低渗透油田油井见水规律分析

为了解决低渗透油田不规则面积注水井网中油井见水时间的计算及其影响因素的定量表征问题,将面积注采井网单元细分为一源一汇三角形最小计算单元,运用非达西渗流流管微元法得到不同面积注采井网类型条件下的生产井见水时间计算通式.以鄂尔多斯盆地X油田为例,研究井网类型、储层非均质性和裂缝发育程度对低渗透油田油井见水时间的影响,并通过统计回归得到沿裂缝方向、裂缝半长与油井见水时间之间的经验公式.结果表明:储层非均质性和裂缝规模对油井见水时间的影响最大,井网类型对其影响程度最小;不规则井网或油井所在最小三角形井网单元差异较大时,油井见水存在一个阶梯上升规律;油井见水时间与裂缝半长呈幂指数减小关系.

Analysis of water breakthrough rules of oil-well in low permeability reservoir

In this article,the injection-production pattern is subdivided into triangular computing unit with a point-fountain and a point-converge.Based on non-Darcy tube differential element method of low permeability reservoir,general formula for water breakthrough time in production well is achieved.The article studied the effects of well pattern,reservoir heterogeneity,and fracture development on water breakthrough time.An empirical formula on water breakthrough time and different factors is also given in this article taking X oil field in Ordos Basin.Based on the statistic regression analysis,an empirical expression for half length fraction and water breakthrough time of oil wells is suggested.Conclusion shows that reservoir heterogeneity and fracture size have the most severe effect,but pattern of well spacing has the least effects on water breakthrough time of oil well.In irregular wells or oil wells where the smallest triangle well pattern units are obviously different,water breakthrough has a stepping up law,water breakthrough time and fraction half length show decreasing power exponent relationship.