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Transient-pressure analysis in geothermal steam reservoirs with an immobile vaporizing liquid phase

Geothermics

By:
,
DOI: 10.1016/0375-6505(78)90015-9

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Abstract

A finite-difference model for the radial horizontal flow of steam through a porous medium is used to evaluate transient-pressure behavior in the presence of an immobile vaporizing or condensing liquid phase. Graphs of pressure drawdown and buildup in terms of dimensionless pressure and time are obtained for a well discharging steam at a constant mass flow rate for a specified time. The assumptions are made that the steam is in local thermal equilibrium with the reservoir rocks, that temperature changes are due only to phase change, and that effects of vapor-pressure lowering are negligible. Computations show that when a vaporizing liquid phase is present the pressure drawdown exhibits behavior similar to that observed in noncondensable gas reservoirs, but delayed in time. A theoretical analysis allows for the computation of this delay and demonstrates that it is independent of flow geometry. The response that occurs upon pressure buildup is markedly different from that in a noncondensable gas system. This result may provide a diagnostic tool for establishing the existence of phase-change phenomena within a reservoir. ?? 1979.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Transient-pressure analysis in geothermal steam reservoirs with an immobile vaporizing liquid phase
Series title:
Geothermics
DOI:
10.1016/0375-6505(78)90015-9
Volume
7
Issue:
2-4
Year Published:
1978
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
253
Last page:
264
Number of Pages:
12