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Abstract Porosity and permeability are two key parameters of reservoir rocks which have been noticed widely for their measuring conditions and methods. The effects of confining pressure and temperature on porosity and permeability are studied through two groups of low permeability sand rock samples. Under the conditions of confining pressure 5 MPa and temperature 25 ℃，porosity of the first group of sand rock sample ranges from 3.2% to 4.6%，permeability from 0.098 8×10－3 μm2 to 0.191 9×10－3 μm2. And the second one?s porosity ranges from 12.8% to 14.2%，permeability from 0.176 7×10－3 μm2 to 0.301 3×10－3 μm2. The first group sandstone rock samples from subsurface formation and the second group from outcrop formation. Experimental temperature ranges from 25 ℃(room temperature) to 80 ℃ and confining pressure varies from 5 MPa to 55 MPa. Results show that porosity and permeability are strongly sensitive to confining pressure from 5 MPa to 55 MPa and temperature from 25 ℃ to 80 ℃. Both porosity and permeability decrease with confining pressure or temperature increase. Pressure effect on permeability is much higher than temperature. Generally，temperature effect on porosity is a little higher than pressure. Keeping confining pressure constant 5 MPa，increasing temperature from 25 ℃ to 80 ℃，porosity and permeability of the first group sandstone samples decrease 34.7% and 75.1% respectively；the second group's porosity and permeability decrease 18.4% and 35.2% respectively. Keeping temperature constant 25 ℃，increasing confining pressure from 5 MPa to 55 MPa，porosity and permeability of sandstone with low porosity and low permeability decrease 32.3% and 89.5% respectively；high porosity and low permeability sandstone porosity and permeability decrease 4.6% and 77.4% respectively.
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Received: 18 June 2010
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2011, Vol. 30 
