Oil and water properties PolyPVT Oil and water properties Lecturer: Marianna Dmitrieva www. sofoil.com
Oil properties
API gravity determined from relative density API oil gravity The API gravity is the ratio of oil density to water density at the same temperature API gravity determined from relative density Conversion of barrels to tons
Typical API gravities Heavy Medium Light Gravity API Relative density Specific weight, N/m3 8 1.014 1012 9 1.007 1005 10 1.000 998 15 0.966 964 20 0.934 932 25 0.904 302 30 0.876 874 35 0.850 848 40 0.825 823 45 0.802 800 50 0.780 778 55 0.759 757 58 0.747 745 Heavy Medium Light *https://en.wikipedia.org/wiki/API_gravity
Bubble-point pressure Bubble-point pressure is the pressure at which gas starts to release from liquid Bubble-point pressure depends on Oil to solution gas volume ratio Oil and gas compositions Reservoir temperature *from PolyPVT
Solution gas to oil ratio Gas-oil ratio is the ratio of the gas volume released from reservoir oil to the degassed oil volume Rs – gas-oil ratio; Vg – gas volume; Vo surf – reservoir oil volume Degassing Contact Differential
Gas-oil ratio vs. pressure Gas liberation
Oil Formation Volume Factor Oil Formation Volume Factor is the ratio of the reservoir oil volume to the volume of oil separated from it under standard conditions ! – for oil Bo > 1 Bo – Oil Formation Volume Factor; Vo res – reservoir oil volume; Vo surf – degassed oil volume 1/Bo is the Reciprocal Formation Volume Factor used to convert the volume of reservoir oil to oil volume at the surface θ – Reciprocal Formation Volume Factor; Bo – Oil Formation Volume Factor
Formation Volume Factor vs. Pressure Gas liberation
Oil compressibility Oil compressibility depends on Oil compressibility is a property that describes how much the oil volume increases when the reservoir pressure decreases by 1 psi until it reaches the bubble-point pressure 120oC 40oC Oil compressibility depends on Temperature Pressure Oil and gas fractions Gas-oil ratio
A falling-ball viscometer Oil viscosity Oil viscosity is a physical property that characterises oil mobility A falling-ball viscometer Operating principle
Viscosity vs. Pressure Gas liberation
Water properties
Water salinity Dissolved salts: Salinity Calcium chloride (magnesium/calcium chloride) Hydrocarbonate (alkaline/sodium bicarbonate) Salinity Brine (> 50 g/l) Saline (10–50 g/l) Brackish (1–10 g/l) Fresh (< 1 g/l) Formation water types are defined by the ion content of dissolved salts Anions OH-, Cl-, SO42-, CO32- and HCO3Cations H+, K+, Na+, NH4+, Mg2+, Ca2+ and Fe3+ Microelement ions I- and Br- Colloidal particles SiO2, Fe2O3 and Al2O3 Naphthenic acids and their salts
Water salinity in PolyPVT
Water Formation Volume Factor The Water Formation Volume Factor relates the volume of water under reservoir conditions to that under standard conditions Bw – water formation volume factor, Vw res – reservoir water volume, Vw surf – surface water volume Range: 0.99–1.06
Formation Volume Factor vs. Pressure Meehan
Water compressibility Water compressibility is a property that shows how a unit water volume under reservoir conditions changes when the pressure changes by 1 psi Water compressibility depends on Temperature Gas content Salinity Range: 3.7∙10-10 – 5∙10-10 Pa-1
Water viscosity Water viscosity mainly depends on Range: 0.2–1.5 cP Water viscosity is a physical property that characterises water mobility Water viscosity mainly depends on Temperature Salinity Chemical composition and to a smaller extent on Gas content Pressure and to a smaller extent on Gas content Pressure Range: 0.2–1.5 cP
Viscosity vs. Pressure Meehan
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