摘要：Exploring the production characteristics of coalbed methane reservoirs with dual pore structure is of great significance for guiding the efficient development of coalbed methane. In this paper, we analyzed the effects of water intrusion, desorption, formation and fluid compressibility on the original gas content G, and the influence of micro-cracks on coal reservoir productivity, based on the material balance equation. The results showed that, due to the low water production of the coal reservoir and the negative pressure of the formation, the influence of water intrusion, formation and fluid compressibility on the original gas content G can be neglected. However, the coal reservoir has a low gas saturation or free gas content, and the gas mainly exists in an adsorbed form. Therefore, the desorption has the greatest influence on the original gas content G. For the coal seams with relatively developed micro-cracks, the initial production capacity is higher, but the production decreases rapidly, and the ultimate recovery rate is significantly lower. For coal reservoirs with relatively underdeveloped micro-cracks, the time required to achieve the desired ultimate recovery is significantly longer than coal seams with relatively developed micro-cracks; however, the cumulative productivity of the reservoirs with relatively underdeveloped micro-cracks is much more higher.
关键词：Coal reservoir;material balance equation;productivity;original gas content;micro-crack
