烃类包裹体气液比的精度对PVT模拟结果可靠性有重要影响,而气液相边界的判断对气液比测定准确性至关重要。本文开发了一种精确测量烃类包裹体体积的方法,即利用高分辨率激光共聚焦显微扫描技术获取烃类包裹体3D图,在透射及荧光模式下用三维坐标标定液相的边界,利用3Dfor LSM软件计算烃类包裹体液相的体积;同时利用激光共聚焦显微荧光技术对横穿气液两相的直线进行线扫描,根据扫描线上荧光强度的突变判断气相边界,多次扫描求平均值作为气相直径。本方法避免了人为判断包裹体气相边界的不可靠性,对气液边界的确定精度可达0.02μm,提高了气液比测试精度,使得利用包裹体恢复古压力结果更加可靠。
The volume ratio between vapor and liquid of hydrocarbon inclusions is an important parameter for PVT simulation. Moreover, the judgment of the boundary between vapor and liquid is very important for the accuracy of the vapor/liquid ratios. A method for accurately determining the volume of hydrocarbon inclusion has been developed in this study. High resolution Laser Confoeal Scanning Microscopy was used to obtain three-dimensional images of hydrocarbon inclusions. The liquid phase boundary was determined by three-direction coordinates under transmission light and fluorescence. 3DforLSM software was used to calculate the liquid phase volumes of hydrocarbon inclusions. Line scan was carried out across the vapor and liquid boundary using Laser Confocal Fluorescence Microscopy, in order to determine the vapor phase boundary according to the change of fluorescence intensity. The average of the results from multiple scans was used as the diameter of the vapor phase. This method avoids the error of manual judgment of the vapor and liquid boundary with a precision of 0.02 p,m. The method improved the analytical precision of vapor/liquid ratios and allows for more reliable reconstruction of the trapping pressure by hydrocarbon inclusions.