ABSTRACT

Despite holding a significant proportion of the known hydrocarbon reserves by the carbonates, enough studies have not been conducted to understand their geomechanical parameters and their predictability, especially in Iran. The present paper introduces a novel approach for obtaining geomechanical parameters of carbonate rocks through investigating the relationship between geomechanical parameters and Archie’s coefficients in one of the Iranian fractured carbonate reservoirs. The geomechanical parameters here included Young’s modulus, bulk modulus, and shear modulus, while Archie’s coefficients were the cementation factor and formation resistivity factor. For this purpose, 14 representative limestone core plugs were chosen and Archie’s coefficients were determined and the effect of increasing confining pressure on these parameters was investigated. Then, through numerical simulations using Particle Flow Code (PFC3D), the geomechanical parameters of the reservoir, including Young’s modulus (E), (dynamic and static), bulk and shear modulus, and Poisson’s ratio were obtained. The numerical results were verified by the laboratory tests and wireline logs’ data and showed a satisfying matching. Finally, the empirical relations between geomechanical parameters and Archie’s coefficients were determined for the target reservoir. According to the obtained results, the average correlation between Young’s modulus and both the cementation factor and formation resistivity factor was about 95%, which is a satisfying accuracy. As expected, shear modulus and bulk modulus had a stronger relationship with E being respectively about 99% and 98%. Moreover, lab-measured porosity and Young’s modulus had a correlation coefficient of about 95%. The obtained results of the present study provide new insights into the simultaneous evolution of the reservoir’s mechanical and petrophysical characteristics.

摘要

尽管碳酸盐岩拥有相当一部分已知的碳氢化合物储量，但仍未进行足够的研究来了解其地质力学参数及其可预测性，尤其是在伊朗。本文通过研究伊朗某裂隙碳酸盐岩储层的地质力学参数与阿奇系数之间的关系，介绍了一种获取碳酸盐岩岩石力学参数的新方法。这里的地质力学参数包括杨氏模量，体积模量和剪切模量，而阿奇系数是胶结因子和地层电阻率因子。为此，选择了14个代表性的石灰岩岩心塞，并确定了阿奇系数，并研究了提高围压对这些参数的影响。E）（动和静态），体积和剪切模量以及泊松比。通过实验室测试和电缆测井数据验证了数值结果，并显示出令人满意的匹配度。最后，确定了目标油藏的地质力学参数与阿奇系数之间的经验关系。根据所得结果，杨氏模量与胶结因子和地层电阻率因子两者的平均相关性约为95％，这是令人满意的精度。不出所料，剪切模量和体积模量与E有更强的关系分别约为99％和98％。此外，实验室测得的孔隙率和杨氏模量的相关系数约为95％。本研究获得的结果为油藏的力学和岩石物理特征的同时演化提供了新的见识。