Reserve replacement by region
Rosneft’s reserve growth in Western Siberia amounted to 269.9 mmt of oil and gas condensate and 65 bcm of gas. 33 exploration wells were completed and tested with a success rate of 88%. 3D seismic surveys totalled 2.1 thousand sq km. One field and 62 new deposits were discovered with a total of 71 mmtoe in АВ1С1+В2С2 reserves.
RN-Uvatneftegaz is consistently implementing the strategy to develop the Uvat project, including by ensuring the annual growth rate target for recoverable reserves. In the reporting period, significantly more oil reserves were discovered than extracted. In 2020, the increase in RN-Uvatneftegaz’s АВ1С1 reserves (12.5 mmt) exceeded production (9.2 mmt) by 136%. The drilling of Linveskaya well No. 324P revealed three new deposits of the Pikhtovoye field with 9,5 mmt of potentially recoverable reserves. The drilling of Vostochno-Pikhtovaya well No. 324P revealed a prospective field with two new deposits and 3,5 mmt of potentially recoverable reserves.
In 2020, RN-Purneftegaz discovered ten new deposits at the Yuzhno-Tarasovskoye, Barsukovskoye, Verkhnepurpeyskoye, and Novopurpeyskoye fields with total reserves of 5.7 mmtoe.
At RN-Vankor, a successful exploration programme aimed at growing Vostok Oil’s resource base led to the discovery of Novoognennoye field containing more than 20 mmt of oil and about 1 bcm of gas. Oil was discovered in the Lower Cretaceous deposits north of the Messoyakhsky ridge, changing the Company’s view of the possible nature of the prospective targets’ saturation.
At its Western Siberian gas assets, Rosneft’s reserve increases in 2020 amounted to 7,2 mmt of oil and condensate and 27.6 bcm of gas.
The Company continued to study the unconventional gas-saturated reservoir of the Berezovskaya suite in Western Siberia. In 2020, Rosneft filed for a patent for its method of localising hydrocarbon reserves in siliceous upper cretaceous deposits. The invention helps assess hydrocarbon reserves in the sedimentary rocks’ siliceous deposits through exploration. The proposed method consists of determining the zonation of silica distribution in the Berezovskaya suite and similar structures.
In 2020, Rosneft studied the permeability and porosity properties of reservoir rocks of the Kharampurskoye field's Turonian deposit using the new Digital Core technology. The studies were carried out by Schlumberger’s Moscow-based laboratory and involved experts from BP Plc. Comparative analysis of the results is underway.
As part of the Gydan Peninsula study in 2020, the interpretation of 3D seismic surveys of the Minkhovskiy licence area confirmed the field potential and verified the location of exploration wells. In 2020, Rosneft drilled and completed well No. 70, the first exploration well of the Minkhovsky licence area. Following extensive Geological Information System and MDT drilling, ten prospective fields are ready for testing, including five that have not been previously recorded on the balance of Russia’s hydrocarbon raw materials. The testing of well No. 70 included the first use of Jet Pump technology on a gas field – previously it had been used only for oil fields. The use of jet pumps accelerates the development of deposits with low permeability and porosity through creating a stronger drawdown within a shorter timeframe, clears the bottom-hole zone from killing fluid and drilling mud, as well as closes the well at the bottom for a faster transition to radial pressure build-up unaffected by the wellbore. The Company is looking into ways to cascade the experience to its other projects.
A new gas cluster will be created based on the Minkhovskoye field.
In 2020, total reserves growth in Eastern Siberia and the Far East was 56 mmt of oil and gas condensate and 38 bcm of gas. 12 exploration wells were completed and tested with a success rate of 92%. 2D seismic surveys of 42 linear km and 3D seismic surveys of 634 thousand sq km. Four fields and 16 new deposits discovered with a total of 811 mmtoe of АВ1С1+В2С2 reserves.
As part of the Vostok Oil project, a unique Zapadno-Irkinskoye field was discovered on the Taimyr Peninsula, with more than 600 mmtoe of C1+C2 reserves.
The Srednebotuobinskoye field had a successful exploration year: a highly promising block identified with a new integrated seismic and geological model was not only confirmed by the drilling of exploration well No. 117 but also turned out to have a record oil-saturated thickness of the Botuobinskoye formation (16.6 m). Rosneft plans to drill another exploration well No. 118 and 38 production wells at the new block. The drilling of well No. 117Р helped to identify new drilling prospects at the field. Production drilling has already confirmed oil deposits in other eastern blocks of the Srednebotuobinskoye field. The drilling revealed gas in the carbonate deposits of the Yuryakhsky horizon, the prospects of which were previously associated only with deposits above the basement protrusions.
The first well within the Predpatomsk foredeep led to a major discovery – the testing of the Vendian terrigenous deposits in Nizhnedzherbinskaya well No. 1 identified a new large gas condensate field named after Ivan Kulbertinov with reserves of more than 75 bcm of gas and 1.4 mmt of gas condensate.
Drilling of Danilovskaya well No. 85 confirmed the industrial oil and gas bearing potential of the Ust-Kutsky horizon outside the zone of the basement protrusions for the first time, which will drive further exploration in the Irkutsk Region. The oil flow rate exceeded 500 cub m per day.
The drilling of Preobrazhenskaya appraisal well No. 14 to the south-east of the Lisovsky field within the reefal buildups confirmed the industrial oil and gas bearing potential of the Early Cambrian intersalt formation. The well once again confirmed the extremely high productivity of the Early Cambrian reefal buildup of the Osinsky horizon: the tests recorded an oil flow of 362 cub m per day.
We continued to drill additional sidetracks to increase the exploration drilling success rate, further study the target reservoirs, and search for new prospects.
In 2020, reserves in the Volga-Urals Region, Timan-Pechora, and Southern Russia increased by a total of 61.9 mmt of oil and gas condensate and 5 bcm of gas. 65 wells were completed and tested, with a success rate of 82%. 3D seismic surveys totalled 1.8 thousand sq. km, while 2D seismic surveys totalled 0.9 thousand linear km. Twelve fields and 130 new deposits were discovered with a total of 24 mmtoe in АВ1С1+В2С2 reserves.
In the Orenburg and Samara regions, the Company continued exploration of Domanic deposits for siliceous limestones. The Company is now planning a pilot development programme to develop a conclusion on the commercial potential of these deposits in the licence areas in the Samara Region. In 2020, Orenburgneft began appraisal drilling in the Kutuluk subsoil area in order to assess the commercial prospects of domanikoid strata within the Orenburg Region. In 2020, Samaraneftegaz's geologists performed the search for missed deposits and exploratory drilling, discovering 29 new deposits and two new fields with a 6.7 mmtoe increase in recoverable AB1C1 + B2C2 reserves.