Enhanced Seismic Imaging in Kuqa Foreland Basin, China - A Case History

The Kuqa foreland basin is rich in oil and gas resources. However, the images of interest subsalt overthrust structures often have significant distortions due to strong lateral heterogeneity in the shallow and middle-deep velocity. The precise velocity estimation is the key to solve this imaging problem. In this paper, two steps are taken: Firstly, we obtain the accurate shallow velocity with the tomographic inversion based on BP (back propagation) neural network. Secondly, we build the proper middle-deep velocity with the ADCIGs (angle domain common imaging gathers) based tomographic inversion under the constraints of geological knowledge and logging data. The resulting PSDM (prestack depth migration) images are greatly improved and consistent with well data.