Abstract: South Bulgaria - New Complex Petroleum Basin

MARINOV, EVELIN, Committee of Geology, Bulgaria, SVETLOZAR POPOV and XENIA BENDEREVA

South Bulgaria is considered by the Bulgarian petroleum geologists as a region of low prospective for exploration of oil and gas, due to the wide distribution of volcanic and metamorphic rocks, as well as the numerous thrust systems. In fact, a lot of oil, gas and bituminous shows on the surface and in the wells have been observed. In most cases, the hydrocarbon shows are connected with the front parts of the thrust sheets. The limited number of seismic data, as well as the water and coal drills show that the Triassic and Jurassic deposits, which have proved hydrocarbon potential in North Bulgaria, are also widely developed in South Bulgaria. They have actually been deposited in a big Moesian basin, which explains the facies similarity between the sediment complexes. During the Austrian and Illyrian tectonic phases, the basin's rocks have been folded and thrusted northwards. In the Sredna Gora zone the Triassic - Lower-Cretaceous rocks have been covered by Upper-Cretaceous volcanic rocks, while in the Rhodope massif and the Strandja zone they most probably built-up the autochthonous part of the section, buried under the Proterozoic and Paleozoic metamorphics. Triassic carbonates, Lower Middle-Jurassic terrigenious rocks and Upper-Jurassic - Valanginian carbonate complex has good reservoir characteristics. There are source rocks in Middle - Upper Triassic, Lower-Middle Jurassic, Lower Cretaceous and Upper Eocene. Anticlinal traps are possible in the autochthonous and less possible in the allochthonous part of the section. The Balkan tectonic zone, southeastern part of Sredna Gora zone and the autochthonous part of Kraishtides are considered as prospective regions.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria