页岩压裂裂缝网络预测方法及其应用

发布时间：2018-04-05 15:31

本文选题：页岩　切入点：储集层　出处：《天然气工业》2017年04期

【摘要】：页岩储层天然裂缝发育,加上水力压裂所形成的复杂裂缝网络,可以为油气流动提供有效通道,然而复杂裂缝网络扩展对压裂裂缝识别与优化设计也提出了新的技术挑战。为此,综合考虑天然裂缝与水力裂缝相互作用、缝间"应力阴影"等影响,应用流体力学与断裂力学理论,建立了裂缝网络扩展模型(FNPM),实现了不同力学参数、不同天然裂缝等条件下裂缝扩展方位、几何尺寸、支撑裂缝面积等多指标预测。理论模拟和现场实例应用结果表明:①改造裂缝网络扩展受控因素多,地应力差、簇间距及净压力等参数决定了"应力阴影"效应的强弱,天然裂缝与水力裂缝之间的相互作用机理决定了改造裂缝网络的复杂程度;②地应力差相同时,簇间距越小,"应力阴影"效应越强,水力裂缝扩展偏离主应力方向,裂缝宽度减小,不利于加砂;③天然裂缝内摩擦系数、天然裂缝与水力裂缝夹角越小,净压力越高,天然裂缝越容易开启或剪切,增加了改造裂缝的复杂性;④裂缝扩展方向、裂缝长度二者预测具有较好的一致性,但受天然裂缝发育差异的影响,局部压裂段有一定的差异性。所提出的裂缝预测方法为页岩改造裂缝识别与后期压裂设计提供了技术支撑。
[Abstract]:The development of natural fractures in shale reservoir, coupled with the complex fracture network formed by hydraulic fracturing, can provide an effective channel for oil and gas flow. However, the expansion of complex fracture network also poses a new technical challenge to the identification and optimization of fracturing fractures.Therefore, considering the interaction between natural and hydraulic cracks and the influence of "stress shadow" between fractures, a fracture network expansion model (FNPM) is established by applying the theory of fluid mechanics and fracture mechanics, and different mechanical parameters are realized.The prediction of crack propagation azimuth, geometric dimension and supporting crack area under different natural crack conditions.The results of theoretical simulation and field application show that the effect of "stress shadow" is determined by many controlled factors, such as stress difference, cluster spacing, net pressure and so on.The interaction mechanism between natural fracture and hydraulic fracture determines that when the complex degree of reforming fracture network is the same, the smaller the cluster spacing is, the stronger the "stress shadow" effect is, and the hydraulic crack propagation deviates from the direction of principal stress.The smaller the angle between natural fracture and hydraulic fracture is, the higher the net pressure is, the easier the natural crack is opened or shearing, the more complex the reconstruction fracture is, the more complex the crack is, and the further the extension direction of fracture is, the smaller the angle between natural crack and hydraulic fracture is, the less the width of fracture is, and the higher the net pressure is.The prediction of fracture length is consistent with each other, but there are some differences in local fracturing due to the difference of natural fracture development.The proposed fracture prediction method provides technical support for shale reconstruction fracture identification and later fracturing design.
【作者单位】：中国石油川庆钻探工程公司井下作业公司;中国石油川庆钻探工程公司地球物理勘探公司;
【基金】：国家科技重大专项“水平井压裂设计优化系统”(编号:2016ZX05023001)
【分类号】：TE357.14

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