Difference Analysis of Hydrocarbon Source Potential in Small Subsags Based on Structural Factors：A Case Study of Panyu 29 Sub-sag in Baiyun Sag

With the advancement of exploration, the exploration of surrounding small sub-sags has become one of the exploration directions in Baiyun Sag. The development of high-quality source rocks which are deposited in semi-deep lacustrine facies is an important factor in the exploration of small sub-sags in Wenchang Formation. Based on drilling and 3D seismic data, the structure, sedimentary filling and development conditions of semi-deep lacustrine facies source rocks in Panyan 29 sub-sag are analyzed by analogy with other proven hydrocarbon rich sags. The study suggests that the Panyu 29 sub-sag is in half-graben shape which faulted in the south part and overlapped in the north part, the Wenchang Formation strata are developed in the Panyu 29 sub-sag.

The magmatic diapirism and the depression-controlling boundary faults jointly promoted the strong subsidence of the lower Wenchang Formation strata and formed a deep-water lake basin. During the Wenchang period, the peripheral material's ratio of source to sink was low, and the under-compensation sedimentary environment is developed, which is conducive to the formation of high-abundance source rocks in semi-deep lacustrine.This study is helpful to promote the exploration process of Baiyun Sag and provides a reference for oil and gas exploration in other similar sub-sags.