论构造应力不是油气初次运移的主要动力

油气初次运移是一个尚未完全解决的学术难题。石油地质学界认为，构造应力是油气初次运移的主要动力之一，笔者对该观点进行了质疑。根据有效应力理论和弹性力学理论，分析了构造应力对孔隙压力的影响，建立了孔隙压力增量的计算模型以及孔隙压力释放驱动油气运移尺度的计算模型。结果表明，相同构造应力条件下，烃源岩的孔隙压力增量主要受杨氏模量影响，杨氏模量越大，孔隙压力增量越小；构造应力导致的孔隙压力增量一般不会超过60 MPa；孔隙压力释放只需要排出少量地层流体即可，驱动油气运移的距离很短，相对于烃源岩厚度几乎可以忽略不计；构造应力对油气初次运移的影响十分微弱，不可能是初次运移的主要动力。

Tectonic Stress is Not the Main Driving Force for Primary Migration of Oil and Gas

The primary migration of oil and gas is an unsolved academic problem. In the field of petroleum geology, structural stress is considered to be one of the main driving forces for the primary migration of oil and gas. According to the theory of effective stress and elastic mechanics, the influence of structural stress on pore pressure is analyzed. The calculation model of pore pressure increment and the calculation model of oil-gas migration scale driven by pore pressure release are established. Theoretical analysis and quantitative calculation results show that under the same structural stress condition, the increment of pore pressure of source rock is mainly affected by Young's modulus. The larger the Young's modulus is, the smaller the increment of pore pressure is; the increment of pore pressure caused by structural stress is generally not more than 60 MPa; the release of pore pressure only needs to discharge a small amount of formation fluid, and the distance to drive oil and gas migration is very short, relatively because the thickness of source rock is negligible, and the influence of structural stress on the primary migration of oil and gas is very weak, which can not be the main driving force of the primary migration.