CH-5 is a vertical "pathfinder" well located about 1 km southeast of the CH-1 discovery well. The pre-drill plan for CH-5 was that it be plugged and abandoned because its primary purpose was to determine the nature and extent of the reservoir in the East Ridge portion of the Cliff Head structure so as to better define the location of a horizontal development well.
It is currently not understood whether CH-5 has come in low to prognosis due to adverse seismic velocity variations which would have an adverse impact on field reserves, or due to drilling inadvertently on the wrong side of a nearby fault, which would probably have a less severe impact on field reserves.
The Joint Venture is actively reviewing the data obtained to date and will integrate that information with the results of the logging program over the next 48 hours. At the moment, it is too early to comment definitively as to whether or not CH-5 was optimally located in relation to a nearby fault. If the full data set indicates that the CH-5 location was less than structurally optimal, the Joint Venture may consider sidetracking the well.
Regardless of the outcome of CH-5, upon completion of well operations the rig will move to drill the CH-6 development well location in the main horst part of the Cliff Head structure.
Commenting on preliminary results from CH-5, Dr John Doran, ROC's Chief Executive Officer, stated that:
"With the results we have seen so far from CH-5 it is pretty clear why we described the well as a 'pathfinder'. If we have ended up on the 'wrong side' of the fault, then the situation may possibly be rectified by a sidetrack to the east. If, however, we are on the 'right' side of the fault, the fact that the top reservoir has been encountered substantially lower than prognosed means that we need to greatly improve our understanding of the East Ridge portion of the Cliff Head structure and this will impact on the details and timing of the Final Investment Decision for the development of the field."
The WA-286-P Joint Venture comprises of Roc Oil as Operator with 37.5%; AWE Petroleum with 27.55; Wandoo Petroleum with 24%; voyager Energy with 6% and Cieco E&P with 5%.
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