The Barents Sea is split by a natural geological border along the midline between Norway and Russia. This border separates a number of enormous gas fields identified on the Russian side from modest discoveries on the Norwegian side.Oil and gas exploration in the Barents Sea has developed slowly due to the costs and political risks involved. Approximately 0.3 billion Sm3 o.e. (standard cubic meters of oil equivalents) of extractable oil have been identified on the Norwegian side mainly as gas, with an estimated 1 billion m3 unidentified.
Unofficial sources indicate that about 8 billion Sm3 o.e. have been discovered on the Russian side.
The seismic surveys in the Russian part of the Barents Sea began in late 1960s. The process that was started consisted of 5 stages:
- until 1973: the first reconnaissance transsections were done in the southern part of Pechora sea shelf
- 1972 -1978: “Sevmorgeologia” conducted research on the entire southern side of the Barents Sea shelf, including Yuzhno-Barents (southern Barents) depression
- 1978-1990s. A number of large and unique deposits of oil, gas and gas condensate were located, primarily in the southern and central parts of the Barents Sea
- started in 1995. Focus on the northern parts of the Barents Sea shelf. The result was a completion of a regional stage of In 1979-1980, three specialised organisations were established in Murmansk – Arktikmorneftegazrazvedka (AMNGR) for exploration drilling and oil production; Sevmorneftegeofizika (SMNG) for seismic research; and Arctic Marine Engineering-Geological expedition (AMIGE) for complex geotechnical investigations
- 2008-2014: the seismic surveys was conducted by the operators: Gazprom and Rosneft on licence areas
- To 2014 on license areas in the Russian part of Barents Sea the 17,315 km of 2D-seismic and 5, 797 square km of 3D-seismic survey works carried out in total.
According to estimations of "VNIIOkeangeologia" to 2014 the total sum of the seismic surveys (state and private) consist of 486,290 linear km in the Russian part of the Barents Sea, which provided the regional (low) network density equal to 0.46 / km2 (Figure 2.5.10). As a result of implementation of seismic surveys and drilling of 55 exploration wells by the state and private companies in the Barents and Pechora seas 11 field deposits were discovered, including 4 oil deposits (Prirazlomnoe, Varandey-sea, sea-Medyn, Dolginskoye), 1 oil and gas deposit (North Gulyaevskaya) 3 condensate deposits (Pomerania, Ice, Shtokman) and 3 gas deposits (North Kilda, Murmansk, Ludlovskoe).
Seismic data acquisition on the Norwegian shelf is divided into several categories: Seismic surveys performed by the authorities, commercial seismic and scientific data gathering. Ever since 1969 the Norwegian authorities have acquired seismic data in unopened areas in the Norwegian Sea and the Barents Sea. The seismic survey that has been done does also include the area around Svalbard. Up until 2001, the purchases of the Norwegian Petroleum Directorate's seismic data sets in the Barents Sea South have been mandatory for companies that wish to acquire other data in the same areas. This requirement has been discontinued in accordance with Storting White Paper No. 39 (1999-2000).
In the period 2007-2009 the Norwegian Petroleum Directorate performed regional 2D and 3D seismic surveys in the area Nordland VII and a limited area in Troms II as a follow up to the integrated management plan. After an agreement between Russia and Norway in 2011 regarding delimitation of neighbouring area in the Barents Sea, the Norwegian Petroleum Directorate performed in the period 2011-2012 regional 2D seismic surveys in the Barents Sea Southeast area. The area was opened for petroleum activity in 2013, and selected blocks are included in the planned 23. Licensing round on the Norwegian continental shelf. Based on a recommendation from the Government, a group of 33 oil companies was established with Statoil as operator, and acquired 3D seismic data in 2014, covering the selected blocks in the Barents Sea Southeast areas (Figure 2.5.10). There is a further differentiation between company-owned seismic, license-owned seismic and marketable seismic. What all these categories have in common is that an exploration permit must be obtained from the Norwegian Petroleum Directorate. These data are being reported to the authorities in accordance with the provisions in Section 10.4 of the Petroleum Act.
The authorities have also issued scientific exploration licences. These licences grant the owner exclusive rights to publish the results. The common map of the seismic surveys in the both parts of Barents Sea is represented on Figure 2.5.10.
Figure 2.5.10. Map reflecting the seismic activity that has been carried out in the Barents Sea before 2014 (source: the Norwegian Petroleum Directorate and “Official report Sevmorgeo for Ministry of Natural Resources and environment "Project of Complex management Plan for Russian part of the Barents Sea", 2015).
