沁水盆地枣园井网区煤层气采出程度

Discussion on recovered percent of coal-bed methane in Zaoyuan well pattern of Qinshui Basin

利用试验井网的生产资料,探讨了煤层气的采收率、采出程度、降压范围和单井产能预测.截止到2003年11月底,沁水盆地枣园井网已累积产气979.79×104m3,井网区的煤层气采出程度约为2.2%,有约2.36×108m3的煤层气可采储量没有被采出.目前枣园井网处于初期开采阶段,形成其压降漏斗的范围小于100m,仍属于单井排采生产.预计枣园井网形成大面积的压降漏斗后,其单井平均产气量在2500～3000 m3/d.开发井网的井距应适当缩小,在200～250m的井距较合适.

The recovery ratio, recovered percent, drainage range and the production forecast of single coal-bed methane (CBM) well were discussed by using the production data of Zaoyuan well pattern. By the end of November 2003, the total accumulative production of CBM in Zaoyuan well pattern was 9.7979 million cubic meters. The recovered percent was 2.2 percent. It is estimated that about 236 million cubic meters of recoverable CBM reserves has not been extracted from the coal beds of this well pattern. At present, Zaoyuan well pattern stands in initial stage of production. The range of single well drainage is less than 10 acres, and these wells have not been connected with pressure produced itself. It is predicted that the average gas rate of single well would be from 2500 cubic meters to 3000 cubic meters per day, after a larger range of pressure drop funnel was formed. So, the well space was suggested to be 20 acres to 25 acres.