Petroleum Geology of the Zhu-1 Depression, Pearl River Mouth Basin, People's Republic of China: ABSTRACT

Abstract

The Pearl River Mouth basin, located in the South China Sea between Hainan Island and Taiwan has been the focus of an intense exploration effort during the l980s. In 1979 the international oil industry, acquired over 60,000 km of seismic, gravity, and magnetic data covering an area of approximately 240,000 km{sup 2}. Three major subbasins, Zhu-1, Zhu-2, and Zhu-3 were defined. Chevron in partnership with Texaco and AGIP (ACT group), concentrated their effort on the Zhu-1 depression which was interpreted to contain as much as 7,800 m of sedimentary section. This subbasin, bounded by the Wansha and Donsha massifs to the north and south, is the most inboard of the three depressions, thereby possibly prolonging anoxic lacustrine conditions prior to the Neogene marine incursion. Additionally, the Zhu- 1 depression should have directly received Miocene sediment potentially supplying the subbasin with high-quality reservoirs. Within the Zhu-1 depression, the ACT group focused in on Block 16/08, which covered the deepest part of the Zhu-1 depression. The block was awarded to the consortium in January 1983. Structuring within the block ranges from Paleogene tensional block faulting created during the early formation of the overall Pearl River Mouth basin to draping over basement highsmore » and carbonate buildups during the Neogene. The Pearl River Mouth basin exhibits classic rift basin geometry with early nonmarine continental fluvial/lacustrine deposition (Zhuhai Formation) during the Oligocene and capped by a lower Miocene marine incursion (Zhu Jiang Formation). Integrated interpretations, exploration drilling, and constant refinement of the geological model led to the discovery of two oil fields, Huizhou/21-1 and Huizhou/26-1, both of which are currently under development and will represent the first commercial oil production from the entire Pearl River Mouth basin.« less