油气倒灌会发生吗？——与王永诗先生商榷

May Downward Flow of Oil and Gas Occur? A Discussion with Mr. Wang Yongshi

李传亮 刘东华

LIChuanliang LIUDonghua

西南石油大学石油与天然气工程学院, 四川 成都 610500 中海石油(中国)有限公司海南分公司, 海南 海口 570312

Petroleum Engineering School, Southwest Petroleum University, Chengdu, Sichuan 610500, China CNOOC China Limited, Hainan Branch, Haikou, Hainan 570312, China

针对石油地质学中油气倒灌会否发生的问题，根据渗流力学的相关理论，通过理论分析深入研究了油气的运移成藏机理及地层超压的形成机理，并获得以下主要认识： 1）运移与流动不同，流动需要压差驱动，运移不需要压差驱动，油气运移是浮力作用下的离散流或滴流； 2）油气可以向上运移，油气倒灌不会发生，因为缺少动力的驱动； 3）室内实验没有模拟地下情况，压差大，流速高，属于油气流动，而非油气运移； 4）泥岩地层为开放地层，并不存在超压，地层水通过流动可以平衡地层压力； 5）油气被地层水分割包围，可以出现超压，超压部分被毛管压力所平衡； 6）上生下储式并不存在，烃源岩不一定位于油气藏的正下方，侧向运移也可以实现油气成藏。

In response to whether downward flow of oil and gas occurs in petroleum geology, based on the relevant theories of flow mechanics in porous media, the migration and accumulation mechanism of oil and gas and the formation mechanism of formation overpressure were deeply studied through theoretical analysis. The main understandings were obtained as follows: firstly, migration is different from flow, flow requires differential pressure drive, migration does not require differential pressure drive, and oil and gas migration is a discrete flow or droplet flow under buoyancy; secondly, oil and gas can migrate upwards, and downward flow of oil and gas will not occur due to the lack of driving force; thirdly, the laboratory experiments did not simulate underground conditions, with a large pressure difference and a high flow velocity, indicating oil and gas flow rather than oil and gas migration; fourthly, the mudstone formation is an open formation and there is no overpressure and formation water can balance formation pressure through flow; fifthly, oil and gas are separated and surrounded by formation water, and overpressure can occur and the overpressure is balanced by capillary pressure; sixthly, there is no upper source-lower reservoir model, and the source rock may not necessarily be located directly below the oil and gas reservoir. Lateral upward migration can also achieve the formation of oil and gas reservoirs.

10.11885/j.issn.1674-5086.2024.05.08.01