流体包裹体热动力学模拟技术的古压力恢复方法及应注意的问题

Methods for Paleopressure Reconstruction Based on Thermodynamic Simulation Technologies of Fluid Inclusion and Some Problems Needing Attention

利用流体包裹体热动力学模拟技术获取沉积盆地古压力已广泛用于石油勘探领域。其原理是根据烃类包裹体和同期捕获盐水包裹体的等容线具有不同的斜率,在p—T空间上必然会相交于一点,该点就代表了烃类包裹体和同期盐水包裹体捕获时的温压状态,获取特定烃类包裹体和同期盐水包裹体的均一温度、气液比和成分参数,并输入到PVT热动力学模拟软件中就可以得到该流体体系的捕获压力,即古流体压力。尽管目前该方法仍然存在着如参数获取的精确性会受到某些不确定因素的影响、人为操作产生的误差等缺陷,但随着各种测试技术的不断革新,流体包裹体热动力学模拟技术将不断成熟,成为石油地质领域一个强有力的工具。

The acquisition of paleopressure using the thermodynamic simulation technology of fluid inclusion has been widely used in the field of petroleum exploration.The principle of the technology is explained as below:the hydrocarbon inclusion and the coeval saline inclusion have different isochors,which will intersect at one point in p-T space.The point represents the trapping temperature and pressure of both hydrocarbon and coeval saline inclusion.The homogenization temperature,the gas-liquid ratio,and the composition parameters of hydrocarbon inclusion and coeval saline inclusion are obtained and are put into the PVT thermodynamic software.The trapping pressure of the fluid system,i.e.,the pa[eofluid pressure,will be then obtained.There are some shortcomings in the method,for example,the accuracy of parameters will be influenced by some uncertain factors,and the error caused by manual operation.However,the thermodynamic simulation technology of fluid inclusion will be more developed and become a powerful tool in the field of petroleum geology along with the development of various testing technologies.