Chapter 4 - Lithostratigraphic Framework

Abstract

The chapter describes the lithographic framework of oil and gas producing areas of Azerbaijan. Discovery of commercial oil and gas accumulations, and reserve evaluation require the investigation of both reservoir and caprock properties. This is especially important for young sedimentary basins that are characterized by thick, rapidly accumulated sand, silt, and shale sequences. The main oil and gas bearing formation within eastern Azerbaijan and the South Caspian basin is the Middle Pliocene productive series. The chapter studies the lithology of the productive series from outcrop samples, and cores and logs from deep wells. These deposits are devoid of fauna and, as a consequence, their stratigraphic position is determined by faunal characteristics of the underlying Pontian stage and overlying Akchagylian stage. Subdivision of the productive series is generally based on lithological changes resulting from cyclic deposition. The lower division of the series consists of Kala, Podkirmaku, Kirmaku, Nadkirmaku Sandy, and Nadkirmaku Shaly suites, whereas the upper division consists of Pereryv, Balakhany, Sabunchi, and Surakhany suites. The chapter also describes lithological characteristics of these suites and units.