Preliminary discussion and application of P-wave technique for prediction the gas-bearing property in CBM reservoir

摘要

The prediction for the gas-bearing property of coal beds becomes a new task for seismic technology. Based on international and domestic research results on the petro-physical and geophysical responses of the gasbearing coal beds, this paper proposes a prediction technique using P-wave data which mainly studies the variation of dynamic characteristics such as the amplitude, frequency, and attenuation of the coal bed reflected wave and discusses the theoretical basis and implementation method of the prediction technique for the gas-bearing property for coal beds which applies a constraint inversion by sonic waves fitted with Gamma, spectral decomposition, AVO inversion and El inversion. From the preliminary application to the seismic data from Qinshui Basin, the prediction results of the gas-bearing property basically coincide with the gas content obtained by wells, which is in accordance with the CBM high-permeability enrichment theory. This study has preliminarily proved the feasibility and validity of the prediction technique for the CBM-bearing property using P-wave data.