PVT Analysis Task

PIPESIM Fundamentals Task Cesar Villegas Capistran

Petrotechnical ServicesCesar Villegas CapistranPVT Analysis task

Objectives:

Upon completion of this on-the-job training module, the learner will be able to:

1. Explain the definition of the 5 hydrocarbon fluid types based on phase envelope definition2. Identify the type of hydrocarbon fluid based on production and PVT data3. Explain the experimental procedures and reported quantities of the Single Stage Flash, Differential Liberation, Constant Composition Expansion and Separator Experiment4. Be able to identify such experiments in a PVT laboratory report, and interpretcorrectly each of the reported quantities.5. Extract from a PVT laboratory report quantities compiled in Black Oil Tables6. Understand and apply the concept of Differential Liberation table correction by separator conditions.The Five Hydrocarbon Reservoir Fluid TypesThe Five Hydrocarbon Reservoir Fluid Types:Dry GasWet GasGas Condensate (Retrograde Gas)Black OilVolatile Oil3/19/20144Questions for students: Which would have the least density. 5Initials3/19/2014P-T Diagram of Dry Gas

DRY GAS RESERVOIRS:

GOR > 100,000 SCF/STBNo liquid produced at surfaceMostly methane

3/19/20145We dont see any phase change.

P-T Diagram of Wet Gas

WET GAS RESERVOIRS:

GOR > 50,000 SCF/STBLiquid S.G. between 60-70 APILight in color/ transparentP-T Diagram of Gas Condensates

GAS CONDENSATE RESERVOIRS:GOR between 3,000-100,000 SCF/STBLiquid S.G. between 50-70 apiLight in colorC7+ composition < 12.5%P-T Diagram of Black Oil Reservoirs

BLACK OIL RESERVOIRS:GOR less than 1,000 SCF/STBDensity less than 45 APIReservoir temperatures less than 250 FOil FVF less than 2.00 (low shrinkage oils)Dark green to black in colorC7+ composition > 30%

P-T Diagram of Volatile Oils

VOLATILE OIL RESERVOIRS:GOR between1,000-8,000 SCF/STBDensity between 45-60 APIOil FVF greater than 2.00 (high shrinkage oils)Light brown to green in colorC7+ composition > 12.5%

Typical Reservoir Fluid CompositionsComponentBlack OilVolatile OilGas Condensate Wet GasDry GasC148.8364.3687.0795.8586.67C22.757.524.392.677.77C31.934.742.290.342.95C41.604.121.740.521.73C51.153.970.830.080.88C61.593.380.600.12C7+42.1511.913.800.42MwC7+225181112157GOR625200018,200105,000-Tank oAPI34.350.160.854.7-LiquidColorGreenishBlackMediumOrangeLightStrawWaterWhite-LABORATORY TESTSANDANALYSISOUTLINESingle Stage FlashConstant composition ExpansionDifferential LiberationConstant Volume DepletionSeparator Test (Flash Test)

Single Stage FlashPROCEDURE

The sample with the original composition is expanded to atmospheric pressure and temperature

Data Obtained

GOR, RsFVF, BoAPIFlashed gas compositionFlashed stock tank oil composition Reservoir fluid composition

Differential LiberationDesigned to simulate a pressure depletion process in reservoir:All gas generated below the bubble point is assumed to be producedTrue black oils are relatively insensitive to pressure depletion step size

Data Obtained

Gas oil ratio (GOR) / Liberated GasFormation volume factor, BoGas properties: MW, density, Z, BgLiquid properties: density, viscosity

Experimental Procedure

Specify a temperature and a series of pressuresAll gas is removed at each pressure stepLast pressure step will be a reduction to standard conditions - automaticWithdrawn GasLiquidLiquidLiquidLiquidVaporVaporCellVolume at Bubble Pointp>pbubp