贾庆升, 钟安海, 张子麟, 丁然. 济阳坳陷泥灰质纹层页岩脆性各向异性数值模拟研究[J]. 石油钻探技术, 2021, 49(4): 78-84. DOI: 10.11911/syztjs.2021086
引用本文: 贾庆升, 钟安海, 张子麟, 丁然. 济阳坳陷泥灰质纹层页岩脆性各向异性数值模拟研究[J]. 石油钻探技术, 2021, 49(4): 78-84. DOI: 10.11911/syztjs.2021086
JIA Qingsheng, ZHONG Anhai, ZHANG Zilin, DING Ran. Numerical Simulation of the Brittleness Anisotropy of Laminated Argillaceous Limestone Facies Shale in the Jiyang Depression[J]. Petroleum Drilling Techniques, 2021, 49(4): 78-84. DOI: 10.11911/syztjs.2021086
Citation: JIA Qingsheng, ZHONG Anhai, ZHANG Zilin, DING Ran. Numerical Simulation of the Brittleness Anisotropy of Laminated Argillaceous Limestone Facies Shale in the Jiyang Depression[J]. Petroleum Drilling Techniques, 2021, 49(4): 78-84. DOI: 10.11911/syztjs.2021086

济阳坳陷泥灰质纹层页岩脆性各向异性数值模拟研究

Numerical Simulation of the Brittleness Anisotropy of Laminated Argillaceous Limestone Facies Shale in the Jiyang Depression

  • 摘要: 为了掌握济阳坳陷博兴洼陷北部沙四纯上亚段页岩脆性各向异性的规律,选用该区块樊页X井泥灰质纹层页岩岩心,以通过室内试验获得的岩心应力–应变曲线为基准标定岩石力学参数,采用三维数值模拟方法,计算分析了岩心的泊松比、弹性模量和强度参数;并采用4种典型的脆性指数计算方法,计量了所有岩心的脆性指数。研究发现:随着围压升高,各力学参数的各向异性度都呈下降趋势,且弹性参数较强度参数的各向异性对围压变化更为敏感,因此建议采用弹性参数评价岩心力学特性的各向异性;基于能量守恒原理的脆性指数计算方法计算出的脆性指数较为客观;脆性指数随围压升高而显著降低,且随着层理倾角增大,脆性指数总体上呈先降低、后升高的变化趋势,也即在与内摩擦角角度接近的方向,脆性指数最低,0°和90°取心方向上的脆性指数较高。研究结果可为济阳坳陷页岩油储层可压性评价及选井选层提供理论依据。

     

    Abstract: Argillaceous limestone facies core samples were drilled from Well Fanye X to reveal the brittleness anisotropy law of shale from the upper Chun submember of the fourth member of Shahejie Formation in the Northern Boxing Subsag of the Jiyang Depression. With the laboratory measured stress–strain curves for rocks as the calibration criterion, a three-dimensional numerical simulation was adopted to calculate and analyze the Poisson’s ratio, Young’s modulus and strength parameters of the cores. Four typical methods were employed to calculate the brittleness index of all cores. Research demonstrates that as the confining pressure increases, the degree of anisotropy of mechanical parameters declines, and the anisotropy of elastic parameters is more sensitive to the variation in confining pressure than that of strength parameters. Therefore, it is recommended to evaluate the anisotropy of core mechanics with elastic parameters. The brittleness index calculation method based on the principle of conservation of energy can objectively evaluate the shale core brittleness. The brittleness index decreases significantly as the confining pressure grows, and it first drops and then rises as the bedding dip increases. In other words, the brittleness index in the direction close to the angle of internal friction is the lowest, while it is relatively higher in the 0° and 90° coring directions. The research results can provide a theoretical basis for evaluating fracturing feasibility in shale oil reservoirs and selecting wells and layers in the Jiyang Depression.

     

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