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The effect of heterogeneities in hydrate saturation on gas production from natural systems

The effect of heterogeneities in hydrate saturation on gas production from natural systems
The effect of heterogeneities in hydrate saturation on gas production from natural systems
Understanding the rate and time evolution of gas release from natural gas hydrate systems is important when evaluating the potential of gas hydrate as a future energy source, or the impact of gas from hydrate on climate. The release of gas from hydrate is heavily influenced by a number of factors, many of which vary through the hydrate system. The fundamental heterogeneity of natural gas hydrate systems is often poorly represented in models. Here we simulate depressurisation-induced gas production from a single vertical well in 34 models with heterogeneous 2D distributions of hydrate that include layered, columnar or random configurations and comparable models with homogenous saturation distributions. We found that the temporal evolution of gas production rate follows a consistent trend for all models, but at any time the gas production rate across the models varied by up to ±35% in the first year of production, and by up to ±25% thereafter. The primary control on the gas production rate is the overall amount of hydrate in the system, but local variations in hydrate saturation cause significant fluctuations in the time evolution of production. These hydrate variations can cause changes in the gas flow path through the system and associated drops in gas production rate continuing for multiple years. Overall, our results suggest that small levels of heterogeneity in hydrate systems can cause variations in the gas production rate similar in scale to much larger variations in homogenous systems. Our work provides an error margin for previously modelled gas production rates, and a note of caution for potential commercial development of gas hydrate.
Natural gas hydrate, Heterogeneity, Gas production, numerical simulation, Depressurisation
0920-4105
1-11
Riley, David, Christopher
f9649d09-cf4f-4b21-9ada-07d08294dad5
Marín-moreno, Hector
e3eb9576-bca1-4d35-9512-e1bb88b0e4a6
Minshull, Timothy
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Riley, David, Christopher
f9649d09-cf4f-4b21-9ada-07d08294dad5
Marín-moreno, Hector
e3eb9576-bca1-4d35-9512-e1bb88b0e4a6
Minshull, Timothy
bf413fb5-849e-4389-acd7-0cb0d644e6b8

Riley, David, Christopher, Marín-moreno, Hector and Minshull, Timothy (2019) The effect of heterogeneities in hydrate saturation on gas production from natural systems. Journal of Petroleum Science and Engineering, 183, 1-11. (doi:10.1016/j.petrol.2019.106452).

Record type: Article

Abstract

Understanding the rate and time evolution of gas release from natural gas hydrate systems is important when evaluating the potential of gas hydrate as a future energy source, or the impact of gas from hydrate on climate. The release of gas from hydrate is heavily influenced by a number of factors, many of which vary through the hydrate system. The fundamental heterogeneity of natural gas hydrate systems is often poorly represented in models. Here we simulate depressurisation-induced gas production from a single vertical well in 34 models with heterogeneous 2D distributions of hydrate that include layered, columnar or random configurations and comparable models with homogenous saturation distributions. We found that the temporal evolution of gas production rate follows a consistent trend for all models, but at any time the gas production rate across the models varied by up to ±35% in the first year of production, and by up to ±25% thereafter. The primary control on the gas production rate is the overall amount of hydrate in the system, but local variations in hydrate saturation cause significant fluctuations in the time evolution of production. These hydrate variations can cause changes in the gas flow path through the system and associated drops in gas production rate continuing for multiple years. Overall, our results suggest that small levels of heterogeneity in hydrate systems can cause variations in the gas production rate similar in scale to much larger variations in homogenous systems. Our work provides an error margin for previously modelled gas production rates, and a note of caution for potential commercial development of gas hydrate.

Text
Effect of hydrate heterogeneities on gas production - Accepted Manuscript
Restricted to Repository staff only until 29 August 2020.
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More information

Accepted/In Press date: 29 August 2019
e-pub ahead of print date: 29 August 2019
Published date: December 2019
Keywords: Natural gas hydrate, Heterogeneity, Gas production, numerical simulation, Depressurisation

Identifiers

Local EPrints ID: 433980
URI: https://eprints.soton.ac.uk/id/eprint/433980
ISSN: 0920-4105
PURE UUID: ff242d99-b987-48b5-b3d4-7180d06025f3
ORCID for David, Christopher Riley: ORCID iD orcid.org/0000-0001-9829-004X
ORCID for Timothy Minshull: ORCID iD orcid.org/0000-0002-8202-1379

Catalogue record

Date deposited: 09 Sep 2019 16:30
Last modified: 03 Dec 2019 02:08

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