Construction of a major natural-gas pipeline across Japan began earlier this year and targets completion by mid 1996.
The 250 km Niigata-Sendai gas pipeline (Fig. 1) is the initial segment in a planned extensive expansion of Japan's gas-pipeline network that by 2005 may be handling up to 82.6 million metric tons/year (mty) of imported LNG. This prospect is predicated upon forecasts of rapidly growing gas demand for domestic use and power generation.
The new 20 in. line will transport gas from an LNG regasification plant at Niigata on the Sea of Japan in western Japan to Sendai City, Niigata Prefecture, on the Pacific Ocean.
Currently, LNG is supplied from the Arun project in Indonesia. Primary customer for the gas will be the gas-fired electric power stations of Tohoku Electric Power Co.
LNG supplied from foreign producers and gas produced from domestic offshore fields in the Sea of Japan will meet fuel demand expected to burgeon to more than 100 million mty of LNG by 2020.
In 1989, by comparison, LNG for power generation, in cogeneration in oil-fired power stations, and in replacement of town gas in Japan's regional cities reached 35.5 mty, says Kawasaki Steel Corp., prime design and construction contractor on the new pipeline.
Also, to secure the greatly increased supplies of natural gas, fields in Siberia and Sakhalin will be developed.
STEEL SUPPLY
Kawasaki Steel conducted the feasibility for the entire project, has responsibility for materials and construction of the project, and is supplying approximately 38% of the pipe.
The remainder of the pipe is being supplied by Japan's other major line pipe manufacturers: Sumitomo Metal Industries Ltd., NKK Corp., and Nippon Steel Corp.
The DSAW (UOE) pipe is 508 mm (20 in.) X 11-91 mm (0.469 in.) W.T. 5L-X60 externally coated with 3 mm of polyethylene as anticorrosive and an adhesive layer of epoxy resin.
Kawasaki is producing its pipe in 11-m (36-ft) lengths.
Construction plans call for 100 km to be laid in each of 1994 and 1995 with the remaining 50 km in 1996. The line will have as many as 30 valving stations along its route.
Approximate pressure at the line's injection point will be 1,000 psi; at delivery 142 psi. The transportation capacity is 4.5 million cu m/day.
JAPAN'S RESOURCES
Although Japan is not rich in resources, the Niigata Prefecture has important natural gas reserves and the LNG storage facilities at Higashi Minato from which to supply demand over a large area.
Currently, the longest gas pipeline in Japan runs 300 km from Tokyo to Niigata (Fig. 1) and is operated by Teikoku Oil Co. Ltd., according to Kawasaki Steel. Even when town-gas pipelines are included, the total length of the nation's pipelines is no more than 2,000 km.
Envisioned is a 3,300 km cross-country network linking Hokkaido in the north with Kagoshima on the southern island of Kyushu. Additionally, new ports and storage areas will be needed for the much higher levels of imports.
Total investment, says Kawasaki Steel, will be nearly 3 trillion yen (1993), with associated investments in the steel industry alone of some 2.3 trillion yen. And Japanese steel production overall may be boosted by more than 10 trillion yen.
Effects of the construction will spread along the Japan Sea coast, the island of Shikoku, and around the pipeline route that crosses Kyushu.
The widespread availability of natural gas throughout the Tohoku (northeast) region, says Kawaski Steel, will also represent a significant enhancement of the infrastructure stimulating industry throughout the region.
ROUTING CHALLENGES
The route presents difficult engineering challenges by crossing the central mountain ranges that form the long spine of Japan. Kawasaki Steel's plans are to lay 100 km in each of the first 2 years and the final 50 km in the third.
One possibility would be to bury the pipeline under Japan's existing motorways, a step that would require revision of the building codes and unprecedented cooperation between government departments with different and overlapping jurisdictions.
The pipe will also need to cross any rivers by bridges that may be swollen by the kind of floods that strike only once in 50 or 100 years.
Copyright 1994 Oil & Gas Journal. All Rights Reserved.
