Physical stratigraphy and tectonic settings of Bolognano Formation (Majella): a potential carbonate reservoir

Excellent continuous exposures of Oligo-Miocene carbonate ramp deposits along the Majella NNW flank (e.g. Orfento and S. Bartolomeo valleys), allow to investigate facies changes both along and across the ramp environment. Relationships among sedimentary structures and depositional processes, among stratigraphic architecture and syn/post-depositional tectonics are investigated and discussed. Moreover, extensive well known bitumen shows, found both along fractured zones and in the rock matrix, are analysed and possible controlling factors are discussed. The main aim of this field trip is to show the geometrical and spatial relationship of the lithostratigraphic units of the Bolognano Formation (Fm) and its structural setting and, secondly, how these elements controlled the migration and trapping of hydrocarbons in this formation. The Bolognano Fm (from fundum Belonianum) is dominated by a heterozoan skeletal carbonates, that were deposited into a wide middle to outer carbonate ramp depositional environment within the oligophotic to aphotic zone, with reworked inner ramp material swept from the shallowest zone and re-deposited into the middle ramp environment. The sedimentological characters of these heterozoan carbonates (dominated by grain supported textures, low percentage of mud and silt fraction, low percentage of aragonite grains) resulted in a combination of petrophysical properties that make them a good potential carbonate reservoir.