气藏工程气藏工程气藏工程 (5).pdf
1.3 Properties of reservoir oils1 Oil formation volume factor The ratio of the volume of oil at the prevailing reservoir temperature and pressure(Vof)to the volume of stock tank oil(Vos)osfooVVBm3/sm3Bo1(1)ppb,pBo the expansion of the oil(2)ppb,pBo；the evolution of the dissolved gas(3)Bo reaches a maximum value at the bubble point pressure1 Oil formation volume factor1 Oil formation volume factorTwo-phase formation volume factor When reservoir pressure drops below the bubble point,the ratio of volume of oil and its evolved gas to the volume of the stock tank oil two phase formation volume factor=total formation volume factor osofgftVVVBVosVofVgf1 Oil formation volume factorogssitBBRRBWhen p=pb,Rs=Rsi,Bt=Bob1 Oil formation volume factor(1)For pressures less than or equal to Pb,Standings correlation2.100012.09759.0FBoFogsTRF25.1/5.0Bo=oil FVF,RB/STB;Rs=solution GOR,scf/STB;g=specific gravity of gas(air=l.0);o=oil specific gravity=141.5/(131.5+API)(water=l.0);TF=temperature,oF.Ranges of properties:130 Pb(psia)7000 psia;100TF(oF)258;20 Rs(scf/STB)1425;16.5API(oAPI)63.8；0.59 g0.95(air=1.0);l.024 Bo(RB/STB)2.05 1 Oil formation volume factor(2)For black oils at pressures above the bubblepoint)(expppCBBbooboBob=oil FVF at original bubble point pressure,RB/STB;Co=isothermal compressibility of oil,psi-1;Pb=bubble point pressure,psia;P=reservoir pressure,psia.2 Solution gas-oil ratio the volume of gas measured at standard conditions,which will dissolve in unit volume of stock tank oil when subjected to reservoir pressure and temperature.osgssVVRsm3/m32 Solution gas-oil ratioInitial gas-oil ratio,Rsi 2)When Ppb.Average compressibility of oil between pi and pb:booboboobobffbfoPPBBBPPBBBPPVVVC1113 Oil compressibility (1)for black oils at pressures below the bubblepoint-McCain et al.correlationssbAPIoRTPCln184.0ln533.0ln115.1ln497.1633.7lngAPIoTPCln446.0ln77.0ln981.0ln394.1114.7lnWhen Rsb is known,When Rsb is not known,Ranges of data:500P(psia)5300,763Pb(psia)5300,78TF(F)330,15 Rs(scf/STB)l947,18API(API)52,0.58g l.2(air=1.0).3 Oil compressibility (2)Oil compressibility at pressures above Pb-Vasquez-Beggs correlation)10/()143361.1211802.175(5PTRCAPIgFsboRanges of data:126P(psia)9500,9.3Rs(scf/STB)2199,15.3API(API)59.5,0.511gpb,p ,o Ppb,p ,o4 Oil viscosity(3)Composition of crude oil The oil viscosity increases with the apparent molecular weight and the specific gravity.4 Oil viscosity(4)the amount of dissolved gas As the amount of dissolved gas increases,the viscosity of crude oil will decrease.4 Oil viscosity (1)Dead oil(gas free)viscosity-Ng and Egbogah correlationFAPIodT10log5644.0025086.08653.1)1lglg(od=dead-oil viscosity,cp;API=specific gravity of oil,API;TF=temperature,F.Ranges:59TF(F)176,5.0API(API)58.0 (2)Live oil viscosity-The Beggs-Robinson correlationBodoA515.0)100(715.10sRA33.0)150(44.5sRB4 Oil viscosity Ranges:0P(psi)5250,20Rs(scf/STB)2070,70TF(F)295,16API(API)58 (3)At pressures above the bubblepoint-the Vasquez-Beggs correlationmboboPP)/()1098.8513.11exp(6.25187.1pPm4 Oil viscosity Ranges:125P(psi)9500,9.3Rs(scf/STB)2199,0.117o(cp)148.0,15.3API(API)59.5,0.511 g1.351(air=1.0).Thank you for your attention!
