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Abstract: The Pelagian Block (Central Mediterranean): Exploration and New Opportunities

Enzo Zappaterra

The Pelagian Block, extending from eastern Tunisia to offshore western Libya and northward to Malta and Sicily, is a complex foreland area structurally active since the Carboniferous, that separates western North Africa from southern Italy.

The north (Sicily) and central parts of the Pelagian Block contain Triassic-Lower Jurassic peritidal carbonates with rare evaporites; Middle Jurassic-Eocene pelagic carbonates; and paralic to marine clastics of Oligocene to Pleistocene age, with Messinian evaporites. The Middle Jurassic/Eocene platform to pelagic carbonates of Sicily are gradually replaced southward by basin margin, marine to paralic carbonates and clastics. In eastern Tunisia, these rocks overlie Triassic-Lower Jurassic evaporites.

Principal petroleum resources occur offshore SE Sicily, offshore Tunisia and in adjacent Libyan waters. The largest oil fields are Bouri (800 MMB recoverable reserves) and Ashtart (recoverable reserves of 250 MMB). The largest gas field is Miskar (recoverable reserves of 800 BCF). Smaller accumulations are distributed throughout the region. New oil discoveries, ranging in size from 8 MMB to 50 MMB, have recently been made onshore and in the shallow offshore.

Proven and potential source beds for hydrocarbons occur in various paleotectonic settings: anoxic lagoons formed in the early continental rifting stages (Triassic/Liassic organic rich units of SE Sicily); subcontinental/paralic coals and shales (Lower Cretaceous of Tunisia); and deeper water anoxic basins (late Mesozoic and Tertiary organic sequences).

Additional exploration opportunities are expected in undrilled or sparsely drilled acreage, with traditional plays similar to those tested in the past; or in new plays directed to the exploration of new reservoir objectives.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France