Discipline: Ecology Environmental and Earth Sciences
Subcategory: Environmental Engineering
Session: 4
Room: Exhibit Hall A
Joshua Ordoñez - Texas A&M University - Kingsville
Methane gas hydrate is a term used to describe the condition when a formation of ice contains molecules of methane trapped inside. These gas hydrates are found in areas of high pressure and low temperature, typically in arctic permafrost or at submarine sand layers. Researchers that have been successful in extracting gas from these hydrates at their natural occurring environments have boasted huge methane yields of up to 164 M3 of methane gas per 1 M3 hydrate. However, the extraction process can create geological disasters and technical difficulties including submarine landslides accompanied by tsunamis and excessive sand forced into production wells. To successfully utilize these hydrates as a next-generation energy source, the physical properties of sand layers and the phase behavior of hydrates must be evaluated. Currently, analyzing the physical properties of gas hydrate bearing sediments in a laboratory is difficult to conduct because naturally occurring gas hydrates tend to be very expensive to recover (Miyazaki et al. [3]). This means that a more efficient and reliable way to analyze the properties of these sediments is of great importance without the added cost and difficulties associated with obtaining samples from their natural locations. When determining a numerical approach for approximating sand and rock characteristics, the main two yield criterion used are the Drucker-Prager and the Mohr-Coulomb. The Drucker-Prager model was established as a generalized format of the Mohr-Coulomb criterion for sediments. Drucker-Prager yield criterion is used here due to its simplicity to manipulate and implement in numerical models (Alejandro et al. [6]). The research performed by (Zhou et al. [5]) utilizes frictional coefficient and cohesion factor as the main equations derived. We will use this approach to describe how the methane gas hydrate sediments will behave in future situations with critical parameters. This research provides for an analytical approach to model methane gas hydrate bearing sediments by utilizing MATLAB scripts to manipulate and modify our input data. Through this research, it was observed that frictional coefficient and cohesion both decrease as gas is extracted from the hydrate bearing sediments. A decrease in these parameters results in a direct decrease in compressive strength of the sand layers containing the gas hydrate. It was also interesting to observe that the strength parameters vary greatly depending on the volume fraction of sediment, ice, and water in the hydrate. As compressive strength continues to decrease during extraction, it could cause failure of the sand layer in the form of landslides. It is important to note that this research assumes crystal ice properties and does not consider methane molecules combined within the ice structures. A lack in research over naturally occurring methane hydrates makes it difficult to model their exact properties. In the future more data needs to be obtained on naturally occurring methane hydrate physical properties to achieve more accurate results. Some areas of research that would be helpful would be the development of pressure and temperature diagrams over methane gas hydrates to help determine more accurate physical properties.
Funder Acknowledgement(s): Appreciation and gratitude is expressed towards Dr. Jong Won Choi, the faculty advisor who oversaw this project. This study was funded by the National Science Foundation (NSF, EEC-1757812). Any opinions, findings or recommendations expressed in this poster were created by authors and not reviewed by nor necessarily reflect the views of NSF.
Faculty Advisor: Jon Won Choi, jong-won.choi@tamuk.edu
Role: All of what is included in the abstract