DE-FE0010496

Goal
The goal of this project is to apply a multi-component, multi-dimensional reactive transport simulation code to constrain modern day methane fluxes and to reconstruct past episodes of methane flux that can be correlated with environmental changes.

Performers
Oregon State University ? Corvallis, OR

Background
The importance of understanding the role that gas hydrates play in the global carbon cycle and in understanding their potential as a future energy resource have long been recognized and are key components of the Methane Hydrate R&D Program. Fundamental questions remain, however, as to the residence time of gas hydrates near the seafloor and deeper within the sediment column, the sources and pathways of methane transport, nature and driving mechanisms for flow, and changes in these variables over time.

In order to better understand these fundamental dynamics of methane in present and past environments, Oregon State University will model the complex nature of these interactions by adapting a comprehensive kinetic transport-reaction model based on the CrunchFlow code (Steefal, 2009) to simulate the processes occurring in the sediment column (diagenesis, sediment burial, fluid advection, and multi-component diffusion) and estimate net seafloor fluxes of solutes. CrunchFlow is a software package for modeling and simulation of reactive flow and transport through porous media including groundwater aquifers, soils, sediments, and crystalline rocks. The software can be used to simulate a range of important processes and environments, including reactive contaminant transport, chemical weathering, carbon sequestration, biogeochemical cycling, and water-rock interaction.

Impact
Development of a set of user-friendly Crunchflow-based geochemical modules, tested and implemented using readily available field data (e.g., Cascadia, India, Ulleung Basin), will result in a more complete set of proxies to reconstruct changes in methane flux over time. A coherent set of simulation tools can be used in an integrated approach for future field projects such as those being proposed for the Arctic margin and other high methane flux sites and climate sensitive gas hydrate-bearing regions worldwide.

Accomplishments
This project commenced on October 1, 2012.

Current Status (January 2013)
The one-year project will develop and validate, using available data from the field, three Crunchflow modules intended to:

• Simulate present carbon cycling at the sulfate methane transition zone (SMTZ), a key biofilter in controlling the methane flux out of the sediment. This module shall be designed to be directly applicable to understanding methane and anoxia in the global ocean and in using the depth of the SMTZ to reconstruct current and past methane fluxes.
• Reconstruct past episodes of methane flux by quantifying sediment proxies (barite), which can help researchers explore gas hydrate response to climate change and its relationship to slope stability.
• Constrain episodic methane gas flux that may lead to the formation/dissolution of massive gas hydrate near the seafloor by investigating massive gas hydrate deposits where the methane supply has apparently ceased.

Project Start: October 1, 2012
Project End: September 30, 2013

Project Cost Information:
DOE Contribution: $88,537
Performer Contribution: $28,831

Contact Information:
NETL ? Robert Vagnetti (Robert.Vagnetti@netl.doe.gov or 304-285-1334)
Oregon State University ? Marta E. Torres (mtorres@coas.oregonstate.edu or 541-737-2902)