致密砂岩油藏水平井分段压裂布缝与参数优化

针对鄂尔多斯盆地致密砂岩油藏五点法联合注采井网的特点,为实现储层改造并控制水窜,对水平井分段压裂的布缝方式和裂缝参数进行了研究.基于水电相似原理,对联合注采井网不同压裂方式进行了电模拟试验,优选了压裂方式及裂缝展布形态;采用油藏数值模拟方法对分段压裂的具体参数进行了优化.电模拟试验结果表明,分段压裂比传统双翼压裂的低压区面积增大36.4%、产能提高72.5%,纺锤形布缝方式最适于五点法联合注采井网;油藏数值模拟结果表明,当裂缝端部连线与油藏边界夹角为23.2°、段间距为92.7 m、裂缝导流能力为15 D·cm时最优.根据研究结果进行了 YP-8 井的压裂设计,压裂后初期日产液量22.66 m3、日产油量18.11 t,投产至今生产基本稳定.研究结果表明,水平井分段压裂采用纺锤形布缝方式,可有效改善近井区域的渗流状况,获得较高的产能,并可均化油藏压力分布,防止过早水窜. 

Staged Fracturing Pattern and Parameter Optimization of Horizontal Wells in Tight Sandstone Oil Reservoir

In order to achieve reservoir stimulation and control water breakthrough,research was conducted on hydraulic fracturing patterns and fracture parameters of horizontal well staged fracturing according to the characteristics of five-spot injection-production well pattern for a tight sandstone oil reservoir in the Ordos Basin.Hydroelectric simulation was conducted on fracturing methods for the pattern,and then the optimal fracturing method and fracture pattern were selected.The specific parameters of staged hydraulic fracturing were optimized using reservoir numerical simulation methods.Hydroelectric simulation showed that staged fracturing would increase the low-pressure area by 36.4 % and would increase productivity by 72.5 % in comparison with traditional dual-wing fracturing,and the spindle-shaped fracture pattern was most suitable for five-spot injection-production pattern.The best values were obtained when the angle between reservoir boundary and the fracture toes trend,fracture spacing and fracture conductivity were 23.2°,92.7 m and 15 D·cm respectively.Study results were used as reference for the fracturing design of Well YP-8 which had achieved goods results,with daily fluid production of 22.66 m3 and oil production of 18.11 t,with stable production until the time of the writing of the results.The results showed that spindle-shaped fracture pattern would achieve better near-wellbore region seepage conditions,would result in higher production and would prevent water channeling.