Australia: Officer basin wildcat nears objectives

Rodinia Oil Corp., Calgary, is preparing to run a second intermediate casing string prior to drilling ahead into prospective formations at Mulyawara-1 exploratory well in the Officer basin in South Australia.

Rodinia spudded Mulyawara-1 on June 9, 2011, and reached the first intermediate casing point of 1,525 m on Aug. 1. The casing shoe is being set above the projected depth of the first series of evaporite seals.

Drilling has been slower than anticipated due to mechanical issues on the rig, drilling in harder rock than predicted and extremely high-rate water inflows from upper zones, which forced drilling operations to switch from air hammer drilling to the slower underbalanced water rotary drilling.

Mulyawara-1 has confirmed the existence of excellent reservoir quality rocks in the Neoproterozoic with the Eidacaran age Murnaroo formation having an average log porosity of 18% (commonly up to 23%) and flowing water at 600-900 bbl/hr while air drilling. The well has also encountered small gas peaks and traces of hydrocarbon fluorescence exhibiting blooming cut over discrete intervals within the undifferentiated Upper Cryogenian.

Although these findings are encouraging and reduce the risks associated with source, migration, and reservoir, the well is still a high-risk venture and yet to be proven, the company said. The primary objectives are yet to be intersected and lie below the prospective regional salt seals.

Rodinia has an 80% working interest in this well and prospect and is the operator.

Mulyawara 1 is in the northwest corner of PEL 253 on a structure of 36.3 sq km per horizon as identified on seven 2D seismic lines.