煤层气藏强化开采流固耦合作用

为准确表征煤层气藏强化开采过程中复杂的地质力学效应,同时考虑多孔介质全组分多过程物质运移特征,构建了适用于强化煤层气采收和CO_2地质埋存的全流固耦合数学模型,开发了相应的基于全隐式有限差分法的数值模拟器。据此进一步剖析了全流固耦合、经验/解析等不同模型对煤层孔渗参数及生产动态指标预测结果的明显差异,评判了解析模型前提假设(固定上覆压力和单轴向应变)的不合理性,证实了全流固耦合模型的准确性与可靠性。所建立的模型能够更准确刻画煤层复杂地质力学效应及多孔介质全组分多过程物质运移特征,对煤层气产能预测具有重要意义。

Coupling Effects of Fluid Flow and Geomechanics during Enhanced Coalbed Methane Recovery

A fully coupled fluid flow and geomechanics model is proposed for ECBM and CO2 underground storage with consideration of multi-component multi-process transportation in porous media to capture the complicated geomechanical effects, and the corresponding numerical solver is developed by the fully implicit finite difference method. The obvious difference of permeability and production index predication between the fully coupled model and empirical/analytical model is investigated, and the irrationality on assumptions of constant overburden pressure and universal axial strain adopted by the analytical models is judged, which verifies the accuracy and effectiveness of the fully coupled model. The model proposed can more accurately capture the fully coupling effects of geomechanics and fluid flow and multi-component multi-process migration in coal seam, which can provide better CBM production prediction.