华南地区晚古生代海相地层油气成藏条件

为推进南方古生代海相油气勘探，应用已有的研究成果，综合分析了华南地区晚古生代海相地层油气成藏条件与有利成藏区带：华南地区晚古生代碳酸盐岩沉积厚度大、分布范围广，泥盆纪、二叠纪是中国南方生物礁主要生长时期；泥盆系、石炭系、二叠系均发育有效烃源岩；台地礁滩相灰岩、台缘斜坡、台间海槽区重力流沉积物、滨海陆源碎屑岩和盆地相浊积岩是有利储集岩；泥岩、泥灰岩和石膏组成良好盖层。烃源岩有印支、燕山和喜山三次油气成藏期。印支、燕山、喜山运动使断裂带附近的油气藏破坏形成古油藏，但构造相对稳定地区的油气藏仍然得以保存。在晚古生代地层沉积厚度大、构造相对稳定的地区，如桂中坳陷，印支期形成的油气藏遭受破坏，但仍保存有原生油气藏。中、新生代沉积覆盖的晚古生代地区，如十万大山盆地、南盘江坳陷以及南海北部海域，燕山-喜山期形成的油气藏容易得到有效保存，是海相油气成藏有利的地区。

AN ANALYSIS OF HYDROCARBON RESERVOIRING CONDITIONS OF LATE PALEOZOIC MARINE STRATA IN SOUTH CHINA

In order to promote petroleum exploration in the Paleozoic marine strata in South China, the reservoiring conditions and favorable plays in the study area are comprehensively studied based on the previous achievements. In South China, the Late Paleozoic carbonates are large in thickness and extensive in distribution. The Devonian and Permian are the main periods for growth of bioherm. Effective source rocks occur in the Devonian, Carboniferous and Permian. Various favorable reservoir faces are developed, including limestone of platform reef flat facies, gravity flow deposits of platform margin slope facies and inter platform trough facies, terrestrial clastic rocks of littoral faices, and turbidite of basinal facies. Mudstone, muddy limestone and gypsum act as good seals. Episodic hydrocarbon generation-migration-accumulation of the source rocks occur in the Indo Chinese, Yanshan, and Himalayan epochs. After the Indosinian, Yanshan, and Himalayan movements, the previous pools near the faults were damaged, but that in the relatively stable areas were preserved. In areas where the Late Paleozoic marine strata are thick and the structures are relatively stable, such as the central Guangxi depression, the pools formed in Indo Chinese epoch are destroyed, but some primary pools are preserved. In areas where the Late Paleozoic marine strata are overlain by the Meso Cenozoic sediments, such as Shiwandashan basin, Nanpanjiang depression, and the northern South China Sea, the pools formed in Yanshan-Himalayan epochs are easy to be effectively preserved, thus these areas are favorable for exploration of marine oil and gas pools.