基于PEBI网格的多段压裂水平井产量分析和压裂方案优化

Productivity Analysis and Fracturing Design Optimization for Multiple Fractured Horizontal Well Based on PEBI Grid

针对致密油气开发中的复杂裂缝,提出了采用PEBI网格表征水力压裂中不同类型裂缝(裂缝与水平井筒轴线垂直、裂缝沿水平井筒轴线方向,以及裂缝与水平井筒轴线成一定角度)的方法。基于PEBI网格及有限体积离散,研发了水平井多段压裂数值模拟程序,通过解析解验证该程序对水平井多段压裂的产能分析结果的准确性。以新疆油田某井为例,设计多种压裂方案,分别计算每种压裂方案下的产能,在此基础上,给出压裂优化方案建议。考虑到水力裂缝的时效性,选取一年内的产能数据,模拟计算了180 d生产数据,模拟结果与半年内实际油产量递减规律一致。

According to complex fractures existing in development of tight oil & gas,the paper proposes a method to describe different types of fractures( fractures perpendicular to,extending along and tilted to the well-bore) with PEBI grids. A numerical procedure for multifractured horizontal wells is developed based on PEBI grids and finite volume discretization,and accuracy is verified by analytical solution of it on productivity results of multi-fractured horizontal wells。Taking an actual fractured well in Xinjiang oilfield as an example,multiple fracturing methods have been designed and productivity of each method is computed,suggestions for fracturing design optimization are proposed based on it. Considering timeliness of hydraulic fractures,production data in a year are chosen,numerical simulation is carried out to model a fractured horizontal well in Xinjiang oilfield during 180 d,and the results are similar to actual decreased production data in half a year.