WestSide said the joint venture decided to drill an additional appraisal well following promising gas show during recent drilling.
"The expanded pilot is expected to enhance the prospects of certifying gas reserves in the area," WestSide said.
Paranui-8 is being drilled by the Ensign Rig 20 and has a target depth of about 1000m.
Once the well is complete, the Paranui pilot will include three appraisal wells, Paranui-5, 6 and 8, and two observations wells, Paranui-4 and 7.
WestSide said the Paranui-4 well was drilled and logged during the week, and would be completed with sensor equipment to collect pressure data from up to 13 individual coal seams while the three appraisal wells are de-watered.
The joint venture partners are reviewing plans for the next stage of activities at Paranui.
WestSide is operator and holds a 50% stake in Paranui, while Sunshine has the remaining 50%.