非对称裂缝垂直压裂井稳态产能计算模型

RESEARCH ON THE CALCULATING MODEL OF STEADY-STATE PRODUCTIVITY FOR ASYMMETRICALLY-VERTICALLY FRACTURED WELL

为了增加单井产量和提高油田开发效益,水力压裂技术在油田开发中广泛应用。但是目前的垂直压裂井产能计算模型几乎都是基于裂缝关于井筒对称分布的假设,鲜有研究非对称裂缝垂直压裂井的产能模型。因此,针对压裂后非对称裂缝特征,考虑了无限导流和有限导流两种情况,提出非对称裂缝垂直压裂井的产能计算模型,同时分析了裂缝的非对称性对垂直压裂井产能的影响。研究表明:无限导流垂直压裂井的产能与裂缝非对称性没有关系,但是裂缝非对称性对有限导流垂直压裂井的产能影响较大;在同等条件下,非对称裂缝有限导流垂直压裂井的产能相对于对称裂缝有限导流垂直压裂井的产能偏低,并且随着裂缝总长度增加或裂缝非对称系数增大,产能偏低得越严重。

In order to increase the productivity of individual oil well and enhance the benefits of the oilfield devel- opment, hydraulic fracturing has been widely applied in the development process. However, almost all the pub- lished productivity models for vertically fractured wells are based on the assumption of the fractures being symmetric about the wellbore. Few productivity models for asymmetrically-vertically fractured wells have been researched. Therefore, according to the characteristics of the asymmetric fractures after the fracturing, the productivity models for infinite-and-finite-conductivity asymmetrically vertically fractured wells have been established respectively. At the same time, the influences of the fracture asymmetry on the productivity of vertically fractured wells are ana- lyzed. The studies show that the productivity of infinite-conductivity vertically fractured wells has no relationship with the fracture asymmetry, on the contrary, the fracture asymmetry has a serious influence on the productivity of finite-conductivity vertically fractured wells. In the same condition, the productivity of finite-conductivity asymmet- rically-vertically fractured wells is lower than the that of finite-conductivity symmetrically-vertically fractured wells ; along with the increases of the total fracture length and the fracture asymmetry coefficient, the dropped productivity becomes more serious.