Hydrocarbon Potential of Deeply Buried Reservoirs in the Astrakhan Oil and Gas Accumulation Zone: Problems and Solutions

Abstract

Global experience in oil exploration and the discovery of the Tupi field in Brazil and the Tiber field in the Gulf of Mexico in the last decade have confirmed the existence of giant oil fields with abnormally high formation pressures at depths of 10 km or greater. Until recently, the discovery of large oil accumulations in deeply buried reservoirs was considered as theoretically impossible. This work suggests that giant oil accumulations at great depths (6–10 km) should be considered important hydrocarbon exploration targets in the Russian Federation and the Eurasian Union. The first-priority oil and gas exploration targets at great depths are deeply buried horizons of the sedimentary cover of the Precaspian basin, whose subsalt hydraulic system is characterized by ubiquitous abnormally high formation pressures. The deeply buried reservoirs in the Astrakhan oil and gas accumulation zone are considered the most promising for the discovery of giant oil accumulations. Data discussed below demonstrate that hydrocarbon exploration and the discovery of giant oil accumulations at great depths require specific exploration procedures and techniques.