ExplorationSoutheast Asia players eye sour gas sweet spotPTTEP, Eni and Repsol are forging ahead despite cost and complexity of dealing with high CO2 and H2S content in region's gas reservesReason to smile: PTTEP chief executive Phongsthorn Thavisin hails Lang Lebah as the company's largest ever gas discoveryPhoto: PTTEPAmanda BattersbyDubai