井下柔性复合管预置电缆数字式分注技术

Digital Separated-Zone Water Injection Technologies with Cable-Preset Downhole Flexible Composite Pipe

低渗透油田分注管柱长期服役后腐蚀结垢严重、分层注水合格率下降快。为此,设计了井下柔性复合管预置电缆数字式分注工艺管柱,研发了智能配水器与过电缆封隔器等关键工具,开展了管柱抗外压、抗拉强度等关键性能室内评价,形成了适用于井下高压条件下的柔性复合管分层注水技术。室内评价结果表明,管柱满足分注井封隔器坐封压力与最大抗外压要求,智能配水器流量测试误差小于2%。现场试验4口井,最长服役时间已超过2年,分层注水合格率100%。研究表明,预置电缆数字式分注技术应用柔性复合管,可以有效提升管柱耐腐蚀性能,实现分层流量自动测调、远程验封和数据监测等功能,满足封隔器坐封、反洗井及后期测试要求,具有较好的应用效果。

Separated-zone water injection string in low-permeability oilfields is challenged by various problems after a long time in service, e.g. severe corrosion, scaling, and rapid decrease of separated-zone water injection conformity rate. To solve these problems, a digital separated-zone water injection string with a technology of cablepreset downhole flexible composite pipes was designed. The key tools, i.e. an intelligent water distributor and a cablepenetrated packer, were developed. Further, the key performances, including external pressure resistance and tensile strength, of the string were evaluated in laboratory. Separated-zone water injection technologies with flexible composite pipes suitable to downhole high-pressure were thereby developed. The laboratory evaluation results demonstrated that the developed string met the requirements on the packer setting pressure in separated-zone water injectors and the maximum external pressure resistance. The measurement error of the intelligent water distributor flow rate was below 2%. Field tests were carried out in four wells. The maximum service time was over 2 years, and the conformity rate of separated-zone water injection was 100%. This study indicates that the application of flexible composite pipes in cable preset digital separated-zone water injection technologies can effectively improve corrosion resistance, achieve automatic measurement and adjustment of separated-zone flow, remote sealing verification, and data monitoring, meet the requirements of packer setting, reverse circulation, and subsequent tests, all of which showcase promising application effects.