| Title | Reinjected Water Return at Miravalles Geothermal Reservoir, Costa Rica: Numerical Modeling and Observations |
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| Authors | M. Parini, J. A. Acuna, M. Laudiano |
| Year | 1996 |
| Conference | Stanford Geothermal Workshop |
| Keywords | |
| Abstract | The first 55 MW power plant at Miravalles started operation in March, 1994. During the first few months of production, a gradual increase in chloride content was observed in some production wells. The cause was assumed to be a rapid return of injectate from two in.jection wells located fairly near to the main production area. A tracer test was performed and showed a relatively rapid breakthrough, confirming the assumption made. Numerical modeling was then carried out to try to reproduce the observed behavior. The reservoir was modelled with an idealized three-dimensional network of fractures embedded into a low permeability matrix. The ìtwo watersî feature of TOUGH2 simulator was used. The numerical simulation showed good agreement with observations. A ìporous mediumî model with equivalent hydraulic characteristics was unable to reproduce the observations. The fractured model, when applied to investigate the mid and long term expected behavior, indicated a reservoir cooling risk associated to the present injection scheme. Work is currently underway to modify this scheme. |