On production behavior of enhanced geothermal systems with CO2 as working fluid
On production behavior of enhanced geothermal systems with CO2 as working fluid
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DOI：
10.1016/j.enconman.2007.12.029
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发表时间：
2008-06-01
影响因子：
10.4
通讯作者：
Pruess, Karsten
中科院分区：
文献类型：
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作者：
Pruess, Karsten
数值模拟用于评估使用二氧化碳或水作为传热流体的增强型地热注采系统的质量流量和热提取率。在索尔兹的欧洲热干岩实验之后，我们发现二氧化碳的热萃取率明显高于水。二氧化碳流动性（=密度/粘度）对温度和压力的强烈依赖可能导致不寻常的生产行为，即使油藏处于热枯竭状态，热萃取率实际上也会在一段时间内增加。我们提出了有史以来第一个二氧化碳注入生产系统的三维模拟。这些结果表明，由于冷注射和热生产条件下CO、密度的巨大反差，重力对质量流和热抽提的影响很大。低温致密CO2沿储层底部优先流动的趋势可能导致热突破提前发生。这个问题可以通过在油藏顶部的有限深度段进行生产来避免。Elsevier Ltd.出版。
Numerical simulation is used to evaluate the mass flow and heat extraction rates from enhanced geothermal injection-production systems that are operated using either CO2 or water as heat transmission fluid. For a model system patterned after the European hot dry rock experiment at Soultz, we find significantly greater heat extraction rates for CO2 as compared to water. The strong dependence of CO2 mobility (=density/viscosity) upon temperature and pressure may lead to unusual production behavior, where heat extraction rates can actually increase for a time, even as the reservoir is subject to thermal depletion. We present the first ever, three-dimensional simulations of CO2 injection-production systems. These show strong effects of gravity on the mass flow and heat extraction due to the large contrast of CO, density between cold injection and hot production conditions. The tendency for preferential flow of cold, dense CO2 along the reservoir bottom can lead to premature thermal breakthrough. The problem can be avoided by producing from only a limited depth interval at the top of the reservoir. Published by Elsevier Ltd.