Thermohaline modelling of hot geothermal fluid systems in coastal environment: the Seferihisar-Balcova Area example (Turkey)

全世界对全球变暖后果的担忧正在增加人们对开发地热资源的兴趣，这些资源既用于发电，也用于直接使用。这为伸展地热系统的地球化学和数值研究提供了新的野外数据。数值模型应探索断层和裂缝对驱动热流体流动的不同作用力的作用，以及人类活动和海水入侵对热流体循环的影响。然而，迄今为止，在系统地确定系统配置(例如水力渗透率、继承的地质结构)与由此产生的地热系统热诱导流动行为之间的基本关系方面所做的努力有限。调查上述问题的一个例外例子是火热的Seferihisar-Balçova地热系统(SBG)，它是土耳其西安纳托利亚塞斯梅半岛的一部分。在SBG中，地热过程极其激烈，表面可以观察到接近沸腾温度的热水。流体流动的驱动机制及其与断层的相互关系还知之甚少。此外，流体运移过程具有复杂的温度和水化学异常特征。他们的起因仍不清楚。更重要的是，该地区沿海含水层地热能的开采会引起海水入侵，污染淡水资源。在过去的几年里，人们对SBG的地热资源进行了彻底的调查。因此，收集了一个广泛的数据库。由于柏林扶轮基金会和伊兹密尔的多库兹·埃勒·L大学之间预先建立的合作，该数据库现在可以用于科学研究。因此，有可能应用数值模拟、水化学、水文地质学等方法来研究地热流体运移的动力学。最终目标是了解驱动SBG内热水的基本过程、不同驱动力的作用以及它们在控制地热过程中的相互作用。这一结果将为地下能量的迁移、活跃的输运过程和构造构造之间的联系提供新的线索。

The worldwide concern about the consequences of global warming is increasing interest in developing geothermal resources, both for power generation and direct use. This is providing new field data for geochemical and numerical investigations of extensional geothermal systems. The numerical models should explore the role of faults and fractures on the different forces driving hot fluid flows as well as the impact of anthropogenic activities and seawater intrusions on thermal fluid circulation. To date, however, there has been limited effort made to systematically determine the basic relationships between system configuration (e.g., hydraulic permeability, inherited geological structures) and the resulting thermally induced flow behaviour of geothermal systems. An exceptional example to investigate the mentioned issues is the hot Seferihisar-Balçova Geothermal system (SBG) which is part of the Cesme Peninsula, Western Anatolia, Turkey. In the SBG, geothermal processes are extremely vigorous and hot waters close to boiling temperature can be observed at the surface. The driving mechanisms of fluid flow and their interrelationships with faults are poorly understood. Furthermore, the fluid transport processes are characterized by complex temperature and hydrochemical anomalies. Their causes remain still unclear. Not at least, the geothermal energy extraction in the coastal aquifers of this area induces seawater intrusion which pollutes freshwater resources. In the last years, the SBG, has been thoroughly investigated for its geothermal resources. As a result, an extensive database has been gathered. Owing to a pre-established collaboration between the FU Berlin and the Dokuz Eylül University, Izmir, the database is now available for scientific research. Thus, it will be possible to apply numerical modelling, water chemistry, hydrogeology approaches to study the dynamics of geothermal fluid migration. The final objective is to understand the basic processes driving the thermal waters within the SBG, the role of different driving forces as well as their interactions in controlling geothermal processes. The results will shed new light on the links between the migration of subsurface energy, active transport processesand tectonic structures.