch tng quan v ti u ha vn chuyn du kh bng ng

ng v mc ch ca vic ti u ny. Bn cnh , cc phng php c s dng cho

bi ton ti u trong thc t hin nay cng c trnh by trong chng ny.

Chng 2: C s l thuyt v dng chy a pha trong ng ng vn chuyn

Trnh by mt cch tng qut l thuyt v dng chy a pha, cc tnh cht c

bn ca cht lu vn chuyn trong ng ng v cc phng trnh ton hc gip m

phng dng chy a pha trong ng ng.

Chng 3: M phng qu trnh nhit thy ng dng chy trong ng ng kt

ni m C Ng Vng n m Bch H v xut phng n ti u ha qu

trnh vn chuyn hn hp du kh

Lun vn trnh by s lc tng quan v m C Ng Vng. Thm vo , cc l

thuyt v dng chy a pha v tnh cht ca cht lu vn chuyn trong ng ng

chng 2 c s dng phn tch cc tnh cht ha l ca du th CNV cng nh

cc thng s lm vic thc t trong ng ng vn chuyn t CNV CPP3. Sau qu

trnh phn tch ny, cc quy trnh m phng c xut. Cui cng, m hnh nhit

thy ng dng chy trong ng ng vn chuyn hn hp du kh c xy dng da

trn cc phng trnh ton hc cp trong chng 2 v phc v cho vic m

phng bi ton ti u ha.

Lun vn tt nghip Tng quan ti u ha vn chuyn du kh ____________________________________________________________________________

SVTH: Xun Ha MSSV: 30800690 1

CHNG 1: TNG QUAN V TI U HA VN CHUYN DU KH BNG NG NG KT NI

1.1. Tng quan v ti u ha vn chuyn du kh bng ng ng kt ni

Trn thc t, vic pht trin cc m nh l mt bi ton kh khn do c nhiu

ri ro, chi ph u t v vn hnh tnh trn mi n v thu hi ln. V vy, pht trin

cc m nh, vic la chn v p dng phng n cng ngh mi thch hp trong lnh

vc vn chuyn l u tin hng u. Trong , phng n pht trin kt ni bng

ng ng c nh gi cao v hiu qu kinh t t c. Vi phng n ny, cc h

thng thit b x l v c s h tng sn c cc m ln cn c tn dng kh hiu

qu cho vic pht trin cc m mi.

c mt s d n pht trin theo phng n ny bao gm m C Ng Vng

(l 09.2, Hon V JOC), m Nam Rng i Mi (l 09.3, cng ty VRJ) v Phng

ng (L 15.1, JVPC). M C Ng Vng v Nam Rng i Mi c ni v h

thng thit b ti m Bch H (Vietsovpetro), m Phng ng c kt ni vo h

thng thit b ca m Rng ng.

Vic chia x thit b thu gom, khai thc, x l v vn hnh chung gia cc m

ln cn gip gim thiu hng trm triu USD chi ph u t v pht trin khai thc.

Nhng bn cnh , cc ri ro lun tn ti i vi h thng ng ng kt ni kh di

gia cc m vi nhau nh lng ng paraffin gy tc nghn, ngng hot ng h thng

ng ng kt ni CNV-CPP3 (2008), s hnh thnh cc nt kh tc ng xu n

ng ng (s tch p trong ng ng gy nguy c n ng) v kh nng tip nhn ca

h thng bnh tch s cp (qu trnh bin i t ngt lng cht lng trc khi vo

bnh tch)... Trc tnh hnh thc t ny, vic kho st bi ton ti u ha vn chuyn

nhm m bo dng chy trong ng ng lun hot ng trng thi tt nht l rt

cn thit. C th, cng ty iu hnh chung du kh Hong Long Hon V JOC v

ang nghin cu vic x l ha phm gim nhit ng c cho du CNV, vic



phng thoi nh k no vt ng ng loi b paraffin lng ng trn thnh ng, lu

lng vn chuyn hp l nht cho mi giai on khai thc ph hp vi iu kin thc

t ca ng ng

1.2. Mc ch ca vic ti u ha vn chuyn du kh trong ng ng

Trn thc t, h thng ng ng vn chuyn du kh trong ng ng ngm

di bin ni m vi nhau lun i mt vi s dao ng p sut, nhit v lu lng

vn chuyn ca cht lu trong ng. Cc yu t ny c th gy ra s phc tp v tnh

mt n nh trong vn chuyn du kh c bit i vi cc h thng ng ng di

hng chc kilomet di y bin. V vy, cng tc ti u ha - m bo dng chy

trong ng ng lun c tin hnh thc hin vi mc ch xc nh ch lm vic

ti thiu m ti cht lu vn c th di chuyn c trong ng ng v tm ra

phng n hp l gim thiu ha ri ro trong qu trnh vn hnh, hnh 1.1.

Hnh 1.1 Mc ch ti u ha vn chuyn du kh trong ng ng

Ti u ha vn chuyn trong ng ng

Gim thiu ri ro

(Lng ng paraffin, tc nghn ng ng, hnh thnh nt kh )

Tit kim chi ph x l

(Ha phm c ch & gim nhit ng c, phng thoi )

m bo dng chy hot ng tt nht c th



1.3. Phng php ti u ha

Qu trnh vn chuyn du kh trong ng ng chu s tc ng bi kh nhiu

yu t t bn trong ln bn ngoi ng ng. V vy, tm ra phng php ti u

hiu qu hot ng vn chuyn trong ng ng, mc tiu ti u v cc thng s kim

sot qu trnh ti u cn phi c xc nh r. Sau , cc phng php ti u s

c xy dng da trn cc mc tiu v tnh hnh hot ng thc t ca ng ng vn

chuyn du kh.

1.3.1. Mc tiu ti u ha

m bo dng chy hot ng n nh trong ng ng vn chuyn, gim thiu

ri ro, ti thiu ha chi ph vn hnh.

1.3.2. Cc thng s kim sot qu trnh ti u ha

Qu trnh m bo dng chy ny lin quan n nhiu yu t v iu kin vn

hnh nh lu lng p sut, nhit , lng ha phm s dng gim nhit ng

c v nht ca cht lu.

1.3.3. Cc phng php s dng cho qu trnh ti u ha

Mt trong nhng nhim v quan trng trong qu trnh vn chuyn du kh bng

ng ng l ci thin cc ch thy lc (Hydraulic regime) da vo vic d bo v

cc iu kin nhit ng lc hc ca cht lu vn chuyn trong ng. thc hin c

iu ny, nhiu phng php s dng cho qu trnh ti u c nghin cu v ng

dng nh tng p sut vn chuyn, gia nhit v cch nhit dc ng ng, x l du

bng ha phm, kh cc lp lng ng trong ng ng (phng thoi no vt ng, bm

du nng, dng nc nng) Nhng trc khi cc phng php ny c a vo s

dng, vic xem xt tnh hnh v iu kin thc t v li ch kinh t phi c xem xt

v kim tra tht k lng i vi cc yu cu t ra cho mc tiu ti u.

Hin nay, da trn tnh hnh thc t ng ng kt ni t m C Ng Vng n

gin x l trung tm s 3 m Bch H, mt s phng php c s dng gii



quyt bi ton ti u ha bao gm cch nhit dc ng ng, x l du bng ha

phm, phng thoi no vt ng ng.

a. Cch nhit dc ng ng

Nhit dng du th c th c duy tr v gim thiu s tn tht bng cc lp

bc cch nhit, hnh 1.2 & bng 1.1. Vi h s truyn nhit 1.913 W/m2K cho ton b

tuyn ng, cc lp bc cch nhit c thit k sao cho nhit ca hn hp du kh

nm trn nhit hnh thnh tinh th paraffin (WAT).

