Summary
This paper experimentally analyzes the production characteristics of
hot-brine stimulation accompanying hydrate reformation in the presence of
methane hydrate. Many attempts have been made to recover methane hydrate
commercially, such as depressurization, thermal stimulation, and inhibitor
injection. Hot-brine injection coupled with thermal recovery with inhibitor
injection has been investigated as an efficient production scheme, but the
hydrate reformation during the dissociation is problematic, and it negatively
influences the recovery rate.
An experimental apparatus divided the sediment sample into 12 blocks not
only to describe 1D dissociation effectively but also to control the
temperature accurately. The specified amount of methane hydrate was formed
artificially in unconsolidated and packed sediments where the average particle
size, absolute permeability, and porosity were 260 μm, 4.4 darcies, and 42%,
respectively. The production trends were observed in the temperature range of
approximately 283.85 - 303.15 K and with injection rates of 10 and 15
cm3/min. Methane hydrate reformed in all the tests; the reason for
this may be the recombination of water and the dissociated methane in the
downstream zones. In the early time, the production rate was low, but it
increased significantly in later time. The former was why most of gas that
dissociated in the upstream zones was consumed to reform hydrate in the
downstream areas, while the latter came from the dissociation of initial and
reformed hydrate. The dissociation front moved fast at the higher temperature
and injection rate. The production efficiency of the test at 15
cm3/min and 294.55 K was similar to that of the test at 10
cm3/min and 303.15 K. The results confirmed the production behaviour
of methane hydrate under the reformation phenomenon and could provide the
fundamentals to develop an efficient production scheme based on hot-brine
stimulation.
© 2012. Society of Petroleum Engineers
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History
- Original manuscript received:
25 October 2010
- Meeting paper published:
19 October 2010
- Revised manuscript received:
17 July 2011
- Manuscript approved:
10 October 2011
- Published online:
9 January 2012
- Version of record:
30 January 2012
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