生物柴油基减阻剂研制及滑溜水压裂液体系构建

Development of Biodiesel-based Drag Reducing Agent and Construction of Slickwater Fracturing Fluid System

为了解决常规白油基滑溜水体系在运输过程中容易分层以及减阻剂溶解太慢、对环境污染大等问题,首先通过测试不同相对分子质量及水解度的减阻剂F1~F6的溶解性和增黏性能优选了减阻剂F4;通过对稠化剂、分散剂及固液比筛选,研制了配方为34.0%生物柴油+3.0%稠化剂F-120+3.0%分散剂S-85+60.0%减阻剂F4的生物柴油基悬浮减阻剂,并将生物柴油基悬浮减阻剂与助排剂、防膨剂构建变黏滑溜水压裂液体系。实验结果表明,减阻剂F4在180℃下恒温剪切2 h后的表观黏度保留率为33.0%,热稳定性较好;变黏滑溜水压裂液具有良好的抗剪切能力和抗温性能,在剪切速率为170 s^(-1)下长期剪切后,常温下黏度保留率均可达90%以上,90℃下黏度保留率均达50%以上,其中高黏滑溜水压裂液黏度保留率可高达70%以上,低黏滑溜水压裂液的减阻率可达70%以上;高黏滑溜水压裂液的携砂性能比低、中黏滑溜水压裂液的高,且沉降速率最低,为0.005272 m/min。变黏滑溜水压裂液破胶后表面张力均小于27 m N/m,与煤油间的界面张力均小于2.0 mN/m,破胶液黏度均小于5.0mPa·s,且残渣含量均小于50 mg/L,满足标准要求。

To solve the problems of easy layering,slow dissolution of drag-reducing agents,and significant environmental pollution in the transportation process of conventional white oil-based slickwater systems,the drag reducing agent F4 was selected through measurement of the dissolution and viscosity-increasing properties drag reducing agents F1—F6 with different molecular weights and ionic degrees.By screening thickeners,dispersants,and solid-liquid ratios,a biodiesel-based suspension drag reducer was developed as follows:34.0%biodiesel+3.0%thickener 2#+3.0%dispersant 3#+60.0%drag reducer F4.A variable viscosity and slickwater fracturing fluid system was constructed by combining biodiesel-based suspension drag reducers with clean up additive and anti-expansion agents.The experimental evaluation results showed that drag reducer F4 had good thermal stability with an apparent viscosity retention rate of 33.0%after shearing at 180℃for 2 hours at constant temperature.The variable viscosity and slickwater fracturing fluid had good shear and temperature resistances.The viscosity retention rate could reach over 90%at room temperature and over 50%at 90℃after shearing at the shear rate of 170 s^(-1).Among them,the viscosity retention rate of high-viscosity slickwater fracturing fluids could reach over 70%,and the drag reduction rate of low-viscosity slickwater fracturing fluids could reach over 70%.The sand-carrying performance of high-viscosity slickwater fracturing fluids was better than that of low and medium-viscosity fluids,and the minimum settling rate was 0.005272 m/min.The surface tension of the variable viscosity slickwater fracturing fluid after breaking was less than 27 mN/m,the interface tension was less than 2.0 mN/m,the viscosity of the fracturing fluid was less than 5.0 mPa·s,and the residue content was less than 50 mg/L,meeting the standard requirements.