High accurate identification on coalbed methane sweet-spot based on fluid flow attribute

The conventional post-stack seismic inversion could indentify the coal seam, but could not predict the gas content of the seam. The fluid flow factor of the seismic wave attenuation theory could be applied to effectively characterize the gas content of the reservoir, to indentify the gas bearing coal reservoir and to provide the fluid flow factor applied to combine with the high accurate matching tracing algorithm. Based on the high accurate time frequency analysis of the seismic signals, a relationship between the gas content seam and the seismic wave attenuation was established to seek the fluid flow attribute and to realize the high accurate identification on the coalbed methane sweet-spot. The study results showed that the matching tracing methane could overcome the limit of the window function in comparison with the other time frequency analysis methods and could finely characterize the signal features both in the time domain and the frequency domain. The fluid detection method combined with the fluid flow attribute and the high accurate time frequency analysis could improve the accuracy of the fluid identification. The prediction results were fitted with the gas logging. Due to the data driven, the results were faithful to the seismic data and were not affected by the structure and the stratigraphic sequence interpretation and could objectively reflect the gas content of the seam.