考虑吸附相视孔隙度的页岩气藏物质平衡方程

MATERIAL BALANCE EQUATION CONSIDERING THE ADSORBEDPHASE APPARENT POROSITIES FOR SHALE GAS RESERVOIRS

页岩气藏储量是确定气藏开发规模和开发设计的必要参数,对于合理有效开发页岩气藏具有重要意义。在前人研究的基础上,建立了综合考虑吸附相视孔隙度、基质和裂缝孔隙体积随压力变化以及吸附相密度等因素的物质平衡方程。通过实例计算可知:考虑吸附相视孔隙度后,计算得到的基质中自由气储量大幅度减少,吸附气储量大幅度增加,总储量增加;而且吸附相密度、基质孔隙度和裂缝压缩系数对于储量的计算结果也有较大影响。

The reserves of the shale gas reservoir are the necessary parameters for the determination of the development scale of the gas reservoir and design of the development,so they possess important significance for the reasonable and effective development of the shale gas reservoirs. On the basis of the previous study achievements,the material balance equation was established considering such factors as the changes of the adsorbed-phase apparent porosity,matrix and fracture porosity volume with the pressure and moreover the adsorbed gas density etc. the case calculation shows that when considering the adsorbed-phase apparent porosity,the free gas reserves in the calculation-presented matrix decrease to a great deal,while those of the adsorbed gas reserves increase greatly,and moreover the total reserves rise as well; and furthermore the influences of the parameters including the adsorbed phase density,matrix porosity and fracture compression factor on the calculated results of the reserves are still rather serious.