Depressurization-induced gas production from Class 1 and Class 2hydrate deposits
Class 1 hydrate deposits are characterized by aHy-drate-Bearing Layer (HBL) underlain by a two-phase zone involvingmobile gas. Such deposits are further divided to Class 1W (involvingwater and hydrate in the HBL) and Class 1G (involving gas and hydrate inthe HBL). In Class 2 deposits, a mobile water zone underlies the hydratezone. Methane is the main hydrate-forming gas in natural accumulations.Using TOUGH-FX/HYDRATE to study the depressurization-induced gasproduction from such deposits, we determine that large volumes of gascould be readily produced at high rates for long times using conventionaltechnology. Dissociation in Class 1W deposits proceeds in distinctstages, but is continuous in Class 1G deposits. Hydrates are shown tocontribute significantly to the production rate (up to 65 percent and 75percent in Class 1W and 1G, respectively) and to the cumulative volume ofproduced gas (up to 45 percent and 54 percent in Class 1W and 1G,respectively). Large volumes of hydrate-originating CH4 could be producedfrom Class 2 hydrates, but a relatively long lead time would be neededbefore gas production (which continuously increases over time) attains asubstantial level. The permeability of the confining boundaries plays asignificant role in gas production from Class 2 deposits. In general,long-term production is needed to realize the full potential of the verypromising Class 1 and Class 2 hydrate deposits.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE. Assistant Secretary for Fossil Energy. DeputyAssistant Secretary for Oil and Natural Gas
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 890694
- Report Number(s):
- LBNL-60366; R&D Project: G30801; BnR: AB0565000; TRN: US200822%%159
- Resource Relation:
- Conference: TOUGH Symposium 2006, Berkeley, CA, 15-17 May2006
- Country of Publication:
- United States
- Language:
- English
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