关键词: 构造—沉积组合, 烃源岩, 成熟度, 油气勘探前景, 对比, 纳米比亚近海盆地区

Abstract: The basin area near the sea on the passive continental margin of West Africa is one of the oil-gas producing areas of world focus and one of the investment concentrated areas in the world. However, the oil and gas producing currently concentrates in the basin area north of Walvis Ridge, while only Kudu gas field has been discovered in Namibia Basin to the south. Based on comparing Namibia Basin with northern oil-gas hosting basins, meaningful discussion is conducted on the prospect of exploration for oil and gas in the area near the sea of Namibia from the perspectives of structural evolution and features of the passive margin of West Africa. It is considered after comprehensive analysis that the main causes of no remarkable breakthroughs made in the exploration for oil and gas in the basin near the sea of Namibia are the impact of politics, low degree of exploration, less information publicized, and low degree of study. Namibia basin area is found to be similar to northern basin area in rifting, seafloor spreading modes, and marginal structure, based on the marginal evolution characteristics, but it is earlier than the latter one. Both southern and northern basin areas have gone through the pre-rift stage, syn-rift stage, transitional stage, and post-rift stage, and finally developed similar structural and sedimentary assemblages and similar source rocks. Maturity and thermal history modeling show that the oil and gas in the area of Namibia margin off a certain distance from the coastline is of medium and high maturity. So the area has the conditions of oil-gas generation. In addition, reservoir and cap rocks, and evaporite rocks which exert great effect on oil production of West Africa well developed in the area. The distribution of turbidite during the plate drafting period is controlled by the major structural traps generated from gravity gliding structures developed in the formation of the period. On the basis of comprehensive analysis, it reveals that Namibia Basin has similar geological background with the basin area in the north and has the conditions of oil-gas generation. Therefore, exploration and development should be strengthened, as well as the area ranging from Namibia basin area near the sea to the coastline is the optimized target for oil and gas exploration.

Key words: structural and sedimentary assemblage, hydrocarbon resource rock, maturity, prospect of exploration for oil and gas, comparison, Namibia basin area near the sea