Otto Energy Limited, as operator of the Service Contract 51 joint venture onshore the island of Leyte in the Philippines, provided the following update on the Duhat-2 exploration drilling campaign.
Otto is pleased to advise that at 1600 hours (local time) July 24, the Desco Rig 30 drilling rig commenced drilling the Duhat-2 exploration well. Drilling is expected to take approximately 31 days on a dry-hole basis.
The forward plan is to drill the 8.5 inch pilot hole to 755 feet (230 meters) and then open this hole to 17.5 inch prior to setting the 13.375 inch casing.
Location and Proposed Depth
The exploration well, Duhat-2, is intended to be drilled to 3,445 feet (1,050 meters) and is proposed to test the San Isidro anticline on the western side of the northwest Leyte peninsula.
The earliest well drilled on northwest Leyte was a stratigraphic test at San Isidro-1 completed in May 1958 on the north-western tip of the island to 1,499 feet (457 meters). No hydrocarbons were detected. This was followed by the off-structure Calubian-1 in November 1958 which reached a total depth of 8,373 feet (2,552 meters). Oil shows were reported in side wall samples from the Tagnocot Formation despite the well being off structure, importantly these shows were in good quality sandstones now being targeted at Duhat-2.
There have been two previous attempts to test the crest of the San Isidro anticline with San Isidro SX-1/2 in 2000 and Duhat-1 in 2011. Both wells were programmed to reach a total depth of 3,281 feet (1,000 meters), though failed to drill beyond feet 984 feet (300 meters) due to an inability to progress beyond stressed claystone formations. A review of lessons learned from the Duhat-1 and Duhat-1A drilling campaign in 2011 highlighted the need for a rig with increased draw works, hook load and mud handling capacity to mitigate the risk of stuck pipe incidents and maximise the ability to reach prognosed reservoir intervals beneath the problematic claystone formations.
During 2012, Otto Energy, on behalf of its Joint Venture partners, acquired 93 miles (150 kilometers) of new, high quality 2D seismic data over the San Isidro anticline. Mapping with the better quality 2012 seismic data and regular line spacing has confirmed a large faulted anticline and allowed the optimal placement of the Duhat-2 well away from the fracture zones seen at Duhat-1.
The proposed Duhat-2 well is planned to test potential for multiple oil bearing sand intervals in the Middle Miocene Tagnocot Formation. Prospective Resource oil volumes range from approximately 1 to 88 million barrels, with a mean Prospective Resource of 34 million barrels.
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