On Friday morning, the company was rigging down Century Rig 11, after drilling to a total depth of 2863 metres and cutting a window in the 178mm (7 inch) casing. It said a completion string was run and a cleanup flow undertaken as planned.

During the six-hour clean-up flow, the well flowed gas from the Dongara Sandstone at varying pressures and rates, ranging from 1.6 million to 3.7 million cubic feet per day. As no separator was used, Arc said it could not determine accurate flow rates.

“The flow rates obtained are broadly similar to the rates obtained for Senecio-1,” managing director Eric Streitberg said.

“The use of a non-invasive drilling fluid does not appear to have resulted in a substantial increase in flow rate from the well. However, the well has confirmed the presence and producibility of what could be substantial volumes of gas in place.”

Streitberg said the company would now review the data, including a possible longer term production test, to plan the well’s forward program.

Senecio-2 was drilled as a sidetrack from the Senecio-1 well bore to see if a commercial flow could be obtained from the Senecio prospect, Arc said earlier this month.

At this time, Streitberg said the prospect had the potential to hold up to 50 billion cubic feet of gas.

Participants in L1 and L2 (excluding the Dongara, Mondarra and Yardarino fields) and Senecio-2 are Arc Energy (operator 50%) and Origin Energy (50%).