非对称裂缝压裂气井稳态产能研究

摘要

为了准确预测非对称裂缝压裂气井的产能，指导和优化气井压裂，根据保角变换原理，通过引入气体压力函数，建立了裂缝内气体流动的微分方程组，最后通过求解微分方程组得到了非对称裂缝压裂气井的产量计算公式。利用某油田非对称裂缝压裂气井的数据，验证了推导出的非对称裂缝压裂气井产量计算公式的准确性。利用该计算公式分析了裂缝的非对称性对压裂气井产能的影响，结果表明：在其他参数相同的条件下，裂缝的非对称性越严重，压裂气井的产量越低；当井底流压较高时，裂缝的非对称性对压裂气井产量的影响较小；当井底流压较低时，裂缝的非对称性对压裂气井产量的影响较大。因此为获得较高的产能，应尽可能保证压裂裂缝沿井筒对称分布。%In order to accurately predict the productivity of asymmetrically fractured gas wells and op-timize gas wells fracturing ,according to the conformal transformation principle ,the productivity computa-tion formula for such wells was established by introducing the gas pressure function and solving the differ-ential equations for gas flow in fractures .This formula was validated by the real data of asymmetrically fractured gas wells in an oil field .The effects of fracture asymmetry on the productivity of fractured gas wells was analyzed with this formula .The results showed that ,given the same parameters ,the more the a-symmetry of fractures ,the lower the production of fractured gas wells .When the flowing bottomhole pres-sure is higher ,the production of asymmetrically fractured gas wells is less affected by the asymmetry of fractures ,but for the lower flowing bottomhole pressure ,the effect is just contrary .So ,the fractures should be kept in symmetric distribution along the wellbore to obtain a relatively high productivity of gas wells if it is possible .