|Properties of Hydrate-Bearing Sediments Subjected to Changing Gas Compositions
||Last Reviewed November 2016
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 CO2 and N2, which will assist in understanding the results of hydrate production field test data.
Accomplishments (most recent listed first)
Budget Period 5 (July 2016 – June 2017)
- Initiated development of new lab pressure cell with increased sample size and additional feed through to allow more efficient setup and control of additional temperature manipulation experiments. Design is nearing completion with manufacturing expected in early 2017.
- Completed initial investigation of the effect of thermal gradient and gradient oscillation on hydrate behavior using existing pressure cell.
- Completed multiple tests on the hydrate dissociation point in saline systems providing indication that brine systems result in a hydrate equilibrium range rather than sharp equilibrium points.
Budget Period 4 (July 2015 – June 2016)
- Completed multiple tests to examine the effect of thermal gradient on hydrate system behavior. Additional changes are needed to better control temperature gradient.
- Completed lab setup for experiments on gas production from layered hydrate system and conducted initial experimental runs.
- Completed a new system for the automated calculation of bulk and shear modulus for sub-volumes of a larger 3D image sequence as part of the effort focused on grain scale computation of HBS properties using MicroCT images.
- 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 a 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 2016)
Efforts under Budget Period 5 will continue into the summer of 2017 with focus on completing the manufacturing of the new pressure cell and use of that cell for additional experimental work on the impact of thermal gradient and gradient oscillations on hydrate system behavior. Researchers will also continue to evaluate experimental data previously collected on gas production from layered hydrate systems in an effort to assess the cause of anomalies in the data set found in prior evaluation.
Project Start: June 1, 2012
Project End: September 30, 2017
Project Cost Information:
DOE Contribution: $560,000; Recipient Contribution: $0
NETL – Richard Baker (Richard.Baker@netl.doe.gov)
LBNL –Timothy J. Kneafsey (email@example.com)
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Research Performance Progress Report [PDF-852KB] Period Ending April, 2016
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