PETROLEUM GEOLOGICAL CHARACTERISTICS AND EXPLORATION DIRECTIONS OF DEEP WATER BASINS IN SOUTH CHINA SEA

Based on the in-depth investigation of petroleum geological conditions, we discussed in this paper the distribution pattern of oil and gas in the South China Sea deep-water basins and their controlling factors on reservoir formation, petroleum resources potentials and favorable exploration directions, so as to provide a scientific basis for decision-making in deep-water oil and gas exploration of the region. The results show that the deep-water basins in the South China Sea are formed on the typical continental margin of a marginal sea, with specialpetroleum geological conditions and significant north-south differences. The deep-water Pearl River Mouth Basin and Qiongdongnan Basin in the northern South China Sea are dominated by structural traps, the southern Zengmu Basin and Brunei Shaba Basin in the south dominated by structural traps; the northern Zengmu Basin dominated by lithologic reservoirs (reef bank type reservoirs); while the Wan’an Basin by structural trap and buried hill types of reservoirs. The petroleum geological characteristics of the deep-water basins in the northern South China Sea and the South Central South China Sea suggest that the deep-water basins in the South China Sea have greatpotential of oil and gas accumulation. The favorable exploration directions include: ① the Central Canyon and Lingnan Slope of Ledong-Lingshui Depression of the Qiongdongnan Basin, the reversed structural zone of Songnan-Baodao Depression, the submarine fan on the north slope of Baodao Depression, the trap belt around A sub-depression (submarine fan) of Changchang Depression, the deep water fan and the two wings of main depressions, and southwest fault step belt of the Baiyun Depression in Pearl River Mouth Basin, and the deep water fan in Liwan Depression. ② Brunei-Sabah, Zengmu and Wan’an basins are favorable exploration directions in the Southern Central of South China Sea.