|Properties of Hydrate-Bearing Sediments Subjected to Changing Gas Compositions
||Last Reviewed 11/27/2015
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).
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720
A number of studies have investigated the impact of injecting CO2 and CO2-nitrogen N2 mixtures into methane hydrate for the purpose of sequestering CO2 and releasing methane (CH4), and review articles have been published summarizing the literature. Most of these studies have investigated the fundamental physical/chemical nature of the exchange of CO2 and/or N2 with CH4 in the clathrate. These studies have helped identify the limits of the effectiveness of CO2 injection into methane hydrate for the purposes of methane production and CO2 sequestration.
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.
The primary benefits of this lab-based research are improved empirical relationships among physical, chemical, mechanical, and hydrologic property changes in methane hydrate-bearing sediments subjected to injection of CO2and N2, which will assist in understanding the results of hydrate production field test data.
Accomplishments (most recent listed first)
Budget Period 4 (July 2015 – June 2016)
- Developed MATLAB interface to allow utilization of ELAS3D finite element code in an automated context to be applied to evaluation of elastic properties of models of hydrate bearing sediments.
Budget Period 3 (June 2014 – June 2015)
- Obtained all materials required for conducting a test of a layered system and working to resolve leak path issues for the experimental setup.
- Rebuilt hydrate pressure vessel.
- Redesigned and built new temperature control jacket allowing teflon coating of pressure vessel to eliminate external corrosion.
- Examined hydrate sample layering techniques using sand and available layered sandstone.
Budget Period 2 (June 2013 – May 2014)
- Completed development of computational protocol to provide theoretical distribution of hydrates in an experimentally measured sediment matrix.
- Developed the permeability and diffusivity calculation codes for use in grain-scale computation of hydrate-bearing sediment properties based on micro CT sample descriptions.
- Completed initial experiments measuring kinetics of gas exchange between a CO2 / N2 mixture and existing CH4 hydrate in a system with excess free water and comparing it to a system without excess free water.
Budget Period 1 (June 2012 – May 2013)
- Completed and documented results of a series of lab tests to monitor changes (gas exchange rates, permeability, and geomechanical properties) in CH4 hydrate-bearing samples exposed to an N2/CO2 gas mixture.
- Completed design and construction of an experimental system to measure kinetics of gas exchange in hydrate-bearing sediments.
- Established a new laboratory set-up (including new CT scanner) capable of performing and monitoring hydrate exchange kinetics experiments.
- Please see the project page for ESD05-048 to view accomplishments from past, related efforts.
Current Status (November 2015)
Efforts will continue toward the capability to make grain scale computation of hydrate bearing sand properties using microCT sample descriptions. Work in this area will focus on completing a modeling environment to allow calculation of hydrate-dependent sediment frame variations for different hydrate cementing habits (contact, grain coating, and pore filling). The team will continue to work to overcome issues with sealing of heat flux sensor wires in their experimental setup designed to examine the effects of small scale sediment layering on hydrate formation and dissociation. An initial assessment is expected in late December 2015 on the viability of a proposed redesign of the LBNL x-ray transparent vessel. Initial indications are that it should be viable. If so, the new design will be manufactured in early 2016 and will then be used for experiments to assess the affect of thermal gradient and gradient oscillation on hydrate system behavior.
Project Start: June 1, 2012
Project End: September 30, 2016
Project Cost Information:
DOE Contribution: $380,000; Recipient Contribution: $0
NETL – Richard Baker (Richard.Baker@netl.doe.gov)
LBNL –Timothy J. Kneafsey (firstname.lastname@example.org)
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Research Performance Progress Report [PDF-188KB] October - December, 2014
Research Performance Progress Report [PDF-251KB] July, 2013 - April, 2014
Research Performance Progress Report [PDF-140KB] July - September 2013
Topical Report : Behavior of Methane Hydrate Bearing Sediments Subjected to Changing Gas Composition [PDF-1.55MB]
Graphical representation of system to measure kinetics of gas exchange in hydrate-bearing sediments
Experimental system shown with reactor vessel inside of CT scanner