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Title: On the production behavior of enhanced geothermal systems with CO2as working fluid

Abstract

Numerical simulation is used to evaluate mass flow and heatextraction rates from enhanced geothermal injection-production systemsthat are operated using either CO2 or water as heat transmission fluid.For a model system patterned after the European hot dry rock experimentat Soultz, we find significantly greater heat extraction rates for CO2 ascompared to water. The strong dependence of CO2 mobility (=density/viscosity) upon temperature and pressure may lead to unusualproduction behavior, where heat extraction rates can actually increasefor a time, even as the reservoir is subject to thermal depletion. Wepresent the first-ever three-dimensional simulations of CO2injection-production systems. These show strong effects of gravity onmass flow and heat extraction, due to the large contrast of CO2 densitybetween cold injection and hot production conditions. The tendency forpreferential flow of cold, dense CO2 along the reservoir bottom can leadto premature thermal breakthrough. The problem can be avoided byproducing from only a limited depth interval at the top of thereservoir.

Authors:
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
929764
Report Number(s):
LBNL-63355
Journal ID: ISSN 0196-8904; ECMADL; R&D Project: CSR012; BnR: 830404000; TRN: US200812%%655
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Energy Conversion and Management; Journal Volume: 0; Journal Issue: 0; Related Information: Journal Publication Date: 0
Country of Publication:
United States
Language:
English
Subject:
54; GEOTHERMAL SYSTEMS; HEAT EXTRACTION; HEAT TRANSFER; PRODUCTION; SIMULATION; WATER; WORKING FLUIDS; enhanced geothermal systems (EGS) heat transmission thermalbreakthrough CO2 storage numerical simulation

Citation Formats

Pruess, K. On the production behavior of enhanced geothermal systems with CO2as working fluid. United States: N. p., 2007. Web.
Pruess, K. On the production behavior of enhanced geothermal systems with CO2as working fluid. United States.
Pruess, K. Thu . "On the production behavior of enhanced geothermal systems with CO2as working fluid". United States. doi:. https://www.osti.gov/servlets/purl/929764.
@article{osti_929764,
title = {On the production behavior of enhanced geothermal systems with CO2as working fluid},
author = {Pruess, K.},
abstractNote = {Numerical simulation is used to evaluate mass flow and heatextraction rates from enhanced geothermal injection-production systemsthat are operated using either CO2 or water as heat transmission fluid.For a model system patterned after the European hot dry rock experimentat Soultz, we find significantly greater heat extraction rates for CO2 ascompared to water. The strong dependence of CO2 mobility (=density/viscosity) upon temperature and pressure may lead to unusualproduction behavior, where heat extraction rates can actually increasefor a time, even as the reservoir is subject to thermal depletion. Wepresent the first-ever three-dimensional simulations of CO2injection-production systems. These show strong effects of gravity onmass flow and heat extraction, due to the large contrast of CO2 densitybetween cold injection and hot production conditions. The tendency forpreferential flow of cold, dense CO2 along the reservoir bottom can leadto premature thermal breakthrough. The problem can be avoided byproducing from only a limited depth interval at the top of thereservoir.},
doi = {},
journal = {Energy Conversion and Management},
number = 0,
volume = 0,
place = {United States},
year = {Thu May 31 00:00:00 EDT 2007},
month = {Thu May 31 00:00:00 EDT 2007}
}