The company said it would investigate the issue before drilling resumes at the well, which had been drilled to a depth of 167m in the Darai limestone.
The Cobra-1 well in petroleum prospecting licence 190 is 13km east of the SE Gobe oilfield and 7km east of the Bilip oil discovery.
It targets the Iagifu sandstone, which is the principal reservoir in the Gobe and SE Gobe fields, in a seismically-defined sub-thrust prospect.
Cobra-1 has a planned total depth of 3100m.
Participants in the well are operator Oil Search (62.556%), Murray Petroleum (26.497%) and Cue Energy (10.947%).
The company is also cleaning out cement at a depth of 2100m at its NW Paua-1 exploration well about 5km northeast of the Moran oil field in PNG.
Oil Search had carried out cementing operations during the week to improve hole integrity after encountering what appeared to be a heavily fractured section.
Participants in NW Paua-1, which has a planned total depth of 3377m and targets the Toro and Digimu sandstones in a seismically defined hanging wall structure, are Oil Search (52.5%) and ExxonMobil (47.5%).
The company is also reaming the wellbore of its South Gharib-X1 well in Egypt after parts of the open hole section experienced instability, resulting in cavings that have to be reamed out of the hole prior to drilling ahead.
Partners in South Gharib-X1 are Oil Search (70%) and Petrogas E&P (30%).
