地层抬升剥蚀对油气成藏贡献初探

含油气盆地普遍发育一个或多个剥蚀面,揭示剥蚀面的形成和油气藏的关系,不仅可以完善和发展已有的油气成藏理论,也必将对我国东部老油气区的勘探起到指导和促进作用。在对含油气盆地剥蚀次数和剥蚀量统计分析的基础上,建立了地层抬升剥蚀与油气成藏的空间和时间匹配关系;通过地质分析,从成藏机理的角度初步探讨了地层抬升剥蚀对油气成藏的贡献。统计分析和地质分析的结果显示:剥蚀层位本身或紧邻其下的层位就是储层;地层抬升剥蚀期多为油气聚集的时期;地层抬升过程中的流体温度降低及孔隙扩容可造成地层低压,从而为油气聚集提供动力,孔隙扩容还可为油气聚集提供更多的空间。

Preliminary Study on Contribution of Rift-Erosion to Oil and Gas Accumulation

There are one or more erosion surfaces in oil-bearing basins. Study on the relationship of erosion surface and reservoirs could not only develop oil theory, but also could promote exploration in the eastern old oil-bearing areas of China. In this paper, a space-time relationship of oil-bearing strata and erosion surface has been established based on the statistic analysis of erosion times and quantities in oil-bearing basins and the contribution of strata rift and erosion to oil accumulation has been discussed in terms of oil accumulation mechanism by geological analysis. The statistic and geological analysis showed that the strata eroded or the strata below the erosion surface are oil-bearing beds; the time of strata rift is coincident with the time of oil accumulation; the fall of fluid temperature and the rebound of the pore during the process of strata rift and erosion will cause underpressure in the strata which pumps oil and gas in the reservoirs, especially, the rebound of the pore offers extra-space to oil and gas accumulation.