The North German Basin is one of the three major type localities in Germany for deep geothermal energy. Here, the pore space is the dominant parameter, in contrast to fractures (Rhine Graben) and karst (Molasse Basin). To further develop the geothermal research platform Groß Schönebeck located in the Northeast German Basin, a subset of the North German Basin, we investigated the geological structure and the existence of possible fault systems in the subsurface. For this purpose, we carried out a high-resolution 3-D reflection seismic survey at the location to overcome methodical restrictions of the few 2-D seismic profiles that cross the area of interest, such as spatial focusing effects and fault imaging. The survey area extends 8 km × 8 km at the surface and focusses down to reservoir depths at 4 km. With four vibrators as source (12–96 Hz sweep, 12 s duration), we used a source line spacing of 700 m and a receiver line spacing of 400 m with both 50 m source and geophone spacing. Data processing encompassed CRS (Common Reflection Surface) stacking, post-stack time migration and depth conversion. We observed a smooth doming of the Zechstein salt from 0.6 to 1 km thickness above the continuous top of the Rotliegend Group at around 4 km depth, and the Mesozoic horizons above appear as mainly continuous reflection surfaces with gentle undulations and occasional normal faulting. We highly resolved the supra-salt sequences in the study area for the first time, which allowed us image an almost complete suite of reflectors mapped in other parts of the Northeast German Basin. However, less resolved, lower frequency images are encountered deeper than ~ 4 km. Two important factors for further field development are that we do not observe an apparent influence of crustal-scale faults, which were expected from former conceptual models for the region, and that at the current status of work, the reservoir does not show a fracture-dominated character.

中文翻译：

---

横跨德国柏林北部深层地热研究平台GroßSchönebeck的3-D地震勘探

北德盆地是德国深层地热能的三大类型地区之一。与裂缝（Rhine Graben）和喀斯特（Molasse盆地）相比，孔隙空间是主要参数。为了进一步开发位于德国东北盆地（北德国盆地的一个子集）的GroßSchönebeck地热研究平台，我们调查了地下的地质结构和可能的断层系统。为此，我们在该地点进行了高分辨率的3-D反射地震勘测，以克服跨越感兴趣区域的少数2-D地震剖面的方法性限制，例如空间聚焦效应和断层成像。勘测区域在地面延伸8 km×8 km，并集中到4 km的水库深度。使用四个振动器作为源（12–96 Hz扫描，12 s的持续时间），我们使用了700 m的源线间隔和400 m的接收线间隔，同时使用了50 m的源和检波器间隔。数据处理包括CRS（公共反射面）堆叠，堆叠后时间迁移和深度转换。我们在4 km深度处的Rotliegend组连续顶部上方0.6到1 km厚度处观察到Zechstein盐的平滑隆起，而上面的中生界地层似乎主要是连续的反射面，具有轻微的起伏和偶然的正断层。我们首次对研究区内的超盐序列进行了高度解析，这使我们能够成像位于德国东北盆地其他地区的几乎完整的反射器组。但是，遇到的分辨率较低，频率较低的图像比〜4 km更深。