Occurrence and Genesis of Multiple Types of High Density Methane Inclusions in Puguang Gas Field

Based on micro-Raman spectroscopic analysis of a great quantity of inclusions, three types of high density methane inclusions were identified in the petroleum reservoir of Puguang gas field. Type I inclusions occur in calcite minerals of carbonate rocks in gas reservoir, and their Raman spectra show 2910-2912cm-1 peaks characteristic of high density methane and apparent peaks characteristic of H2S as well as peaks characteristic of trace amount of CO2, but do not show peaks characteristic of solid pyrobitumen; Type II inclusions occur in early-formed calcite minerals in carbonate reservoir, and their Raman spectra not only show peaks characteristic of high density methane, but also show D and G peaks characteristic of solid pyrobitumen, basically with no peaks for H2S; Type III inclusions are high density methane inclusions trapped in quartz minerals in the upper clastic reservoir, their Raman spectra may or may not show peaks characteristic of pyrobitumen, but basically exhibiting no …