Seismic reflection modeling of an atoll: A comparison between pre- and post-stack migration sections

Atoll structures formed in complex geological settings act as stratigraphic hydrocarbon traps and are typically circular or elliptical reef structures with a large lagoon at the center. Initially, the circular reef with flat limestone serves as a potential reservoir rock and holds significant importance in the petroleum industry, as it forms hydrocarbon-bearing traps. Therefore, identifying these structures in seismic sections is crucial. To understand the seismic behavior of atoll structures, seismic shot gathers of a geological model were generated, and migration sections were obtained. In this study, artificial data modeling of an atoll structure containing oil traps was carried out using the two-dimensional acoustic finite difference method due to its practicality and the flexibility to select different trap models as needed. Seismic data modeling was performed in a pre-stack shot domain, and two different data processing stages were applied to the shot data to obtain pre-stack and post-stack Kirchhoff time migration sections. The spatial location and size of hydrocarbon traps in the migration sections were determined and compared with the initial atoll model. In this way, the seismic response of hydrocarbon trap structures in the atoll model was analyzed. The importance of the two different data processing methods was also examined. As a result, it was observed that the pre-stack Kirchhoff time migration method provides better results than the post-stack time migration method for the atoll model.