Heat transfer processes during low or high enthalpy fluid injection into naturally fractured reservoirs
Disposal of hot separated brine by means of reinjection within the limits of the geothermal reservoir is, at present, a problem that remains to be solved. Possible thermal, as well as chemical contamination of the resources present key questions that have to be appropiately answered before a reinjection project is actually implemented in the field. This paper focusses on the basic heat-transfer process that takes place when a relatively cold brine is injected back into the naturally fractured hot geothermal reservoir after steam has been separated at the surface. The mathematical description of this process considers that rock matrix blocks behaves as uniformly distributed heat sources, meanwhile heat transfer between matrix blocks and the fluid contained in the fractures takes place under pseudo-steady state conditions with the main temperature drop occurring in the rock-matrix blocks interphase. Analytical solutions describing the thermal front speed of propagation are presented. Discussion on the effect of several variables affecting the thermal front speed of propagation is included, stressing the importance that a proper “in-situ” determination of the effective heat transfer area at the rock-fluid interphase has on the whole process. Solutions are also presented as a type-curve that can be practically used to estimate useful parameters involved in heat transfer phenomena during cold fluid reinjection in naturally fractured geothermal systems.
- Research Organization:
- Gerencia de Proyectos Geotermoelectricos, Morelia, Mich., MX
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 889197
- Report Number(s):
- SGP-TR-147-20
- Resource Relation:
- Conference: Proceedings, nineteenth workshop on geothermal reservoir engineering, Stanford University, Stanford, CA, January 18-20, 1994
- Country of Publication:
- United States
- Language:
- English
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Issues in geothermal reservoir engineering, modeling, and numerical simulation
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