威远地区页岩气压裂返排液配制钻井液技术研究

Study on Recycling Hydraulic Fracturing Flow-back Fluid of Shale Gas to Make up Drilling Fluid in Weiyuan Area

为了解决威远地区页岩气压裂返排液无害化处理成本高、处理手段单一、安全环保隐患突出等问题,文章分析了威远地区压裂返排液的碱度、密度、离子含量、物化指标等,明确了影响压裂返排液直接回用配制钻井液的主要因素。通过对比测试优选处理剂,对压裂返排液进行了碱度调节、抑泡处理、杀菌处理、高价金属离子处理。回用处理后的返排液配制钻井液,与未处理返排液配制的钻井液相比,高温高压失水从48 mL降至12 mL,起泡率从13.3%降至0。经过对钻井液体系中处理剂种类和加量进一步优选,优化后的钻井液体系高温高压失水降低至8.8 mL,综合性能与清水配制的钻井液体系一致,满足现场钻进需求,实现压裂返排液在现场直接处理回用,保障页岩气绿色勘探开发。

In order to solve the problems of high cost of harmless treatment,less treatment means,safety and environmental hidden dangers for hydraulic fracturing flow-back fluid of shale gas in Weiyuan area,this paper analyzes the alkalinity,density,ion content,physicochemical index,etc.of the hydraulic fracturing flow-back fluid in Weiyuan area,and makes clear the main factors that affect the direct recycling hydraulic fracturing fluid to make up drilling fluid.The treatment agent was optimized through comparative tests,and the fracturing flowback fluid was treated with alkalinity adjustment,anti-foam treatment,sterilization treatment,heavy metal ion treatment.Compared with the drilling fluid prepared by the untreated flow-back fluid,the HTHP filtrate loss of the drilling fluid prepared by recycling the treated flow-back fluid is decreased from 48 mL to 12 mL,and the foaming rate is decreased from 13.3%to 0.Though further optimization of the type and the increment of treatment agent in the drilling fluid,the optimized drilling fluid system has a HTHP filtrate loss of 8.8 mL,and the comprehensive performance is consistent with the drilling fluid system prepared by the clean water,which meets the on-site drilling requirements,so that the hydraulic fracturing flow-back fluid of shale gas can be directly processed and reused at the site to ensure the green exploration and development of shale gas.