羟丙基胍胶压裂返排液的循环利用技术

Recycling Technology of Hydroxypropyl Guar Gum Fracturing Flowback Fluid

张敬春 潘竟军 怡宝安 邬国栋 翟怀建

ZHANG Jingchun，PAN Jingjun，YI Baoan，WU Guodong，ZHAI Huaijian

随着油气储层压裂改造技术的广泛应用，压裂用水短缺和压裂返排液的有效处理已成为油气田亟待解决的问题。为了缓解新疆油田油田压裂用水与降低返排液处理成本，开展了羟丙基胍胶压裂返排液的循环利用技术研究。研究结果表明，电解氧化处理可实现返排液的快速降黏与杀菌，然后利用气浮、沉降等方式即可将返排液中的悬浮物有效去除。通过调节处理后返排液的 pH至 6.5左右，实现了羟丙基胍胶粉在返排液中的分散起黏，即快速配制羟丙基胍胶基液。通过引入 0.05%～ 0.2%的缓交联剂葡萄糖酸钠，利用缓交联剂与残余交联剂之间的络合作用，有效解决由残余交联剂的引起的交联过快问题，返排液配制的压裂液交联时间可控制在 10～ 120 s之间。通过添加稳定剂亚硫酸钠消除返排液中残余的破胶剂，有效提升了压裂液的耐温能力。利用该方法累计完成 2.2万方返排液的处理，配制出的羟丙基胍胶冻胶压裂液应用于新疆油田 75口井的压裂改造中，井底温度范围 22～ 97℃，施工成功率 100%。图 5表 4参 20

The widespread use of hydraulic fracturing has resulted in a dramatic increase in the demand of fresh water and the treatment of flowback water. In order to relieve the shortage of water and decrease the cost of the waste water treatment of Xinjiang oilfield，the recycling technology of hydroxypropyl guar gum（HPG）fracturing flowback fluid was studied. The results showed that the rapid gel breaking and sterilization of the flowback fluid could be realized by electrolysis. The suspended matters were effectively removed by air flotation and settlement treatment. After adjusting the pH of the treated flowback fluid to about 6.5，the hydroxypropyl guar gum could disperse well in flowback fluid，and the base fluid could be quickly prepared with the flowback. The flash crosslinking caused by residual crosslinker could be eliminated by introducing a crosslinking delayer sodium gluconate and the crosslinking time could be controlled between 10—120 s. The high temperature stability of the fluid was improved by adding sodium sulfite to eliminate the residual breaking agent. In this method，about 2.2×104 m3 flowback fluid was treated to prepare HPG fracturing fluid，and was applied in the fracturing of 75 wells in Xinjiang oilfield with the bottom hole temperature of 22—97℃ with 100% operation success rate.