Evolution Model For The Absheron Mud Volcano: From Stratified Sediments To Fluid Mud Generation

Submarine mud volcanoes (MVs) are one of the most spectacular methane expulsion features at the seafloor and they represent a significant geohazard worldwide. In this work, we focus on the physical processes controlling the initiation and early evolution of the Absheron mud volcano (AMV). Our analyses were carried out based on basin modeling calibrated thanks to existing seismic interpretation of the AMV, analysis of sediment samples from seabed, and data from two exploration wells. Acquired laboratory geotechnical data allowed us to derive laws considering the impact of gas exsolution on host sediment behaviors. In this study, we identified key geological and physical conditions that led to MV formation: by coupling diffusion processes with hydrofracturing and fluid advection, we were able to simulate the conditions required to generate mud 3.5 km below the AMV. Mud remobilization up to the seabed was reproduced by using Navier-Stokes equations modified to account for the impact of gas expansion on mud density. Considering density inversion only, simulations indicate that mud would be extruded at the seabed 100 years after its generation, an ascent rate similar to extrusion rates measured at the active Kotyrdag MV in Azerbaijan.