Abstract
The construction of a shale rock physics model and the selection of an appropriate brittleness index (BI) are two significant steps that can influence the accuracy of brittleness prediction. On one hand, the existing models of kerogen-rich shale are controversial, so a reasonable rock physics model needs to be built. On the other hand, several types of equations already exist for predicting the BI whose feasibility needs to be carefully considered. This study constructed a kerogen-rich rock physics model by performing the selfconsistent approximation and the differential effective medium theory to model intercoupled clay and kerogen mixtures. The feasibility of our model was confirmed by comparison with classical models, showing better accuracy. Templates were constructed based on our model to link physical properties and the BI. Different equations for the BI had different sensitivities, making them suitable for different types of formations. Equations based on Young’s Modulus were sensitive to variations in lithology, while those using Lame’s Coefficients were sensitive to porosity and pore fluids. Physical information must be considered to improve brittleness prediction.
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This study is financially supported by the NSFC and Sinopec Joint Key Project (No. U1663207), National Science and Technology Major Project (No. 2017ZX05049-002), and National 973 Program (No. 2014CB239104).
Qian Ke-Ran is an engineer and a post-doctoral fellow from Petroleum Exploration and Production Research Institute of Sinopec. He received his Bachelor’s degree from Yangtze University (2010), Master’s degree from University of Edinburgh (2011), PhD degree from China University of Petroleum (Beijing) (2016). Currently, he works in Sinopec exploration and Development Research Institute. His research interests mainly focus on anisotropic rock physics modeling and sweet spot prediction of unconventional reservoirs.
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Qian, KR., He, ZL., Chen, YQ. et al. Prediction of brittleness based on anisotropic rock physics model for kerogen-rich shale. Appl. Geophys. 14, 463–479 (2017). https://doi.org/10.1007/s11770-017-0640-y
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DOI: https://doi.org/10.1007/s11770-017-0640-y