基于PEBI网格的水平井井底压力计算

Numerical simulation of horizontal wells based on PEBI grids

针对PEBI非结构网格,研究了水平井的数值试井网格划分方法,推导出定流量下的耦合井筒储集系数与表皮因子的无限传导与均匀流量井产量计算公式;通过将水平井看作内边界,提出了水平井内边界模型,避免Peaceman水平井模型因井所在网格尺度变化对早期计算精度影响.根据提出的模型进行实例计算,并将计算结果与Eclipse公司的Weltest软件结果进行对比,对比表明,水平井内边界无限传导模型计算结果介于解析解与Peaceman模型结果之间,比Peaceman模型的更为精确,并且与解析解吻合更好;而在中后期水平井内边界均匀流量模型计算结果与解析解吻合很好.

PEBI meshing method of numerical well tests for horizontal wells was researched,while the flow equation of infinite conductivity and uniform flux horizontal wells was derived. By regarding the horizontal well as the internal boundary,an internal boundary model for horizontal wells was proposed,which could avoid the influence of variant well grid scales on the calculation precision of the early flow period in the Peaceman model. An example was calculated with the model,whose results were compared with the analytical and numerical results of Eclipse Weltest software. The comparison indicates that the result of internal boundary infinite conductivity model is between Weltest analytical and numerical results,while the uniform flux model result accords with the analytical result in the middle-and-final period.