Segmented sealing of cores and collection and test of escaped light hydrocarbons and its preliminary application

Abstract

Light hydrocarbons easily escape from hydrocarbon-bearing cores when they are recovered from wellbores, which makes it necessary to improve the methods for collecting light hydrocarbons from cores and characterizing the differences of hydrocarbon losses. A new method for the segmented sealing of cores and the collection and test of light hydrocarbons was developed based on the patent "a segmented sealing device for cores and its instructions(2013101681829)". The device has a cylindrical structure with several annular seals built in, which can non-destructively seal the core inserted therein to form several closed spaces that are not interconnected to store light hydrocarbons escaping from the core. The device is matched with auxiliary equipment such as gas sampling pumps, portable methane detectors, and gas chromatographs, which are used to sample light hydrocarbons in different confined spaces to determine the concentration and composition of mobile light hydrocarbons. The concentration of escaped light hydrocarbons in confined spaces can be converted to escape quantity. Preliminary applications show that the device and method can be used to obtain light hydrocarbons that escape after the cores are recovered from the wellbores, and then to characterize the differences in the amount and components of light hydrocarbons escaping from different parts of the core in an axial direction. Combined with lithology and physical properties, it provides a basis for the evaluation of shale oil and gas formation heterogeneity and its main controlling factors.

Keywords

• core
• segmented seal
• escaped light hydrocarbon
• measuring device
• gas content
• oil content