scholarly journals Modeling, design, and life performance prediction for energy production from geothermal reservoirs. Quarterly report, January--March 1998

1998 ◽  
Author(s):  
D. Swenson
Keyword(s):  
Performance Prediction ◽  
Energy Production ◽  
Geothermal Reservoirs

scholarly journals Thermal Energy Production From Closed Geothermal Reservoirs

2018 ◽  
Vol Volume-2 (Issue-3) ◽  
pp. 961-965 ◽  
Author(s):  
Bhupesh Saini ◽  
Mr. Mayank Sharma ◽  
Keyword(s):  
Thermal Energy ◽  
Energy Production ◽  
Geothermal Reservoirs

Negative-Saturation Approach for Compositional Flow Simulations of Mixed CO2/Water Injection Into Geothermal Reservoirs Including Phase Appearance and Disappearance

SPE Journal ◽  
2012 ◽  
Vol 17 (02) ◽  
pp. 502-522 ◽  
Author(s):  
Hamidreza Salimi ◽  
Karl-Heinz Wolf ◽  
Johannes Bruining
Keyword(s):  
Energy Production ◽  
Single Phase ◽  
Storage Capacity ◽  
Co2 Storage ◽  
Water Injection ◽  
Phase Flow ◽  
Two Phase ◽  
Solution Approach ◽  
Geothermal Reservoirs ◽  
Compositional Flow

Summary Cold mixed CO2/water injection into hot-water reservoirs can be used for simultaneous geothermal-energy (heat) production and subsurface CO2 storage. This paper studies this process in a 2D geothermal homogeneous reservoir, a layered reservoir, and a heterogeneous reservoir represented by a stochastic-random field. We give a set of simulations for a variety of CO2/water-injection ratios. In this process, often regions of two-phase flow are connected to regions of single-phase flow. Different systems of equations apply for single-phase and two-phase regions. We develop a solution approach, called the nonisothermal-negative-saturation (NegSat) solution approach, to solve efficiently nonisothermal compositional flow problems (e.g., CO2/water injection into geothermal reservoirs) that involve phase appearance, phase disappearance, and phase transitions. The advantage of this solution approach is that it circumvents using different equations for single-phase and two-phase regions and the ensuing unstable switching procedure. In the NegSat approach, a single-phase multicomponent fluid is replaced by an equivalent fictitious two-phase fluid with specific properties. The equivalent properties are such that the extended saturation of a fictitious gas is negative in the single-phase aqueous region. We discuss the salient features of the simulations in detail. When two phases are present at the injection side, heterogeneity and layering lead to more CO2 storage compared with the homogeneous case because of capillary trapping. In addition, layering avoids movement of the CO2 to the upper part of the reservoir and thus reduces the risk of leakage. Our results also show that heterogeneity and layering change the character of the solution in terms of useful-energy production and CO2 storage. The simulations can be used to construct a plot of the recovered useful energy vs. maximally stored CO2. Increasing the amount of CO2 in the injection mixture leads to bifurcation points at which the character of the solution in terms of energy production and CO2 storage changes. For overall injected-CO2 mole fractions less than 0.04, the result with gravity is the same as the result without gravity. For larger overall injected-CO2 mole fractions, however, the plot without gravity differs from the plot with gravity because of early breakthrough of a supercritical-CO2 tongue near the caprock. The plot of the useful energy (exergy) vs. the CO2-storage capacity in the presence of gravity shows a Z-shape. The top horizontal part represents a branch of high exergy recovery and a relatively lower storage capacity, whereas the bottom part represents a branch of lower exergy recovery and a higher storage capacity.

scholarly journals Geothermal Power Project’s Manageable Risks in Hungary

2021 ◽  
Author(s):  
Aniko Toth ◽  
Peter Szucs ◽  
David K. Fenerty
Keyword(s):  
Geothermal Energy ◽  
Energy Production ◽  
Time Budget ◽  
Geothermal Resources ◽  
Geothermal Reservoirs ◽  
Energy Projects ◽  
Tremendous Amount ◽  
Term Energy ◽  
Project Objectives

Abstract There are many compelling arguments for using geothermal energy in Hungary. One of the most important is that the country could thereby exploit its abundant, relatively untapped network of geothermal reservoirs. These are considerably warmer and closer to the surface than in most of Europe. In the foreseeable future, Hungary’s geothermal resources can satisfy the conditions required for efficient energy production. The tremendous amount of energy stored in our geothermal reservoirs could satisfy much of the country’s long-term energy demand.Every geothermal project is designed to fulfill its project objectives by meeting time, budget, technical, and legal/regulatory provisions. Geothermal development is necessarily exposed to risks of varying degrees throughout its development, something which distinguishes geothermal from other kinds of renewable-energy projects. These risks most often concern the availability, amount, suitability, sustainability and use-potential of the geothermal resource, but may also include market, financing, commercial and macro-economic risks.

Thermal energy production from closed geothermal reservoirs using reinjection

2017 ◽  
Author(s):  
Codruta Calina Bendea ◽  
Cornel Antal ◽  
Florica Popa ◽  
Florin Georgescu ◽  
Bogdan Popa
Keyword(s):  
Thermal Energy ◽  
Energy Production ◽  
Geothermal Reservoirs

Mitochondrial matrix calcium ions regulate energy production in myocardium: A cytochemical study

1990 ◽  
Vol 48 (2) ◽  
pp. 166-167
Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet
Keyword(s):  
Energy Metabolism ◽  
Calcium Ions ◽  
Energy Production ◽  
Regulation Of Respiration ◽  
Free Calcium ◽  
Mitochondrial Matrix ◽  
Cytochemical Study ◽  
Nmr Techniques

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.

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