A prestack seismic inversion method constrained by facies-controlled sedimentary structural features

Abstract

The inversion of thin-bed reservoirs using seismic data is important for precise reservoir prediction. Most of the current thin-bed reservoir inversion methods are constrained by facies or sedimentary characteristics in reservoirs. The accuracy of the sedimentary characteristics severely affects the precision of the inversion results. There are differences in sedimentary patterns among different facies, but the same facies have similar sedimentary characteristics, and the similarity brings the sparsity of sedimentary structure within a facies. Thus, various representations should be used to describe the differences in the sedimentary patterns between facies. After analyzing the sparse representation (SR) patterns for different facies, a prestack seismic inversion method constrained by facies-controlled sedimentary structural features is developed. Our method first uses seismic attributes that provide rich details of seismic features to divide facies. Then, the sedimentary structural features within each facies are extracted. The inversion results are represented by structural features in the corresponding facies. We have used the represented results as the initial value of the inversion to iterate. Using this iterative inversion framework, we obtain results that are consistent with the sedimentary features of each facies. The representation of reservoir parameters by different SR patterns can avoid the mixing of sedimentary structural features in different facies. Synthetic and field examples are used to verify the effectiveness of our method. The method obtains inversion results that are consistent with seismic data and the distribution of thin-bed in well logs. Therefore, the method can be successfully applied to thin-bed sandstone reservoirs.