QUANTITATIVE EVALUATION OF GAS BEARING SANDSTONE RESERVOIR OF LOW PERMEABILITY WITH ARRAY ACOUSTIC LOGGING

Pore structure has remarkable effect on gas zone identification and saturation calculation in gas-bearing sand reservoirs with low porosity and permeability.P-wave and S-wave of array acoustic logging provides a non-electrical method to solve the problem.Based on theoretical response characteristic simulation of gas bearing sand reservoirs,the cross-plot of wave speed ratio-p-wave time difference is coincident with the data distribution features of practical wells.Contrarily,gas saturation can be estimated with real logging data when wave speed ratio, matrix parameter and porosity are given.The research has been successfully applied in evaluating the reservoirs of Qikou depression and Sulige gas field.