Exploration and appraisal wells
There have been petroleum activities in the Norwegian part of the Barents Sea since 1980, and the first discovery, 7120/8-1 Askeladd, was discovered the following year. This discovery is now a part of the Snøhvit field. More than 100 exploration wells have been drilled up to the end of 2014, and 6 main discoveries have been made, Johan Castberg, Wisting, Gotha, Alta and the fields Snøhvit and Goliat. The locations of the 55 exploration wells in Russian part of Barents Sea are presented on Figure 2.5.10a. According the License agreements before 2024 г. it is planed to drill 34 exploration wells.
Currents status of petroleum activities
On the Norwegian part there is one field in production (Snøhvit), and one field will start production during 2015 (Goliat). In addition, one discovery is in the planning phase (Johan Castberg) .
Figure 2.5.11. Map reflecting current status of petroleum activities in the Barents sea (source: the Norwegian Petroleum Directorate and Official report Sevmorgeo for Ministry of Natural Resources "Cadastre of the Russian offshore zone", 2007.
Snøhvit is a gas and condensate field with an underlying thin oil zone. The field is located in the central part of the Hammerfest basin, and is developed with subsea templates with slots for 19 production wells and one CO2 injection well. So far, nine production wells and one CO2 injection well has been completed. Snøhvit was the first development in the Barents Sea, and has no surface installations. The gas is being transported to Melkøya outside Hammer¬fest in a 160 km pipeline. The field came on stream in august 2007.
The reception facilities at Melkøya outside Hammerfest receive the unprocessed well stream from Snøhvit. Gas condensate, water and CO2 are separated before the natural gas is being cooled down to liquid form (LNG) and stored in huge tanks. The gas is transported to the buyers in specially built tankers. CO2 is transported back to the field in a separate pipeline, and is injected in a formation under the producing gas leg.
Goliat is located 50 km southeast of Snøhvit, only 70 km from the coast of Norway, and is a field in the developing phase. The field is developed with a floating production and storage facility with subsea wells. Oil will be processed at the installation and transported by ship. The plan for the associated gas is to inject it into the reservoir for pressure support,. Production of the gas will be evaluated at a later stage. The field will come on stream during 2015. The recoverable resources in Goliat are approximately 28 million Sm3 oil and approx. 7,5 billion Sm3 of gas.
Johan Castberg is located 100 km north of Snøhvit and 210 km from the coast of Norway. Johan Castberg includes three oil discoveries; Skrugard, Havis and Drivis, and is a project in the planning phase. Johan Castberg will be developed with a floating production facility with subsea wells. The recoverable resources in Johan Castberg are in the range 72-105 million Sm³ oil.
Currently, in the waters of the Russian sector the oil production is carried out only at the Prirazlomnoye field with the use the of the same name offshore ice-resistant fixed platform (MISP). According to the press service of JSC "Gazprom", recoverable oil reserves from Prirazlomnoye constitute 71,960,000 tonnes of oil.
20 December 2013 on a platform "Prirazlomnoya" a commercial production of oil has been started. The first batch of Arctic oil ARCO type (Arctic Oil) was shipped on April 18, 2014, and in September 2014 MISP "Prirazlomnaya" produced its 1st million of barrels of oil.
License for exploitation of Prirazlomnoe field owned by "Gazprom Neft Shelf" (subsidiary of JSC "Gazprom Neft"). The platform is designed specifically for field development and provides all the necessary technological operations - drilling, production, storage and shipment of oil tankers, the production of heat and electricity. The uniqueness of the MISP "Prirazlomnaja" that the world's first production of hydrocarbons in the Arctic shelf is conducted from a fixed platform (artificial island) in the difficult conditions of drifting ice floes. The platform is designed to operate in extreme climatic conditions, meets the most stringent safety requirements and is able to withstand the maximum ice loads.
The extracted oil is stored in tanks located in the caisson platform, which three-meters concrete walls covered with a two-layer sheet plated steel, maintain resistance to corrosion and wear out. Caisson can store about 94 thousand tonnes (113 thousand m³). Its margin of safety surpasses actually existing load. The platform is also used "wet" method of storing oil, which prevents ingress of oxygen in tanks and thus prevents the formation of an explosive conditions.
The Russian Arctic shelf biggest hope is the Shtokman gas field in the Barents Sea. This field is located in the central part of the Russian sector of the Barents Sea shelf, about 600 km northeast of the city of Murmansk at local sea depths of 320-340 metres.
For the implementation of Phase I of the Shtokman project in February 2008 the company set up a project-of "Shtokman Development AG" - a joint project of the three leading global corporations: JSC "Gazprom" (51%), Total SA (25%) and Statoil ASA (24%). Terms of cooperation - 25 years from the date of commissioning. Indicative life of the deposit is predicted to be over 50 years.
In 2012 the exit of the underwater of the gas pipeline (length is 550 km and tube diameter - 36 inch) on coast was changed on Opasova Bay.
