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Describing the Pressure Dependence of Lamé Coefficients on Coal Samples
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Near Surface Geoscience 2014 - 20th European Meeting of Environmental and Engineering Geophysics, Sep 2014, Volume 2014, p.1 - 5
Abstract
Understanding the relationship between pressure and rock physical parameters, such as acoustic velocity, elastic moduli, porosity is essential for exploring and exploiting of natural reserves. Therefore a petrophysical model for describing the pressure dependence of P and S wave velocities was developed. The advance of the model is that it provides the required physical explanation of the pressure dependence with its three-parameter exponential function. On the basis of the model the pressure dependent Lamé coefficients were deduced. To prove the applicability of our method laboratory data of coal specimen was inverted to estimate the model parameters. Since the model valid for P and S wave velocity has a common parameter a joint inversion technique was applied. The velocity data were measured under varying confining pressure with pulse transmission technique on dry samples. A very good fitting between measured and calculated data was found thus inversion results strengthened the applicability of the petrophysical model.