The Prirazlomnoye project
The development of the Prirazlomnoye field marks the first oil production project on the Russian Arctic Shelf.
Offshore regions (the continental shelf) — and the Arctic Shelf, in particular — are among the most difficult areas of all to develop: which is why meaningful prospecting was not initiated at Prirazlomnoye until the late 1970s. The Prirazlomnoye field, in the Pechora Sea, was discovered in 1977 and made ready for deep-hole prospecting (deep drilling) over the following 10 years. Specialists from Arktikmorneftegazrazvedka, engaged in exploratory drilling, confirmed the presence of economically recoverable oil reserves here in 1989, and a geological model of the Prirazlomnoye field was put together in 1991.
Manufacturing group Sevmash (Severodvinsk), constructed a special ice-resistant offshore stationary platform (rig) that would allow the field to be developed, which was delivered to the Pechora Sea in 2011 for installation 60 metres from the shore. Oil production at Prirazlomnoye commenced in December 2013 through Gazprom Neft subsidiary Gazprom Neft Shelf, and the first consignment of “ARCO” Arctic oil was on its way to European consumers within five months, in April 2014.
Prirazlomnoye is the only field being developed under the freezing sea conditions of the Arctic. Ice cover here remains in place for seven months, with ice ridges reaching two metres high. The Prirazlomnaya platform, designed specifically for this project, is specially adapted to operate in these conditions, and to withstand maximum ice loads. The platform is equipped to cover all technological operations, including well drilling, production, processing, storage, the offloading of oil to tankers, and heat and power generation.
The platform’s residential module is designed to accommodate up to 200 people, all year round. Due to the depth of the sea (19.2 metres), the facility — at 126 square metres the size of two football fields, and weighing 500,000 tons — has been installed directly onto the seabed and reinforced with a protective 45,000 cubic-metre-plus stone berm (weighing 120,000 tonnes) ensuring the well cluster has no direct contact with the water.
All wells in operation on the platform are horizontal wells. A total 32 wells are expected to be drilled by 2023 — 19 production wells, 12 injection wells, and one absorption well. Eleven directional wells will run to depths of more than 6,000 metres, with horizontal sections of up to 1,000 metres and horizontal displacement of up to 4,000 metres.
The risk of an oil blow-out during drilling or well operations has been minimised through the installation of a two-tier protection system — an emergency shutdown valve (ESDV), together with a back-up hydraulic valve forming part of the wellhead equipment. This unique piece of equipment was specially developed for the conditions of the Prirazlomnoye oilfield, in line with the specific characteristics and operational requirements for working in this region.
Storage and Offloading
Tanks for storing the crude produced are located in the bottom of the platform — the “caisson”. For greater protection against corrosion and wear, its walls comprise a four-centimetre layer of clad steel, with the three-metre space between the walls being filled with heavy-duty concrete.
Any risk of explosion is eliminated through the use of “wet-sump” storage, preventing oxygen ingress into the storage tank. The ballast water used in wet-sump storage ensures a constant pressure is maintained within the oil storage tank, thus ensuring not only that the tank is filled to
Offloading of oil from the platform’s storage facilities onto tankers is undertaken with the use of two direct offloading systems. In order to prevent any spills during pumping and offloading operations the offloading line is equipped with an emergency shutdown system, with a maximum seven-second response time.
Prior to commencing offloading operations, shuttle tankers, equipped with bow-loading systems, undertake non-contact docking. A dynamic positioning system means tankers can be held in place regardless of wind or waves.
In order to ensure full environmental safety, specialist icebreaking vessels, equipped with cutting-edge oil-spill response equipment, are on permanent standby around the platform. In addition to this, additional oil-spill response resources — to ensure the full protection of the coastline — are also in place, onshore, near the settlement of Varandey.
Various risk scenarios were considered as part of a detailed oil spill response (OSR) and prevention strategy, an assessment of resources and capabilities in establishing emergency response units undertaken, and the company’s own professional units for spill response and containment — together with engagement with professional government units — organised.
A range of cutting-edge technological solutions are in place at the Prirazlomnaya rig itself, ensuring the optimum reduction in environmental impacts on the natural environment of the Arctic. “Zero emissions” technology has been integrated into the platform to prevent the discharge of any production or drilling waste into the sea, with used drilling mud, slurry and other wastes, instead, re-injected directly into the strata through a special absorption well, or transported onshore for recycling. Process water is supplied via special fish-protection devices.
To reduce noise impacts, helicopters delivering personnel to the platform fly over the sea at a height that will not disturb its inhabitants — i.e., not less than 500 metres. In addition, Prirazlomnaya has a specialist birdlife protection facility, covering a range of 3,000 metres. Broadcasting disturbing and annoying sounds, as well as authentic predator calls and man-made noises, it prevents birds from nesting and forming permanent flocks in the protected area.
Particular attention has been paid to researching the habitats and breeding grounds of Atlantic walruses around the Prirazlomnaya platform. The company has been undertaking the research around the Dolgy, Matveev, Golets, Vaigach, and Bolshoi and Maly Zelenets islands since 2012. The research results reveal no significant fluctuations in the migration patterns and distribution of marine mammals in the Pechora Sea since oil production began.