超压对油气成藏的影响及其评价

Influence and Evaluation of Overpressure on Oil and Gas Reservoir Forming

世界含油气盆地中超压分布广泛,且对油气勘探开发影响深远。通过对我国几个超压盆地的研究分析得到,超压对有机质热演化的抑制作用在不同地区影响程度明显不同。超压条件下有效应力引起的机械压实程度减弱,及有机酸对矿物的溶解作用使深埋超压储层保持较高的孔隙度和渗透率。超压为油气运移提供动力,并为油气运移拓宽通道;异常超压还可以提高盖层的封闭能力。文中还采用神经网络方法对超压在油气成藏的影响进行评价。

The overpressure is widely distributed in the oil-bearing basin of the world,and it has great influence on the oil and gas exploration.Through the study of some overpressured basins in china,it is considered that overpressure has different effect on the evolution of organic matter in different area.The weak mechanical compaction caused by the low effective stress in overpressured conditions leads to the preservation of relatively high porosity and permeability for the deeply-buried sandstone.The overpressure provides motive and bigger access for the oil and gas migration.Owerpressure has also improved the sealing ability of caprock.The influence of overpressure on the oil and gas accumulation can be evaluated by the neural network.