Hnh 1.2 Cc lp bc cch nhit ng ng vn chuyn CNV CPP3 [9]



Bng 1.1 Cc c tnh c bn ca ng ng vn chuyn CNV CPP3 [9]

Yu t thit k Thng s Gi tr n v

Steel Pipe

ng knh ngoi 273.1 mm

B dy 20.1 mm

Vt liu API 5L X65 -

dn nhit 45 W/mK

T trng 7850 kg/m3

1st Layer of Coating

B dy 0.15 mm

Vt liu FBE -

dn nhit 0.3 W/mK

T trng 1450 kg/m3

2nd Layer of Coating

B dy 0.35 mm

Vt liu PP adhesive -

dn nhit 0.22 W/mK

T trng 1450 kg/m3

3rd Layer of Coating

B dy 3.5 mm

Vt liu Solid Polypropylene -

dn nhit 0.215 W/mK

T trng 900 kg/m3

4th Layer of Coating

B dy 26 mm

Vt liu PU Foam

dn nhit 0.04 W/mK

T trng 165 kg/m3

5th Layer of Coating

B dy 4 mm

Vt liu Solid Polypropylene

dn nhit 0.215 W/mK

T trng 900 kg/m3

Concrete Weght Coating

B dy 48.26 mm

T trng 2242.6 kg/m3



b. X l du bng ha phm

S dng ha phm gim nhit ng c trong x l du (nhng cht lm

gim nht v ng sut dch chuyn ti hn ca du) l phng php c nhiu trin

vng trong x l du nhiu paraffin vn chuyn bng ng ng.

nhit cao ha phm cho vo du s khng lm thay i nht ca du.

nh hng ca ha phm ch nhn thy nhit thp, khi m trong du din ra s

hnh thnh cu trc cc tinh th paraffin. Hin nay, cha c quan im thng nht v

c ch hot ng ca nhng ha phm gim nhit ng c. Tuy nhin, a s cc

nh nghin cu u nhn thy s hot ng lng tnh ca chng: th nht, nhng

phn t ha phm gim nhit ng c cng vi paraffin to ra nhng tinh th hn

hp, iu ny dn n cu to ca chng thay i v ngn chn s hnh thnh mng

li cu trc lin tc; th hai, nhng phn t ha phm gim nhit ng c ng

vai tr nh nhng trung tm m xung quanh chng paraffin b tinh th ha to nn

nhng hp th khng lin kt c vi nhau.

Tnh hiu qu s dng ha phm gim nhit ng c ph thuc vo bn

cht ha hc ca du. Khng c loi ha phm chung cho tt cc loi du. Thc t

quan st cho thy nhng tnh cht lu bin ca du m CNV c ci thin ng

k khi chng c x l bng ha phm gim nhit ng c. Kh nng gim nhit

ng c i vi du CNV khong 10 15oC.

c. Phng thoi no vt ng ng (Pigging)

Thc t cho thy qu trnh vn chuyn du CNV b nh hng bi kh nhiu

yu t nh s tn hao nhit trong h thng ng ng vn chuyn di, thnh phn cht

lu phc tp, nhit hnh thnh v ng c paraffin kh cao gy ra nhiu kh

khn trong cng tc x l v vn chuyn du kh. Khi cc bin php phng chng lng

ng paraffin trong ng ng khng t hiu qu, bin php c hc - phng thoi no

vt ng ng c thc hin nhm mc ch loi b paraffin ra khi ng ng.



T u nm 2010 n nay cng ty Hon V thc hin phng thoi nh k vo

mi thng v mi t thc hin phng 2 qu thoi:

- Con thoi th nht vi ng knh l 8.5" mc ch qut nhng cn sp trong ng ng.

Hnh 1.3 Hnh dng con thoi 8.5" - Con thoi th hai c nhim v qut ng ng v lm sch mt ln na vi

ng knh 9.25".

Hnh 1.4 Hnh dng con thoi 9.25"

Nguyn tc hot ng ca con thoi: Di p sut c thit lp y thoi pha

sau, ton b con thoi c nn theo chiu dc ng ng v m rng hon ton nh

mt ci nm vo ng ng. Di p sut cao t pha sau, cht lng s pht qua con

thoi c tc dng bi trn v lm mt con thoi, gip con thoi gi c c tnh v hnh

dng trong sut qu trnh di chuyn. Hnh ng phun ny rt quan trng, n cng gip

cho qu trnh ct cc lp cn sp trn ng ng, lm cho cc lp lng ng trn

ng ng b mm, lng lo, trc khi con thoi qut qua.

Lun vn tt nghip L thuyt dng chy a pha trong ng ng ____________________________________________________________________________


CHNG 2: C S L THUYT DNG CHY A PHA TRONG NG NG VN CHUYN

2.1. Tng quan v dng chy a pha

Dng chy a pha l dng dng chy rt hay gp trong ngnh cng nghip du

kh. Loi dng chy ny xut hin xuyn sut t qu trnh khai thc n qu trnh x l

v vn chuyn bng ng ng. Vic hiu bit mt cch y v chnh xc v dng

chy a pha l mt vn rt kh khn v phc tp. Nhiu cng trnh nghin cu v

dng chy a pha c thc hin t nhng nm 1950. Cho n nay vn cha c mt

m hnh thng nht v chnh xc p dng cho vic tnh ton c th i vi dng chy

trong h thng khai thc v vn chuyn. Hu ht cc m hnh thng c tin hnh

thng qua thc nghim, v vy, kt qu vn ch dng li mc tng i.

Khi nghin cu v dng chy hai pha trong ng ng, c rt nhiu thng s

lin quan tng tc ln nhau. Trong , s khc nhau v t trng v nht lm cho

vn tc gia cc pha kh v lng khc bit nhau trong ng ng. i vi dng hng

ln, pha kh c mt v nht thp hn c khuynh hng di chuyn vi vn tc cao

hn so vi pha lng. Ngc li, i vi dng hng xung, pha lng thng di chuyn

nhanh hn pha kh. Ngoi ra, cc thng s nh ch dng chy, tn hao p sut, t

phn lng cng l mt trong nhng thng s kh quan trng khi nghin cu v dng

chy a pha.

2.1.1 Cc ch dng chy trong ng ng nm ngang

Trong ng ng nm ngang, dng chy a pha c th thay i thnh nhiu ch

dng chy khc nhau. i vi dng chy hai pha kh lng th c th tn ti cc

ch dng chy nh hnh 2.1:



- Dng chy bt kh: cc pha kh tn ti di dng bong bng kh nh v

phn tn trong pha lng. Khi vn tc pha lng tng ln, kch thc ca cc

bong bng kh ny tng do s tch t cc bong bng kh nh li vi nhau.

Cui cng, mt dy lin tc cc bong bng kh c hnh thnh trong pha

lng v c khuynh hng tp trung gn pha trn thnh ng.

- Dng chy dng nt: t dng chy bt, khi vn tc ca pha kh c tng

ln, cc bong bng kh s kt t li vi nhau to thnh nhng bong bng kh

ln hn, di hn v c dng nn. Nhng bong bng kh ny hay c gi l

bt kh Taylor. Dng chy dng nt gm c bt kh Taylor, b tch bit trong

vng dng chy dng bt kh c gi l nt.

Nhng nt cht lng ny c th lm cho p sut trong ng ng thay i

bt thng trong qu trnh vn hnh, gy ra nhng tc ng xu i vi cc

thit b vn chuyn v x l.

- Dng chy dng bt ko di (Elongated bubble flow): c cu trc tng

t nh dng chy dng nt, nhng cc bt kh b tc nghn mt thi gian

ngn, v vy, dng chy tr nn gin on, nhng bt kh nh hn v di

chuyn chm hn so vi dng chy dng nt.

- Dng chy dng phn tng: pha lng phn b dc theo pha di tuyn

ng, pha kh nm trn pha lng v c ngn cch nhau bi mt phn gii

kh-lng.

Loi dng chy ny c khuynh hng xut hin nhiu ti nhng oan ng

ng c dc xung v dng chy nm ngang vi cht lu c tc thp.

- Dng chy dng sng: xut hin khi vn tc ca pha kh trong dng chy

dng phn tng tng ln, cc dao ng ca sng bt u hnh thnh ln dn.

Cc gn sng ny c th t c n thnh ng.

- Dng chy dng vnh xuyn: ch dng chy vnh xuyn c c im l

mng cht lng tri quanh thnh ng bao bc phn li kh bn trong chuyn

ng vi vn tc cao v trong li kh cn c nhng git cht lng nh.



Hnh 2.1 Cc ch dng chy trong ng ng nm ngang [3]

2.1.2 Cc ch dng chy trong ng ng thng ng

Trong ng ng thng ng, dng chy hai pha c th c phn loi thnh

cc ch dng chy nh hnh 2.2.

Hnh 2.2 Cc ch dng chy trong ng ng thng ng [3]

Cht lng c vn tc thp th cht kh c sinh ra trong du b phn tn nh cc

bt kh ring bit. Ch dng chy ny c gi l dng chy dng bt kh.

