Prediction Techniques and Application Effects of Sweet Spots in Transitional Marine-Land Shale Gas Reservoirs at the Eastern Margin of the Ordos Basin

The shale gas resources of the marine-continental transitional facies in Section 2 of the eastern margin of Ordos Basin are rich, but they have thin single-layer thickness, strong heterogeneity, and rapid lateral changes. This paper uses the three-dimensional seismic data of the shale gas test area in the Daji W well area as a basis. Based on the high-precision seismic data obtained from interpretative target processing, this paper redivides the mud shale in this area into three categories through the analysis of shale logging sensitive curves and seismic response characteristics. Prediction techniques for geological dessert evaluation parameters such as shale thickness, organic carbon content, and gas content of high-quality shale were formed. Through comprehensive evaluation of geological sweet spots, favorable areas are selected, effectively guiding the deployment and optimization adjustment of horizontal wells. The results of drilling of horizontal wells match well with predictions, with a high rate of encounter in sweet spots, providing a reliable basis for efficient exploration and development of shale gas in the marine-continental transitional facies on the eastern margin of the Ordos Basin.