Storage and disposal potential of the Triassic Röt Formation in the east of the Netherlands: Subsurface mapping and facies interpretation

Abstract

Salt formations are used and considered for temporary underground storage and permanent disposal of gas, oil, and (radioactive) waste. To ensure safe storage and disposal, geological information of a salt formation is required. Its thickness, geographic distribution, depth and tectonic history must be understood to predict its likelihood to become affected by future geological processes. Geological information about the salt layer of the Triassic Röt Formation is limited and therefore it is unclear if this Main Röt Evaporite Member is suitable for either temporary storage or permanent disposal. Distribution, isopach, and depth maps of the Main Röt Evaporite Member in the subsurface below Enschede using 2D and 3D seismic and well log data are presented. These maps have been evaluated in relation to the tectonic evolution of the area to improve the understanding of the geological development of the unit. The thickness of the Main Röt Evaporite Member in the study area ranges between 10 and 130 m, and the depth of the top is between 300 and 1500 m. This distribution is controlled by Triassic extension and subsequent Cretaceous inversion. The depositional environment of the Main Röt Evaporite Member is a sabkha with salt pans with episodic marine incursions. Due to insufficient thickness, only in a small part of the study area, the member is potentially suitable for storage/disposal. However, based on other storage and disposal concepts, this area is not reliable for storage/disposal of gas, oil, and (radioactive) waste.