纳米材料改善压裂液性能及驱油机理研究

Study on Mechanism of the Fracturing Fluid Performance Improvement and Oil Displacement Using Nanomaterials

为给研发功能性压裂液提供理论依据,在纳米尺度(50 nm)对SiO_(2)进行C_(8)和季铵盐(QAS)修饰,合成了疏水纳米材料SiO_(2)-C_(8)和疏水带电纳米材料SiO_(2)-QAS,评价了SRFP型聚合物清洁压裂液分别加入SiO_(2),SiO_(2)-C_(8)及SiO_(28)-QAS等3种纳米材料后的配伍性、稳定性及综合性能;利用量化模拟手段,建立了纳米材料在砂岩表面的吸附结构模型及吸附动力学模型,分析了纳米材料在砂岩表面的吸附及油水分离特征。试验及模拟结果表明:SiO_(2),SiO_(2)-C_(8)及SiO_(2)-QAS等3种纳米材料在压裂液中具有较好的分散稳定性,可有效降低表界面张力,表现出良好的耐温、耐剪切性能;SiO_(2)-C_(8)和SiO_(2)-QAS加入压裂液后有利于砂岩表面油分子被置换出,促进油水分离;SiO_(2)-C_(8)和SiO_(2)–QAS加入压裂液后可有效改善压裂液性能,提高驱油效果,降低压裂液波及范围内的含油饱和度。研究结果可为功能性压裂液发展和研制提供理论依据,为优化致密油、页岩油压裂方案和优选压裂液提供参考。

To provide a theoretical basis for the development of functional fracturing fluids,SiO_(2) was modified with C_(8) and quaternary ammonium salt (QAS) on nanoscale (50 nm).The hydrophobic nanomaterial SiO_(2)-C_(8)and hydrophobic charged nanomaterial SiO_(2)-QAS were synthesized.The compatibility,stability,and comprehensive performance of the SRFP polymer clean fracturing fluid systems were evaluated as nanomaterials SiO_(2),SiO_(2)-C_(8),and SiO_(2)-QAS were added.Quantitative simulation methods were employed to build the adsorption structure models and adsorption kinetics models of the nanomaterials on the sandstone surface.The adsorption and oil-water separation characteristics of nanomaterials on sandstone surfaces were analyzed.The experimental and simulation results show that the three nanomaterials,SiO_(2),SiO_(2)-C_(8),and SiO_(2)-QAS,display favorable dispersion stability in fracturing fluids.They can effectively reduce the surface and interfacial tension and demonstrate good temperature and shear resistance.SiO_(2)-C_(8) and SiO_(2)-QAS nanomaterials are beneficial to the replacement of oil molecules on the sandstone surface and the oil-water separation when they are added into fracturing fluids.The addition of nanomaterials SiO_(2)-C_(8) and SiO_(2)-QAS can also effectively improve the performance of fracturing fluids,enhance oil displacement,and reduce oil saturation within the spread range of fracturing fluids.The research results can provide a theoretical basis for the development of functional fracturing fluids and a reference for fracturing design optimization and fracturing fluid selection for tight oil and shale oil.