Russia plans to use the most advanced technology available to ensure that its huge arctic gas pipeline system crossing an arm of the Kara Sea from western Siberia's Yamal Peninsula to the mainland coast is ecologically secure.
Safety measures not seen before in Russia are being taken to assure that the proposed eight 48 in. pipelines spanning the 70 km (43 1/2 mile) wide Baidaratskaya Bay pose the least threat of damage to the permafrost terrain at the northern and southern ends of the crossing.
Onshore, before going beneath the water, each line will be enclosed in a tunnel with about 3 m (115 in.) ID and surrounded by a thick layer of gravel.
In this way, Russian reports assert, only a small amount of heat from the pipeline will reach the permafrost. The danger of line breaks due to warming and shifting of the frozen ground near the water crossing is expected to be nearly eliminated.
GETTING PREPARED
Preproject engineering for laying of the first two Baidaratskaya Bay pipelines was contracted to the Dutch firm Heerema Oil & Gas Development last fall. Heerema formed the Petergaz joint venture with Russia's state owned gas monopoly Gazprom.
The Moscow business newspaper Delovoi Mir (Business World) said that after the engineering study is complete, Gazprom will decide on the firm or firms that will be given contracts to participate in work on the underwater crossing.
Nationalist minded Gazprom is expected to favor Russian firms to provide as much of the equipment, supplies, and personnel as possible. Western companies other than Heerema have expressed an interest in helping with the project.
While the greatest water depth in the proposed Baidaratskaya Bay crossing area is only 25 m (82 ft), Delovoi Mir described the subsea pipeline project as "a technically difficult task." But it expressed confidence that Heerema's engineering expertise will calm the fears of environmentalists and the local population that the ecological integrity of the shoreline area near the pipelines and safe operation of the pipelines themselves will be assured during the long term.
The newspaper quoted "foreign constructors" as estimating that each of the eight 48 in. Baidaratskaya Bay lines will cost Gazprom about $300 million. An earlier report said the first two lines slated to be ready for use in 1996 will cost $570 million, with the remaining lines expected to cost less than the first pair.
A tentative schedule calls for the last line to be complete by about 2005.
SYSTEM CAPACITY
Ultimate capacity of the entire system crossing Baidaratskaya Bay has been placed at 170 billion cu m (6 tcf)/year. That means each of the eight lines will have a throughput of 21.25 billion cu m (750 bcf)/year.
However, 48 in. Russian gas pipelines in use today have a capacity of only 15 billion cu m (529.5 bcf)/year/line. They operate at 1,102 psi.
If the eight Baidaratskaya lines were operated at that pressure, throughput of the entire system would be 120 billion cu m (4.2 tcf)/year.
It's believed that use of higher strength steel and possible double wall construction may be employed in the pipelines from Yamal fields. The former Soviet Union more than a decade ago experimented with construction of short sections of high pressure pipelines using stronger domestically produced "multilayered" pipe and improved compressor stations to transmit cooled gas through permafrost areas of western Siberia.
Soviet reports said shipping gas at 100-120 atm (1,469-1,763 psi) instead of 75 atm (1,102 psi) would permit a 30% increase in throughput. Use of those higher pressures originally was planned for the late 1980s.
If throughput of the Yamal pipelines were increased 30%, each line could handle 19.5 billion cu m (688 bcf)/year instead of 15 billion cu m/year. That would jump the system's total capacity to 156 billion cu m (5-5 tcf)/year, fairly close to the 170 billion cu m/year proposed for the Yamal transmission project.
Even with a capacity of 120 billion cu m/year, the Yamal project would handle one of the largest volumes among Russia's big gas transmission systems. It's claimed that no Russian, former Soviet, or other world gas system carries a volume close to 6 tcf/year underwater for a distance as great as 70 km.
GAS SUPPLY
There's little doubt that the approximately 20 gas and gas/condensate fields discovered on the Yamal Peninsula could supply 6 tcf/year for the proposed transmission system. Moscow officials last year estimated Yamal gas reserves at about 16.6 trillion cu m (586 tcf).
Supergiant Bovanenkovskoye field, where the Yamal pipeline system likely will start, is credited with about 79 tcf of explored (proved plus probable) reserves and an additional 67.5 tcf of possible reserves.
Discovered in 1971, Bovanenkovskoye alone could provide the Yamal transmission system with more than 100 billion cu m (3.53 tcf)/year when peak production is reached. Bovanenkovskoye lies nearly 300 miles north of the Arctic Circle near the Kara Sea coast.
Moscow has estimated the cost of the Yamalgazenergo (Yamal gas energy) development project at $15 billion (OGJ, Sept. 7, 1992, p. 17).
THE PROBLEMS
The Baidaratskaya Bay pipeline project holds major logistical and climatic problems. The site is 200 km (124 miles) north of the Arctic Circle, where the work season is only 60-100 days/year.
Offshore there is shorefast and pack ice. Continuous and discontinuous permafrost prevails onshore in the Baidaratskaya Bay area.
There are no permanent roads in the region, and the closest railroad is more than 200 km away.
Nearest major port is Murmansk, about 850 miles west. The navigable season through the Kara Sea to Baidaratskaya Bay is 60 70 days/year.
Even so, the project's goals are to lay 70 km of 48 in. underwater pipeline in 30 days, trench and backfill the line by the end of the short work season, perform hydrostatic testing, and make tie-ins.
Copyright 1993 Oil & Gas Journal. All Rights Reserved.
