SOUTH-ORENBURG BAR – NEW EXPLORATION TARGET ОF SOL-ILETSK DOME

Abstract

The relevance of the study is explained by the need to maintain and consolidate the hydrocarbon raw materials base of Orenburg natural gas chemical complex due to depletion of reserves of the main source of raw materials – Orenburg oil-gas condensate field and search for the new lines of hydrocarbon exploration. Lithological features of the section, sedimentary environment, rock dating by faunal remains, reservoir properties, oil-and-gas content indicators, bitumen survey results were considered. Sandstone strata (reservoirs) and loamy-argillous series were identified as caps (impermeable layers). Porous, fractured-porous reservoirs with prevailing poor-porous reservoirs with low matrix permeability. Poor deep-hole prospecting study of a thick deposit section was demonstrated (core definition of the penetrated section is 2%). Drilling and seismic survey results were used to specify the structure of the Ordovician series within Orenburg bar and adjacent territories. Exploration HC deposit targets were identified and their predicted resources were estimated. A new large exploration target with a range of 1,200 m and more than 100 km long was identified as an East-West direction strip to the south of Orenburg bar. The existence of South-Orenburg bar along deposits from Ordovician through to Lower Permian subsalt deposits is assumed. This object with major predicted resources is a new potentially promising line of prospecting in the area of operations of Gazprom Dobycha Orenburg LLC.