An important feature of the Maghrebian and southern Apennine chain is the presence of deep water quartz-sandstones, at the base of the syn-orogenic succession, which represent a proven gas play in Sicily. These sediments, known as Numidian Flysch, derived from North Africa, in early Miocene times, and deposited in the foreland to the fledgling orogenic belt. The Numidian sequences are made of a lower interval of varicoloured or brown clays, a middle interval with mainly quartzarenites and an upper interval with marls and cherts. The geological setting of the Numidian Flysch suggests deposition over a large basin, the external side of which was represented by the relatively undeformed Africa plate margin. Intense Miocene-Pliocene deformation and crustal shortening occurred during the progressive building of the Maghrebian chain, sometimes masking and/or inverting original stratigraphic contacts. The Numidian Flysch is structured into several south-verging structural thrust slices, detached mainly along Oligocene clay detachment surfaces. The deformed and dismembered tracts of Numidian sands form the reservoir with seals provided by the older Numidian basinal clays and deformed Argille Varicolori. However, the tight stacked clastic reservoirs may show different properties. The integration of stratigraphic, structural, petrographic, and petrophysical data (thickness of sedimentary successions and distribution of lithofacies, style and kinematics of deformation, compositional, fabric-related and geotechnical features of lithotypes) with thermal maturity data derived from the inorganic (e.g., fission tracks, X-ray diffraction of clay minerals) and the organic fraction of sediments (e.g., vitrinite reflectance, FTIR spectroscopy) provides quantitative constraints to the reconstruction of the time-space evolution of the burial/exhumation history of the Numidian Flysch units. Additionally, informations obtained from outcrops investigation provide interesting analogues for understanding reservoir heterogeneities, finding useful references for drilling operations and for interpreting well logs.
|Titolo:||Deep water Numidian sandstones in Sicily: a proven gas play|
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||4.2 Abstract in Atti di convegno|