特低渗透油藏水平井整体压裂裂缝参数优化

Optimization of Integrated Fracturing Parameters of Horizontal Wells in Ultra-low Permeability Reservoirs

在特低渗透油藏水平井分段压裂数值模拟过程中,模型网格对压裂缝的描述精度直接影响了模拟仿真程度。采用整体PEBI网格方法,以牛圈湖油田东Ⅱ井区为例,进行了水平井整体压裂开发井组油、水井裂缝匹配关系以及裂缝半长和导流能力的优化研究。研究发现,压裂缝的导流能力与裂缝半长综合影响油井产能,但两者作用阶段存在差异;在低导流阶段,油井产能主要受裂缝导流能力影响,受裂缝半长影响较小;而高导流阶段,油井产能主要受见水快慢影响,即受注水井裂缝端部间压力梯度的影响。

In the numerical simulation of staged fracturing of horizontal wells in ultra-low permeability reservoirs,The description accuracy of the model grid for the fractures directly affected the simulation degree.By using integrated PEBI grid method and taking Wellblock DII in Niujuanhu Oilfield for instance,the the fracture matching relationship,fracture length and conductivity of oil and water wells in integrated fracturing development wells of horizontal well were optimized.It is found out that the well productivity is comprehensively affected by fracture length and conductivity,both of them existed differences in the phase.In the period of low conductivity,the productivity was mainly affected by conductivity of the fractures and it is less affected by fractural length.While in the period of high conductivity,the productivity is mainly affected by fast or slow of water production,that is,it is affected by the pressure gradient between the ends of fractures in horizontal wells.