低渗透油藏五点法井网见水时间计算方法研究

A Calculation Method of Water Breakthrough Time of 5-Point Well Pattern in Low Permeability Reservoir

针对低渗透油藏储层发育特征、流体渗流规律及五点法井网特点划分流动单元,建立了考虑压敏效应、变启动压力梯度、排距井距、裂缝与井排角度、裂缝长度及非均质性等因素的见水时间计算模型,分析了不同因素对见水时间的影响规律。与已有成果相比,所建立见水时间计算模型考虑因素更加全面,更趋于矿场实际情况。分析结果表明,井距与排距之比越大、非均质性越强、裂缝长度越大、启动压力梯度越小、原始地层压力越小,见水时间越早;随着裂缝与井排夹角的增大,见水时间呈波动性变化;原始含水饱和度在0.4~0.5,见水时间早。研究成果可为低渗透裂缝性油藏开发调整方案编制提供理论保障。

According to the reservoir development characteristics,fluid seepage law and five-point well pattern characteristics of low permeability reservoirs,a water breakthrough time calculation model considering pressure-sensitive effect,variable starting pressure gradient,well spacing,fracture and well spacing angle,fracture length,heterogeneity and other factors is established,and the influence law of different factors on water breakthrough time is analyzed.Compared with the existing results,the water breakthrough time calculation model established in this paper is more comprehensive and fits the actual situation of the mine better.The analysis results show that the larger the ratio of well spacing to row spacing,the stronger the heterogeneity;the longer the fracture length,the smaller the starting pressure gradient and the original formation pressure,the earlier the water breakthrough time.With the increase of fracture and well row angle,the water breakthrough time changes,when the water saturation is between 0.4∼0.5,the water breakthrough occurs early.The research results can provide theoretical support for the development adjustment scheme of low permeability fractured reservoirs.