Integrating Petrophysical, Geological and Geomechanical Modelling to Assess Stress States, Overpressure Development and Compartmentalisation Adjacent to a Salt Wall, Gulf of Mexico [dataset]

High pore fluid pressures exert a major influence on important geological processes such as subsidence, slope failure, faulting and folding. A quantitative understanding of pore fluid pressure also underpins the safe design of wellbore drilling operations, as well as the injection rates and maximum volume of subsurface storage of CO2 and H2 since resulting high pore pressures can lead to fracturing of the overburden. Here, hydro-mechanical forward models are used to understand the development and distribution of very high and spatially variable fluid pressures in channel sands within the Magnolia Field, which is located close to a salt dome on the continental slope of the Gulf of Mexico. Whilst the main contributor to high fluid pressures is loading due to the high rate of deposition of mud-rich sediments, tectonic loading related to salt dome movement contributes around seven percent of the observed overpressure. The models also show that linked to the high sedimentation rates, small variations in the permeability and connectivity of the mud-rich sections that bound channel sands result in highly compartmentalised pressure distributions in adjacent sand bodies; these are very hard to predict prior to drilling.