South Adriatic – New Plays in Hydrocarbon Exploration
Prospectivity of the area relies on a new seismic grid which was shot in 2011/12 so that the edge of the carbonate platform is covered with a 1219.0 km2 of 3D seismics and the basin itself with 843.0 km of 2D seismics. Southern margin of Adriatic Carbonate Platform which is here a narrow horst dividing South Adriatic Basin and, most likely, Budva Basin, differ from Italian margin. It is aggrading margin which preserved its original growing structure since Triassic till Cretaceous. Draping of late Plio-Pleistocene prograding delta and turbidite fans over the underlying Miocene clastics and pre-existing Mesozoic carbonates produces high relief of large size biogenic gas traps characterized by amplitude anomalies. Main working petroleum system relies on Ladinian-Carnian Burano type paleo-shoreface of sabkhas and hyper-saline lagoons and Early Jurassic horst to graben topography of scattered carbonate platforms and intra-platform basins. Within euxinic basins good source rocks, such as Meride, Riva di Solto, Streppenosa, Emma formations are expected. Beside Burano Formation they are the main source rock for about 90% of the discovered oil accumulations onshore and offshore Italy. The most promising plays are related to carbonate platform margin built-ups along the northern and eastern edge of the South Adriatic Basin, which is time-spanned from Lower Jurassic? to Miocene time. Basin modelling of potential Upper Triassic and Lower Jurassic source rocks defined the oil and gas windows (-4200 m and −6500 m, respectively). Structural maps confirm thermal maturity of possible source rocks for Jurassic and Triassic oil and gas, depending on the depth of burial. Reservoirs, presumed shoals or reefs of aggrading carbonate platform edge and associated slope deposits, display a very good porosity as indicated by attribute analysis. Slope related re-deposited carbonates, conturites and fans are recognized as additional traps of the same play. Very promising play but insufficiently covered with seismics, is a chain of deep basin carbonate structures. Proposed reservoirs are Jurassic and Cretaceous fractured pelagic limestones capable to preserve economic amount of oil and gas. Oligocene and Miocene pinch-out sandstone bodies could be considered as less promising but still interesting play, mainly because of questionable volumetry. Biogenic gas play is also important and amplitude anomalies and AVO analyses indicate the presence of viable resources of gas.
AAPG Datapages/Search and Discovery Article #90194 © 2014 International Conference & Exhibition, Istanbul, Turkey, September 14-17, 2014