非均质油藏水平井分段变密度射孔优化模型

基于油藏数值模拟技术,耦合油藏渗流、井壁流体入流、井筒流体管流,建立三维三相水平井分段变密度射孔优化设计模型。分析了水平井跟(趾)端与中部渗流差异、避射段、渗透率非均质、油层厚度非均质、孔隙度非均质、井筒压降、最大射孔密度、射孔优化原则等8个因素对水平井分段变密度射孔孔密与入流剖面的影响及流体黏度、套管直径、管壁粗糙度对井筒压降的影响。结果表明,跟(趾)端与中部渗流差异、避射段、渗透率非均质性、油层厚度非均质性对分段变密度射孔有显著影响;考虑与不考虑水平井跟(趾)端与中部渗流差异可能会得出相反的孔密优化结果;避射段的存在会影响流体入流剖面;国内陆上大多数水平井分段变密度射孔不必考虑井筒压降的影响。塔河油田AT9-7H井预测与实际生产指标对比表明,该模型具有较高的精度。

Segmentally variable density perforation optimization model for horizontal wells in heterogeneous reservoirs

A 3D three-phase segmentally variable density perforation optimization model of horizontal wells is built by coupling reservoir fluid filtration, near wellbore inflow and wellbore conduit flow based on reservoir numerical simulation. The effects of 8 factors (filtration difference between heel/toe and middle intervals, imperforated interval, permeability heterogeneity, oil layer thickness heterogeneity, porosity heterogeneity, wellbore pressure drawdown, maximum perforation density, and perforation optimization principles) on perforation density and inflow profile, and that of fluid viscosity, casing diameter and pipe wall coarseness on well bore pressure drawdown, are analyzed for segmentally variable density perforation of horizontal wells. Results show that filtration difference between heel/toe and middle intervals, imperforated interval, permeability heterogeneity and oil layer thickness heterogeneity have significant effects on segmentally variable density perforation. In particular, different perforation density optimizations may occur when filtration difference between heel/toe and middle interval is not considered; imperforated interval may affect inflow profile; well bore pressure drawdown can be ruled out for segmentally variable density perforation of most horizontal wells onshore in China. The contrast between predicted and actual production of Well AT9-7H in the Tahe Oilfield indicates that the model is highly accurate.