Described by the company as a relatively “aggressive step-out”, the Wei-6-12S-1Sb sidetrack, which spudded almost a week ago, was this morning at a depth of 2217m. It is currently at a southwest lateral distance of 300m from the original well and approximately 50m vertically down-dip from equivalent horizons in that well.

The well is currently being drilled ahead in the main reservoir section, the Weizhou Formation, towards a proposed total depth of 2849m.

Wei-6-12S-1Sb is designed to intersect a number of the reservoir intervals down-dip from the original discovery well.

Roc said the reservoir equivalents of the original well, expected to be encountered in the lower part of the second sidetrack, are likely to be water bearing because they are a considerable distance down-dip.

However, it hopes that this second sidetrack will encounter one or more down-dip oil legs in the higher part of the Weizhou Formation.

Wei-6-12S-1Sb also has an exploration element designed to target a specific sand not present in the original well but may possibly be present towards the bottom of the second sidetrack, according to Roc.

The detailed outcome of the drilling will not be known until next week when the second sidetrack is expected to have been logged at total depth.

Roc is the operator and owns 40% of the Wei-6-12S-1 well. Other partners in the Australian joint venture are Horizon Oil, which holds a 30% stake, Petsec Energy (25%) and First Australian Resources (5%).