新型暂堵酸化用自降解暂堵剂的制备及现场应用

针对传统暂堵酸化用暂堵剂颗粒耐酸性差、降解性差和除堵工艺复杂等问题，本研究通过水溶液自由基聚合法制备了一种新型的自降解暂堵剂CQZDJ。考察了单体加量、交联剂加量、引发剂加量对CQZDJ凝胶强度和降解性的影响；通过FT-IR、TGA、SEM对其结构进行表征；并对其降解机理进行了探讨；最后在长8区块的环平81-8实验井进行了现场实践。结果表明：CQZDJ凝胶强度及降解时间与单体加量、交联剂加量、引发剂加量成正比关系，且降解时间可控；降解性实验表明CQZDJ在(1%~10%)HCl溶液、水、（2%~10%）NaCl溶液中均可在4 d内完全降解，具备良好的降解性能，对地层伤害小；SEM照片显示CQZDJ的降解过程是从初始三维网状结构逐渐崩解为层状结构，最终降解为无规则线性小分子链的过程；暂堵后现场流压上升6.3 MPa，日产油由3.87 t/d增产至5.22 t/d，实现了储层的有效改造，增产效果显著。

Development and Field Application of A Novel Self-degrading Temporary Plugging Agent for Temporary Plugging Acidification

A new self-degrading temporary plugging agent CQZDJ was prepared by aqueous free radical polymerization method for the problems of poor acid resistance,poor degradability and complicated removeling process of traditional temporary plugging agent particles which for acid treatments.The effects of monomer,crosslinker and initiator addition on the gel strength and degradability of CQZDJ were investigated,respectively.The CQZDJ’s structure was characterized by FT-IR,TGA and SEM.and its degradation mechanism was discussed.Finally,a field practice was conducted in the experimental well of Huanping 81-8 in the Chang 8 block.The results show that the gel strength and degradation time of CQZDJ are proportional to the amount of monomer addition,crosslinker addition and initiator addition,and the degradation time can be controlled.Degradability experiments show that CQZDJ can be completely degraded in(1%~10%)HCl solution,water and(2%~10%)NaCl solution within 4 days,with good degradability and little harm to the form.SEM tests showed that the degradation process of CQZDJ could be described as a process from the initial three-dimensional mesh structure to the degradation to a laminar structure and finally to irregular linear small molecular chains.After temporary plugging and acidification,the flow pressure at the site increased by 6.3 MPa,and the daily oil production increased from 3.87 t/d to 5.22 t/d,which realized the effective transformation of the reservoir and the significant effect of increasing production.