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Three-dimensional analysis of coupled thermohaline flow and reactive transport in fractured geothermal reservoirs

裂缝性地热储层温盐流与反应输运耦合的三维分析

基本信息

批准号：
175644494
负责人：
Professor Dr. Thomas Graf
金额：
--
依托单位：
Institut für Strömungsmechanik und Umweltphysik im Bauwesen
依托单位国家：
德国
项目类别：
Independent Junior Research Groups
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2015-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/175644494?language=en
关键词：
Three dimensional analysis coupled thermohaline

项目摘要

Studying coupled 3D thermohaline flow and reactive transport in fractured materials is important in the context of estimating lifetime and efficiency of geothermal reservoirs. Thermal energy extraction with the common Hot Dry Rock method will lead to steep gradients of water temperature, water density and presumably solute concentration. As a result, chemical reactions (precipitation/dissolution) and a modification of the flow regime due to coupled thermal-solutal (“thermohaline”) flow is expected to occur in the 3D fractured reservoir. To date, a number of coupled geoprocesses in the 3D subsurface have not yet been investigated. These include, amongst others, thermohaline flow in fractured rock, 3D variable-density flow in fractured rock, and the effect of reactive transport on geothermal reservoir efficiency. In particular, this project will focus on (i) the study of viscosity-effects on variable-density flow in porous and fractured-porous reservoirs, (ii) the impact of chemical reactions on geothermal reservoir efficiency, (iii) the study of variable-density flow in 3D fractured reservoirs, (iv) thermohaline (“double-diffusive”) convection in fractured geothermal reservoirs, (v) the transient analysis of thermohaline flow in porous media, and (vi) the efficient representation of complex 3D fracture networks in a finite-element mesh of variable topography and inclined hydrogeological units. The goal of this project is to provide adapted and efficient modelling tools to theoretically examine coupled processes. Numerical models are useful tools because systems of high complexity can be studied, which is difficult and sometimes impossible in field or laboratory experiments. The results of this project will (i) yield fundamental knowledge on the above mentioned coupled geoprocesses in 3D fractured rock as well as their interaction, (ii) assist in the identification of important processes relevant for the long-term operation of georeservoirs, (iii) help to identify the relevant parameters, (iv) provide adapted tools for the long-term prediction of reservoir productivity and efficiency, and (v) help to estimate the relative importance of individual coupled processes.

研究裂缝材料中的耦合 3D 温盐流和反应输运对于估计地热储层的寿命和效率非常重要。使用常见的干热岩方法提取热能将导致水温、水密度和可能的溶质浓度的陡峭梯度。因此，化学反应（沉淀/溶解）和由于耦合热溶质（“温盐”）流动而导致的流动状态的改变预计会在 3D 裂缝性储层中发生。迄今为止，尚未对 3D 地下的许多耦合地理过程进行研究。其中包括裂隙岩石中的温盐流、裂隙岩石中的 3D 变密度流以及反应输运对地热储层效率的影响。特别是，该项目将重点关注（i）多孔和裂缝性多孔储层中变密度流的粘度效应研究，（ii）化学反应对地热储层效率的影响，（iii）3D裂缝性储层中的变密度流研究，（iv）裂缝性地热中的温盐（“双扩散”）对流 (v) 多孔介质中温盐流的瞬态分析，以及 (vi) 在可变地形和倾斜水文地质单元的有限元网格中有效表示复杂的 3D 裂缝网络。该项目的目标是提供适应性强且高效的建模工具，以从理论上检查耦合过程。数值模型是有用的工具，因为可以研究高度复杂的系统，这在现场或实验室实验中是困难的，有时是不可能的。该项目的结果将 (i) 产生关于 3D 裂隙岩石中上述耦合地质过程及其相互作用的基础知识，(ii) 帮助识别与地质储层长期运行相关的重要过程，(iii) 帮助确定相关参数，(iv) 为储层产能和效率的长期预测提供合适的工具，以及 (v) 帮助估计相对各个耦合过程的重要性。