大规模增产作业中液体的回用技术探讨

针对页岩气、致密气等非常规气藏体积压裂过程中存在的配液用水缺乏、压裂返排液处理困难、环境污染风险大等问题,探讨了大规模增产作业中的液体回用技术。大规模增产作业对水资源的需求量大,井场用水供需矛盾突出,且产生的压裂返排液量大,面临的环境形势严峻,制约了非常规气藏的开发。压裂返排液的组成复杂,其成分主要取决于压裂液配液水质、压裂液化学组成、储层地质化学、地层水等,影响其回用时的压裂液性能,需针对性地进行处理。大规模增产作业中的液体回用技术主要是通过杀菌、沉降除机械杂质、化学沉淀除高价金属离子、补充损失的添加剂等措施使压裂返排液的性能满足再次施工要求。该技术在四川盆地须家河致密气储层及侏罗系致密油储层中得到了广泛应用,返排液回收后的利用率达95%,节约了水资源,实现了循环经济。

Discussion on liquid recycling technology in mass production operation

For lack of water source ,processing difficulties of fracturing flowback fluid and en-vironmental pollution risk in volume fracturing process of shale gas ,tight gas and other uncon-ventional gas reservoir ,the fluid recycling technique in the mass increase production was dis-cussed .Mass increase production requires a lot of water ,so the contradiction between supply and demand of water near the well site is very outstanding .At the same time ,to produce a large a-mount of fracturing flowback fluid ,it faces the grim situation of environment .and restricts the development of unconventional gas reservoir . The composition of fracturing flowback fluid is complex ,mainly depends on water quality of fracturing fluid ,fracturing liquid composition ,res-ervoir geologic chemistry ,and formation water ,etc .These substances will influence the reuse performance of fracturing flowback fluid ,so they need to be dealt with .The fluid recycle tech-nique in the mass increase production can satisfy the performance of fracturing flow back fluid construction requirements once again mainly through the disinfection ,settlement in addition to the mechanical impurities ,chemical precipitation in addition to the high metal ions ,compensato-ry loss additives etc .The technology was widely used in tight gas reservoirs of Xujiahe and tight oil reservoirs of Jurassic in Sichuan basin .The utilization ratio of flowback fluid after recycling is 95% ,saving water source and achieving the circular economy .