试论油气的应力圈闭

DISCUSSION ON THE STRESS TRAPS OF OIL/GAS

祁林

Qi Lin

地质矿产部西南石油地质局

Southwest China Bureau of Petroleum Geology, Ministry of Geology and Mineral Resources

笔者根据四川区内若干三叠系油气藏赋存地质特征,提出控制油气藏的因素,不仅是"重力分异"、 "水动力驱动"等,地应力控制圈闭,应该是主要的因素。笔者应用固体力学理论,把含油气藏的背向斜构造,看作是各向同性,均匀连续的弹塑体受力失稳产生的挠曲,分析其应力分布状况,结合实例,建立地应力圈闭的简单成藏模式,得出油气运移、聚集、形成油气藏都受地应力场的控制,或与受地应力控制的构造形变过程同时进行及完成的。

The main factors of crust deformation are of the changes of stress fields and the geological stress itself.Therefore,the movements of all materials which include oil,gas and water in petroliferous formations and basins are controlled and driven by geological stresses.As the petroliferous formation are considered as elastic-plastic bodies with isotropic,homogeneous and continuous characters,a series of anti-clines and synclines would be analogous to deflection of solid materials which is due to unstable by force.Based on the relationship amound the isopleth distribution of tri-dimensional principal strsses,known oil/gas migration directions and the location of oil/gas accumulation,it is suggested that oil/gas migration direction is perpendicular to the trace of main pres-sure stresses(σ3),and parallel to the trace of main tensile stresses(α1).The oil/gas accumulation is located at low pressure zone in a closed tri-dimensional stress-gradient space composed by the traces of the main tensile stress(σ1)and the central main stress(σ2).

https://doi.org/10.11781/sysydz198704358