Characterization of Gas hydrates

Abstract: Gas hydrates are naturally occurring crystalline formations consisting of crystal structural “cages” which make up cavities where gas molecules can be trapped. Hydrates are formed under specific pressure and temperature conditions in the ground, which limits their presence to permafrost and deep sea continental margins. The interest for gas hydrates has grown bigger in the past time, mainly because of the potential as a new energy source but also because of the possibility of carbon dioxide (CO2) storage and its potential linkage to different geological hazards. Gas hydrates are still relatively poorly understood with many questions to be answered. Therefore research in this area is important. In our study we have been focusing on characterization of gas hydrate structures and their gas composition. By using the two different analytical methods X-ray powder diffraction (XRD) and gas chromatography. For this study to be successfully carried out we needed access to equipment and expertise which is only to be found in few places on Earth. Our lab work was therefore done at Pontifica Universidade Catolica do Rio Grande do Sul in Porto Alegre Brazil where a research project in gas hydrates is on going. Because of the research projects secrecy we do not know where our gas hydrate samples come from which mean we cannot link our results to any geographic area. The structural analysis shows structure I hydrate which is characterized by the presence of small gas molecules such as hydrocarbons. The results from the gas content validated that it is structure I since large concentrations of methane gas (CH4) and sulphur gas (H2S) were detected. The presence of these gases implies that the formation conditions are in a marine environment at the sulphate-methane transition zone (SMTZ).