Title: Linking basin-scale and pore-scale gas hydrate distribution patterns in diffusion-dominated marine hydrate systems: DIFFUSION-DRIVEN HYDRATE GROWTH IN SANDS

Abstract

The goal of this study is to computationally determine the potential distribution patterns of diffusion-driven methane hydrate accumulations in coarse-grained marine sediments. Diffusion of dissolved methane in marine gas hydrate systems has been proposed as a potential transport mechanism through which large concentrations of hydrate can preferentially accumulate in coarse-grained sediments over geologic time. Using one-dimensional compositional reservoir simulations, we examine hydrate distribution patterns at the scale of individual sand layers (1 to 20 m thick) that are deposited between microbially active fine-grained material buried through the gas hydrate stability zone (GHSZ). We then extrapolate to two- dimensional and basin-scale three-dimensional simulations, where we model dipping sands and multilayered systems. We find that properties of a sand layer including pore size distribution, layer thickness, dip, and proximity to other layers in multilayered systems all exert control on diffusive methane fluxes toward and within a sand, which in turn impact the distribution of hydrate throughout a sand unit. In all of these simulations, we incorporate data on physical properties and sand layer geometries from the Terrebonne Basin gas hydrate system in the Gulf of Mexico. We demonstrate that diffusion can generate high hydrate saturations (upward of 90%) at the edges ofmore » thin sands at shallow depths within the GHSZ, but that it is ineffective at producing high hydrate saturations throughout thick (greater than 10 m) sands buried deep within the GHSZ. As a result, we find that hydrate in fine-grained material can preserve high hydrate saturations in nearby thin sands with burial.« less

Authors:

Nole, Michael  ^[1];

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Daigle, Hugh  ^[1];

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Cook, Ann E.  ^[2];

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Hillman, Jess I. T. ^[3]; Malinverno, Alberto  ^[4]

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• Search OSTI.GOV for ORCID "0000-0003-4442-9055"
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+ Show Author Affiliations

1. Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin Texas USA
2. School of Earth Sciences, Ohio State University, Columbus Ohio USA
3. School of Earth Sciences, Ohio State University, Columbus Ohio USA; GEOMAR Helmholtz Centre for Ocean Research, Kiel Germany
4. Lamont Doherty Earth Observatory of Columbia University, Palisades New York USA

Publication Date:

2017-02-01

Research Org.:

Univ. of Texas at Austin, Austin, TX (United States)

Sponsoring Org.:

USDOE Office of Fossil Energy (FE)

OSTI Identifier:

1343742

Grant/Contract Number:  

FE0013919

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Geochemistry, Geophysics, Geosystems

Additional Journal Information:

Journal Volume: 18; Journal Issue: 2; Journal ID: ISSN 1525-2027

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

03 NATURAL GAS; gas hydrate; reservoir simulation; short migration; basin simulation