Correlation of shale anisotropic parameters and their influence factors
Xie Jianyong1,2,3, Wei Jian-xin1,2,3, Di Bangrang1,2,3, Luan Xinyuan1,2,3
1. State Key Laboratory of Petroleum Resources and Prospecting, Beijing 102249, China;
2. CNPC Key Laboratory of Geophysical Prospecting, Beijing 102249, China;
3. China University of Petroleum(Beijing), Beijing 102249, China
Abstract：Thomsen parameters ε and γ are the critical parameters for shale anisotropy characterization. Based on relevant experiment data, we do some researches on the relationship between these anisotropic parameters under different conditions such as dry and brine saturated, and different confining pressure. We establish corresponding empirical formula between ε and γ based on the linear regression of their correlation. This is useful for estimating one parameter from the other, or offering reference calibration value for the measurement. Under the conditions of different confining pressures, S-wave anisotropy and P-wave anisotropy have good linear relationship. Both ε and γ decrease with confining pressure increase and ε decreases quicker. Besides, shale anisotropy parameters under the condition of dry and brine saturated have also the linear relationship. Furthermore, based on the analysis of pertinent data, we concluded that the VP/VS ratio will decrease sharply with Kerogen content increase when Kerogen contents is less than 0.1. While Kerogen content is more than 0.15, almost all the VP/VS ratio are less than 1.65. So high Kerogen content may be a good reason when VP/VS ratio is less than 1.65.
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