T dng chy dng bt kh, khi tng vn tc dng chy ca pha kh, cc bt kh s

kt t li vi nhau to thnh bt kh ln hn, di hn v c hnh dng nn. Nhng bt



kh ny c gi l bt kh Taylor. Dng chy dng nt gm c bt kh Taylor, b tch

bit trong vng dng chy dng bt kh c gi l nt, v mt lp cht lng bao xung

quanh bt kh Taylor c xu hng chy xung. S phn b ca cc bt kh Taylor

trong dng chy thng ng c tnh i xng.

dng chy dng khuy, hay cn c gi l dng si bt, cc bt kh v nt kh

tr nn b bin dng nhiu v xut hin s ho ln vo nhau khi pha kh c vn tc

dng chy ln. S khc bit gia dng chy dng nt kh v dng chy khuy l mng

cht lng bao quanh nt kh s khng xut hin dng chy khuy.

Ch dng chy vnh xuyn c c im l mng cht lng tri quanh thnh

ng bao bc phn li kh bn trong chuyn ng vi vn tc cao v trong li kh cn c

nhng git cht lng nh. Dng chy i ln ca lp mng cht lng ny ngc vi

trng lc l kt qu do lc tc ng ca li kh c vn tc chuyn ng ln.

2.1.3 Biu ch dng chy (Flow regime maps)

V tr tng i ca pha lng i vi pha kh trong qu trnh vn chuyn bng

ng ng to nn cc dng cu trc v ch dng chy khc nhau. Vic xc nh

ch dng chy trong ng ng vn chuyn du kh l rt cn thit cho qu trnh

tnh ton v m phng. Nhiu cng trnh nghin cu a ra cc phng php khc

nhau nhm d bo ch dng chy ca cht lu trong ng ng. mi phng

php, cc ch dng chy thng c biu din trn cc biu , hay cn gi l

biu ch dng chy.

Thng thng trn biu , ch dng chy c xc nh da vo hai thng

s c bn khng th nguyn l h s Froude v hm lng th tch kh hoc t phn

lng iu kin khng trt L (No-slip liquid fraction), chng c biu din trn ta

log log. Cc thng s khng th nguyn ny c trng cho vn tc ca cc pha kh

v pha lng. Mt s phng php c s dng ph bin nh Beggs & Brill (1973),

Taitel & Dukler (1976).



Trong phng php Beggs & Brill (1973) cho dng chy nm ngang hnh 2.3,

tc gi da vo cc nhm khng th nguyn Froude, FrM v t phn lng iu

kin khng trt L :

( )2 2

G G L L MM

v v vFrgD gD

+= = (2.1)

L LLG G L L

vv v

=+

(2.2)

Cc ch dng chy c xc nh da trn bn h s Froude.

0.3021 316 LFr = (2.3) 2.46842 0.0009252 LFr = (2.4)

1.45163 0.10 LFr = (2.5)

6.7384 0.5 LFr = (2.6)

Ch dng chy n (Segregated) nu:

10.01,L MFr Fr < < hoc 20.01,L MFr Fr <

Ch dng chy chuyn tip (Transient) nu:

2 30.01,L MFr Fr Fr

Ch dng chy gin on (Intermittent) nu:

3 10.01 0.4,L MFr Fr Fr < < hoc 3 40.4,L MFr Fr Fr

Ch dng chy phn tn (Distributed) nu:

10.4,L MFr Fr < hoc 10.4,L MFr Fr >



Hnh 2.3 Biu ch dng chy Beggs & Brill (1973) cho ng ngang [3]

Nh m hnh dng chy Beggs & Brill (1973), Taitel & Duckler (1976) xy

dng ln phng php xc nh ch dng chy trong ng ng da trn s hi t

ca phng trnh (2.7):

( ) ( )2 2 21 1 sin 02 8 8

GL G GL GW G GW LW L LWG L G L G L

G L G G G L L

f O f O f Ov v v v gA A A

+ + =

(2.7)

Trong ,

G, L : ln lt l t phn pha kh, pha lng, vG , vL : ln lt l vn tc pha kh, pha lng, A, O : mt ct tit din, G, L : ln lt l t trng pha kh, pha lng, f : h s ma st c tnh t phng trnh (2.8), (2.9).

64

0.184G

G0.2

GW-

Re

Re

for laminar flow

for turbulent flowf

= (2.8)



64

0.184GL

G0.2

GL-

Re

Re

for laminar flow

for turbulent flowf

= (2.9)

Khi phng trnh (2.7) hi t, ch dng chy tng c xc nh t (2.10):

( )*0.5

cos1 L G G

G GL

LG B

g Ahvd S

= (2.10)

Trong ,

d : ng knh ng, hL : chiu cao ct cht lng, SGL : mt ct tit din dng chy phn tng.

Phng trnh (2.11) xc nh s n nh (Smooth) hay s gn sng (Wave) trong

ch dng chy tng:

( )*0.5

4 cosL L GL G L

G w

gv

s v

= (2.11)

Nu phng trnh (2.10) khng tha ch dng chy tng, th ch dng chy

bt phn tn c xc nh phng trnh (2.12).

*0.5

4 cos 1G GD

GL LL

A gvS f

= (2.12)

Nu phng trnh (2.12) vn cha tha, ch dng chy c tip tc xc nh

iu kin sau:

*

*

0.35

0.35LG G B

LG G B

Annular flow if v v and h d

Slug flow if v v and h d

> >



Hnh 2.4 Biu ch dng chy Taitel v Dukler (1976) cho ng ngang [3]

2.2 C s tnh ton v xy dng m hnh dng chy hai pha

Trong bi bo (Kjell H. Bendlksen, Dag Malnes, Randi Moe, and Sven Nuland,

Inst. for Energy Technology, 1991), cc tc gi xy dng v kim chng thnh cng

m hnh ng hc cho dng chy hai pha da trn cc phng trnh bo ton khi

lng, ng lng, nng lng trn mi pha v cc s liu thc t.

2.2.1. Phng trnh bo ton khi lng

i vi pha kh,

( ) ( )1G G G G G G GA v Gt A x = + +

(2.13)

Mng lng trn thnh ng,

( ) ( )1 L eL L L L L LG dL D

A v Gt A x

= + + +

(2.14)



Cc git lng,

( ) ( )1 D eD L D D D DG dL D

A v Gt A x

= + + +

(2.15)

Trong :

G, L, D : ln lt l t phn pha kh, pha lng v cc git lng,

vG, vL, vD : ln lt l vn tc pha kh, pha lng v cc git lng,

A : mt ct tit din ca ng,

G : t l truyn khi gia cc pha,

e, d : t l sinh ra v lng ng cc pha,

Gf : lu lng khi lng ca pha f,

Cc k hiu g, L, i v D ch pha kh, pha lng, mt phn cch cc pha

v cc git lng.

2.2.2. Phng trnh bo ton ng lng

i vi pha kh,

( ) ( )21 12 4

1 cos2 4

GG G G G G G G G G G G

ii r r a DG G G G

Spv V A v v vt x A x A

Sv v V g v FA

=

+ + (2.16)

Cc git lng,

( ) ( )21 cosD L D D D L D D LD

a e i D DG dL D

pv V A v V gt x A x

V v v v FV V

= +

+ ++

(2.17)



Kt hp phng trnh (2.16) v (2.17), ta c phng trnh bo ton ng lng

cho kh/cc git lng:

( ) ( ) ( )

( )

2 21

1 1 cos2 4 2 4

D L D D D L DG G G G G G G

G ii r r D LG G G G G G G

La e i DG d

L D

pv v V V A v A vt x A x

S Sv v v v V V gA A

V v v vV V

+ = + +

+ +

+ + +

(2.18)

Mng lng trn thnh ng,

( ) ( )

( )

21 12 4

1 cos2 4

sin

LL L L L L L L L L L L

i Li r r a e iL LG G

L D

LgD L Ld

Spv V A v v vt x A x A

S Vv v V g v vA V V

Vv V d gx

=

+ + +

+

(2.19)

Trong ,

: gc nghing ca ng ng so vi phng thng ng, SG, SL, Si : ln lt l chu vi thm t ca pha kh, pha lng v mt

phn cch cc pha.

2.2.3. Phng trnh bo ton nng lng

Phng trnh bo ton nng lng cho c hn hp:

2 2 2

2 2 2

1 1 12 2 2

1 1 12 2 2

g g g g gL L L D

g g g g L L L L D D D D S

m E v gh m E v gh m E v ght

m v H v gh m v H v gh m v H v gh H Ux

+ + + + + + + +

= + + + + + + + + + +

(2.20)



Trong ,

E : ni nng trn mt n v khi lng, h : chnh cao ca ng, Hs : enthalpy ca lu cht, U : s truyn nhit t thnh ng.

