Marine Circular Electric Dipole (MCED): A new innovative electromagnetic technique for the exploration of submarine groundwater resources

最近进行的海洋电磁测量划定了以色列南部沿海平原近海深层次海底含水层内30公里长、至少3公里宽的淡水水体。 结果允许未开采的淡水估计。然而，由于所应用的地球物理方法的分辨率较低，结果不足以充分了解控制该发现的水文地质结构和机制。特别是淡水水体的横向几何形状，水文地质建模的重要性，无法解决。如果没有这样的认识，就不可能合理地管理这一未开发的地下水库。本项目的目的是通过在世界范围内首次实施基于圆形电偶极子（CED）在海洋环境中应用的高分辨率电磁法来回答淡水地下水体的水文地质边界条件。除了发射天线的开发外，该项目的主要重点将是为这种新的电磁技术开发解释方案（例如一维反演和二维/三维正演模拟）。根据地球物理研究的结果，可以为今后使用这一地下水资源制定一项管理计划，这项研究将增加以色列淡水资源的潜力，并开发一种新的高分辨率海洋电磁技术，这种技术不仅可以在全世界应用于海底地下水，而且可以应用于碳氢化合物和天然气水合物勘探。利用合成数据进行的理论模型研究表明，与使用直列/宽边配置的常规海洋长偏移距电磁（LOTEM）技术相比，MCED技术对电阻性地下水层具有更好的横向分辨率

Recent marine electromagnetic measurements yielded the delineation of a 30 km long and at least 3 km wide fresh groundwater body within the deep-seated sub-seafloor aquifer offshore the southern coastal plain of Israel. The results allowed an estimation of unexploited fresh groundwater. However, due to the low resolution of the applied geophysical methods, the results turned out insufficient in order to fully understand the hydrogeological configuration and mechanism controlling the occurrence of this discovery. Especially the lateral geometry of the freshwater body, important for the hydrogeological modeling, could not be resolved. Without such an understanding, a rational management of this unexploited groundwater reservoir is impossible.The proposed project aims at answering the hydrogeological boundary conditions of the fresh groundwater body by implementing for the first time worldwide a high-resolution electromagnetic method based on the application of a Circular Electric Dipole (CED) in the marine environment regarding groundwater studies. In addition to the development of the transmitter antenna, the development of an interpretation scheme (e.g. 1D inversion and 2D/3D forward modeling) for this novel electromagnetic technique will be the main focus of the project. Based on the results of the geophysical study, a management scheme for future usage of this groundwater resource can be developed.The research will result in an increased potential of fresh groundwater resources in Israel and in the development of a new high-resolution marine electromagnetic technology, which can be applied worldwide not only for submarine groundwater but also for hydrocarbon and gas-hydrate exploration. Theoretical model studies with synthetic data have shown that the MCED technique has a better lateral resolution of the resistive groundwater layer compared to the conventional marine Long Offset Electromagnetic (LOTEM) technique using the inline/broadside configuration