it looks like it may have always been the plan to use the PS to drill an exploration well at OPL 223 (Owowo) before drilling at Obo in JDZ-1. From row 779 of the "Prospects" tab...
Rig Name - Pacific Scirocco Drilling Notes - exploration well planned for Q3/2011; rig still in S Africa undergoing modifications as of Sept 2011
Or now, since the destination is shown as Usan, perhaps they have now decided to first drill the Usan West appraisal well and then maybe the Owowo well discussed in this recent Nexen PR.
Our West Africa investment program will allow the company to continue with production and injector well drilling, and resume exploration and appraisal drilling in West Africa with the Usan West appraisal well and an exploration well at Owowo West to follow up on the previous discovery at Owowo South B.