成烃增压数值模拟

NUMERICAL MODELING ON PRESSURIZING CAUSED BY HYDROCARBON GENERATION

干酪根热解成烃作用是烃源岩中异常高压的重要成因之一。由于成烃增压作用主要是伴随生、排烃作用而发生的，因此很难直接进行恢复和计算，通常借助数值模拟方法来描述。通过成烃作用的物理化学机制建立了成烃增压机制的数学模型。该数学模型表明，生烃越多、干酪根与烃类流体的密度差越大、烃源岩越致密，则成烃增压强度就越大；天然气的生成比石油的生成具有更显著的增压效应。应用该数学模型可模拟研究烃源岩演化过程中的成烃增压，并能再现由此导致的微裂缝幕式排烃的地质过程。成烃增压数值模拟在我国几个典型含油气盆地中得到了有效的应用。

Abstract Generation of hydrocarbon from kerogen is one of important genetic types of abnormal pressure in source rock. Because the pressurizing caused by generation was taking place during the period of genera ting and expulsion, it is difficult to recover or calculate it directly. Usually it can be measured by numerical modeling. The mathematical model of pressurizing was built according to the physico chemical mechanism of generation. It shows that the more the generated hydrocarbon, and the more compact the source rock, the larger the intensity of pressurizing. The pressurizing caused by gas generation is stronger than that caused by oil generation. The pressurizing caused by generation can be modeled, and also the expulsion through microfracture caused by the pressurizing can be recovered by using this mathematical model. Numerical modeling on pressurizing caused by generation has been effectivelg applied in several typical petroleum basins in China.