Lithologic Reservoir Prediction Using Relative Energy Change Rate

Oil reservoirs identified by complex fluvial facies sequence stratigraphy are always small and thin and occur with a scattered distribution, which makes their exploration and development challenging. The identification of the reservoirs themselves is especially difficult. To address these problems and the actual demands of oil exploration, a new method for estimating the relative energy change rate based on time–frequency analysis is proposed in this paper. A comparison of results of time–frequency continuous wavelet transform (TFCWT), discrete Fourier transform, S transform, and continuous wavelet transform shows that the resolution of TFCWT in calculating the relative energy change rate is the highest. Therefore, the proposed method uses TFCWT to calculate the relative energy change rate between strong low-frequency energy and the weak energy of high frequencies resulting from attenuation processes. Taking the study of the C2-6 wellblock of the Chunguang oil field in China as an example, and comparing the results of the proposed method with those of multiple seismic attributes, it was shown that the distribution pattern of the Shawan reservoirs identified by the proposed method is clear and highly consistent with existing drilling data.