Resource Potential Assessment of Series of Strata with Few Drilled Wells in the Huizhou Sag,the Pearl River Mouth Basin,South China Sea

Abstract

Huizhou sag is located in the depression zone in the north of the Pearl River Mouth basin. In recent years, great progress has been made in the exploration focused on the deep Paleogene, opening up new areas of exploration and necessitating the evaluation of both the hydrocarbon generation potential and the exploration potential of the Paleogene. The Enping Formation and the Wenchang Formation have become new exploration series of strata. The research utilizes paleotectonic recovery, sequence stratigraphy analysis, basic parameter prediction of hydrocarbon source rock and basin modeling, as well as other techniques. It is carried out to examine the tectonic inversion effect of the Huidong low uplift, the sedimentary facies of the Wenchang Formation, hydrocarbon source rock thickness and organic carbon content in the series of strata that have not been extensively drilled, with the calculation of both the hydrocarbon generation intensity and amount from the source rock. It is considered that: (1) after sedimentation, the Wenchang Formation suffers from tectonic inversion and severe uplift and denudation, especially the Huidong low uplift, changing the sedimentary pattern; (2) during the sedimentation of the Wenchang Formation, LF13 low-lying to Huizhou 14 low-lying is at the center of the lake basin, dominated by deep lake – semi-deep lake facies, with hydrocarbon source rock developing; (3) in total, 659.46×10⁸ t of hydrocarbon is generated in Huizhou sag, with total oil and gas resources with the Wenchang Formation as source rock at about 34.3232×10⁸ t; (4) comparing with the parameters and results of the previous resources assessment and considering the exploration practices in the area, it is believed that the deep part of Huizhou sag still has great exploration potential as a sag with large amount of remaining oil and gas resources in Zhu I depression.