Structural restoration and basin modelling of the Central Apennine orogen/foredeep/foreland system: new insights on the regional petroleum system.

Abstract Basin modelling represents an important approach for the prediction of hydrocarbon generation/migration, identifying possible prospects and reducing the risk in exploration areas. This modelling can be also used to study the structural evolution of an area. Main input are the thermal/burial history of the sedimentary basin (key parameters for source rock maturity) and the adopted crustal model. We applied a basin modelling approach to the study of a portion of the Central Apennine orogen (Central Italy), where both thick- vs thin-skin interpretation models were historically proposed, and to the adjoining Central Adriatic foredeep/foreland system, to contribute reducing the tectonic and petroleum system uncertainties of this structurally complex area. We started from the available dataset obtained from the past hydrocarbon exploration activities, that resulted in several small/medium oil discoveries (evidence of an active petroleum system), making a structural review of the different crustal models proposed by the literature. We built two balanced 2D regional sections using MOVE software: one across the off-shore Central Adriatic foreland; and one from the front of the Central Apennine through the Central Adriatic foredeep/foreland system. This last section was modelled testing both a thick and a thin-skin structural scenario, implementing a structural restoration step using Dynel2D software. Using PetroMod2D we then compared the obtained petroleum system results to verify which structural scenario better fit with the present-day known distribution of hydrocarbon occurrences, both on-shore/off-shore. A 3D model was then implemented over key sectors to better understand the main hydrocarbon generation trends. Results suggest the thick-skin model as most suitable to justify the known hydrocarbon occurrences in the area. In addition, modelling indicates a lateral hydrocarbon migration as a key process for known hydrocarbon accumulation, active from the Upper Miocene (in the Central Apennine foredeep) and Upper Pliocene (in the Central Adriatic foreland) to present-day.