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油气倒灌运移成藏现象在东部中新生代含油气盆地勘探中引起普遍关注,但对于是否确切存在仍有不同观点,对于倒灌成因机制以及倒灌运移距离,也有不同的认识和计算方法。本文从当前主要石油地质认识进展出发,从运移动力、超压成因、运移通道三个方面,分析认为油气倒灌成藏符合地质规律,其机理可以表述为在烃源岩层系上覆广泛分布厚层泥岩控制下,以主力源岩层系生烃超压为动力,沿开启断层或裂隙等超毛细管空间,以油水混相方式进行的流体幕式活动,下注距离主要取决于生烃中心与目的层间压差大小、运移路径形式、压力衰减方式等,并形成了相应计算公式。
Oil and gas migration and accumulation have attracted widespread attention in the exploration of the Mesozoic and Cenozoic petroliferous basins in the eastern part of the world. However, there are still different opinions on whether there is an accurate existence or not, and also have different understandings and calculation methods on the genesis mechanism of intrusion and the range of inversion and migration. Based on the current understanding of the major petroleum geology, this paper analyzes that the hydrocarbon accumulation is in conformity with geological laws from the aspects of migration motivation, overpressure origin and migration channel. The mechanism can be expressed as follows: Under the control of thick mudstone, the hydrocarbon generation overpressure in the main source rock strata is used as the driving force, and the curtain event is carried out along the open ultra-capillary space such as faults or fractures in the form of oil-water mixed phase. The betting distance mainly depends on the hydrocarbon generating center and purpose The size of the pressure difference between layers, the form of migration path, the way of pressure decay, etc., and formed the corresponding formula.