SYDNEY, Australia  Visitors hoping to peek at Australia’s exotic marine life usually head straight for the Great Barrier Reef. But conservationists say that an equally remarkable, but lesser known, marine environment is under threat from the booming oil and gas exploration taking place among the reefs and atolls off Australia’s northwest coast.

A damaged oil well in the region has been spewing thousands of gallons of crude oil into the Timor Sea since Aug. 21, when a blowout forced the evacuation of all 69 workers on the platform. Emergency crews have been working overtime to contain the spill, but officials say it could take about three more weeks to plug the leak.

The platform is above the Montara oil field, about 155 miles northwest of Mungalalu Truscott Airbase in the remote Kimberley region of Australia. The leaking well head is owned by Thailand’s national petroleum company, PTT Exploration and Production, one of many energy companies that have set up operations in western Australia to feed Asia’s growing appetite for oil and gas.

In the first half of this year, more than 50 wells were drilled in the tropical waters off western Australia, adding to hundreds of other recent projects. Last month, the government gave Chevron the green light to expand its exploration of the huge Gorgon gas field, a $40 billion project that was opposed by conservationists because of its potential environmental impact.