国内变黏滑溜水研究进展及在川渝非常规气藏的应用

Research progress of variable viscosity slick water in China and its application in unconventional gas reservoirs in Sichuan and Chongqing

综述了国内变黏滑溜水技术的最新进展,举例分析了变黏滑溜水在川渝非常规气藏的应用情况,提出了变黏滑溜水的发展方向。变黏滑溜水通过调节降阻剂含量和/或引入交联剂的方式实现低、中、高黏液体实时切换;关键的降阻剂研究主要是含AMPS或SSS等耐盐基团的聚丙烯酰胺或疏水缔合聚合物的合成与性能评价等,满足压裂返排液配液和变黏的需要;变黏滑溜水性能研究主要是黏度对携砂性能、裂缝形态、降阻性能等的影响规律,但究竟何种黏度适合何种储层还未有定论;变黏滑溜水在川渝非常规气藏应用获得成功,在致密气应用的整体黏度较页岩气高,在深层页岩气的携砂能力还需进一步增强;疏水缔合聚合物类降阻剂、固体型降阻剂是变黏滑溜水的发展方向,有望解决高黏液体摩阻高、乳液降阻剂潜在环保风险等问题,对变黏滑溜水的研究和应用有一定的指导意义。

This paper summarizes the latest progress of variable viscosity slick water technology in China,analyzes the application of variable viscosity slick water in unconventional gas reservoirs in Sichuan and Chongqing,and puts forward the development direction of variable viscosity slick water.The variable viscosity slick water realizes the real-time switching of low,medium and high viscosity liquids by adjusting the concentration of drag reducer and/or introducing cross-linking agent.The research of drag reducer focuses on the synthesis and performance evaluation of polyacrylamide containing AMPS or SSS salt-tolerant groups and hydrophobic associating polymer,to meet the needs of preparing fracturing flowback fluid mixing and change viscosity.The research on the performance of variable viscosity slick water mainly focuses on the influence law of viscosity on sand carrying performance,fracture morphology and drag reduction performance,but it is not yet determined what viscosity is suitable for what reservoir.The application of variable viscosity slick water in unconventional gas reservoirs in Sichuan and Chongqing was successful.The overall viscosity in tight gas is higher than that in shale gas,and the sand carrying capacity in deep shale gas needs to be further enhanced.Hydrophobically associating polymer drag reducer and solid drag reducer are the development direction of variable viscosity slick water.It is expected to solve the problems of high frictional resistance of high viscosity liquid and potential environmental risks of emulsion drag reducer.This paper has certain guiding significance for the research and application of variable viscosity slick water.