The company said while the sidetrack penetrated the formation at the right depth and location relative to the original hole, pressure measurements across the Toro showed the sands to be water-bearing at this location.

The pressures recorded in the Toro formation also indicates the reservoir interval has possibly been affected by production of hydrocarbons in the Usano field.

Oil Search managing director Peter Botten said the company is considering the possibility of using Arakubi-1A as a water injector to enhance production at Usano.

Wireline logs also indicate the sands in the deeper Digimu, Hedinia and Iagifu reservoirs may be hydrocarbon-bearing.

The potential commerciality of production from these sands will be assessed as part of the ongoing development programme for the Usano field area.

Information about the pressure, fluid content, and reservoir potential of these sands will also be used for planned future development wells in Usano.

Arakubi-1A is in PDL 2 about 5km east of the Kutubu oil field.

Participants in Arakubi-1A are Oil Search 60%, ExxonMobil 14.5%, AGL 11.9%, Merlin Petroleum 6.8% and Petroleum Resources (Kutubu) 6.8%.