Abstract In-depth water flooding profile modification is a new problem for low permeability formation under fracturing. Profile control study for in-depth cross flow which couples fracture and matrix is neither comprehensive nor complete at present. Artificial hydraulic fracturing core is manufactured to conduct core flood experiment. In-depth profile modification mechanisms of gel-nitrogen-foam are revealed based on microstructure analysis and mechanical stability evaluation. The instantaneous stability and durability of gel-nitrogen-foam are evaluated by breakthrough pressure and residual resistance factor. Weak movement ability restrains the distribution of gel in cross zone and bubble burst effect declines the active time of nitrogen-foam. Gel-nitrogen-foam displays promised profile modification performance based on synergistic effect which combines movement ability of nitrogen-foam and durability of gel. Nuclear magnetic resonance (NMR) test result shows that sweep area of matrix significant increases after profile modification, which indicates that enhance oil recovery (EOR) main contributes by the remaining oil in matrix nearby injection fracture. The optimized gas/liquid ratio and injection volume are 1.95 and 2.8 PV separately with incremental EOR of 9.74%. Coupling laboratory experiment with numerical simulation, this work offers a new insight of in-depth cross flow profile modification mechanism for formation under fracturing from macroscopic and microscopic views.

中文翻译：

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压裂下低渗透地层凝胶-氮-泡沫调剖性能室内评价与数值模拟研究

摘要 深部注水调剖是压裂下低渗透地层面临的新问题。目前对裂缝与基质耦合的深部错流的调剖研究既不全面也不完整。制作人工水力压裂岩心进行岩心注水试验。基于微观结构分析和机械稳定性评估，揭示了凝胶-氮-泡沫的深入剖面改性机制。凝胶氮泡沫的瞬时稳定性和耐久性是通过突破压力和残余阻力系数来评估的。较弱的运动能力限制了凝胶在交叉区域的分布，气泡破裂效应降低了氮泡沫的活性时间。凝胶-氮-泡沫显示出基于协同效应的良好的调剖性能，结合了氮-泡沫的运动能力和凝胶的耐久性。核磁共振（NMR）测试结果表明，调剖后基质波及面积显着增加，表明提高采收率（EOR）主要由注入裂缝附近基质中的剩余油贡献。优化后的气液比和注入量分别为 1.95 和 2.8 PV，EOR 增量为 9.74%。这项工作将实验室实验与数值模拟相结合，从宏观和微观角度对压裂下地层的深度错流剖面修正机制提供了新的见解。核磁共振（NMR）测试结果表明，调剖后基质波及面积显着增加，表明提高采收率（EOR）主要由注入裂缝附近基质中的剩余油贡献。优化后的气液比和注入量分别为 1.95 和 2.8 PV，EOR 增量为 9.74%。这项工作将实验室实验与数值模拟相结合，从宏观和微观角度对压裂下地层的深度错流剖面修正机制提供了新的见解。核磁共振（NMR）测试结果表明，调剖后基质波及面积显着增加，表明提高采收率（EOR）主要由注入裂缝附近基质中的剩余油贡献。优化后的气液比和注入量分别为 1.95 和 2.8 PV，EOR 增量为 9.74%。这项工作将实验室实验与数值模拟相结合，从宏观和微观角度对压裂下地层的深度错流剖面修正机制提供了新的见解。8 PV 单独增加 EOR 为 9.74%。这项工作将实验室实验与数值模拟相结合，从宏观和微观角度对压裂下地层的深度错流剖面修正机制提供了新的见解。8 PV 单独增加 EOR 为 9.74%。这项工作将实验室实验与数值模拟相结合，从宏观和微观角度对压裂下地层的深度错流剖面修正机制提供了新的见解。