A combine of Afren PLC and Amni International Petroleum Development Company Ltd. of Nigeria has tested a light oil discovery on OML 112 off southeastern Nigeria 45 km southeast of Port Harcourt.
Afren ran three drillstem tests at the Okoro East discovery well, on an undrilled structure 2 km east of the companies’ producing Okoro field, in Tertiary sands equivalent to those that produce at Okoro. The tests confirmed high-quality, 38-40° gravity oil in reservoirs with 30-35% average porosity and permeabilities of several darcies.
The Transocean Adriatic IX jack up drilled the well to 8,751 ft measured depth, 8,016 ft true vertical depth. The well encountered 549 ft true vertical thickness of net oil pay and 41 ft of net gas pay in excellent quality reservoir sands, Afren said. Drilled on a prospect mapped on good quality 3D seismic data, the well also targeted a deeper horst block structure, a play concept not previously explored on the block.
“The discovery of significant pay in the previously unexplored deeper zones opens up further prospectivity at similar levels on the main Okoro field and elsewhere on the block,” Afren said.
Pressure data helped with the company’s structural understanding of the field and support the predrill mean volumetric estimates of 47 million bbl of oil in place in the Okoro reservoirs and 110 million bbl in place in the deeper reservoirs.
Based on test data, the company expects future horizontal production wells at Okoro East will be capable of 4,500-7,000 b/d/well.
Afren will drill two production wells using the free wellhead slots on the Okoro platform in the second half of 2012, to be tied back to the Armada Perkasa FPSO, and as many as eight production wells under a full-field, stand-alone development scenario.