Application of In Situ Cryogenic Raman Spectroscopy to Analysis of Fluid Inclusions in Reservoirs

作者:Chen Yong*; Lin Cheng-yan; Yu Wen-quan; Zheng Jie; Wang Ai-guo
来源:Spectroscopy and Spectral Analysis, 2010, 30(1): 95-97.
DOI:10.3964/j.issn.1000-0593(2010)01-0095-03

摘要

Identification of salts is a principal problem for analysis of fluid inclusions in reservoirs. The fluid inclusions from deep natural gas reservoirs in Minfeng sub-sag were analyzed by in situ cryogenic Raman spectroscopy. The type of fluid inclusions was identified by Raman spectroscopy at room temperature. The Raman spectra show that the inclusions contain methane-bearing brine aqueous liquids. The fluid inclusions were analyzed at -180 degrees C by in situ cryogenic Raman spectroscopy. The spectra show that inclusions contain three salts, namely NaCl, CaCl(2) and MgCl(2), Sodium chloride is most salt component, coexisting with small calcium chloride and little magnesium chloride. The origin of fluids in inclusions was explained by analysis of the process of sedimentation and diagenesis. The mechanism of diagenesis in reservoirs was also given in this paper. The results of this study indicate that in situ cryogenic Raman spectroscopy is an available method to get the composition of fluid inclusions in reservoirs. Based on the analysis of fluid inclusions in reservoirs by in situ cryogenic Raman spectroscopy with combination of the history of sedimentation and diagenesis, the authors can give important evidence for the type and mechanism of diagenesis in reservoirs.