中国近海新生代盆地至今仍然是油气成藏的活跃期

Cenozoic China offshore basins keeping active hydrocarbon accumulation to present

传统的石油地质学理论表明:石油、天然气是在漫长的地质历史时间内由有机质降解产生的,又是在漫长的地质历史时间内,缓慢渗流运移到有圈闭的储集层中。在中国近海油气勘探实践中,运用了这些传统的理论和概念,又逐步充实了某些新的认识,即油气生成、运移、聚集不只是漫长地质历史时期中存在的,而且至今仍然存在;特别是上新世至今的新构造运动对盆地的油气田分布和定型都有重要的控制作用。新构造运动控制晚期油气成藏,而且总是处于供聚大于逸散的动平衡状态中。以墨西哥湾尤金岛330区块油气晚期补给、渤海盆地PL19-3油田、莺歌海DF1-1气田晚期成藏以及我国近期几次大地震与油气相关性来阐述至今油气仍处于活跃的成藏过程及可能存在的突发性的幕式快速运聚充注过程,其中天然地震可能是油气运移的主要驱动力之一。

The classical petroleum geology suggests that oil and gas are generated from the degradation of organic matters and then slowly migrated into the traps with reservoirs by the seepage flow in the long period of geologic history. The process of hydrocarbon accumulation is slow and long. The traditional theories and concepts applied to the hydrocarbon exploration of the China offshore basins are gradually enriched with some new ideas. The hydrocarbon generation, migration and accumulation happened in the long period of geologic history and have still kept activity up to present. Especially, the neotectonism from Pliocene to present has been playing an important role in the distribution and formation of oil and gas fields in offshore basins. The neotectonism controls the latestage hydrocarbon accumulation and maintains the sustained dynamic equilibrium, in which the amount of accumulation is always greater than that of the diffusion lost of oil and gas. In the slow and long-term geologic process of oil and gas migration and accumulation, the paroxysmal and rapid episodic migration, infilling and accumulation of oil and gas happened. The natural earthquake may be one of the main drive forces. The above viewpoints are discussed by elaborating the samples of the late-stage hydrocarbon supply of Eugene Island Block 330 in the Gulf of Mexico, the late-stage hydrocarbon accumulation of the PL19-3 Oil Field in the Bohai Bay Basin and the DF1-1 Gas Field in the Yinggehai Basin as well as the correlation between hydrocarbon activities and recent major earthquakes in our country.