Shale oil reservoirs are usually developed by horizontal wells completed with multi-stage hydraulic fractures. The fracture interference between clusters in a single stage and between consecutive stages has an impact on the stimulation quality in terms of fracture geometries and fracture widths. This study introduces a non-planar hydraulic fracture model based on the extended finite element method and its use in quantifying the effects of relevant parameters on multi-stage fracture quality in a realistic shale oil scenario. The numerical model is validated with field diagnostics based on vertical seismic profiling. Relevant parameters including stress contrast, fracturing fluid viscosity, cluster density, and fracturing in consecutive stages are quantitatively analyzed in the numerical study. Results show that effects of stress contrast on fracture quality are greater than those of fracturing fluid viscosity, while the effects are more significant in outer fractures instead of the inner fracture. Denser cluster design leads to greater inhibition for the growth of inner fractures which eventually divert them transversely. In fracturing for consecutive stages, the opening of fractures in the subsequent stages is inhibited and the fracture geometries are also altered by the inter-stage interference caused by the previous stage. Based on field data and numerical modeling, this study identifies key parameters and quantifies their effects on inter-fracture and inter-stage interference in multi-stage hydraulic fracturing in horizontal wells.

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基于数值模拟的裂缝簇与段间水力压裂干扰参数化研究

页岩油藏通常由多级水力压裂完井的水平井开发。单个阶段中簇之间和连续阶段之间的裂缝干扰对裂缝几何形状和裂缝宽度方面的增产质量有影响。本研究介绍了基于扩展有限元方法的非平面水力压裂模型及其在实际页岩油情景中量化相关参数对多级压裂质量影响的用途。该数值模型通过基于垂直地震剖面的现场诊断进行了验证。数值研究中对应力对比、压裂液黏度、簇密度、连续压裂等相关参数进行了定量分析。结果表明，应力对比对裂缝质量的影响大于压裂液粘度，而外裂缝的影响比内裂缝更显着。更密集的集群设计对内部裂缝的生长产生更大的抑制，最终将它们横向转移。在连续段压裂过程中，后段裂缝的张开受到抑制，前一段引起的段间干扰也改变了裂缝的几何形状。本研究基于现场数据和数值模拟，确定了关键参数，并量化了它们对水平井多级水力压裂中裂缝间和级间干扰的影响。而外裂缝的影响比内裂缝更显着。更密集的集群设计对内部裂缝的生长产生更大的抑制，最终将它们横向转移。在连续段压裂过程中，后段裂缝的张开受到抑制，前一段引起的段间干扰也改变了裂缝的几何形状。本研究基于现场数据和数值模拟，确定了关键参数，并量化了它们对水平井多级水力压裂中裂缝间和级间干扰的影响。而外裂缝的影响比内裂缝更显着。更密集的集群设计对内部裂缝的生长产生更大的抑制，最终将它们横向转移。在连续段压裂过程中，后段裂缝的张开受到抑制，前一段引起的段间干扰也改变了裂缝的几何形状。本研究基于现场数据和数值模拟，确定了关键参数，并量化了它们对水平井多级水力压裂中裂缝间和级间干扰的影响。前一阶段引起的级间干扰抑制了后续阶段裂缝的张开，裂缝几何形状也发生了改变。本研究基于现场数据和数值模拟，确定了关键参数，并量化了它们对水平井多级水力压裂中裂缝间和级间干扰的影响。前一阶段引起的级间干扰抑制了后续阶段裂缝的张开，裂缝几何形状也发生了改变。本研究基于现场数据和数值模拟，确定了关键参数，并量化了它们对水平井多级水力压裂中裂缝间和级间干扰的影响。