Showing papers in "Geothermics in 2007"

TL;DR: In this paper, the authors present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced earthquakes.

TL;DR: In this paper, the authors compared the results from a 3D finite-element numerical model with those of a simple analytical line-source solution and tested their sensitivity to the duration of the tests.

TL;DR: In this article, the authors reviewed the appropriateness of the Carnot cycle as the ideal model for geothermal binary power plants and showed that the ideal trilateral cycle is more suitable than the traditional triangular cycle.

TL;DR: In this paper, the authors studied fluid pressure and permeability changes in a fracture in a rock mass by taking into account the effects of thermal stresses and silica precipitation/dissolution, which is computed using linear reaction kinetics.

TL;DR: In this paper, the potential for groundwater contamination of the different organic anti-freeze compounds (ethylene glycol, propylene glycol and betaine) used in these pumps, based on a literature review of their biodegradability and the results of their own laboratory experiments on aquifer material.

TL;DR: In this article, a field-wide groundwater model was developed for the Chikushi Plain (western Japan) using field-survey data and a numerical modeling study, and the results matched against measured groundwater levels and vertical temperature profiles.

TL;DR: Stibnite (Sb2S3) was found to form at a rate of 8.7 and 15.8 kg/day at Rotokawa and Ngawha power stations, respectively.

TL;DR: The authors describes a database on the low-temperature geothermal resources of Algeria that includes information on thermal springs and wells, a description of hot water resources, and thematic maps.

TL;DR: In this paper, the utility of electrical surveys for geothermal reservoir characterization using existing exploration and well data sets from the operating Beowawe geothermal field located in the Basin and Range Province of western USA was investigated.

TL;DR: In this article, a conceptual study has been carried out to convert geothermal water and condensate into a valuable industrial, agricultural or drinking water resource, referred to treatment facilities handling 750 kg/s of geothermal waters and 350 kg /s of steam condensates.

TL;DR: In this paper, a versatile 3D modeling method that can be used to determine the temperature, flow velocity, and distribution of geological units within a geothermal field based on well log data is presented.

TL;DR: In this paper, a three-dimensional, porous-media numerical model of the Momotombo geothermal field was developed and calibrated using the code iTOUGH2, and was utilized to study the response of the geothermal reservoir under different fluid production and injection scenarios.

TL;DR: The Miravalles geothermal power station in Costa Rica is described before and after the addition of Unit 5, a bottoming binary power plant as mentioned in this paper, and the performance of unit 5 is assessed both on a cycle and an overall plant basis.

TL;DR: The Cordon Caulle geothermal system is located in a NW-trending volcano-tectonic depression of the Southern Andean Volcanic Zone of Chile and gas data from fumaroles and hot springs have been used to assess the nature and temperature of the deeper, underlying geothermal reservoir.

TL;DR: The Gonen project in Balikesir province, the first system to begin citywide operation in the country, is described in this paper, where the geology and geothermal resources of the area, the history of the project's development, the problems encountered, its economic aspects and environmental contributions are all discussed.

TL;DR: Karaha-Telaga Bodas is a partially vapor-dominated, fracture-controlled geothermal system located adjacent to Galunggung Volcano in western Java, Indonesia as discussed by the authors, which consists of a caprock, ranging from several hundred to 1600m in thickness, and characterized by a steep, conductive temperature gradient and low permeability.

TL;DR: In this paper, the authors compared the steam-water and air-water capillary pressure in geothermal reservoir engineering, and found that in the cases studied, the steam water capillary pressures were smaller.

TL;DR: In this article, three different types of model were calibrated, namely, uniform porous medium, dual-porosity, fractured medium, and fractional dimension, and the best match to the pressure data was achieved with the fractional dimensions model.

TL;DR: The authors in this paper showed that the region of liquid resaturation had the shape of a cone of impression, which reached from the bottom of the reinjection aquifer up to shallow (100-200m) depths.

TL;DR: Synthetic schwertmannite was able to selectively remove dissolved arsenic without any significant accompanying decrease in silica concentrations, which will likely make silica retrieval more feasible.

TL;DR: In this paper, the authors investigated the factors affecting pump setting depths in low-temperature, liquid-dominated geothermal systems and defined the relationship between flow rate and pressure drawdown based on multi-rate test results.

TL;DR: In this paper, the authors used system dynamics software STELLA to obtain mass and thermal balances of a spring in the Orakeikorako geothermal field, New Zealand, based on field measurements of water level, barometric pressure, rainfall and spring temperature.

TL;DR: In this article, a 3D conductivity model was constructed from a seriesof 2D resistivity images obtained using the inline electric fieldmeasurements (Zyx impedance elements) along several measurementtransects.

TL;DR: In this paper, a new technique to calculate the temperature at the wall of an infinitely long, cylindrical, time-dependent heat source is presented, which is used in geothermal applications to determine terrestrial heat flow, evaluate heat losses to the surrounding formations in wells and to design borehole heat exchangers.

TL;DR: In this article, the distribution of subsurface temperatures in the Cap Bon basin reflects local groundwater circulation patterns and correlates with the location of known oil and gas fields, and the results of geothermal studies could therefore prove useful in the search for new hydrocarbon resources in the region.

TL;DR: In this paper, the results of preliminary laboratory tests carried out on 20 mineral waters indicate that the infrared (IR) method for the determination of total dissolved inorganic carbon (TDIC) is more accurate than the pH-alkalinity method, especially for high and low-TDIC waters.

TL;DR: The results of a Fourier analysis of water level measurements recorded near the nationally significant Pohutu Geyser in New Zealand are reported in this paper, which clearly identifies periodic pressure variations induced by barometric, gravity, thermal, anthropogenic and subsurface disturbing influences.

TL;DR: In this article, a mechanistic model has been developed for upward two-phase flow in vertical geothermal wells, based on existing correlations for the various flow regimes, using data measured in wells at the Therma-Nigrita geothermal field, Greece.