缝内破胶压裂液的研究及应用

在水基聚合物压裂液加砂压裂施工过程中，往往需要添加破胶剂来满足压裂液的顺利破胶返排。目前使用较多的破胶技术是过硫酸盐、胶囊破胶剂结合的楔形追加破胶技术，但仍然存在压裂液的残胶伤害。为此，开展了新型破胶技术的室内研究，成功地研究出能使压裂液彻底破胶的破胶剂组合技术——缝内破胶技术。采用缝内破胶技术的压裂液（缝内破胶压裂液）和常规压裂液比较，缝内破胶压裂液破胶残液最大分子量是常规压裂液的1／8～1／6，岩芯渗透率伤害率降低了30％～40％。在四川GA区块的B井区进行了5井次缝内破胶压裂液和5井次常规破胶压裂液现场应用试验。试验结果表明，缝内破胶压裂液平均返排率比常规高10％左右，平均单井增加天然气测试产量是常规压裂液的1～2倍。

Research and Application of the Gel Breaking in Fracture Technology

In the course of Water-based polymer fracturing fluid sand fracturing,in order to make fracturing fluid breaking and flowback,we often need to add a certain amount of gel breaker.Currently,persulfate,capsule and the technology of wedge-shaped mixing have been widely used as an ordinary breaker,however,there is still residual gum fracturing fluid damage.Therefore,This paper researches on a new gel-breaking technology based on persulfate breaker by laboratory experiment,and successfully developed a completely breaking fracturing fluid combination technology-the technology of gel breaking in fracture.To compare the fracturing fluid which used this technology(fracturing fluid gel breaking in fracture) with the conventional fracturing fluid,we found that the maximum residue molecular weight of fracturing fluid gel breaking in fracture is 6 ~ 8 times lower than conventional fracturing fluid,and at the same time,the permeability of core damage reduced by 30%～40%.there are five wells with the the technology of gel breaking in fracture and five wells of conventional fracturing fluid gel-breaking application tests in GA block B area of Sichuan,the results show that fracturing fluid with the technology of gel breaking in fracture average rate of return is about 10% higher than conventional fracturing fluid,and an average single-well test production of natural gas increases by 2 to 3 times.