South Adriatic, Croatia, in Wider Adriatic and Mediterranean Context, Hydrocarbon Plays and Analogies

Vlasta Tari-Kovačić

The Deep Adriatic implies the area where the water depth exceeds 300 m and in Croatian offshore it is the part of the South Adriatic Basin (SAB) between sea boundaries with Montenegro and Italy. Since the exploration of the Adriatic Carbonate Platform (ACP) structures has not been successful so far, attention is focused on deep water plays. A new seismic grid was shot in 2011/12 covering the carbonate platform margin with a 1215 km2 of 3D seismic and the basin plane with 843 km of 2D seismic. Defined new plays are:

Play 1- northern edge of the SAB, time-spanned from Jurassic to recent time is defined by the slope of the ACP. Basin modelling of potential source rocks defined the oil and gas windows at the depth of -4200 m and -6500 m, respectively. The basin and the corresponding edge of the carbonate platform are generally not affected by Tertiary compressions providing a relatively simple up-dip and/or lateral migration paths into the slope and platform edge reservoirs after the formation the Neogene clastic cover.

Play 2- pelagic carbonates of SAP where four way dip closures can be expected on top of carbonates as per analogy with Italian Rovesti and Aquila oil discoveries.

Play 3- biogenic gas in stratigraphic and structural traps within Neogene clastic reservoirs in the SAB differs from the Po River affiliated gas fields of the northern Adriatic. In SAB the origin of Plio-Pleistocene clastics is related to erosion of post-Miocene uplifted Dinarides and clastic material is transported into the basin across the narrow coastal shelf so that the possibility of finding economic reserves of biogenic gas is higher in distal turbidite fans. Miocene and Oligocene clastics display a very promising play, as well.

So far processed new seismic lines confirm the prediction about efficiency of plays and confirm the presence of oil and gas leads.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013