低渗透油层非达西渗流单井产能计算

低渗透油层渗流阻力大,存在启动压力梯度,常规的单井产能计算方法难以适用于低渗透油层油井。合理计算和评价低渗透油层油井产能,科学分析产能的影响因素,对于提高低渗透油层开发效果具有重要意义。运用渗流理论,根据低渗透油层的渗流物理特征,考虑非达西渗流特征,结合计算机辅助计算,推导了低渗透油层平面径向流和一源一汇注采井之间压力分布及产能计算公式,分析了压力分布特征及产能影响因素。由于低渗透油藏油井大部分压裂求产和投产,因此利用坐标变换方法推导了低渗透油藏直井、压裂直井的单井产能公式。产能公式可对低渗透油藏油井产能进行定量评价和影响因素分析,为提高单井产能及油田开发效果提供理论依据。

PRODUCTIVITY CALCULATION FOR THE INDIVIDUAL WELL WITH NON-DARCY FLOW IN LOW-PERMEABILITY OIL RESERVOIRS

Seepage resistance of low-permeability reservoirs is large and there is a starting pressure gradient.Conventional single-well productivity calculation methods are difficult to apply to low-permeability oil wells.Reasonably calculating the productivity of low-permeability reservoir wells and scientifically analyzing the influencing factors of the productivity are of great significance to improve the development effects of the low-permeability oil reservoirs.With the help of the seepage theory and according to the flow characteristics of the physical ones and the non-Darcy flow for the low-permeability oil reservoirs,and furthermore integrating with the computer-aided calculation,the pressure distributions and productivity calculating formula between the planar radial flow and the one-for-one injection-production well of the low-permeability reservoir were deduced,the pressure distribution characteristics and productivity influencing factors were analyzed.Since most of the oil wells in the low-permeability reservoirs are subject to fracturing production,the single-well productivity formulas for the vertical well and fracturing vertical well in the low-permeability reservoirs were deduced by means of the coordinate transformation method.The productivity calculating formula can be used to quantify the oil well productivity in the low-permeability reservoirs and analyze the factors that affect the productivity,thus the theoretical bases for improving the single well productivity and oilfield development effects can be provided.