The tanker British Sapphire just finished its own version of Homer’s Odyssey.

BP Plc’s vessel, capable of holding 155,000 cubic meters of liquefied natural gas, set sail from Trinidad in mid-February in search of the highest price on world markets. It headed for Asia, changed course toward Europe when it was halfway to the Cape of Good Hope, and then sailed back toward the Caribbean. It docked in the Dominican Republic after completing a 9,000-mile, month-long trip that left it 800 miles from its starting point, and unloaded, signals from the ship compiled by Bloomberg from IHS Maritime data showed.

Unlike the crude oil market, gas trading will split into three regional markets by 2020, with no more than 10 percent to 20 percent of cargoes moving between them, according to Alan Whitefield, managing director of industry consultant AW Energy Solutions in London. British Sapphire’s journey is explained by converging global prices for LNG that have made it cheaper for users to buy closer to home.

“LNG will be more available,” Per Christian Fett, director of Fearnley LNG, an Oslo-based shipbroker, said April 7 by e-mail. “The market will see less long haul and more swapping of cargoes,” he said, referring to the practice of traders exchanging shiploads to minimize transport costs.

Whitefield said the three regional markets for LNG, which is gas chilled to minus 160 degrees Celsius (minus 256 Fahrenheit) to shrink it 600 times, are the Atlantic basin including the U.S. Gulf Coast, the Caribbean, South America and Europe; a Pacific area centered on Japan and a Middle Eastern region that includes India.

The shift comes as charter rates declined to the lowest level since 2010. The 34 vessels delivered last year, the most since 2009, took the global fleet to a record 421 tankers, according to the April 8 annual report of the International Group of LNG Importers, or GIIGNL, a Paris-based lobbying group.

After leaving the Dominican Republic, the empty British Sapphire sailed to Trinidad in the middle of March before going to Nigeria to pick up LNG. It is now anchored off Brazil, the shipping data show. Robert Wine, a BP spokesman in London, declined to comment on the tanker or the company’s LNG operations.

For global operators such as BP, the journey may have been a so-called portfolio play, whereby traders swap cargoes to limit long journeys, according to Malcolm Johnson, a Guildford, England-based faculty member of The Oxford Princeton Programme, an energy training provider.

Diversions for uncommitted cargoes may be attractive for various reasons, including volatile spot prices in different regions and lower charter rates, Johnson, who spent more than 30 years at Royal Dutch Shell Plc in gas jobs, said by e-mail March 23.

LNG prices in Asia dropped 52 percent in the past year amid more supply and milder weather, with the premium to Europe narrowing to 3.6 percent in the week to April 6 from as much as 68 percent in December 2011, according to assessments by New York-based World Gas Intelligence of cargoes for delivery in four to eight weeks.

“It will be more challenging for traders from this year,” Hiroki Sato, Chubu Electric Power Co.’s general manager at the fuels department and head of LNG business, said in an interview March 4 in Singapore. “Traders cannot divert the European volumes to Asian markets” without the risk of incurring a loss, while portfolio players can still do so to optimize their shipping operations, he said.

Asia-Pacific buyers got more than half their supply last year from outside the region, according to GIIGNL. Deliveries to Asia, which accounts for 75 percent of global demand, rose every year since Japan’s Fukushima nuclear disaster in 2011 led to the closing of reactors. Increased use in Asia gave rise to shipments from Europe of previously imported cargoes.

Asia will keep driving demand, and tankers will sail from west to east, Steve Hill, president of BG Group Plc’s global energy marketing and shipping unit, said March 4 at a market outlook presentation. Demand growth in Asia outpaced global growth of 1 percent last year, according to GIIGNL.

The elevated demand in Asia gave rise to re-exports of previously imported cargoes from Europe. Because of contractual restrictions on diversions at sea, ships would make the journey from Qatar to Spain before sailing back empty. Other tankers would then pick up fuel for destinations as far away as Japan, meaning LNG was traveling thousands of miles more than if it had gone directly to Asia.

Re-exports have slowed as the Asian premium shrank, with just seven tankers scheduled to reload in Spain this year through May, compared with 28 in the same period of 2014. Since November, none of the exports from the Iberian country, which accounted for 60 percent of reloads last year, have left the Atlantic basin.

“If your market doesn’t have the need for the gas, it doesn’t matter how cheap it is, it’s not going to go there,” Keith Bainbridge, managing director of consultant CS LNG in London, said in an interview in London Feb. 24. “It has to go to the next market that needs it. At the moment it comes to Europe.”