As a result of geological prospecting operations undertaken in 2015, Gazprom Neft has increased estimates of C1 commercial reserves at its East Siberian fields (the Ignyalinsky, Tympuchikansky and Vakunaisky fields, collectively the “Chonsky Project”) by 48 percent. This increase in recoverable C1 oil reserves amounts to 6.9 million tonnes. Recoverable (C1) gas reserves are increased by 22.3 billion cubic metres (an increase of 64 percent). The outcomes of these most recent estimates have been successfully confirmed by the State Commission for Mineral Reserves.
The Ignyalinsky, Tympuchikansky and Vakunaisky fields are located on the border between the Irkutsk Oblast and the Sakha Republic (Yakutia). Specialists from Gazpromneft-Angara (a subsidiary of Gazprom Neft) continued analysis of seismic data (based on innovative UniQ technology) throughout 2015. This high-density and high-frequency seismic data — 16 times more informative than that obtained under typical seismic operations — has allowed the structure to be detailed in full (including the bedding of the strata, and its geomorphological characteristics), as well as allowing the geological model of the field to be further fine-tuned.
Active geological prospecting operations throughout the Chonsky project were initiated three years ago. During this time 13 prospecting, evaluation and exploration wells have been drilled, across all three fields. 3D seismic operations (in the order of 2,600 square kilometres, including 1,550 square kilometres of UniQ high-density seismic and electro-prospecting works totalling approximately 13,000 kilometres) have been undertaken, making these the most extensive operations not just in Eastern Siberia but also the world, thanks to the record number of electromagnetic field transmitters and signal receptors utilised. Six hundred square kilometres of UniQ high-density seismic, as well as 300 square kilometres of 3D seismic investigations, were undertaken in 2015, and four exploration wells drilled — one each at the Vakunaisky and Ignyalinsky fields, and two at the Tympuchikansky field.
The Chonsky-group licence blocks are located 100 kilometres from the East Siberia—Pacific Ocean (ESPO) pipeline. Licenses for the development of the Tympuchikansky, Vakunaisky and Ignyalinsky blocks are held by Gazprom Neft subsidiary Gazpromneft-Angara.
This increase in reserves at the Chonsky-group fields has been made possible thanks to exploratory drilling, the re-testing of previously drilled wells, and the interpretation of geological and geophysical data, including data obtained through 3D seismic operations and geo-electric prospecting.