This project seeks to bring new understanding of the coupled hydrologic, thermodynamic, and geomechanical processes that control the outcome of applying production technologies to natural gas hydrate bearing reservoirs for the purpose of recovering methane economically and at commercial scales.
Pacific Northwest National Laboratory (PNNL), Richland, WA
Hydrate systems in geologic media are multiple phase systems, in which the potential for both mobile and immobile phases occupy the same pore space, with the potential mobile phases being aqueous, gas, and nonaqueous liquid, and the potential immobile phases being ice and hydrate. Gas hydrates form at high pressures and low temperatures, and the stability envelope for natural gas hydrates span the triple-point of water, complicating the thermodynamics of hydrate systems via phase transitions, appearances, and disappearances. For example, a hydrate bearing formation, stable at temperatures above freezing, could yield ice formations with strong depressurization, resulting in hydrate dissociation and cooling. Hydrate structures vary across their host geologic settings, from large concretions in suboceanic muds to connected, pore-filling bodies in subarctic sandstones. The geomechanical reaction of a hydrate-bearing formation to the dissociation process depends on the contribution of the hydrate structure to the mechanical properties of the formation. Production of natural gas hydrates from geologic reservoirs is controlled by coupled processes, each with inherent complexities.
This project will investigate the numerically and experimentally coupled hydrologic, thermodynamic, and geomechanical processes which dominate the production of natural gas hydrates from geologic accumulations. Production technologies will include both conventional — such as depressurization, thermal stimulation, and inhibitor injection — and unconventional — such as nitrogen injection, air injection, and former swapping. Production of natural gas hydrates from geologic reservoirs is controlled by coupled processes, each with inherent complexities.
This project will bring new understanding of the coupled hydrologic, thermodynamic, and geomechanical processes that control the outcome of applying production technologies to natural gas hydrate bearing reservoirs for the purpose of recovering methane economically and at commercial scales. Numerical simulation provides scientists and engineers with analytical tools for investigating the behavior of hydrate systems, incorporating coupled processes in the governing and constitutive equations.
This Field Work Proposal (FWP) initiated in October 2018. No accomplisments to date.
Please see the project page for FWP 65213 to view accomplishments from previous related efforts.
Activities under this effort initiated in October 2018. In the FWPs first budget period focus will be on verifying and advancing the PNNL developed STOMP-HYDT-KE computer code via comparisons against an international community of like scientific simulators through the 2nd International Gas Hydrate Code Comparison Study (IGHCCS2) on a series of problems involving coupled flow, transport, thermodynamics, and geomechanics. In addition to these activities, the simulator’s execution speed will be improved by converting it to execute in parallel on shared-memory computers and then work will begin on the development of a distributed memory implementation, allowing for solving much larger problems.
All DOE Funding
Total Funding to Date: $100,000