定点堵水用触变凝胶研发及性能评价

Development and performance evaluation of thixotropic hydrogel for fixed-point water plugging

为解决油田开发过程中割缝筛管完井的水平井定点封堵问题,研发了一种适用于60~80℃油藏的水平井环空化学封隔材料Annular Chemical Paker(ACP),并针对其触变性、环空充填性能、持压强度、堵水率及降解性能等进行了评价。研究表明:改性聚多糖+丙烯酰胺(AM)单体+引发剂过硫酸铵+交联剂N’N-亚甲基双丙烯酰胺(MBA)+触变剂纳米二氧化硅(SiO_(2))和有机钛(TiTE)+阻聚剂对苯二酚在70℃的环境可以稳定成胶,且成胶时间2~8 h可控,触变性优良,可实现瞬时环空充填,无重力“坍塌”现象,完全成胶后凝胶强度高,封堵效果好。在70℃、模拟地层水条件下(注入速度为1 mL/min,注入量为0.8 PV),测试体系最大轴向滑移压力为3.13 MPa,最大径向击穿压力为2.16 MPa,突破压力梯度高达9.52 MPa/m,堵水率98.48%,解决了油田割缝筛管完井的水平井定点封堵问题,对于筛管完井的水平井控水稳油战略有重要的指导意义。

To solve the problem of fixed-point sealing of horizontal wells of oilfields,a horizontal well annulus chemical packing(ACP)material suitable for 60-80℃ reservoirs was introduced,aiming at evaluating the thixotropic performance,annulus filling performance,holding strength,water shutoff rate and degradation performance.Studies show that the modified polysaccharide+acrylamide(AM)monomer+initiator ammonium persulfate+crosslinking agent MBA+thixotropic agent SiO_(2) and TiTE+inhibitor hydroquinone can be stably gelled in a high temperature environment of 70℃,and the gelation time can be controlled in the range of 2 to 8 h,and the thixotropic property is excellent.It can realize instantaneous annulus filling,no gravity"collapse"phenomenon.The hydrogel strength is high after complete gelation,and the sealing effect is good.At 70℃ and simulated formation water(the injection speed is 1 mL/min,the plugging amount is 0.8 PV),the axial slip pressure of the test system is 3.13 MPa,the radial breakdown pressure is 2.16 MPa,and the breakthrough pressure gradient is up to 9.52 MPa/m.The plugging ratio is 98.48%,which solves the problem of fixed-point sealing of horizontal wells in the seam formation in oil fields,and has important guiding significance for the horizontal well-controlled water-stabilizing strategy of screen completions.