水平井水力喷射分段酸压技术

Multistage hydraulic jet acid fracturing technique for horizontal wells

针对深层碳酸盐岩储集层水平井酸压面临的井下温度高、破裂压力高、压裂液流动摩阻高、储集层非均质性严重等难点,研发了水平井水力喷射分段酸压新技术。基于喷射分段酸压机理,自主研制了用于水力喷射分段酸压的井下喷射器和配套管柱,给出了水力喷射酸压工艺设计中喷嘴数量与喷嘴直径组合、喷砂射孔参数、泵注程序的优化设计准则。研究表明,水力喷射压裂酸化技术依靠水动力封隔实现分段酸压,井下工具简单、耐高温(160℃),可节约成本,降低作业风险;水力喷射注酸可延长近井地带有效酸蚀距离,增强酸化效果;井下喷射器最优喷嘴相位60°,宜采用螺旋布置喷嘴;建立了喷嘴最优排量与井口压力的关系图版,可在井口装置承压范围内提高施工排量,实现大排量、深穿透酸压,最终确定喷嘴直径及喷嘴数量布置。现场试验表明,水力喷射酸压试验井最大作业垂深可达6 400.53 m,喷射酸量高达618 m3,对深部水平井分段酸压具有较强的适应性。

Acid fracturing in deep carbonate reservoirs is challenged by deep well stimulation with high temperature（120 ℃）,high fracture pressure（2.0 MPa/m）,high flow friction,and strong reservoir heterogeneity.To meet these challenges,a new stimulation method,called the hydraulic jet acid fracturing technique,was developed.According to the mechanisms of hydraulic jet acid fracturing,the authors self-design the downhole injector and pipe columns used in multistage hydraulic jet acid fracturing and provide optimization standards for nozzle number and diameter combination,abrasive perforating parameter,and pumping program.The technique realizes multistage acid fracturing by hydraulic separation and features simple downhole tools,high temperature resistance（160 ℃）,low cost and risk.In addition,hydraulic acid injection can extend effective acid corrosion distance nearby well and enhance the acidification effect.The optimal jet phasing is 60 degrees with spiral arrangement to lower formation fracture pressure.A relationship chart between optimal flow rate and wellhead pressure is established,which helps to increase flow rate as far as possible under wellhead assembly capacity and to determine nozzle diameter and number.Results from field tests show that this method can work at a maximum depth of 6 400.53 m,with a total acid volume of up to 618 m3.It is effective in creating acid fractures in ultra deep horizontal wells.