页岩气藏水平井开采动态数值模拟研究

Numerical Simulation Study on Production Performance of Horizontal Wells in Shale Gas Reservoir

页岩气藏具有特低孔低渗、吸附气含量高、无自然产能等特点,只有利用水平井技术及大型压裂增产措施,才能获得商业气。为了更为准确地对页岩气藏水平井开采动态进行模拟研究,综合考虑页岩气解吸、扩散、基质内运移和气体滑脱效应等特征,运用数值模拟软件Eclipse建立相应的单井数值模型,并对产能影响因素进行敏感性分析。研究表明,气体滑脱效应在开发中后期有利于水平井产气量的提高,在生产开发过程中,应尽量考虑气体滑脱效应对产气量的影响;天然裂缝渗透率、分段压裂裂缝导流能力、裂缝间距和裂缝半长的变化对水平井产气量影响很大,敏感性很高;水平井分段压裂参数是影响页岩气井产量的重要参数,应对相应压裂参数进行合理优化。

Shale gas reservoir has such characteristics as low porosity, low permeability, high content of adsorption gas and little natural production. Commercial gas can be exploited only by using horizontal well technology and some fracturing stimulation measures. In order to conduct simulation study on production performance of horizontal wells in shale gas reservoir accurately, comprehensively considered are such characteristics as gas desorption, diffusion, migration in matrix and slippage effect, applied is the Eclipse numerical simulation software to establish a corresponding single-well numerical model and conducted is sensitivity analysis on production effect factors. The results show that the slippage effect is beneficial to horizontal well production increase in the middle and later stage of development, the variation of natural fracture permeability, fracture diverting capacity, fracture spacing and fracture half-length has a great influence on horizontal well gas production and has very strong sensitivity, horizontal well staged fracturing parameters have an important influence on shale gas well production and it is necessary to optimize some corresponding fracturing parameters reasonably.