Big Oil’s Pledge to Curb Methane Faces Test in Gulf of Thailand

A natural gas platform in the Gulf of Thailand has attracted a fresh warning over methane emissions first detected more than a decade ago, another test of global pledges to curb releases of the potent greenhouse gas.

Emissions from the site, operated by a joint venture between units of two state-backed energy companies — Malaysia’s Petroliam Nasional Bhd. and Thailand’s PTT Exploration and Production Pcl — have been observed at least 60 times by satellite since 2013, and the owners were most recently urged in May to address the problem.

Both companies are among about 50 oil and gas producers that agreed in ...