Quantifying occurrence of deformation bands in sandstone as a function of structural and petrophysical factors and their impact on reservoir quality: an example from outcrop analog of Productive Series (Pliocene), South Caspian Basin

Abstract Deformation bands (DB) are known to influence porosity and permeability in sandstones. This study aims predict the occurrence of DB quantify their impact on reservoir properties based field measurements steeply dipping limb a kilometer-scale fold Yasamal Valley, western South Caspian Basin. An integrated approach characterizing effect included natural gamma radioactivity using portable tools, along with bed dip count across distinct facies. A set core analyses was performed outcrop plugs without estimate alteration rock at pore scale. Interpretation gamma-ray data indicates absence Balakhany sandstones containing shale volume greater than 18% for unconsolidated 32% calcite-rich high amount calcite cement appears increase number DB. poor, positive trend between concentration identified. We show that net gross, defined as thickness fraction sandstone bound by mudstones, is among parameters controlling bands. Samples single 33% 3% decrease porosity, respectively, relative host rock. reveal new lithological petrophysical factors influencing occurrence. offers direct tool can be applied subsurface analogs properties.