Petrophysical Characterization and Reservoir Simulator for Methane Gas Production from Gulf of Mexico Hydrates

• Main Authors: Mohanty, Kishore, Cook, Bill, Hakimuddin, Mustafa, Pitchumani, Ramanan, Ogunlana, Damiola, Burger, Jon, Shillinglaw, John
• Other Authors: United States. Department of Energy.
• Format: Report
• Language: English
• Published: Westport Technology Center 2006
• Subjects: Methane; Thermodynamics; Dissociation; Sodium Iodides; Sediments; Acoustics; Hydrates; 29 Energy Planning; Policy And Economy; Temperature Gradients; Boundary Conditions; Production; Gas Hydrates; Water; Fluid Withdrawal; Simulators; Gulf Of Mexico; Depressurization; 03 Natural Gas; Fossil Fuels; Permafrost; Arctic; Ice; permafrost
• Online Access: https://doi.org/10.2172/920371; https://digital.library.unt.edu/ark:/67531/metadc898195/

Gas hydrates are crystalline, ice-like compounds of gas and water molecules that are formed under certain thermodynamic conditions. Hydrate deposits occur naturally within ocean sediments just below the sea floor at temperatures and pressures existing below about 500 meters water depth. Gas hydrate is also stable in conjunction with the permafrost in the Arctic. Most marine gas hydrate is formed of microbially generated gas. It binds huge amounts of methane into the sediments. Estimates of the amounts of methane sequestered in gas hydrates worldwide are speculative and range from about 100,000 to 270,000,000 trillion cubic feet (modified from Kvenvolden, 1993). Gas hydrate is one of the fossil fuel resources that is yet untapped, but may play a major role in meeting the energy challenge of this century. In this project novel techniques were developed to form and dissociate methane hydrates in porous media, to measure acoustic properties and CT properties during hydrate dissociation in the presence of a porous medium. Hydrate depressurization experiments in cores were simulated with the use of TOUGHFx/HYDRATE simulator. Input/output software was developed to simulate variable pressure boundary condition and improve the ease of use of the simulator. A series of simulations needed to be run to mimic the variable pressure condition at the production well. The experiments can be matched qualitatively by the hydrate simulator. The temperature of the core falls during hydrate dissociation; the temperature drop is higher if the fluid withdrawal rate is higher. The pressure and temperature gradients are small within the core. The sodium iodide concentration affects the dissociation pressure and rate. This procedure and data will be useful in designing future hydrate studies.