Application of Well-Controlled Waveform Indication Inversion Technology in Prediction of Coal-Bearing Sandstone Reservoir

The southeastern part of the South Turgai Basin mainly develops shore-shallow lake and delta facies deposits. The southeastern part of the South Turgai Basin mainly contains coal-bearing reservoir, and the delta front sand body is a favorable reservoir. Due to the development of coal seams in this stratum and the unstable lateral distribution of coal seams, they have a strong shielding effect on the seismic response of sandstone reservoirs, resulting in difficult reservoir prediction. In this paper, based on the well-controlled waveform indication inversion method, the drilling lithology is used as the constraint condition, and the well-side trace of seismic data is used as the learning sample to establish the corresponding relationship of seismic waveform characteristics of different lithology combinations. Different lithology has own seismic waveform response characteristics. The seismic well-controlled waveform indication inversion of reservoir sensitive parameters of P-wave impedance and gamma in this area is completed based on seismic waveform characteristics. Based on the inversion results of sensitive parameters, using the method of Bayers fuzzy judgment, P-wave impedance inversion combined with gamma inversion is used to interpret the lithofacies probability of sandstone, mudstone and coal seam, and the spatial distribution characteristics of different lithology are also obtained. The multi-parameter joint coal removal inversion method based on waveform indication inversion combined with Bayes fuzzy judgment greatly improves the prediction accuracy of sandstone reservoir, and the inversion results are in agreement with the drilling results by more than 75%. So the method provided by this paper is reasonable and feasible.