2.2.4. Phng trnh p sut

c tnh v t trng ca cht lu di chuyn trong ng ng c gi thit l

hm ca p sut, nhit v t phn khi lng ca kh:

( ), ,f f sp T R = (2.21)

Trong ,

GsL DG

mRm m m

=+ +

(2.22)

mG, mL, mD ln lt l khi lng ring ca pha kh, mng lng, v cc git lng trn ng ng.

S dng cc phng trnh (2.13), (2.14), (2.15) kt hp vi phng trnh (2.21),

(2.22), ta c c phng trnh p sut cho c h thng:

( )

( ) ( ),,

1 1

1 1 1 1

1 1 1

ss

g G G GG G L

LG GT RT R

L L L L L LG

L L LG

L DGL LG

A vpp p t A z

A v A vA z A z

G G G

+ =

+

+ + +

(2.23)

2.2.5. S truyn khi gia b mt phn cch cc pha

S chuyn pha l mt hm ca p sut v nhit :

( ), , sG G p T R = (2.24)



Trong ,

( )s s s s L DG GpT T p

R R R Rp p z T T z m m mp t p z t p t T z t

= + + + + +

(2.25)

Vi sT

R pp t

l s truyn khi t khi lng ban u khi c s thay i p

sut trong mt on ng; sT

R p zp z t

l s truyn khi khi c mt dng chy i t

v tr ny sang v tr khc trong mt on ng.

2.3. Cc tnh cht c bn ca cht lu vn chuyn trong ng ng 2.3.1. Tnh lu bin

c tnh ph thuc ca dng chy theo ng sut trt gia hai lp cht lng v

nht gi l tnh lu bin ca cht lng. V tng qut, tnh lu bin ph thuc vo

cc thng s nh nht ng hc, ng sut trt, vn tc trt, nhit v p sut.

a. nht ng hc

nht ng hc () l mt c tnh ca lu cht, th hin kh nng chng li

s dch chuyn tng i gia cc phn t ca lu cht, c nh ngha bng t s

gia ng sut trt () v tc trt ().

= (2.26)

b. ng sut trt

ng sut trt () l i lng c trng cho bn cu trc (hay tnh lu bin)

ca cht lu trong ng, c tnh bng lc (F) trn mt n v din tch b mt (A) m

cht lu trt qua.

FA

= (2.27)



T khi nim v tnh lu bin v c tnh nht, cht lng c chia thnh hai

loi bao gm cht lng Newton v cht lng phi Newton.

Hnh 2.5 Cc m hnh cht lng Newton v phi Newton [2]

i. Cht lng Newton i vi cht lng Newton, nht ph thuc vo tc ct. V vy, khi vn tc

ca cht lng Newton trong ng tng, ng sut trt ti thnh ng cng tng theo.

. . vy

= = (2.28)

Trong ,

: tc trt, (N/m2)

: nht ng hc,

vy

: gradient vn tc (y = d/2 r, trong d l ng knh ng, r bn knh

tnh t tm ng n im kho st nh hnh 2.6).



Hnh 2.6 Hnh v biu din ng sut trt ca cht lng Newton [2]

Trong m hnh cht lng Newton, quan h gia v vy

l tuyn tnh, l mt

ng thng qua gc ta vi h s gc .

ii. Cht lng phi Newton

i vi cht lng phi Newton, nht khng ph thuc vo tc trt. Cc

m hnh ca cht lng phi Newton bao gm m hnh Hershel-Buckley, m hnh cht

lng do Bingham (Birmingham plastic), m hnh cht lng gi do Ostwald

(Pseudoplastic), m hnh Dilatant.

- M hnh cht lng nht - do khng tuyn tnh (Hershel-Buckley)

M hnh Hershel-Buckley:

0 0. .n

n vk ky

= + = + (2.29)

ng cong chy ca m hnh Hershel-Buckley c m t hnh 2.5. M

hnh Hershel-Buckley l m hnh tng qut cho cc loi cht lng.

Khi o = 0, n =1 ta c m hnh Newton : .vy

=



Khi o = const, n = 1 ta c m hnh Bingham : 0 .pvy

= +

Khi o = 0, n < 1 ta c m hnh Ostwald : .n

vky

=

Khi o = 0, n > 1 ta c m hnh Dilatant : .n

vky

=

- M hnh cht lng nht do Bingham (Birmingham plastic)

Tt c nhng quan h trong pha lng b rng buc bi mt cu trc mng

cht rn (mng tinh th paraffin trong du th), h ch c kh nng chuyn ng khi

h thng mng b ph v. Khi h thng mng b ph v hon ton, dng chy tun theo

quy lut ca cht lng Newton th h c gi l cht lng nht do Bingham.

Cc nghin cu m hnh lu bin ca du m chng minh rng iu kin nhit

ng c, dng chy ca du tun theo m hnh Bingham. S dng m hnh

Bingham trong nghin cu du nhiu paraffin nht cao c trnh by trong cc

cng trnh nghin cu l thuyt v thc nghim ca Mirzanzadeh, Gubin. Phng trnh

lu bin:

( )

0

0

0 0

0YP + PV. .

1p

p

v ifyv withvy ify

= > = = + =

(2.30)

Nu 0 , lc ny cht lng khng chy,

Nu 0 > , xut hin chy nht.

Trong ,

YP : gii hn chy (yield point), PV - p : nht do (plastic viscosity), o : ng sut trt tnh (ng sut trt ti hn), (Pa).



ng sut trt tnh l gi tr m p lc tip tuyn phi thng c gy ra s

trt gia hai lp ln cn, khi s qu trnh ph hy cu trc trong du to ra dng

chy. o pht sinh do qu trnh ti to cu trc du trng thi tnh c nhit thp nn

n l hm s ca thi gian tnh (thi gian ngng vn hnh). Thi gian cng di th cu

trc cng bn v o cng tng, ko theo s tng ca ng sut trt v do n lm

tng p sut khi ng ng ng.

- M hnh cht lng gi do Ostwald (Pseudoplastic)

Cht lng gi do l nhng cht lng c nht gim nhanh khi gradient vn

tc tng. Hin tng gim nht khc vi cht lng Bingham, cht lng gi do

bt u chy khi gi tr ca cn rt nh. S ph thuc ca ng sut trt vo vn tc

l ng cong i qua gc ta v c biu din bng phng trnh c dng hm s

m.

. 1n

vk with ny

= (2.32)



c. Tnh cht phi Newton ca du C Ng Vng (CNV)

Khi nhit thay i, tnh cht lu bin ca du cng thay i theo. Thc t du

th m CNV cho thy, khi nhit ca du ln hn 35oC th du l cht lng

Newton, cn khi nhit ca du nh hn 35oC th du CNV lc ny tr thnh cht

lng phi Newton, c th l cht lng Bingham. iu ny c th gii thch l do trong

du th CNV c cha mt hm lng paraffin kh cao nn nhit ng c ca du

cao.

Khi nhit ca du thp th cu trc ca cht keo nha tr nn bn vng hn

dn n nht ca du cao, du s tr nn c snh hn (nht - do) th hin c

tnh cht ca cht lng phi Newton. Ngc li, khi nhit ca du cao, cc cu trc

ca paraffin b ph v, nht gim, th hin c tnh cht ca cht lng Newton.

2.3.2. Nhit kt tinh

Nhit kt tinh (WAT) l nhit m ti cc tinh th paraffin bt u xut

hin hay cn gi l im m (CP). Ti nhit i im CP, cc tinh th bt u tng

dn. Cc tinh th ny c th hnh thnh di dng khi lng, nhng ht nh v di

chuyn dc theo ng ng cng vi s di chuyn ca cht lu hoc lng ng li

nhng b mt c nhit thp.

2.3.3. Nhit ng c

Nhit ng c ca du l nhit m ti y du khng cn kh nng di

chuyn (khng linh ng na) hay nhit m ti y du bt u chuyn t trng thi

lng sang trng thi rn. Nhit ca du ph thuc vo thnh phn hydrocacbon, cc

cht keo nha. Hm lng paraffin, c bit l cc cu t nng s quyt nh nhit

ng c ca du.



2.3.4. nh hng ha phm gim nhit ng c n cc tnh cht ca cht lu

Cht lm gim nhit ng c (PPD) l mt cu t quan trng s dng trong

khai thc v vn chuyn du th. Ty thuc vo thnh phn v tnh cht ca du th m

ngi ta a ra mt PPD thch hp nhm t c hiu qu tc dng ti u.

