油层物理英文课件：1.4 Properties of Crude Oils

Bo
Vo f Vos
m3/sm3
Bo≥1
Provincial Bilingual Teaching Demonstration Course
Trend of Bo:
(1) p>pb, p↓Bo↑ due to the expansion of the oil. (2) p<pb, p↓Bo↓； due to the evolution of the dissolved gas.
Eo
Vf Vs Vf
Rs
Vgs Vos
sm3/m3
Vgs = volume of gas at standard conditions, sm3 Vos = volumeห้องสมุดไป่ตู้of oil at stock tank conditions, m3
Provincial Bilingual Teaching Demonstration Course
2.1 Formation volume factor of oil
The ratio of the volume of oil (plus the gas in solution) at
the prevailing reservoir temperature and pressure (Vof) to the volume of stock tank oil (Vos) , Bo.
G = NRsi (sm3)
Provincial Bilingual Teaching Demonstration Course
2 Formation volume factor and shrinkage factor of oil
2.1 Formation volume factor of oil As liquid is transported to the surface, p , T and gas evolves from the liquid.
Bob
Boi
(3) Bo reaches a maximum value at the bubble point pressure. Provincial Bilingual Teaching Demonstration Course
2.2 Shrinkage factor (收缩率)
the shrinkage in volume when unit volume of reservoir oil is degassed at surface, expressed in percentage.
Facts: the quantity of liquid that reaches the stock tank is less than the quantity of liquid entering the wellbore from the reservoir.
Provincial Bilingual Teaching Demonstration Course
Trend of the GOR curve:
Initial gas-oil ratio, Rsi (原始溶解气油比)
Provincial Bilingual Teaching Demonstration Course
1) The line is horizontal at pressures above the bubble-point pressure pb. Rs=Rsi
2) When P<Pb: P↘,Rs↘ At these pressures gas evolves from oil.
Initial gas-oil ratio, Rsi (原始溶解气油比)
Provincial Bilingual Teaching Demonstration Course
Producing gas-oil ratio: the ratio of cumulative gas production to the cumulative oil production of an oil well (or an oil zone/ oilfield) over a certain period of time.
Provincial Bilingual Teaching Demonstration Course
1 Solution gas-oil ratio (溶解气油比)
Definition: 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.
1.4 Properties of Crude Oils (地层油的性质)
Provincial Bilingual Teaching Demonstration Course
Contents
• Solution Gas-oil Ratio (溶解气油比)
• Formation Volume Factor and Shrinkage Factor of Oils • Crude oil density and specific gravity • The coefficient of isothermal compressibility of oil • viscosity of oil (粘度) •Properties of crude oil correlations •PVT test of reservoir oil
Example: The OIIP of an oil reservoir is N(surface)m3，the initial gas-oil ratio is Rsi sm3/m3，calculate the dissolved gas initially in place？
Solution: