Acoustic Rock Physics Property Research on Gas Bearing Reservoir with Low Porosity and Low Permeability

In order to know the propagation law in reservoir with low porosity and low permeability and provide theoretical base,a modified White model is used to simulate different water saturation variations of compressional wave and shear wave properties with different frequencies in reservoir with low porosity and low permeability,the result of which is compared with that of conventional reservoir and high porosity and high permeability reservoir,and the differences of the acoustic propagation property between low porosity and low permeability reservoir and other reservoirs are summarized.Further more,the effect of gas pockets on acoustic property is analyzed.On the basis of theoretical simulation and the lab data,the differences of the acoustic property in the reservoir with low porosity and low permeability and other reservoirs are analyzed,and how to select gas pocket radius is also given.The results show that when the frequence is unchangeable,the propagation law in reservoir with low porosity and low permeability is similar to that in conventional reservoir and high porosity and high permeability reservoir.The acoustic velocity and attenuation all change significantly when the reservior contains gas,only with a smaller gas saturation take-off point.