ANALYSIS OF FAULT-RELATED FLUID FLOW IN NATURAL CO2 RESERVOIRS USING UAV TECHNOLOGY, SALT WASH GRABEN, SOUTHERN UT

The use of Unmanned Aerial Vehicles (UAVs) in geoscience research allows for rapid and extensive data collection, such as the acquisition of high resolution imagery that is beneficial when studying structurally complex regions. The Salt Wash Graben in southern Utah is an exhumed paleo-reservoir-top seal system exhibiting evidence of past and current flow of CO₂-charged fluids. To test hypotheses that the Salt Wash fault impacted deep fluid-gas flow in the area, we employed a DJI Mavic 2 Pro quadcopter to collect high-resolution aerial imagery that was processed using Pix4Dmapper software. Three-dimensional models and orthomosaics were rendered to aid in larger-scale visualization and delineation of structural features. These visualization tools are coupled with field-based observations to investigate the relationships between fault zone architecture and evidence of fluid flow in the region.

Large carbonate veins, ancient travertine mounds, active CO₂-charged springs, and regions of bleached sandstone–all products of CO₂-rich fluid flow–were mapped in detail. These features are spatially linked to fault geometries and our 3D model allows us to examine relationships between flow indicators, carbonate vein networks, and fault and fracture systems. Lateral vein connections across Salt Wash were used to quantify the extent of fluid flow, travertine deposition, and vein emplacement. Our imagery and 3D models tentatively support our hypothesis that the Salt Wash fault zone served as a conduit for CO₂-charged fluid flow into the higher structural level sandstone reservoir.

Future work includes coupling our imagery and models with geochemical data and petrographic observations to complete a more comprehensive structural analysis of the area and further test our hypothesis. In addition to rapid data acquisition and processing, implementing UAV methods provides geoscientists with the opportunity to safely access and view inaccessible locations. By making these sites more accessible, structural relationships can be examined in greater detail from a better perspective, potentially strengthening and expanding geologic interpretations.