Timor Sea

Tropical cyclone Floyd over the Timor Sea, 2006

The International Hydrographic Organization (IHO) defines the Timor Sea as being one of the waters of the East Indian Archipelago. The IHO defines its limits as follows:[7]

On the North The Southeastern limit of the Savu Sea [By a line from the Southwest point of Timor to the Northeast point of Roti, through this island to its Southwest point] the Southeastern coast of Timor and the Southern limit of the Banda Sea [A line from Tanjong Aro Oesoe, through Sermata to Tanjong Njadora the Southeast point of Lakov (8°16′S 128°14′E) along the South coasts of Lakov, Moa and Leti Islands to Tanjong Toet Pateh, the West point of Leti, thence a line to Tanjong Sewirawa the Eastern extremity of Timor].

On the East. The Western [limit] of the Arafura Sea [A line from Cape Don to Tanjong Aro Oesoe, the Southern point of Selaroe (Tanimbar Islands)].

On the South. The North coast of Australia from Cape Don to Cape Londonderry (13°47′S 126°55′E).

On the West. A line from Cape Londonderry to the Southwest point of Roti Island (10°56′S 122°48′E).

Many tropical storms and cyclones originate or pass through the Timor Sea. In February 2005, Tropical Cyclone Vivienne disrupted oil and gas production facilities in the area, and the next month, Severe Tropical Cyclone Willy interrupted production. Petroleum production facilities are designed to withstand the effects of cyclones, although as a safety precaution production work is often reduced or temporarily halted and workers evacuated by helicopter to the mainland - usually to Darwin or Dili.

August 2005 NASA satellite photograph of the Rowley Shoals

A number of significant islands are located in the sea, notably Melville Island, part of the Tiwi Islands, off Australia and the Australian-governed Ashmore and Cartier Islands. It is thought that early humans reached Australia by "island-hopping" across the Timor Sea.

Scott and Seringapatam Reefs formed in the area and to the west, on the same underwater platform, are the Rowley Shoals.

During the 1940s the Japanese navy conducted air raids on Australia from ships in the Timor Sea. On the 19 February 1942 the Japanese aircraft carrier Kaga with other vessels, launched air strikes against Darwin, Australia, sinking nine ships, including the USS Peary. This bombing marked the beginning of the Battle of Timor in the Pacific theatre of World War II.

The Timor Current is an oceanic current that runs south-west in the Timor Sea between the Malay Archipelago and Australia. It is a major contributor to the Indonesian Throughflow that transports water from the Pacific Ocean to the Indian Ocean.

The largest petroleum project in operation in the Timor Sea is the Bayu-Undan project operated by Santos.[10] The Bayu-Undan field is located approximately 500 km (310 mi) north-west of Darwin in the Bonaparte Basin.[11] Production commenced in 2004 as a gas recycle project - with liquids (condensate, propane and butane) being stripped from the raw production stream and exported. Gas was pumped back down into the reservoir. At around the same time, construction commenced on a 500 km (310 mi) subsea natural gas pipeline connecting the Bayu-Undan processing facility to a liquefied natural gas plant situated at Wickham Point in Darwin harbour. Since the completion of the pipeline and the Darwin LNG plant in 2005, gas produced offshore at Bayu-Undan is now transported to the Darwin plant where it is converted into a liquid and transported to Japan under long-term sales contracts.[12] Timor-Leste has made, as of 2017, over $18 billion from Bayu-Undan since production began; however, it is predicted its reserves will be exhausted by 2023.[13]

The Ichthys gas field is a natural gas field located in the Timor Sea, off the northwestern coast of Australia. The field is located 220 km offshore Western Australia and 820 km southwest of Darwin, with an average water depth of approximately 250 metres.[14] It was discovered in 2000. First Gas from the Ichthys field was achieved on 30 July 2018.[15]

AED Oil owns the large oil project at Puffin oilfield and Woodside Petroleum is producing oil at the Laminaria oilfield. The Greater Sunrise gas field, discovered in 1974, is one of the largest in the area and is expected to earn East Timor several billion dollars in royalty revenues. Woodside Petroleum plans to process gas from Greater Sunrise via a floating platform, however Xanana Gusmão, East Timor's Prime Minister opposes this plan and instead wants the gas to go to Beaço via a pipeline for processing.[16]

The Timor Sea Treaty, which was signed on the 20 May 2002, led to the establishment of the Timor Sea Designated Authority (TSDA). This organisation is responsible for the administration of all petroleum-related activities in a part of the Timor Sea known as the Joint Petroleum Development Area (JPDA). The treaty was ratified in February 2007.[17]

Under the terms of the treaty, royalties on petroleum production in the JPDA are split in a 90:10 ratio between East Timor and Australia.[18] It has been criticised because the treaty did not finalise the maritime boundary between East Timor and Australia.[17]

The Australia–Timor Leste Treaty Establishing Their Maritime Boundaries in the Timor Sea was signed on 6 March 2018 at United Nations headquarters in New York in the presence of United Nations Secretary-General Antonio Guterres.[19]