The gas zone was clocked up over the Toro, Digumu and P'nyang sandstones and an Oil Search spokesperson told PNGIndustryNews.net it was in line with predrill estimates.
Oil Search is drilling the well on behalf of its operator ExxonMobil. It was at a depth of 1991m on March 1.
The next drilling target is the underlying Koi-Iange sandstone.
This will be the first time this sandstone has been drilled in the P'nyang area, with two other P'nyang wells drilled in previous decades, but a development well in the Kutubu oilfield of the Southern Highlands hit hydrocarbons from the Koi-Iange last year.
The P'nyang South 1 well is 4km southwest of the P'nyang 1x gas discovery well and about 90km northwest of the Juha field, which is in the existing scope of the PNG LNG project.
Success at the well could open up more exploration and associated commercialisation opportunities in Western Province - a region far cheaper to drill than the mountainous terrain of PNG LNG project fields in the Southern Highlands.
Once complete the rig will move east to spud the ExxonMobil-operated Trapia-1 exploration well in the Southern Highlands.
Exxon has a 49% stake in P'nyang South-1; Oil Search owns 38.5% while JX Nippon owns 12.5%.