Production tests on three separate oil columns have been accomplished successfully at the Wei-6-12S-1 exploration well in the Beibu Gulf.
As of early this morning, the current operation was preparing to drill a sidetrack hole, primarily to obtain core data from the oil reservoirs. The Wei-6-12S-1 production testing program is designed to provide the JV 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 111m gross column (35m net pay); to determine if a hydrocarbon-water contact was present; and to provide productivity data.
The test perforated 12m between 2435.5 and 2447.7m below the rotary table and flowed 35 degree API oil through various choke sizes, up to a 32/64-inch choke, at stabilised rates up to 1725 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 has confirmed this and suggests that the oil-water contact may be more than 20m down dip from the base of the oil column seen in the well.
The second test obtained productivity data from the 65m gross oil column . Specifically, the test perforated a total of 28m over two zones, 2228.5-2241.5m and 2201-2216m.
The test flowed 39 degree API oil, through various choke sizes up to 48/64 inch, at stabilised rates up to 2575 bopd with no associated water production. The test results indicate that the reservoir has good natural productivity.
The third test was to provide productivity data from the 71m gross oil column 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 16m between 2054 and 2070m and flowed 38 degree API oil, through various choke sizes up to 44/64 inch at stabilised rates up to 1450 bopd. The test results indicate a reasonably productive reservoir. Pressure gradient information suggests that the oil column extends down 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 start drilling later this week.
Due to the proximity of the sidetrack to the discovery well, the JV does not expect to make any further announcements on the progress of drilling until the first sidetrack is completed in late June.
Roc said it was expected that a second sidetrack well would be drilled after the first sidetrack was completed.
The second sidetrack will be designed to intersect the various reservoir sands in a down-dip position relative to the discovery well, including the possible down-dip development of a small sand section intersected in the lower part of the upper sand package in the discovery well.
The company said 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 the various hydrocarbon sands have recognisable seismic signatures.
Roc chief executive Dr John Doran said the JV was 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.
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%).