Vic nghin cu a ra cht lm gim nhit ng c (PPD) cho du th m

C Ng Vng (CNV) nhm p ng yu cu m bo dng chy trong qu trnh khai

thc v vn chuyn du.

PPD cn c tc dng c ch qu trnh kt tinh & pht trin tinh th paraffin c

trong du th v qua ci thin tnh cht chy ca du th. Thnh phn v t l cc

hp cht ha hc c trong du th nh hng n hiu qu tc dng ca PPD v v th

i vi tng mu du cn nghin cu a ra loi PPD ph hp.

Thng thng PPD gm 03 nhm cu t chnh: nhm cht iu chnh tinh th

paraffin, nhm cht phn tn paraffin v nhm dung mi. Cht iu chnh thng l

cc hp cht, cc polime hoc copolime nh 2-hydroxy-naphtalene, polyethylene,

copolyme ethylene-butene, copolime ethylene-vinylaxetate, copolime olefin-ester,

polyacrylate, polymethacrylate, nha alkylphenol Cc cht ny cng kt tinh vi

paraffin v ngn cn s pht trin tinh th paraffin bng cch lm cho cc tinh th

paraffin c kch thc nh dn.

Cht phn tn paraffin l cc cht hot ng b mt c tc dng h tr phn tn

cc tinh th paraffin, lm gim nht ca du v ma st gia du v thnh ng, chng

s kt t v pht trin tinh th. l cc hp cht nh l asphaltene trong du th, cc

hp cht sunphonat, dn xut ca alkylphenol, ketone, terpene, polyamide,

naphtalene

Dung mi c s dng lm mi trng ha tan/phn tn cc cht iu chnh v

phn tn paraffin. Vic s dng dung mi/hn hp dung mi ph thuc vo cc nghin



cu ph hp vi cc thnh phn ca PPD. Mt s cng trnh cng b ch ra rng

dung mi cng c nh hng n nhit ng c ca du th.

Hnh 2.7 Cc tinh th paraffin trc (tri) v sau (phi) khi s dng ha phm [16]

Vic s dng mt hay nhiu cht iu chnh tinh th, cht phn tn v dung mi

ph thuc vo tc dng ca chng ti nhit ng c v tnh cht chy ca du th.

Nhm tm ra loi PPD th hp nht s dng, cc mu du th CNV c tin

hnh thu thp v th nghim vi cc cht lm gim nhit ng c khc nhau

(Bng 2.1) theo tiu chun ASTM D5853.

Bng 2.1 Bng lit k cc cht PPD s dng cho vic sng lc

Stt PPD 1 Baker's Sepaflux 2 EC5351A 3 EC6393A 4 EC6393B 5 EC6509A 6 EC6560A 7 VX7951 8 VX9788 9 VX9589 + 500ppm EC6508A

10 VX9590 + 500ppm EC6508A 11 VX9591 + 500ppm EC6508A



Kt qu kho st nh hng ca cc cht lm gim nhit ng c n du

th CNV c trnh by hnh 2.8.

Hnh 2.8 Kt qu th nghim cc cht lm gim nhit ng c khc nhau vi cc liu lng khc nhau

Quan st th t hnh 2.8, cc cht lm gim nhit ng c sau khi c

sng lc l Baker's Sepaflux, EC5351A, EC6509A, VX9591 + 500ppm EC6508A. Cc

kt qu ny s c tip tc sng lc cho ti khi tm ra c cht PPD tt nht.

Tin hnh s dng cc cht Baker's Sepaflux, EC5351A, EC6509A, VX9591 +

500ppm EC6508A vi liu lng 1000ppm nh gi nh hng ca chng n

nht ng hc v cn ban u i vi du th CNV. Kt qu c biu din hnh

2.9, hnh 2.10 v bng 2.2

0

5

10

15

20

25

30

35

Baker'sSepaflux

EC5351A EC6393A EC6393B EC6509A EC6560A VX7951 VX9788 VX9589 +500ppm

EC6508A

VX9590 +500ppm

EC6508A

VX9591 +500ppm

EC6508A

Tem

pera

ture

(oC

)

Pour Point Chemicals for manual screening

0ppm 500ppm 1000ppm 1250ppm 1500ppm



Hnh 2.9 nh hng ca cc cht PPD vi liu lng 1000ppm n cn ban u

Hnh 2.10 nh hng ca cc cht PPD vi liu lng 1000ppm n nht ng

hc du ca CNV



Bng 2.2 Bng kt qu nh gi hiu qu s dng cc loi PPD khc nhau

PPD Liu lng nht ng hc ti 15oC, [Pa]

cn ban u ti 15oC, [Pa]

Blank - 1270 80

EC5351A 1000pm 227 30

EC6509A 1000pm 130 14

NES 320 - 155 + 500ppm EC6508A 1000pm 488 56

Baker's Sepaflux 1000pm 275 54

Qua qu trnh sng lc cc cht PPD, kt qu bng 2.2 cho thy rng sn phm

EC6509A c nh gi tt nht trong s cc sn phm trn, n c th lm nhit

ng c ca du th CNV gim t 33oC xung cn 18oC, bn cnh , nht ng

hc v cn ban u (Yield value) i vi du th CNV khi x l bng EC6509A t

gi tr thp hn so vi cc sn phm khc.

Lun vn tt nghip Ti u ha qu trnh vn chuyn du kh ____________________________________________________________________________


CHNG 3: M PHNG QU TRNH NHIT THY NG DNG CHY TRONG NG NG KT NI M C NG VNG N M BCH H V XUT PHNG N TI U HA QU TRNH VN CHUYN HN HP DU KH

3.1. Tng quan h thng kt ni m C Ng Vng m Bch H

3.1.1. Gii thiu chung m C Ng Vng

M C Ng Vng (CNV) c pht hin vo thng 9 nm 2002, nm l 09.2

thuc khu vc bn trng Cu Long trn vng bin Bnh Thun cch m Bch H 17km

v pha ng bc vi ta = 090 50' 43,38 "N - 1800 09' 22,37" E, vi su mc

nc bin xp x 60m nc. M C Ng Vng c iu hnh bi cng ty lin doanh

iu hnh chung Hong Long Hon V JOCs, do x nghip lin doanh Vietsovpetro

vn hnh v bo dng v c a vo khai thc t ngy 25 thng 7 nm 2008.

` Hnh 3.1 S v tr m C Ng Vng [9]



Khu vc m C Ng Vng thng xuyn chu nh hng trc tip ca hai loi

gi ma r rt :

+ Gi ma Ty Nam thnh hnh t thng 4 n thng 9 trong nm. + Gi ma ng - Bc thnh hnh t thng 10 nm trc n thng 3 nm sau.

Trong ma gi chng sc mnh cp 6, cp 7, c lc ln trn cp 7, cao sng

t 3 5m, nhit y bin thp 20 21oC nh hng rt ln n qu trnh

khai thc v vn chuyn hn hp du kh.

3.1.2. H thng ng ng kt ni CNV CPP3

Hnh 3.2 S vn chuyn du kh t CNV WHP [9]

Gin u ging C Ng Vng (CNV WHP) c xy dng trn phn trung tm

ca m cch y bin 55m v c kt ni vi gin cng ngh trung tm s 3 (CPP-3)

cch y bin 46,5m thuc m BH ca x nghip lin doanh du kh Vietsovpetro bng

hai tuyn ng ngm vi ng knh 10 inches (Bng 3.1). y l tuyn ng ngm khai

thc vi cng dng vn chuyn sn phm hydrocacbon t m CNV v gin CPP-3 m

BH x l. Sau , du thng phm s c bm n cc tu cha du FSO 01

ca Vietsopetro v phn kh s c vn chuyn v b n nh my Dinh C, tuyn



ng ngm th hai l tuyn ng bm p vi cng dng vn chuyn nc bm p t gin

CPP-3 n CNV WHP bm vo ging duy tr p sut va. Khong cch t gin u

ging CNV WHP n CPP-3 l 25km.

