In this study / gas production by depressurization method from a hydrate reservoir containing free gas zone below the hydrate zone is numerically modeled through 3 dimensional, 3
phase, non-isothermal reservoir simulation.
The endothermic nature of hydrate decomposition requires modeling to be non-isothermal / hence energy balance equations must be employed in the simulation process. TOUGH-Fx, the successor of the well known multipurpose reservoir simulator TOUGH2 (Pruess [24]) and its very first module TOUGH-Fx/Hydrate, both developed by Moridis et.al [23] at LBNL, are utilized to model production from a theoretical hydrate reservoir, which is first studied by
Holder [11] and then by Moridis [22], for comparison purposes.
The study involves 2 different reservoir models, one with 30% gas in the hydrate zone (case 1) and other one with 30% water in the hydrate zone (case 2). These models are further
investigated for the effect of well-bore heating.
The prominent results of the modeling study are:
& / #8226 / In case 1, second dissociation front develops at the top of hydrate zone and most substantial methane release from the hydrate occurs there.
& / #8226 / In case 2 (hydrate-water in the hydrate zone), because a second dissociation front at the top of hydrate zone could not fully develop due to high capillary pressure acting on
liquid phase, a structure similar to ice lens formation is observed.
& / #8226 / Initial cumulative replenishment (first 5 years) and the replenishment rate (first 3.5 years) are higher for case 2 because, production pressure drop is felt all over the
reservoir due to low compressibility of water and more hydrate is decomposed.
Compared to previous works of Holder [11] and Moridis [22], amount of released gas contribution within the first 3 years of production is significantly low which is primarily attributed to the specified high capillary pressure function.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12606241/index.pdf |
| Date | 01 July 2005 |
| Creators | Alp, Doruk |
| Contributors | Parlaktuna, Mahmut |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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