Roc Oil Completes Production Testing at Wei-6-12S-1 Offshore China

Since May 24th three separate production tests have been conducted successfully on the Wei-6-12S-1 exploration well in Block 22/12, Beibu Gulf, offshore China. Currently preparations are underway to drill a sidetrack hole, primarily to obtain core data from the oil reservoirs.

As stated in previously, the Wei-6-12S-1 production testing program was designed to provide the Joint Venture with the maximum amount of technical data for possible field development rather than maximum flow rates.

The first test had three main aims: to confirm the hydrocarbon type in the 111 meters gross column (35 meters net pay); to determine if a hydrocarbon-water contact is present; and to provide productivity data.

The test perforated 12 meters between 2,435.5 meters below rotary table ("mBRT") and 2,447.7 mBRT and flowed 35 degree API oil through various choke sizes, up to a 32/64 inch choke, at stabilized rates up to 1,725 BOPD.

The test conclusively proved that the hydrocarbon type present is oil. The test did not produce any water, despite being located near the possible oil-water contact, which strongly indicates that oil-water contact is not present in the well. Preliminary pressure analysis confirms this and suggests that the oil-water contact may be more than 20 meters down dip from the base of the oil column seen in the well.

The purpose of the second test was to obtain productivity data from the 65 meters gross oil column (31 meters net pay) encountered.

Specifically the test perforated a total of 28 meters over two zones, 2,228.5 mBRT to 2,241.5 mBRT and 2,201.0 mBRT to 2,216.0 mBRT. The test flowed 39 degree API oil, through various choke sizes up to 48/64 inch, at stabilised rates up to 2,575 BOPD with no associated water production. The test results indicate that the reservoir has good natural productivity.

The third test aimed to provide productivity data from the 71 meters gross oil column (14.5 meters net pay) in the upper sand package and to obtain further insight as to how far down dip the oil bearing reservoir may extend.

This test perforated 16 meters between 2,054 mBRT and 2,070 mBRT and flowed 38 degree API oil, through various choke sizes up to 44/64 inch, at stabilized rates up to 1,450 BOPD.

The test results indicate a reasonably productive reservoir. Pressure gradient information suggests that the oil column extends down structure from the discovery well.

The next phase of appraisal will be the drilling of a sidetrack hole close to the original discovery well in an attempt to further delineate and core the relevant reservoirs. The Wei 6-12S-1Sa sidetrack is expected to commence drilling later this week. Due to the proximity of the sidetrack to the discovery well, the Joint Venture does not expect to make any further Stock Exchange announcements about the progress of drilling until this first sidetrack is completed in late June.

It is anticipated that a second sidetrack well will be drilled after the first sidetrack is completed. This second sidetrack will be designed to intersect the various reservoir sands in a down dip position relative to the discovery well, including the possible downdip development of a small sand section intersected in the lower part of the upper sand package in the discovery well. This sand section was not production tested in the discovery well but oil was recovered during wireline sampling.

Another important phase of appraising the Wei South discovery is the integration of well and seismic data to determine whether or not the various hydrocarbon sands have recognizable seismic signatures. Initial results of this work are encouraging.

Commenting on the production test results of the well, ROC’s Chief Executive Officer, Dr. John Doran stated that:
"The Joint Venture is maintaining its methodical approach to appraising the commercial potential of the Wei South discovery and on the basis of the recent production test results it would seem to be a case of - so far so good." The Block 22/12 Joint Venture is comprised of Roc Oil as operator with 40%; Horizon Oil with 30%; Petsec Energy with 25% and Oil Australia Pty with 5%. CNOOC is entitled to participate up to a 51% funding equity level in any commercial development within Block 22/12.

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