耐高温耐剪切压裂返排液的制备与性能评价

Preparation and Performance Evaluation of High-temperature and Shear Resistant Fracturing Flowback Fluid

随着常规油气资源的不断开发,深层低渗透油气已逐渐成为勘探开发的主要资源,设计新结构耐温稠化剂和配套交联剂,构建适用于高温深井的耐温压裂液体系是深层低渗透油气勘探开发的关键问题。以三种丙烯酰胺类单体为原料,采用溶液聚合方法制备出聚合物稠化剂NWJ-1,通过红外光谱、XRD和DSC表征聚合物的组成和结构,结果表明:聚合物分子符合设计的结构。通过对稠化剂基液浓度、交联剂与基液体积比以及延迟交联剂加量进行优选,获得耐高温聚合物压裂液体系:0.6%聚合物稠化剂NWJ-A+0.2%助排剂DRKJ-16+0.4%HCl(20%质量分数)+0.06%延迟交联调节剂FAY-3+0.6%交联剂MP200。该压裂液体系具有良好的黏弹性,180℃高温环境下剪切2 h,压裂液体系的初始黏度为152 mPa·s,最大黏度可到1165 mPa·s,保留黏度68 mPa·s;180℃下的静态滤失实验显示,压裂液体系的滤失系数为1.47×10^(-5)m/min^(1/2),滤失速率为2.45×10^(-5)m/min,初滤失量为9.47×10^(-5)m^(3)/m^(2);同时体系具有良好的破胶性,破胶时间可控。此方法对耐温压裂液体系的研究具有理论参考意义。

With the continuous development of conventional oil and gas resources,deep low-permeability oil and gas has gradually become the main resource for exploration and development.Designing a new structure temperature-resistant thickening agent and supporting cross-linking agent and constructing a temperature-resistant fracturing fluid system suitable for high-temperature deep wells are the key issues in deep and low permeability oil and gas exploration and development.In this paper,three kinds of acrylamide monomers are used as raw materials,and the polymer thickener NWJ-1 is prepared by solution polymerization.The composition and structure of the polymer are characterized by infrared spectroscopy,XRD,and DSC.The results show that the polymer molecules conform to the designed structure.By optimizing the concentration of the thickener base fluid,the volume ratio of the crosslinking agent to the base fluid,and the dosage of delayed crosslinking agent,a high temperature resistant polymer fracturing fluid system is obtained:0.6%polymer thickener NW J-A+0.2%drainage aid DRKJ-16+0.4%HCl(20%mass fraction)+0.06%delayed crosslinking regulator FAY-3+0.6%crosslinking agent MP200.Under high temperature environment,the fracturing fluid system has good viscoelasticity.After shearing at 180℃for 2 hours,the initial viscosity of the fracturing fluid system is 152 mPa∙s,the maximum viscosity can reach 1165 mPa∙s,and the retained viscosity is 68 mPa∙s.The static fluid loss experiment at 180℃shows that the fluid loss coefficient of the fracturing fluid system is 1.47×10^(-5) m/min1/2,the fluid loss rate is 2.45×10^(-5) m/min,and the initial fluid loss is 9.47×10^(-5) m^(3)/m^(2).At the same time,the system has good gel breaking performance,and the gel breaking time is controllable.This method can provide a theoretical reference for the study of temperature-resistant fracturing fluid systems.