Chapter 10 – Properties of Black Oils - Reservoir Fluid Studies PETE 310 Lecture # 17 Chapter 10 – Properties of Black Oils - Reservoir Fluid Studies

Fluid Properties for Reservoir Engineering Processes The fluid properties of interest to the Reservoir Engineer are those that affect the mobility of fluids within the reservoirs these are used in material balance calculations Properties at surface conditions for transportation and sales (API, viscosity, oil quality)

Fluid Properties for Reservoir Engineering Processes PVT properties are determined from 5 specific lab procedures Flash liberation tests Differential Liberation Tests Viscosity Measurements Separator Tests Compositional measurements

Fluid Properties Determined Oil Properties Bubble Point Pressure Bo Rs Bt Co and mo Gas properties z Bg and mg Compositions oil & gas

Oil Sampling Procedures Bottom hole or subsurface samples Separator Samples SAMPLE BEFORE RESERVOIR PRESSURE DROPS BELOW Pb

1.Flash Vaporization Test = b t5 t4 oil gas Hg P 1 >> 2 > 3 4 < 5 < P Temperature of Test = Reservoir Temperature

1.Flash Vaporization Test Properties determined Pb Co

Determination of Pb

Determination of Co

2.Differential Separation Test gas oil Hg P 1 = b 2 < 3 < P 4 5 Gas off Temperature of Test = Reservoir Temperature

2.Differential Separation Test Properties Determined Oil formation volume factor at the Bubble Point pressure Bodb and below the bubble point pressure Bod Solution gas-oil ratio at the Bubble Point pressure Rsdb and below the bubble point pressure Rsd Isothermal compressibility (derived property)

3. Separator Tests Tests performed at a combination of different Temperature and Pressure pairs

3. Separator Tests Goals: Maximize API, minimize BoSb & RsSb

Optimization of Separator 2 Conditions 3160 3180 3200 3220 3240 3260 3280 3300 Solution Gas Oil Ratio at Pb (Rsb) 2.76 2.78 2.80 2.82 2.84 2.86 Formation Volume Factor at Pb (Bob) 50 100 150 200 250 300 Separator 2 Pressure (psia) High Pressure Separator @ 900 psia and T Sep2 = 75 o F 100 ºF

Comparison between 1 & 2 Separators Stages (volatile oil) 3360 3380 3400 3420 3440 3460 Solution Gas Oil Ratio at Pb (Rsb) 2.90 2.92 2.94 2.96 Formation Volume Factor at Pb (Bob) 400 500 600 700 800 900 1000 Separator 1 Pressure (psia) Low Pressure Separator @ 300 psia and T Sep1 = 160 o F 75ºF One Separator Stage

Typical PVT Properties for a Black Oil and a Volatile Oil 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 Formation Volume Factor (Bo) 1000 2000 3000 4000 5000 Pressure (psia) Black Oil Volatile Oil Black Oil Correlation T R =180 o F P b

Typical PVT Properties for a Black Oil and a Volatile Oil 1000 2000 3000 4000 Solution Gas Oil Ratio (Rs) 5000 Pressure (psia) Black Oil Volatile Oil Black Oil Correlation T R =180 o F P b

Nomenclature

4. Compositional Tests http://www.rpi.edu/dept/chem-eng/Biotech-Environ/CHROMO/chromintro.html http://www.rpi.edu/dept/chem-eng/Biotech-Environ/CHROMO/chroanim.html