Poro-mechanical, thermal, and chemical processes can play a significant role when developing enhanced geothermal systems. These processes occur on various time scales and the significance of their interaction varies with the problem of interest. Of particular importance is the thermo-mechanical coupling during injection operations (time scale of months/years). In fact, the phenomena of the vari...

Numerical simulation techniques have been employed by several suthors (see e.g. Benson and Approximate analytical solutions a rived for Bodvarsson, 1982; Garg and Pritchett, 1384 to cold water injection into single0-phase “porous medium” geothermal reservoirs. A (liquid) and two-phase (liquid water/steam) numerical geothermal reservoir simulator is used “porous medium” reservoirs. Injection of ...

The demand from a geothermal modeler’s point of view has grown beyond the features provided by existing geothermal reservoir simulators. Existing packages are either built on code which is over 30 years old (e.g. TOUGH2) or is proprietary (e.g. TETRAD); in both cases adapting the code to include new features required for simulating a developed geothermal field is challenging. In particular, the...

Analyses of fracturing and thermal performance of fractured reservoirs in engineered geothermal system (EGS) are extended from a depth of 5 km to 10 km, and models for flow and heat transfer in EGS are improved. Effects of the geofluid flow direction choice, distance between fractures, fracture width, permeability, radius, and number of fractures, on reservoir heat drawdown time are computed. T...

Modern portable gravimeters can routinely achieve a 5 ugal uncertainty with careful measurement procedures involving multiple station occupations in the same day, and stacking of readings over at least 15 minutes during each occupation. Although further improvements in gravimeter accuracy are feasible, other practical factors relating to repeat surveys of geothermal fields make such improvement...

Fluid flow in most of geothermal reservoirs is dominated by fractures and their distribution. In this study, the following process of cold water injection into a fractured geothermal reservoir is considered: the cold water from a injection well advances along the fractures and gradually extract heat from the adjacent rock matrix, and eventually arrives at a production well. Both analytical and ...

In this paper, a lumped parameter mathematical model for hot water geothermal reservoirs is developed and applied to the Cerro Prieto geothermal field in Mexico. The production and pressure histories of Cerro Prieto were assembled from field data. A computer program was then used to perform sensitivity studies on reservoir size, porosity, aquifer recharge, and temperature of recharge fluid. Two...

system at Coso. This investigation is Part of an ongoing study being perCos0 is one of several high-tempeformed through an agreement betwen rature geothermal systems associated California Energy Company and the Earth with recent volcanic activity in the Science Laboratory Division/university Basin and Range province. Within this of Utah Research Institute. fracture-dominatedsystem, temperatnres...

Mita is a moderate temperature geothermal system that was discovered in 1997 during gold exploration in south-eastern Guatemala. This system is associated with bimodal basaltrhyolite volcanism, and occurs alongside (and overlapping with) the Cerro Blanco 2 million ounce epithermal gold deposit. Four 1000-1500m deep slim holes were drilled in 2008-09 to confirm the nature of the deep reservoir. ...

The method of analysis of the first temporal moment (mean residence time) of tracer return data was utilized to investigate the swept volume and fluid velocity between pairs of injection and production wells in the Dixie Valley geothermal field. Calculations were made using a spreadsheet program available from the Idaho National Laboratory. Jointly sponsored industry–government research at the ...