Mud volcanoes are abundant geological phenomena in the southern Caspian Basin related to very high subsidence and sedimentation rates. In Azerbaijan more than 200 mud volcanoes were mapped onshore. In the surrounding of the mud volcanoes ascending hydrocarbon rich fluids and gases affect groundwater and soil quality. Hydrocarbon systems are closely related to mud volcano fluid systems and fluids mainly consist of methane. The aim of our project is to map micro-seepage and draw conclusions about migration pathways of gas in the wider area of mud volcanism, as well as to evaluate the environmental influence of these seepages. Therefore, we couple Structure from Motion with methane measurements and soil and groundwater analysis and integrate all the data in a subsurface model.
We couple a hexacopter with a methane gas sniffer based on laser detection and map the area around mud volcanoes, where micro-seepage occurs along fractures often related to regional anticline systems. In a first field campaign we test this innovative method on selected mud volcanoes from different regions in Azerbaijan. Simultaneously we conduct photogrammetry of the area around mud volcanoes to image fracture systems and support the results from methane measurements. ... mehrIn addition to mapping fractures and related microseepage of methane by aerial photogrammetry on the ground around mud volcanoes, we study outcrops in order to understand the petrophysical characteristics of the lithologies related to fluid migration.
First tests of our new workflow were promising. Calibration measurements show concentrations of down to 10ppm x m for background noise of methane in the air and measurement limit of the laser detector. Errors can occur due to low or high reflection intensity of the laser beam, e.g. caused by sunlight or strongly reflecting surfaces. Other factors influencing the measurement are mostly caused by wind and air pressure conditions, which are continuously recorded during measurement. Data evaluation of a first field work campaign in different test areas in Azerbaijan will show us how to improve the workflow for future measurements.