Bng 3.1 Cc c tnh k thut ca ng ng ngm khai thc [9]

S TT M t Thng s k thut

1 ng knh ngoi (mm) 273.1

2 Chiu dy thnh ng (mm) 20.10

3 ng knh trong (mm) 232.9

4 Mc thp lm ng ng API 5L X65

5 Mc thp lm ng cong API 5L X65

6 Lc ko ti a ca vt liu lm ng SMYS (MPa) 448.27

7 Lc ko ti a ca vt liu lm ng cong SMYS (MPa) 448.27

8 Chiu di thit k (m) 24,917

9 Chiu di thc t lp t (m) 25,177

10 Lp bc cch nhit 41.9mm PU

11 Lp bc b tng 53.5mm

12 Lp bc gia cc mi hn 33mm PU

13 Lp bc ca on ng ng 12.7mm

14 Th tch mi m chiu di ng (m3/m) 0.043

15 Dng mt bch lin kt 1500# RTJ

16 p sut vn hnh ti a 22.8 MPa

17 p sut th thy lc 34.1 MPa

18 p sut u vo ng ng (pha CNV WHP) 710 - 750 Psi

19 p sut u ra ng ng (pha CPP-3) 500 - 560 Psi

20 Nhit u vo ng ng 75oC

21 Nhit u ra ng ng 43oC

22 Cng sut vn chuyn thit k 20,000 bbl/ngy

23 Lu lng vn chuyn thc t 7,500 bbl/ngy



Gin CNV WHP c thit k vn hnh theo ch khng c ngi trn

gin, c gim st vn hnh, iu khin t gin cng ngh CPP-3. S lng thit b,

phng tin phc v sn xut trn gin c hn ch ti a tit kim chi ph xy

dng. vn hnh khai thc m CNV c hiu qu, cng ty Hon V t ng ho

cc thit b iu khin, ng dng cc phn mm tin tin nh : HYSYS, OLGA,

PIPESIM nhm vn hnh cc thit b ca m CNV hiu qu nht.

3.1.3. Thnh phn v tnh cht du th CNV a. Thnh phn & cc thng s c bn ca du th CNV

Bng 3.2 Kt qu phn tch cc thnh phn trong du th 9.2-CNV-4XST, DST#1

Thnh phn Mol, [%] Wt, [%] T trng [g/m3] Mol wt

H2S - Hydrogen Sulfide 0 0 0.8006 34.08 N2 - Nitrogen 0.303 0.168 0.8086 28.01 CO2 - Carbon Dioxide 0.033 0.029 0.8172 44.01

C1 - Methane 62.96 20.05 0.2997 16.04

C2 - Ethane 10.51 6.273 0.3562 30.07

C3 - Propane 6.265 5.482 0.507 44.1

iC4 - i-butane 1.343 1.549 0.5629 58.12

nC4 - n-butane 2.404 2.773 0.584 58.12

C5 - i-pentane 0.924 1.324 0.6244 72.15

nC5 -n-pentane 1.036 1.483 0.6311 72.15

C6 - Hexanes 1.59 2.651 0.685 84

C7 - Heptanes 1.879 3.579 0.7222 96

C8 - Octanes 1.486 3.155 0.745 107

C9 - Nonanes 1.338 3.212 0.764 121

C10 - Decanes 0.965 2.567 0.778 134

C11 - Undecanes 0.75 2.187 0.789 147

C12 - Dodecanes 0.585 1.871 0.8 161

C13 - Tridecanes 0.6 2.083 0.811 175

C14 - Tetradecanes 0.453 1.709 0.822 190

C15 - Pentadecanes 0.411 1.679 0.832 206



C16 - Hexadecanes 0.293 1.29 0.839 222

C17 - Heptadecanes 0.284 1.335 0.847 237

C18 - Octadecanes 0.269 1.341 0.852 251

C19 - Nonadecanes 0.247 1.287 0.857 263

C20 - Eicosanesplus 3.067 30.93 - 508.3

Bng 3.3 Cc thng s c bn ca du th CNV

Stt Thng s Phng php n v Kq phn tch

1 API @ 60 oF ASTM D 5002 - 99 oAPI 43.3 44.6

2 T trng @ 15oC ASTM D 5002 - 99 g/mL 0.8071

3

nht ng hc @ 55 oC ASTM D 445 - 03 cSt 2.467



4 Hm lng Asphaltene IP 143/78 % < 0.05

5 Hm lng Paraffin UOP 46 % 18.1

6 Hm lng axit ASTM D 664 - 01 mgKOH/g 0.26

7 WAT (STO) DSC

CPM oC

51.8

53.9

WAT (Live Oil) NIR oC 49.4

8 PP (Live Oil) Corelab SOP oC 27

9 Hm lng nc ASTM D 6304 - 03 % 0.32

10 im nng chy (MP) ASTM D 87 - 87 oC 45.3

11 Khi lng ring ASTM D 5002 - 99 Kg/m3 813,2

12 Hm lng kh trong du (GOR) ASTM D 5002 - 99 Scf/bbl 2694

Bng 3.3 cho thy hm lng asphaltene trong du CNV tng i thp, nh

hn 0,05 % trng lng ton phn. Hm lng paraffin c trong thnh phn cht lu l

kh cao 18,1 %. S c mt ca paraffin vi hm lng cao lm cho du th mt tnh

linh ng.



b. Kh nng lng ng paraffin ca du CNV

Qua nghin cu v phn tch mu du 9.2-CNV-4XST, DST #1 ca m CNV do

Core Lab Reservoir Optimization thc hin thu c kt qu v kh nng lng ng

paraffin ca du CNV, bng 3.4 & 3.5.

Bng 3.4 Kt qu phn tch kh nng lng ng ca du CNV

Nhit ban u ca du [oC]

Nhit du sau khi lm lnh [oC]

T l lng ng [kgm-2hr-1]

60 55 0.0320 55 50 0.0336 50 45 0.0368 45 40 0.0370 40 35 0.0649 35 30 0.5945 30 25 1.3811

Hnh 3.3 th biu din s thay i tc lng ng paraffin khi gim nhit

0

0.2

0.4

0.6

0.8

1

1.2

1.4

20 25 30 35 40 45 50 55 60

T l

ln

g

ng p

araf

fin k

g/m

2 .hr

Nhit lm lnh oC

T l lng ng paraffin & Nhit lm lnh

Tc lng ng paraffin vi cc nhit khc nhau



Bng 3.5 Kt qu phn tch hm lng ha tan paraffin trong du theo nhit

Nhit

[oC]

Hm lng paraffin

ha tan trong du, [%]

Hm lng paraffin

kt tinh, [%]

55 17.9 0.2 50 17.1 1.0 45 16.6 1.5 40 16.3 1.8 35 16.1 2.0 30 15.5 2.6 25 14.4 3.7

Hnh 3.4 th biu din hm lng % paraffin ha tan trong du theo nhit

Qua cc kt qu phn tch t bng 3.4, 3.5 kt hp vi hnh 3.3, 3.4, khi nhit

cht lu gim dn th tc lng ng tng nhanh, phn trm trng lng paraffin

trong du cng tng. V ngc li, nhit cht lu trong ng ng tng th phn

trm trng lng paraffin du cng gim dn.

- Tc ng c ln ti nh khi nhit cht lu vo khong 25oC, ti

du b ng c hon ton.

14

15

16

17

18

19

20

202530354045505560

Hm

ln

g pa

raff

in %

Nhit oC

Hm lng ha tan paraffintrong du



- Tc ng c gim ti thiu khi nhit cht lng vo khong 55o C, ti

du ang b nng chy hon ton.

- T l ha tan paraffin trong du 55o C l 17 - 19%, 25 oC l 14 - 15 %.

c. Tnh lu bin du th CNV

Bng 3.6 Cc gi tr nht ng lc du CNV cc nhit khc nhau

nht ng lc, [cP] Nhit

[oC]

Stock Tank Oil Live Crude

Tc trt 20 (1/s) Tc trt

35(1/s) Tc trt

50(1/s) Tc trt

20(1/s) Tc trt

35(1/s) Tc trt

50(1/s) 71 1,6 1,6 1,6 1,3 1,3 1,3 69 1,6 1,6 1,6 1,4 1,4 1,3 67 1,6 1,6 1,6 1,5 1,5 1,4 65 1,7 1,7 1,7 1,6 1,6 1,5 63 1,7 1,7 1,7 1,7 1,7 1,6 61 1,8 1,8 1,8 1,8 1,8 1,7 59 1,8 1,8 1,8 1,9 1,9 1,8 57 1,9 1,9 1,9 2,0 2,0 1,9 55 1,9 1,9 1,9 2,1 2,1 2,0 53 2,1 2,1 2,0 2,2 2,1 2,1 ... 39 11,3 7,7 5,7 4,2 3,4 3,1 37 17,8 12,1 9,5 4,8 3,7 3,3 35 58,1 36,8 27,1 6,1 4,5 3,7 33 185 130 98 8,5 5,6 4,2 31 220 159 122 12 7 5 29 385 228 163 23 14 10 27 540 338 230 33 20 14 25 720 492 340 56 33 23 23 951 653 490 96 57 41 22 1080 786 573 110 73 53

Quan st t bng 3.6 kt hp hnh 3.5 n 3.7, vi tc trt khc nhau ca

du th (STO), khi nhit cht lu gim dn t 71oC n 55oC, gi tr nht ng

lc vn khng thay i. Nu tip gim nhit , cc gi tr nht ng lc lc ny



bin thin vi tng tc trt khc nhau i vi c du th (STO) v du cha tch

kh (Live Crude).

