国内外页岩气压裂液技术现状与发展趋势

Current situation and development trend of fracturing fluid technology for shale gas at home and abroad

研究了国内外近年来发展的页岩气压裂液技术,分析了降阻剂及压裂液配方的研究进展,提出了页岩气压裂液的重点发展方向。结果表明:①页岩气压裂液均以聚丙烯酰胺及其衍生物为降阻剂,并根据不同需求添加其他添加剂形成压裂液体系;②为满足压裂返排液回用需求,在降阻剂分子结构中引入2-丙烯酰胺基-2-甲基丙磺酸(AMPS)等耐盐基团或疏水单体以提升压裂液耐盐性已成为国内外共识,研究热点集中在疏水缔合型聚丙烯酰胺降阻剂方面;③黏度可调的变黏滑溜水已成为页岩气压裂液的主流,变黏方式主要是通过改变降阻剂浓度以及引入交联组分来实现,满足高强度加砂和处理裂缝发育复杂等要求;④中高黏滑溜水携砂以弹性为主,形成的砂堤形状与注入参数相关,提升压裂液黏度有助于降低支撑剂沉降速率;⑤利用超分子结构强度携砂和结构强度降阻是解决滑溜水低摩阻与高携砂性能难以兼顾的有效途径,但低黏压裂液结构强度的增大是否影响体积压裂缝网的复杂程度还需研究;⑥将矿石浮选技术引入压裂过程中,对支撑剂表面改性实现气悬浮,从而使低黏滑溜水具备高携砂性能是近期研究热点,而如何将支撑剂表面改性剂直接用于压裂液是今后发展方向。总结的页岩气压裂液技术进展和提出的发展方向对于新型页岩气压裂液的研发和应用有重要的指导意义。

It is summarized the shale gas fracturing fluid technology in recent years at home and abroad,analyzed the research progress of drag reducer and fracturing fluid formula,and put forward the key development direction of shale gas fracturing fluid.The results show that:①Polyacrylamide and its derivatives are used as drag reducer for shale gas fracturing fluids researched and applied,and other additives are added according to different needs to form fracturing fluid systems;②In order to meet the demand of fracturing flowback fluid reuse,it has become a consensus at home and abroad to introduce salt resistant groups or hydrophobic monomers such as 2-acrylamido-2-methylpropane sulfonic acid(AMPS)into the molecular structure of drag reducer to improve the salt resistance of fracturing fluid,and research focuses more on the hydrophobic as-sociative polymer based polyacrylamide drag reducer;③The variable viscosity slick water with adjustable viscosity has become the mainstream of shale gas fracturing fluid.The variable viscosity mode is mainly achieved by changing the concen-tration of drag reducer and introducing some cross-linking components to meet the requirements of high-strength sand addition and treatment of complex fracture development;④The medium and high viscosity slick water sand carrying is mainly elas-tic,and the shape of the sand dike formed is related to the injection parameters(including the viscosity of the fracturing fluid).Increasing the concentration of drag reducer to increase the viscosity of the fracturing fluid will help reduce the proppant set-tling rate;⑤How to give consideration to the properties of high sand carrying and high resistance reduction has become the focus of shale gas fracturing fluid research.Using supermolecule structural strength to carry sand and reduce resistance is an effective way.However,it still needs to be studied whether the increase in structural strength of low viscosity fracturing fluid affects the complexity of volumetric fracturing network;⑥Introducing ore flotation technology into the fracturing process to achieve air suspension by modifying the surface of the proppant,thus enabling low viscosity smooth water to have high sand carrying performance.This technology is a recent research hotspot.How to directly use the proppant surface modifier in the fracturing fluid system is one of the development directions.The technical progress and development direction of shale gas fracturing fluid summarized in this paper have important guiding significance for the research,development and application of new shale gas fracturing fluid.