According to the company "Shtokman Development AG" for the extraction of gas condensate the underwater (bottom) mining complex will be used consisting of 6 paired bottom plates at 4 drill window (each box of 20 wells) each. The average depth of the wells on the trunk of 3388 m. Now, this Project will pass on the future time.
Potential petroleum resources
The proven by Rosnedra for 2012 petroleum resources in the Russian part of the Barents Sea are 33 328,1 mln. tonn oil equivalents (o.e.), including the resources of the Pechora sea - 5 728,1 mln. tonn o.e. The petrolium resources of the Russian part of the Barents Sea consist of 32% resources of the all Russian Arctic.
The proven petroleum resources in the Norwegian part of the Barents Sea as per 2014 are 510 million Sm3 o.e., and of these 34 million o.e. have been produced. There has been an increase in the resource estimate the last year due to new discoveries. The estimate for undiscovered resources in the Norwegian Barents Sea is 1,2 billion Sm3 o.e.
Emission, operational and accidental discharges
Operational discharges to the sea
The main discharges into the sea from the oil and gas activities come from drilling and well operations, and from the production phase. In Russian part of Barents Sea the extraction of the oil on Prirazlomnoe resources conducts with principle “Zero discharge”.
During drilling, two types of drilling waste are created: used drilling fluids and cuttings (solid material from the well bore). The harmfulness of discharging these will depend on the type of drilling fluid used. The drilling fluid consists of water or oil as a base fluid, and different kinds of chemicals. The effects of the discharges of these are evaluated based on their intrinsic properties (potential for accumulation in tissue, bio¬degradation rate and acute toxicity).
Discharges of oil based drilling fluids or cuttings drilled with oil based drilling fluids have been prohibited from Norwegian drilling operations since 1992 due to the proven harmfulness of the mineral oil. Used drilling fluids and cuttings is now injected into the reservoir or brought to shore for proper handling.
Water based drilling fluids contain sea water and additives which normally are not considered harmful to the environment. Discharges of used drilling fluids and cuttings drilled with water based drilling fluids are permitted on most parts of the Norwegian Continental Shelf.
Discharges of cuttings will lead to a certain degree of smothering of the sea bed. This has been shown so far to have very limited effect on the sea bed communities, and the amount of rocks, pebbles, sand and clay deposited is often less than what is deposited as a result of natural movement of solids caused by under water currents along the sea bed. However, special care has to be taken in area with proved or expected occurrence of cold water corals and swamps.
A source of discharge to sea from production phase is produced formation water in connection with oil production, which is water produced from the wells together with the oil, condensate and gas. Since the 2011 revision of the Lofoten – Barents Sea Integrated Management Plan, discharge of produced water has been allowed in the Norwegian part of the Barents Sea on the same conditions as for the rest of the Norwegian Continental Shelf. Produced water contains dispersed oil (small oil droplets), dissolved oil and naturally occurring chemical components like heavy metals (for example lead and chromium) and radionuclides (226Ra and 228Ra) and organic compounds as inter alia carboxylic acids, volatile fatty acids (acetic acid), BTX (benzene, toluene and xylene), phenols, PAH (polyaromatic hydrocarbons) and alkyl phenols.
In the early years of oil production, the amounts of produced water are usually low, but the water/oil ratio will increase over time (a water content of 80 – 95 % is not uncommon from some old fields in the North Sea). In most parts of the Norwegian waters produced water is injected into the formation or discharged into the sea if the content of dispersed oil and the Environmental Impact Factor is sufficient low. Other types of fluids that may occur are drainage water, cooling water, household water and sewage water.
Large amounts of chemicals are used during drilling and production. The chemicals used in production follow the produced water treatment and disposal. The effects of the discharges of these are evaluated based on their intrinsic properties (potential for accumulation in tissue, bio¬degradation rate and acute toxicity) and their contribution to the Environmental Impact Factor.
Emissions to air
Offshore oil and gas activities contribute to air pollution for example by emission of CO2, NOx, non-methane volatile organic compounds (NMVOC), methane, soot/black carbon and SO2. The emissions arise from energy production, gas flaring and from venting (release of unburned gas from pipes and valves in the processes etc during normal operations).
Noise from seismic surveys, drilling and production may have an effect on fish and marine mammals.
During drilling and production activities, there is always a risk of accidental discharges. Most accidental discharges of oil or chemicals are small, and caused by overfilling of tanks, leakages from pipes or transfer lines, loose fittings or couplings and alves that have been left open, . Ruptures of pipelines may occur.
Blowouts are very uncommon, but could result in large amounts of oil released. A blowout may occur if there is a loss of control during exploration drilling due to lack of knowledge of the geology in the area.
Other large technical failures like breakage of pipelines, refilling lines etc may also cause large spills.