Hnh 3.5 th biu din bin thin nht ng hc STO theo nhit

1

10

100

1000

10000

20 25 30 35 40 45 50 55 60 65 70

nht

n

g h

c (c

P)

Nhit oC

nht ng hc (Stock Tank Oil) & Nhit

Tc trt 20(1/s) Tc trt 35(1/s) Tc trt 50(1/s)

Tpp (Stock Tank Oil) TWAT (DSC)

TWAT (CPM)

Tpp (STO) = Nhit ng c du th CNV TWAT (DSC) = Nhit kt tinh o bng phng php DSC TWAT (CPM) = Nhit kt tinh o bng phng php CPM



th hnh 3.5 cho thy nhit kt tinh (WAT) ca STO i vi phng php

o CPM 53.9oC, phng php DSC 51.8oC. Hai phng php o ny sai lch khng

ng k. Nhit ng c ca STO 30oC.

Hnh 3.6 th biu din bin thin nht ng hc Live Crude theo nhit

1

10

100

1000

20 25 30 35 40 45 50 55 60 65 70

nht

n

g h

c (c

P)

Nhit oC

nht ng hc (Live Crude) & Nhit

Tc trt 20(1/s) Tc trt (1/s) Tc trt 50(1/s)

Tpp (Live Crude) TWAT (NIR)

Tpp (Live Crude) = Nhit ng c ca du cha tch kh. TWAT (NIR) = Nhit kt tinh o bng phng php NIR.



th hnh 3.6 cho thy nhit kt tinh (WAT) ca Live crude i vi phng

php o NIR 49.45oC. Nhit ng c ca Live crude 27oC.

Hnh 3.7 th so snh nht ng hc bin thin theo nhit ca STO & Live crude

1

10

100

1000

10000

20 25 30 35 40 45 50 55 60 65 70

Nh

t

ng

Hc

, (c

P)

Nhit , oC

Nht ng Hc (STO & Live Crude) & Nhit

STO 20 (1/s) STO 35 (1/s) STO 50 (1/s)

Live Crude 20 (1/s) Live Crude 35 (1/s) Live Crude 50 (1/s)

Tpp (STO) TWAT (DST)

TWAT (CPM) Tpp (Live Crude) TWAT (NIR)



T th hnh 3.7, so snh s bin thin nht ng hc ca STO v Live

crude theo nhit vi tc trt khc nhau. Ti cng gi tr nhit :

nht ng hc ca Live crude thp hn so vi STO. Khi nhit Live crude & STO di nhit nng chy (Melting point),

nht ng hc t l nghch vi tc trt (Shear rate).

Khi nhit Live crude & STO ln hn nhit nng chy, gi tr nht ng hc ca du s khng thay i ng k vi tc trt khc nhau.

Nhit ng c ca Live crude (27oC) thp hn so vi STO (30oC), nguyn

nhn l do trong Live crude c cha mt hm lng kh nht nh trong du, cc phn

t kh ny lm chm qu trnh lin kt gia cc phn t paraffin c trong du dn n

nhit ng c ca Live crude thp hn nhit ca STO.

3.1.4. Hin trng lm vic thc t trong ng ng vn chuyn du kh CNV CPP3

Trong qu trnh khai thc v vn chuyn hn hp du kh, cc d liu thc t

c tin thnh thu thp bao gm hai loi, (bng 3.7) :

Thng s cng dn (Accumulative) : lu lng du v kh trong 24h. Thng s tc thi (Instantaneous) : p sut v nhit .

Vic thu thp cc d liu ny l rt cn thit. Vi cc d liu thu thp c, cc

ch lm vic trong thc t c th c xy dng li. T , qu trnh phn tch,

nh gi ch lm vic ny s c tin hnh v rt ra cc kt lun, phng n hp

l cho vic khai thc trong tng lai. Bn cnh , cc d liu ny cn phc v cho qu

trnh xy dng v hiu chnh cc m hnh.



Bng 3.7 Cc thng s lm vic trong ng ng vn chuyn CNV - CPP-3

Thi gian Lu lng ng ng trn CNV WHP

ng ng trn CPP-3

Qoil t/d

W %

QGas m3/d

PCNV bar

TCNV 0C

PCPP3 bar

TCPP3 oC

28-Jul-08 930.0 0.23 318.529 48.3 86 39.3 50.4

29-Jul-08 910.0 0.22 291.739 53 87 45 51.3

30-Jul-08 936.0 0.1 317.128 48.2 87 39.2 50.5

31-Jul-08 904.3 0.17 214.308 48.3 88 39.1 50.7

1-Aug-08 844.2 0.29 720.038 49.2 93 39.1 51.4

2-Aug-08 884.0 0.1 443.165 48.8 94 38.6 51.7

3-Aug-08 973.0 0.1 542.501 47.7 90 38.9 51.7

4-Aug-08 839.0 0.1 542.940 48 91 39.9 52.2

5-Aug-08 854.0 0.87 568.074 48 91 39.6 52.7

6-Aug-08 838.0 0.11 354.597 47.8 92 39.5 52.6

7-Aug-08 822.0 0.1 496.797 47.7 92.3 39.6 52.2

8-Aug-08 836.0 0.1 497.285 48.7 94 40 52.1

9-Aug-08 853.0 0.1 497.874 48.5 93.5 40.5 52.5

10-Aug-08 842.0 0.1 493.881 48.4 93.6 40.3 52.4

11-Aug-08 834.0 0.1 488.591 45.7 93.8 37.2 52.4

.. .. .. .. .. .. .. .. 28-Aug-09 1038.0 0.1 515.536 51.5 77.2 38.2 47.9

29-Aug-09 969.0 0.1 496.656 51.6 78.9 38.5 46.7

30-Aug-09 963.0 0.1 496.656 51.1 78.1 38.7 46.5

Trong ,

Qoil : Lu lng du th thnh phm trong 1 ngy, t/d. W : Phn trm nc trong du, %. QGas : lu lng kh thnh phm trong 1 ngy, m3/d. PCNV : p sut trn CNV, bar. TCNV : Nhit trn CNV, oC. PCPP3 : p sut trn CPP3, bar. TCPP3 : Nhit trn CPP3, oC .



Da trn cc thng s trn, xu hng bin i lu lng, p sut v nhit ti

thi im t khi m ging khai thc c tin hnh xy dng, hnh 3.8, hnh 3.9.

Hnh 3.8 th biu din lu lng v p sut lm vic trn CNV & CPP-3

th hnh 3.8 cho thy lu lng du kh khai thc trn CNV tng lin tc t

7000STB/D ln ti gi tr cao nht khong 13000 STB/d, sau gim chm li v t

gi tr n nh 7500STB/d 2 thng cui.

Khi gi tr lu lng du kh gim, p sut trn CNV v CPP-3 cng gim theo.

iu ny c th kt lun rng bin thin ca p sut t l thun vi bin thin ca

lu lng khai thc.

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

30

40

50

60

70

80

90

100

110

120

26-May-08 14-Aug-08 2-Nov-08 21-Jan-09 11-Apr-09 30-Jun-09 18-Sep-09

L

u l

ng

Bbl

/d

p

sut

, ba

r

Thi gian

p sut trong ng trn CNV WHP p sut trong ng trn CPP3 Lu lng du



Hnh 3.9 th biu din lu lng v nhit lm vic trn CNV & CPP-3

Quan st t th hnh 3.9, khi gi tr lu lng du kh gim, nhit trn CNV

v CPP-3 cng gim theo. iu ny c th kt lun rng, bin thin ca p sut t l

thun vi bin thin ca lu lng khai thc.

