Prediction of Late Paleocene Source Rocks in Lishui Sag, East China Sea Shelf Basin

For most oil and gas fields, it significantly predicts the spatial distribution of hydrocarbon source rocks. Generally, the evaluation of source rocks depends on geochemical analysis and a significant quantity of wells. However, for offshore exploration areas, the prediction of source rocks is limited by the wells’ data. With the development of 3D seismic exploration technology, combining wells and seismic reflection data can obtain important information to forecast source rocks. We describe an integrated method involving non-standard processing of seismic reflection data with sedimentary facies analyses to control the prediction accuracy of source rocks. And we applied the method to our study area, Lishui Sag, located in East China Sea Shelf Basin. The results show that the seismic reflection of source rocks in this area is characterized by low frequency and high amplitude. And source rocks mainly distribute in the Yueguifeng and Lingfeng Formation, characterized by a high percentage of mudstone. Source rocks in the East Subsag and South Subsag are few and thin because these two places are far away from the sediment source. The thickness of the source rocks is less than 200 m. On the contrary, the thickness of source rocks in the West Subsag is the largest in the area, reaching 500 m. By comparing the literature results, we believe combining sedimentary facies analyses with geophysical data can provide reliable information on the spatial distribution of potential source rocks.