Having signed up its first two customers, Triton Energy Ltd. is looking for companies interested in its stake in a Southeast Asian gas field.

The Dallas company holds 50 percent of Block A-18 in a joint Thailand-Malaysia development area, judged to hold 1.4 trillion cubic feet of natural gas.The Petronas Carigali exploration unit of Malaysia's state oil company, Petronas, holds the rest.

The field is one of three blocks in the joint development area covering nearly 3,000 square miles and thought to hold some 10 trillion cubic feet. Complete work-ups on A-18, B-17 and C-19 are projected to cost $1.5 billion.

Natural gas deliveries, mostly for power generation, are forecast to generate about $5.5 billion in sales, with Triton entitled to about 30 percent. The initial production target is 390 million cubic feet a day, equivalent to 370 million British thermal units.

A ''heads of agreement'' signed last week by Triton and the two governments allows the company to proceed with development of A-18. Executives have been seeking a firm contract since 1996.

First deliveries are scheduled for early 2001, continuing for 20 years, a Triton spokesman said.

The gas will be taken by the state-owned Petroleum Authority of Thailand, or PTT, and Petronas, each buying half, moved by pipeline to Thailand.

The agreed base price is $2.30 per million BTUs, a standard measure of the amount of heat needed to raise the temperature of 1 pound of water 1 degree Fahrenheit. The actual price will be adjusted periodically by a formula including U.S. dollar-denominated inflation and fuel oil price indexes.

Triton said after the signing it is looking for partners to develop A-18 and hopes for a deal this summer. Thomas Sinck, chairman and chief executive, declined to elaborate.

''Triton, like other companies, seeks partners from time to time for projects. PTT recently announced that it was looking for partner for a pipeline project. In similar fashion, we are looking for partners to help us develop our projects,'' he said.

Industry analysts say Triton needs help because of the size of the field and high costs of bringing it into production. They also suggest the company is weary of the protracted negotiations even to get to this stage.

Thailand said it will forgo its half of the output for the first few years, citing its economic crisis. Petronas will take all the gas during that time, with Thailand accepting deliveries starting in about 2004, officials said.

The Thai agency, through PTT Exploration & Production PLC, and Petronas will also buy gas from B-17 and C-19. It should begin flowing by late 2002 at an initial rate of 250 million cubic feet a day.

Prajya Pinyawat, president of PTT Exploration, said development of the two other fields will cost about $700 million, and that PTT has set aside funds for that. It and Petronas Carigali are responsible for that project.

He said the sale of any or all of Triton's stake in A-18 would not affect the project. ''We believe there will be a lot of interest in the project.''