Tin hnh xy dng mi quan h gia lu lng v p sut trn ng ng vn

chuyn du kh t CNV n CPP-3 ti cc cc thi im khc nhau nhm phn tch v

nh lng cc c tnh v nhit thy ng hc ca cht lu trong ng ng :

1st t giai on m ging n 31-12-2008, hnh 3.10 ; 2nd t 01-01-2009 n 28-02-2009, hnh 3.11; 3rd t 01-03-2009 n 30-04-2009, hnh 3.12; 4th T 01-05-2009 n 30-06-2009, hnh 3.13; 5th T 01-07-2009 n 31-08-2009, hnh 3.14.

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

20.0

40.0

60.0

80.0

100.0

120.0

140.0

26-May-08 14-Aug-08 2-Nov-08 21-Jan-09 11-Apr-09 30-Jun-09 18-Sep-09

L

u l

ng

, B

bl/d

Nhi

t

, o

C

Thi gian

Nhit trong ng trn CNV WHP Nhit trong ng trn CPP3 Lu lng du



Hnh 3.10 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 1st

Hnh 3.11 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 2nd



Hnh 3.12 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 3rd

Hnh 3.13 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 4th



Hnh 3.14 Quan h gia lu lng v p sut trong ng ng CNV- CPP3, 5th

Da vo cc th biu din mi quan h gia lu lng v p sut trong ng

ng CNV - CPP3 cc thi k trn, ta c nhn xt rng :

- Mi quan h lu lng v p sut ba thi k u t khi m ging n 30-

04-2009 c dng ng cong parabol, tn tht p sut vi cc lu lng

khc nhau khng i theo thi gian.

- Nhng hai thi k cui t 01-05-2009 n 31-08-2009, p sut tc thi

tng khong 1.5-2bar vi cc lu lng khc nhau so vi 3 thi k u. iu

ny c gii thch bng cc gi thit sau:

S thay i tnh cht ca cht lu trong qu trnh dng cht lu di chuyn dc h thng ng ng (p sut gim di p sut im bt

kh lm thay i thnh phn hydrocarbon ca cht lu, s thay i

nht ). Nu thnh phn cht lu thay i trong qu trnh vn



chuyn, GOR s tng ln, tng lng hydrocarbon vn chuyn trong

ng ng s tng dn n kt qu tng p sut tn tht;

S hnh thnh paraffin trong ng ng (khi paraffin lng ng dc theo thnh ng s lm gim ng knh thy lc ca dng cht lu

trong ng, lm tng tn tht p sut do ma st dc theo thnh ng).

Theo gi thit u tin, nu paraffin lng ng bn trong ng ng, qu trnh

ny s lm tng p sut tn tht t t (Gradually). Nhng quan st hnh 3.14 cho thy

rng p sut tn tht ch tng tc thi (Instantly) t 1.5 2 bar. iu ny ni ln rng

thnh phn cht lu b thay i trong qu trnh vn chuyn lm cho GOR tng ln dn

n p sut tn tht tng ln.

Nhn xt

Cc nghin cu v h thng ng ng kt ni m CNV - CPP3, tnh cht ha

l ca du CNV, hin trng lm vic thc t cho thy :

- ng ng vn chuyn hn hp du kh t m CNV sang gin cng ngh

trung tm s 3 m BH di khong 25km, c di ln nht so vi cc s

thu gom hin hnh ti Vit Nam. V vy, mc tn hao nhit, p sut l rt

ln, y l mt trong nhng kh khn trong vic khai thc & vn chuyn ca

cc nh iu hnh m CNV.

- Mt khc, vic phn tch tnh cht ho l ca du CNV c th thy du CNV

c thnh phn phc tp, hm lng paraffin kh cao. Vi tnh hnh khai thc

hin nay, sn lng ca m CNV ch t 1/3 sn lng d tnh ban u, p

sut v nhit trong ng ng vn chuyn di y bin v gin cng

ngh trung tm CPP-3 gim xung lm cho qu trnh hnh thnh v lng

ng paraffin trong ng ng din ra nhanh, gy nhiu kh khn v ri ro

trong vic khai thc, vn chuyn du kh.



V vy, vn t ra l phi s dng nhng phng php vn chuyn du kh

ti u ph hp vi tnh cht ca m CNV v mang li hiu qu kinh t cao.

Trong lun vn ny, nhm gii quyt bi ton ti u ha vn chuyn du kh

trong ng ng CNV CPP3, tiu ch cho bi ton ti u ha vn chuyn c t ra,

c th l kim sot nhit ng c ca cht lu v qu trnh lng ng paraffin trong

ng ng vn chuyn. thc hin c iu ny, qu trnh nhit-thy ng ca

dng chy trong ng ng c tin hnh kho st thng qua vic m hnh ha & m

phng. Cc kt qu t c t qu trnh m phng s c phn tch, nh gi & tm

ra phng n hp l nhm gim thiu mc lng ng paraffin v tng hiu sut vn

chuyn trong ng ng, hnh 3.15.

Hnh 3.15 S quy trnh m phng chung cho bi ton ti u ha qu trnh vn

chuyn du kh trong thc t

Chn phng n hp l cho vic ti u ha vn chuyn

Xy dng m hnh nhit thy ng dng chy trong ng ng vn chuyn

Thu thp cc d liu khai thc

M phng cc ch dng chy trong ng ng vn chuyn

Phn tch v nh gi kt qu m phng

Xc nh tiu ch cho bi ton ti u ha vn chuyn



3.2. Xy dng m hnh dng chy a pha trong ng ng vn chuyn

Vic xy dng m hnh dng chy a pha trong ng ng vn chuyn da trn

cc m hnh ton hc ca cc tc gi (Kjell H. Bendlksen, Dag Malnes, Randi Moe,

and Sven Nuland, Inst. for Energy Technology, 1991) c trnh by mc 2.1 &

2.2. Cc bc chung trong qu trnh xy dng m hnh c trnh by trong s

hnh 3.16

Hnh 3.16 S m t cc bc chung trong qu trnh xy dng m hnh

Thu thp d liu thc t

Xy dng m hnh nhit thy ng dng chy trong ng ng vn chuyn

M phng qu trnh nhit thy ng trong ng ng vn chuyn

nh gi cht lng m hnh

Hiu chnh m hnh

M hnh cui cng

Sai

ng



3.2.1. Cc d liu thc t cn thit cho vic xy dng m hnh a. Thnh phn cht lu

Bng 3.8 D liu thnh phn cht lu CNV trn PVTsim 19.0

b. p sut, nhit v lu lng vn hnh

Bng 3.9 D liu p sut, nhit v lu lng

Thng s Gi tr n v p sut u vo ng ng CNV WHP 710-750 psi

p sut u ra ng ng CPP3 500 560 psi Nhit u vo ng ng CNV WHP 75

oC Nhit u ra ng ng CPP3 43

oC Nhit y bin 24

oC H s truyn nhit 1.913 W/m

2K Lu lng khai thc 5000- 7500 bbl/d



c. Cc c tnh c bn ca ng ng vn chuyn

Bng 3.10 D liu c bn vt liu ca ng ng

Material Thermal Conductivity (W/mK) Density (kg/m)

Heat Capacity (J/kg-K)

Steel (API 5L X 65) 45 7,850 400 FBE 0.3 1,450 1,200

PP Adhesive 0.22 900 1,000

PU Foam 0.04 165 1,500

Solid Polypropylene 0.215 900 1,800 Concrete Weight Coating 2.0 2242.6 1,000

d. M hnh h thng tuyn ng CNV - CPP3

Hnh 3.17 th m phng mt ct tuyn ng CNV-CPP3 trn OLGA 7.0



3.2.2. Xy dng m hnh nhit thy ng dng chy trong ng ng vn chuyn

Hnh 3.18 M hnh h thng ng ng vn chuyn hn hp du kh CNV CPP3

T m hnh va xy dng c, qu trnh m phng nhit thy ng dng chy

trong ng ng vn chuyn c tin hnh thc hin, hnh 3.19 & 3.20.

Hnh 3.19 Kt qu m phng p sut trn CNV & CPP3 trong 24h (start-up) sau khi

chy m hnh.

Trend data

PRESSURE FLOWLINE,TOPSIDE_CNV,2 [bar]PRESSURE FLOWLINE,TOPSIDE_CPP3_1,1 [bar]

bar

60

55

50

45

40

35

30

25

20

Time [m]CNV to CPP3 - Initial StartUp

150010005000



Hnh 3.20 Kt qu m phng nhit trn CNV & CPP-3 trong 24h (start-up) sau

khi chy m hnh

3.2.3. Hiu chnh m hnh nhit thy ng dng chy trong ng ng vn chuyn

Sau qu trnh thu thp s liu, xy dng m hnh v m phng qu trn