(China) - Australia-based ROC Oil Co. Ltd. said initial wireline log data indicated significant oil in the Wei-6-12S-1 exploration well, drilled in block 22/12 in the Beibu Gulf, offshore China.
The preliminary analysis showed numerous separate reservoir sands, which collectively represent 100 m of net oil pay with generally good reservoir characteristics. Overall individual sands range in thickness up to 25 m.
The block 22/12 Joint Venture is considering immediate appraisal.
On May 10, a wireline logging program was conducted at a total depth of 2,535 m below rotary table (mBRT), at the Wei-6-12S-1 exploration well in block 22/12, said ROC.
Its preliminary analysis indicated that the gross reservoir interval targeted by the well within the Weizhou Formation of Oligocene age contains numerous oil-bearing sands.
The top of the highest oil sand is at about 1,950 mBRT and the base of the lowest oil sand is at 2,450 mBRT. The intervening 500 m is comprised of a gross sand-shale-silt sequence within which individual oil-bearing sands range up to 25 m in thickness.
The total collective net thickness of these oil sands is approximately 100 m, which substantially exceeds the JV's most likely pre-drill expectation, it said.
The Wei-6-12S prospect represents an unusual structural target: the area of structural closure is relatively small (about one sq km) but the vertical structural closure is considerable (up to 95 m) and the gross prospective reservoir section is very thick (500 m).
The well, designed to penetrate most of the target sands about 30 m down dip from the crest of the structure, is in 30 m of water, approximately 3 km southwest of the 2002 Wei-6-12-1 oil discovery.
The block 22/12 JV partners are: ROC Oil (China) Co. 40% and operator; Horizon Oil Ltd. 30%; Petsec Energy Ltd. 25%; and Oil Australia Pty Ltd. 5%. The China National Offshore Oil Co. is entitled up to a 51% participation in any commercial development within block 22/12.