Application of In Situ Cryogenic Raman Spectroscopy to Analysis of Fluid Inclusions in Reservoirs
CHEN Yong1,2, LIN Cheng-yan1, YU Wen-quan3,ZHENG Jie1, WANG Ai-guo4
1.College of Geo-resources and Information, China University of Petroleum, Qingdao 266555, China 2.State Key Laboratory of Enhanced Oil Recovery, China National Petroleum Corporation, Beijing 100083, China 3.Research Institute of Geosciences, Jiangsu Oil Field Company, SINOPEC, Yangzhou 225009, China 4.Postdoctoral Research Center，Chinese Dagang Oilfield，Tianjin 300280, China
Abstract：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 ℃ by in situ cryogenic Raman spectroscopy.The spectra show that inclusions contain three salts, namely NaCl, CaCl2 and MgCl2.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.
