滑脱流动影响的低渗储层甲烷运移采出规律研究

Research on Migration and Extraction Law of Methane in Low Permeability Reservoir(Considering Slippage Flow)

为了达到低渗储层甲烷抽采过程甲烷采井优化设计和产能准确预测的目的,基于现场测井数据,采用非线性流体数值计算方法,以柳林煤层甲烷试验采区为例,对滑脱流动影响的煤层甲烷采场压力非线性分布和产能预测进行研究。数值计算结果表明:低渗储层甲烷运移采出受气体滑脱流动影响显著,考虑滑脱流动影响时,采场压力衰减区域变大,气体速率变快;对比测井产能历史拟合数据发现,计算所得的滑脱流动影响的产能预测值更加准确。由计算结果验证了单井开采具有采场压力影响范围较小,产能较低等缺点,并得出五采出四压裂的布井方式是既能够准确预测产能又能够更好避免井间干扰效应的最优布井方式。

In order to achieve methane extraction process methane production well optimization design and productivity accurate prediction in hypotonic reservoir,taking Liulin coal bed methane test mining area as an example,the pressure nonlinear distribution and coal-bed methane productivity prediction were studied,based on the field logging data and nonlinear fluid numerical calculation method.Calculation results have shown that methane migration and extraction processes were influenced significantly by gas slip flow in hypotonic reservoir,that when considering slip flow influence,the stope pressure attenuation area became larger,the gas velocity became higher,and that calculation considering slip flow could give more accurate methane productivity prediction values.Results confirm the single well mining has the stope pressure coverage smaller and capacity lower faults and so on.It was found that the optimal mode of mining was ＂five exploitation wells plus four injection wells＂.