The objective of this research is to measure physical, chemical, mechanical, and hydrologic property changes in methane hydrate-bearing sediments subjected to: injection of carbon dioxide (CO2) and nitrogen (N2), the effects of sediment layering, and the effects of relevant gradients (thermal, chemical , and capillary pressure) within the system.
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720
Few studies have examined the hydrologic and physical/mechanical property changes that occur during a hydrate composition change. In the studies that have been conducted, researchers did not measure hydrologic properties; quantification of the effluent gas was crude and performed over a limited range of conditions (mostly dry hydrate) and failed to address important reservoir issues such as pressure increase upon injection and the effect of changes in gas composition in a system where the gas composition varies. This research will investigate processes associated with the injection of N2, CO2, and mixtures of these gases into methane hydrate-bearing porous media under non-stirred batch and flow-through conditions, and will attempt to quantify the exchange kinetics of the N2 and CO2 replacement into methane hydrate using flow-through reactors and breakthrough curve analysis. Permeability will be measured to detect changes, and geophysical property changes will be measured using either the Split Hopkinson Resonant Bar apparatus or a flow-through vessel with p- and s- wave transducers in the end platens.
Much of the investigated hydrate-bearing sediments that are thought of as potential energy targets are contained in layered sediments, having sands and silts or clay layers. Few laboratory studies have studied these layered systems. Layering affects the local and global permeability to both gas and water, further affecting gas and water flow, the location of hydrate formation and dissociation, and the impact of pressure signals. Layered systems are by nature complex, and simplification is required in laboratory studies to generate conceptual models that can be expressed numerically to aid in predicting gas production and mechanical changes of the sediments. Early studies have used fine and coarse sand, and sandstone and sand layers. Few laboratory tests of gas hydrate dissociation from layered systems have been performed. Also few tests have been performed examining important gradients. Tests with better quantification of processes are needed. This effort will measure physical, chemical, mechanical, and hydrologic property changes in layered sediments containing methane hydrate, water, and gas.
In addition to the studies of layered systems, numerical simulation of flow and mechanical properties of hydrate-bearing sands at the multigrain scale will be conducted here to extend earlier work by LBNL.
The primary benefits of this lab-based research is the provision of critical information for interpreting other laboratory and field tests including injection of CO2 and N2 into methane hydrate-bearing reservoirs, and production of methane from layered hydrate-bearing sediments, and systems under thermal, chemical, or capillary pressure gradients. Questions asked and answered on this project will be from a reservoir perspective understanding that many nonideal conditions can exist.
Budget Period 6 (July 2017–June 2018)
Budget Period 5 (July 2016–December 2017)
Budget Period 4 (July 2015–June 2016)
Budget Period 3 (June 2014–June 2015)
Budget Period 2 (June 2013–May 2014)
Budget Period 1 (June 2012–May 2013)
Final Status (March 2019)
Efforts under the project are complete. A summary final report on activities and findings under the field work proposal is accessible via the link in the Additional Information section below Lab-based gas hydrate studies will be ongoing at LBNL but new work will be conducted under new project number FP00008137.
Key Findings resulting from activities completed under this project include:
Final Report [PDF] March, 2019
Topical Report : Behavior of Methane Hydrate Bearing Sediments Subjected to Changing Gas Composition [PDF-1.55MB]
CT scans of hydrate bearing system showing controlled temperature grasient