The Sydney-based company said drilling stopped after it became increasingly difficult to control the formation pressures and keep the six-inch hole open.

“This was primarily for safety reasons, but also to safeguard the substantial productive zones already penetrated,” Horizon said.

“Accordingly, the open-hole section was abandoned back to the seven-inch casing, behind which there lies 219 feet gross/74 feet net pay in three zones.”

As a result, another well may be drilled to access the deeper targets not reached in AMI-1. Horizon said this well would be drilled vertically and slightly down-dip away from the salt-induced pressures encountered in the exploration well.

In addition, the company said potential for an additional well location existed up-dip of AMI-1 at the Cib Haz level.

The timing of these two wells was still under discussion, it said.

AMI-1 was the first of an initial three-well exploitation program targeting zones up-dip of existing production around the Bayou Choctaw salt dome.

The well is located in the Victory Financial Lease. Horizon Oil has a 14% interest in the AMI-1 well and will have a 19.8% interest in the following two wells. Icon has a 19% stake in the lease and is fully-carried through the drilling by remaining equity holder CLK Energy.