American Shale and Russian Bazhenov Formation: Similarities and Differences

By Elena Zhuk, November 16, 2012

Against the backdrop of increased oil production in the USA, to a considerable degree resulting from the breakthrough in shale oil recovery, Russian oil companies turned their eyes on oil resources of the Bazhenov formation in West Siberia as a potential source for sustaining the declining level of oil production in the region.

However, American shales and the Russian Bazhenov formation are not one and the same thing.  Varvara Nemova, senior research associate of the company Modelirovaniye E Monitoring Geologicheskikh Obyektov (Simulation and Monitoring of Geological Features), told OGE about similarities and differences in the structure and properties of the Bazhenov formation and strata containing shale oil being developed now in North America.

“The similarity of these formations is that they both have source rock properties; they are composed by a material of mostly pelitic grain size (up to 0.005 mm); containing abnormally high amounts of organic matter, and these dense beds are reservoirs in these formations”,- noted Nemova.

According to Nemova’s opinion, their main difference is reservoir thickness and their position in the section. “Thus, in the Bakken formation (USA), a reservoir more than 40 meters thick is located between the thinly laminated rocks rich in organic matter. Whereas in the Bazhenov formation reservoir beds 0.5-3 meters thick are located at several stratigraphic levels segregated by fine-laminated formation members rich in organic matter, these members being 3-8 meters thick. Thus, reservoirs in the Bazhenov formation are confined to the thin discrete layers along the section”, - she commented.

The specialist believes that the technologies for shale oil field development could be efficiently used for oil production from the Bazhenov formation pools only after these technologies are adapted to isolated reservoirs scattered along the Bazhenov formation section.

Nemova’s presentation on the structure, properties and techniques for laboratory studies of the Bazhenov formation, made last Tuesday at the seminar of SPE Moscow section, aroused great interest among the attendees.  In her presentation, Nemova focused on the work done by her company on core sampling from argillaceous-siliceous deposits of the Bazhenov formation and analysis of these core samples, which enabled them to receive fundamentally new information on reservoir structure in this formation.

You will be able to read detailed information on the results of these studies in the article of Varvara Nemova in the next issue of OGE.