Lithofacial aspects of oil and gas forecast in non-anticlinal traps of the Kura river basin

The Kura depression is a part of the South Caspian mega-depression located in the central segment of the Alpine-Himalayan orogeny. The study areas consist mainly of the Lower Kura, filled with Paleogene-Pliocene sediments, and the Yevlakh-Aghjabedi sedimentary basins, filled with Mesozoic, Paleogene-Miocene sediments. To enable prospecting and study of non-anticlinal traps in the Kura basin, seismostratigraphic and structural formation methods are used. By the help of these methods the pinch-out zones of separate horizons of Meso-Cenozoic sediments with favorable geological conditions were discovered. As a result of the conducted research, the lithological composition, stratigraphic age and prospects of exploiting the sediments forming these traps were studied. Thus, for identification of oil and gas deposits on the north-eastern and south-western slopes of the Yevlakh-Aghjabedi depression, non-anticlinal traps formed by pinching out of Eocene and Maykop sediments were studied. At the same time, for finding of oil and gas deposits mainly formed by pinching out of Productive Series sediments, the north-western part of the Lower Kura depression was also studied. In order to predict the oil and gas potential of non-anticlinal traps in the study areas, actual data on the presumed area of non-anticlinal traps determined by geological and geophysical indicators were studied. In addition, the thickness of prospective lithological-stratigraphic-facial complexes, the thickness of impermeable nappes, and the reservoir properties of rocks participating in the sedimentary section of the study areas were analyzed. The wide variation in the area of non-anticlinal traps, the thickness of prospective sediments and nappes forming them in the Yevlakh-Aghjabedi and Lower Kura depressions afford grounds for a favorable assessment of the oil and gas prospects of the area. In the section of Meso-Cenozoic sediments forming non-anticlinal traps in the Lower Kura and Yevlakh-Aghjabedi depressions there are sandy-silty, and terrigenous-carbonate and volcanogenic oil-and-gas-bearing reservoirs with high poroperm.