A material balance based method of determining the proportion of shale adsorbed gas production

Abstract

The production of shale adsorbed gas cannot be measured separately in the production process, and the method for determining the proportion of shale adsorbed gas output is insufficient. Desorption residual amount of adsorbed gas and free gas residual amount are introduced. Langmuir isothermal adsorption equation, shale gas well geology and production data are used. The analytical models of desorption residual amount of adsorbed gas, free gas residual amount of adsorbed gas and output ratio of adsorbed gas are derived respectively, and the method of determining output ratio of adsorbed gas based on material balance is established. The results show that the proportion of adsorbed gas output is low in the initial stage of shale gas production. With the extension of production time, the proportion of adsorbed gas output gradually increases, and the adsorbed gas plays an increasingly strong role in supporting the productivity of gas wells. To keep shale gas well exploitation for a long time is conducive to the full release of shale gas adsorption potential. This research is of practical significance and provides a new technical way for the study of shale adsorbed gas production.