| Bibliographic Citation | |
| Full Text |  1 Mb |
|---|---|
| Title | Reservoir environment of the Onuma geothermal power plant, northeast Japan, estimated by forward analysis of long-term artificial-tracer concentration change, using single-box-model simulator |
| Creator/Author | Shigeno, Hiroshi ; Takahashi, Masaaki ; Tetsuro, Noda |
| Publication Date | 1993 Jan 28 |
| OSTI Identifier | OSTI ID: 888913 |
| Report Number(s) | SGP-TR-145-19 |
| Resource Type | Conference |
| Resource Relation | Conference: Proceedings, eighteenth workshop on geothermal reservoir engineering, Stanford University, Stanford, CA, January 26-28, 1993 |
| Research Org | Geological Survey of Japan, Hokkaido Branch, Sapporo, JP; Geological Survey of Japan, Geothermal Research Department, Tsukuba, JP; Geological Survey of Japan, Environmental Geology Department, Tsukuba, JP |
| Sponsoring Org | USDOE |
| Related Subject | Geothermal Legacy |
| Description/Abstract | A single-box-model numerical simulator for personal computer analysis was developed in order to estimate macroscopic parameter values for exploited geothermal reservoirs and essential fluids coming from the depth. The simulator was designed to compute history data concerning total production and reinjection fluids at geothermal power plants from the assumed parameter values, based on conservation laws for water mass, heat energy and masses of conservative chemical constituents of geothermal fluids. Using two kinds of forward analysis techniques, i.e. the cast-net and pursuit methods, programs containing the simulator can semiautomatically select the optimum combination of the unknown parameter values by minimizing the differences between the simulated and measured history data for specific enthalpy and chemical compositions of the production fluids. The forward analysis programs were applied to the history data from the Onuma geothermal power plant (production capacity, 10MWe) where waste hot water reinjection, chemical monitoring and artificial tracer tests have been conducted since 1970, almost the beginning of the geothermal exploitation. Using the history data, enthalpy and iodine concentrations of the total production fluids with the amounts of KI tracer injected as spikes, the macroscopic parameter values for the exploited reservoir and the essential hot water from the depth were uniquely determined as follows: mass of the hot water convecting in the exploited reservoir (M0), 3.23x109kg; recycling fraction of the reinjected waste hot water to the reservoir (R), 0.74; specific enthalpy of the essential water from the depth (H1), 385kcalkg; iodine concentration of the water (I1), 0.086mg/kg with chlorine concentration (C1), 259mg/kg. These results support the conceptual model that the exploited Onuma reservoir mainly in the Tertiary volcanics is supplied with the neutral Na-Cl type hot water of abnormally high B/CI mole ratio of around 1.0 by a large essential reservoir distributed at depth in the Paleozoic to Mesozoic detrital marine sedimentary rocks. |
| Country of Publication | United States |
| Language | English |
| Format | Medium: ED; Size: 135-140 |
| System Entry Date | 2006 Sep 18 |
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Last Updated: 11/20/2009