Application of Pre-stack Inversion in Fine Potential Tapping of Old Oilfield

In view of the problems of fast phase change, strong multi-solution of the position prediction of the inter-well narrow channel sand body and unclear type of the sand body connectivity in Daqing Oilfield, this paper takes the Soil group in Block A of Sartu Oilfield in Daqing Oilfield as an example to carry out the integrated research of seismic processing, pre-stack inversion and development evaluation. The correction processing technology such standardization is adopted to provide high-quality logging data, and the absorption compensation technology and some seismic angle gather stacking optimization technology are adopted to provide highly consistent seismic angle gather data, and the pre-stack inversion is carried out using the quality control logging and seismic data; The rock physical simulation technology based on xu-white is adopted to determine the boundary value of sandstone and shale; The well point is guided by the P-wave curve, and the inter-well is constrained by the partial stacked seismic trace data. The Markov chain Monte Carlo algorithm of seismic waveform indication is used to realize the prediction of the P-wave and S-wave combined sand body and fluid identification. Through qualitative and quantitative methods to evaluate the inversion results. The quantitative method is the statistical analysis of the post-test well data, and the qualitative method is to depict the sedimentary facies map of the inversion results. Statistics of post-test well data shows that the accuracy of pre stack inversion can reach 80.7% for thin interbedded sand bodies with a thickness of 1–2 m, and over 85% for sand bodies with a thickness of more than 2 m; The fluid prediction has also been verified by oil saturation analysis of coring wells. Based on the sedimentary facies zone map depicted by pre stack inversion results, the number of narrow and small river channels identified between wells has increased, the continuity has increased, and the river boundary is clear, which is consistent with geological understanding. This achievement has been applied in the fine adjustment and potential tapping of S group in the study area, guiding the fracturing and hole patching measures of 12 wells, and achieving good development results and economic benefits.