超低渗透油藏压裂水平井注采缝网形式研究

为了延长压裂水平井的无水采油期、提高水平井单井产量和采出程度、降低水平井含水上升率，推导了直井 注水压裂水平井开采水驱前缘推进距离计算公式，采用油藏数值模拟和油藏工程分析方法，优化了直井水平井注采缝 网形式和水平段长度，研究了最优裂缝穿透比和最优排距。研究结果表明，五点法注采井网与七点法注采井网相比， 阶段采出程度高、含水上升慢；均匀布缝、哑铃型裂缝和纺锤型裂缝相比，纺锤型裂缝累产量高，采出程度大，在相同 采出程度下纺锤型裂缝含水率低，水驱前缘到达纺锤型裂缝的时间长，延长了其无水采油期；超低渗透油藏水平井水 平段越短阶段采出程度越高，水平段长度超过500 m 后随着长度增加投资回收期增大、净现金流量减小；纺锤型裂缝 五点法井网在最优裂缝穿透比为0.7 时的最优排距为300 m。

Research on Well Patterns and Fracture Models for Fractured#br# Horizontal Well in Ultra-low Permeability Reservoir

In order to extend the water-free production period，to improve well production and oil recovery，and to reduce water cut rising of fractured horizontal well，the formula of water flooding front is deduced in this article，and the horizontal well patterns，fracture models，horizontal section length，fracture penetration ratio and the row spacing are optimized by reservoir numerical simulation and reservoir engineering. The results show that the five-spot well pattern is of higher oil recovery and lower water cut rising，compared with the seven-spot well pattern. Among the equal-length fracture model，dumbbell-shaped model and spindle-shaped model，the spindle-shaped model gives the highest cumulative oil production，oil recovery and the longest water-free production period，and the spindle-shaped model gives the lowest water cut with the same oil recovery. In the ultra-low permeability reservoir，the shorter the horizontal section，the higher the oil recovery. When the horizontal length is more than 500 m，the payback period increases and the net present value decreases with the increase of horizontal length. When the optimal fracture penetration ratio is 0.7，the optimal row space is 300 m. The results have certain significance for researches on horizontal well patterns and fracture models of similar reservoirs.