低渗透煤储层煤层气开采有效技术途径的研究

Study on the effective technology way for mining methane in low permeability coal seam

概括地介绍了通过实验揭示的三维应力作用下 ,煤体基质岩块与裂缝的渗流物性规律 ,据此提出三维地层压力是导致煤层渗透性降低的主要因素 .基于实验、理论与数值分析 ,论述了水力压裂技术在改造低渗透煤层中的局限性 ,其机理是水力压裂技术仅能在煤层中产生极少量的裂缝 ,而且在压裂裂缝周围还会产生应力集中区 ,该区事实上成为煤层气开采的屏障区 ;本煤储层割缝 ,使煤层卸压的同时 ,还产生大量裂缝 ,是改造低渗透煤储层的最有利的技术方向 。

The seepage law of coal matrix and single fracture under 3D stress is introduced, based on the our test research and the idea which 3D stress is a brief factor to decrease permeability of coal seam is put forward. Based on the test research, theoretical and FEM analysis, the limitation of water fracturing to reform the low permeability coal seam is discussed, its mechanism is only to create a few crack in coal seam by water fracturing, but to produce a high stress area at the same time which it is a obstruct area in fact. Cutting crack in coal seam will unload of coal seam and create a great deal of crack, is a prior technology direction to reform low permeability coal seam, and a effective highness of cutting crack is studied.