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煤储层厚度对其渗透率和含气性具有显著影响。研究表明 :华北石炭二叠系煤储层厚度与渗透率的关系明显分布在两个区域 ,构造煤发育的煤储层其厚度与试井渗透率之间具有负相关趋势 ,原生结构保存完好的煤储层其厚度与试井渗透率之间关系以渗透率 0 5m D为界 ,表现出截然相反的两种相关趋势 ;我国部分地区煤储层含气量具有随厚度增大而增高的规律 ;我国具有商业性开发价值的煤储层的临界渗透率似乎应在 0 5m D左右。煤储层厚度与渗透率之间关系分别受控于沉积作用、地应力、煤级煤岩特征或构造变形特征 ,但不同地质背景条件下的主要控制因素可能有所侧重。煤储层厚度越大 ,煤层气向顶底板扩散的阻力就越大 ,这也许就是某些地区煤储层厚度与含气量之间具有正相关越势的根本原因。
The thickness of coal reservoir has a significant effect on its permeability and gas content. The results show that the relationship between thickness and permeability of Permo-Carboniferous reservoirs in North China is obviously distributed in two regions. There is a negative correlation between the thickness of coal reservoirs with tectonic coal and permeability of well test, and the original structure is well preserved The relation between the thickness of coal reservoir and the permeability of well test shows two opposite trends with the permeability of 0 5 m D as the boundary. The gas content of coal reservoir in some areas in China increases with the increase of thickness. The critical permeability of coal reservoirs with commercial development value in China seems to be about 0 5m D. The relationship between coal reservoir thickness and permeability is controlled by sedimentation, in-situ stress, coal grade coal-rock characteristics, or tectonic deformation, respectively, but the main controlling factors under different geological backgrounds may be emphasized. The larger the coal reservoir thickness, the greater the resistance to the diffusion of coalbed methane into the roof and floor. This may be the root cause of the positive correlation between coal seam thickness and gas content in some areas.