The bedrock of Skåne, the southernmost province of Sweden, has been targeted for geothermal feasibility studies since the late 1970s. An exploration project concerning the geothermal potential in the Romeleåsen Fault Zone was launched outside the town of Lund in 2001. Besides geophysical imaging of the thrust fault zone, the investigations included drilling and investigations of a 3701.8-m-deep exploration well, DGE-1, with the aim to find > 100 °C warm and hydraulically conductive fractured crystalline bedrock associated to the fault zone. The well penetrates a heavily thrusted and predominantly strongly inclined sedimentary succession in hanging rock blocks along the main fault before entering the fractured crystalline basement at 1946 m, primarily composed of gneiss, granite, and metabasite. This paper represents the first comprehensive description and evaluation of the geological, physical, and hydrological properties of the bedrock at these depths in the Romeleåsen Fault Zone coupled to a geothermal assessment. In addition, the applicability of the four drilling methods used in the crystalline basement section is discussed. The outcome of the DGE-1 well shows significant fracturing in the crystalline bedrock at target depth. The investigations show an average thermal gradient of 22 °C/km, an average heat flow of 58 mW/m2, and an average heat production of 5.8 µW/m3. The values are relatively high in comparison to thermal conditions noted in other deep wells in the Fennoscandian Shield. However, a bottomhole temperature of around 85 °C and insufficient fluid production rate made a commercial geothermal system unviable. Despite this, the experiences from drilling and investigations of the crystalline bedrock at several kilometers depth constitute important proxies for assessing the geothermal potential in similar geological settings and for engineered geothermal systems in the crystalline bedrock of south Sweden.

中文翻译：

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瑞典南部罗密勒森断裂带隆德深层地热勘探项目的评估：案例研究

自1970年代后期以来，瑞典最南端的省斯科讷（Skåne）的基岩便成为了地热可行性研究的目标。2001年，在隆德镇外启动了一个有关Romeleåsen断层带地热潜力的勘探项目。除了对冲断层带进行地球物理成像外，研究还包括钻探和研究3701.8米深的探井DGE-1目的是寻找与断层带相关的> 100°C的热导水力破裂的结晶基岩。该井在沿主要断层悬挂的岩石块中穿透了一个强烈冲断且主要是强烈倾斜的沉积演替，然后才进入1946 m的裂缝性结晶基底，该基底主要由片麻岩，花岗岩和偏辉石组成。本文是对Romeleåsen断层带这些深度的基岩的地质，物理和水文性质的首次综合描述和评估，并结合了地热评估。此外，讨论了在结晶基底部分中使用的四种钻孔方法的适用性。DGE-1井的结果表明，在目标深度处的结晶基岩中有明显的裂缝。研究表明，平均热梯度为22°C / km，平均热流量为58 mW / m2，平均热量产生为5.8 µW / m3。与Fennoscandian Shield的其他深井中记录的热条件相比，该值相对较高。但是，井底温度大约为85°C，而流体生产率不足，使得商业地热系统无法实现。尽管如此，