MODELOWANIE 3D W GEOLOGII I GÓRNICTWIE SOLNYM 3D modele geologiczne i geochemiczne pokładowego złoża soli kamiennej w rejonie Zatoki Puckiej—możliwości zastosowania w typowaniu najlepszych miejsc pod ługowanie kawern do celów magazynowych

Abstract

3D geological and geochemical models of stratiform salt deposit in the Puck Bay area for selection of best localities for leaching of storage cavernsA b s t r a c t . Geological and geochemical 3D models can be used to image parts of salt deposits with best parameters for cavern leaching. This method was applied for the Oldest Halite (Na1) deposits occurring in the Puck Bay. These deposits are well recognized by more than 100 deep boreholes and the obtained depth data have been used to construct the top and the base surfaces of geological units. Core descriptions and results of chemical analyses of rock salt samples were applied to build a spatial models of distribution of facies as well as individual elements and compounds within the salt body. To have a good control on salt leaching it is important to quantify spatial distribution of NaCl, SO4, KCl and content of clay minerals. The first stage of modeling finalized with image of the depth of salt seam top and its thickness. It allows to eliminate areas which do not match geological-technical requirements such as a maximum depth of salt top and a minimum salt thickness. Depth data were used to interpolate the surfaces using DSI method (Discrete Smooth Interpolation). The top and the base surfaces of salt seam [Na1] and of the two anhydrite layers [A1d and A1g] were created. These surfaces were used to construct the voxel model – in this case it is a 3D irregular grid that can be fit between two boundary layers to model a deposit volume. Horizontal and vertical resolution of 3D model is limited by data density and CPU power. During the second stage the 3D model (voxel) model have been filled with the geochemical data, using the Kriging interpolation method. Five models of distribution of compounds and elements were created. Such models are very useful to compute and select these parts of the salt body which have the best parameters for cavern leaching, that is the maximum content of NaCl and minimum content of KCl, SO4 and clay minerals