复杂小断块采收率及经济合理井网密度模型

国内外学者通过定量描述井网密度对采收率的影响,对油藏井网密度与采收率的关系公式开展了大量的研究,但这些公式对于复杂断块油藏的适用性较差。因此,在经典谢尔卡乔夫公式的基础上,文中借助数值模拟方法,根据边界形状将复杂断块分为矩形、60°三角形及120°三角形断块,引入复杂小断块边界形状因子进行表征;根据断块是否存在边水能量,考虑了断块开启、闭合以及地层倾角等因素,应用曲线回归方法建立了不同边界形状复杂小断块的井网密度与采收率经验关系式,且公式与数值模型拟合效果较好。基于修正方程,结合现金流量法和最优化理论,考虑油藏开发的阶段性及原油的价格上涨率和商品率等因素,建立了适用于复杂小断块油藏不同开发阶段的经济合理井网密度模型。实例测算结果表明,该模型具有较高的准确性和可行性。

Recovery ratio of complex small fault blocks and economic reasonable well pattern density model

In order to quantitatively describe the influence of well pattern density on oil recovery ratio,a large number of studies by scholars in China and abroad had been carried out on the relationship between well pattern density and recovery ratio in oil reservoir,but the applicability to complex fault block reservoirs was not good.Based on the classical Selkachev formula and numerical simulation technology,this paper divides the complex fault blocks into rectangular fault block,60°triangle fault block and 120°triangle fault block in accordance with the boundary shape,which is characterized by the complex boundary shape factor.According to the edge water energy in fault block,the curve regression method is adopted to establish the empirical relationship between the recovery ratio of complex fault blocks and the well pattern density considering the opening and closing of fault block and the dip angle of the formation,and the data fitting result is perfect.Based on the above formula,considering the development stage of reservoir and the rise of oil price and crude oil commodity rate,a reasonable well pattern density model combined with the cash flow method and optimization theory for different development stages of complex fault block reservoirs is established.The calculation results of the example show the good feasibility and accuracy of the proposed model.