Gazprom Neft increases reserves estimates at the Chonsky group of fields

Gazprom Neft has discovered new hydrocarbon reserves at the Ignyalinsky licence block, located in the Irkutsk Oblast. Reserves estimates are expected to increase by more than 19 million tonnes of oil — almost 10 percent of total recoverable reserves at the Chonsky group of fields.

Drilling of a prospecting well at the Ignyalinsky licence block by Gazprom Neft subsidiary Gazpromneft-Geo has revealed four new deposits, with reservoir testing delivering a natural well flow of over 40 tonnes per day, confirming the commercial viability of this discovery.

Taking these new reserves into account, recoverable reserves could reach 19.4 million tonnes of oil — the typical size of a standalone, average-sized field. Total recoverable liquid hydrocarbon reserves at the Chonsky project now stand at more than 213 million tonnes of oil — 67,8 million of these being at the Ignyalinsky block.

The viable development of the Chonsky group of fields is complicated by their anomalous geological structure and the wide occurrence (bedding) of hydrocarbons. A seismic and geological model of the Ignyalinskoye-field strata was used to determine the location of the exploration and appraisal well. Developing this model involved interpreting a large volume of information on the structure of the block, including the results of 75 drilled wells and 3D seismic data, as well as construction of 3D terrigenous-strata models, with Gazprom Neft specialists, together with the company’s technology partner, Schlumberger, developing a detailed velocity—depth model of this asset, taking the specific features and historic technological development of this oil-bearing region into account. These digital products have made it possible to identify key oil-bearing zones at blocks under development.

Gazprom Neft plans to drill pilot-testing wells at the Ignyalinsky block in 2020, and a further eight exploration and appraisal wells by 2022.

“Eastern Siberia is one of Gazprom Neft’s strategic development zones: and the development of the Chonsky fields, where reserves in place exceed a billion tonnes of oil, is a key project for the company in this region. The volume of geological information accumulated over recent years has allowed us to formulate a holistic view of these areas, and we plan to begin pilot development of these as soon as 2021.”
Vadim Yakovlev
Vadim Yakovlev Deputy CEO for Upstream, Gazprom Neft
Notes for editors

* Gazprom Neft’s Chonsky project involves developing the Ignyalinsky, Tympuchikansky and Vakunaysky licence blocks, located on the border between the Irkutsk Region and the Republic of Sakha (Yakutia). The Chonsky-field licence blocks lie some 100 kkilometres away from the Eastern Siberia—Pacific Ocean (ESPO) oil pipeline. The fields included in the Chonsky project have total booked reserves of over one billion tonnes of oil, and some 300 billion cubic metres of natural gas.

The Ignyalinsky oil and gas condensate field, located in the license block of the same name in the Katangsky District of the Irkutsk Oblast, is being developed as part of implementing the Chonsky project.

The total area of the Ignyalinsky licence block is 2,153 square kilometres. The field’s recoverable C1+C2 reserves are estimated at 67.8 million tonnes of oil and 45.4 billion cubic metres of natural gas. The first batch of oil from the Ignyalinsky licence block was shipped to the ESPO in February 2018. The field is expected to go into full-scale production in 2024. The first horizontal well was drilled at the Ignyalinskoye field in 2018, with commercial inflow secured after multi-stage fracking.

Active geological prospecting works were initiated throughout the Chonsky project six 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.