底水油藏水平井变密度射孔设计及应用

Design and Application of Variable Perforation Density for Horizontal Wells in Bottom Water Reservoir

利用水平井开发底水油藏过程中,底水快速突破、油井提早见水是影响水平井开发效益的关键因素。针对采用射孔完井的水平井,通过在水平段不同部位采用不同的射孔密度,实现均衡各部位见水时间、延长无水采油期的目标。建立了考虑射孔密度、井眼轨迹、井筒流动压降、渗透率各向异性等影响因素的水平井分段产量和见水时间计算方法,基于此计算方法对东海海域XH井进行了变密度射孔方案设计。实际应用表明,建立的计算方法预测见水时间的准确性较高,变密度射孔能够提升无水采油期产油量,在一定程度上节约完井费用,提升水平井综合开发效益。

When using horizontal wells to develop bottom water reservoirs,the rapid breakthrough of bottom water and early water breakthrough are key factors affecting the development benefits of horizontal wells.For horizontal wells completed by casing and perforation,this paper proposes to achieve the goal of equalizing the water breakthrough time of the horizontal section and prolonging the water-free production period by using different perforation densities at different parts.Therefore,this paper establishes a calculation method for sectional production and water breakthrough time of horizontal wells considering such factors as perforation density,wellbore trajectory,wellbore flow pressure drop,permeability anisotropy,etc.Based on the calculation method,a variable density perforation scheme was designed for XH well of East China Sea.The practical application shows that the established calculation method has high accuracy in predicting water breakthrough time.Variable density perforating can increase oil production during the water-free oil recovery period,save completion costs to a certain extent,and improve the comprehensive development benefits of horizontal wells.