By OGJ editors
HOUSTON, Mar. 22 -- The Sea Lion oil discovery in the North Falkland basin is “highly likely to prove commercial,” and at least three more appraisal wells will be drilled to probe its extent, said Rockhopper Exploration PLC.
Rockhopper also said it will begin development planning for Sea Lion and is considering extending its campaign to include more appraisal and exploratory wells.
The 14/10-4 downdip appraisal well went to a total depth of 2,801 m 2.3 km west-northwest of the 14/10-2 discovery well, the islands’ first well to flow oil to surface. The wells are in less than 550 m of water on the PL032 license.
Rockhopper said 14/10-4 was successful, proving a thick, high quality reservoir package, a substantial oil column, and recognition of the first oil-water contact (OWC) in the license to date. The geological prognosis came in close to prediction.
The top Sea Lion reservoir sands were encountered 66 m (216 ft) downdip from the 14/10-2 discovery well. A total reservoir package of 107 m (351 ft) comprising four main sands was encountered with a net to gross of 76%. Average porosity is 20% and permeability is over 100 md.
Thirty meters of net pay were encountered in the upper of the four sands, representing the main Sea Lion southern fan. The gross oil column now proven in the main Sea Lion southern fan is 104 m (341 ft).
Three meters of net oil pay are present in the lower sands; these thin oil sands are below the water leg of the upper sands, indicating at least one additional oil column. The lower fan encountered in 14/10-2 was neither strongly developed nor prognosed at this location, but the thin lower oil sands at 14/10-4 confirm prospectivity for lower fan sequences developed elsewhere downdip.
A mini-DST (wireline drillstem test) was performed using a dual-packer MDT tool over a 1-m interval at 2,486 m (drilled depth) in the oil column. This test successfully flowed oil into the wellbore, providing additional samples and pressure build-up data. These data indicate that flow rates and producibility at the location could be significantly better than at 14/10-2. A single MDT sample chamber was opened on the rig and initial wellsite analysis indicates a medium grade oil similar to that in 14/10-2.
An OWC is indicated from cores, wireline logs, and MDT pressure and sampling data at a depth of 2,503 m drilled (2,477 m TVD subsea).
The northern fan penetrated by the 14/10-3 well is represented as a thin sand at the base of the main section at this location. The sand was in the water column. Potential remains in the main northern fan updip of this location.
The well cut 57.5 m (189 ft) in two conventional cores from near the top of the reservoir with 100% recovery. The extensive reservoir information from cores, wireline logs, seismic, and wireline MDT test data is being evaluated to establish reservoir extent across the area for both the upper and lower fan systems.
Rockhopper believes the results of this successful first appraisal well will greatly increase the contingent P90 volume for this oil discovery. The P50 and P10 contingent volumes will be defined as the appraisal program progresses through the rest of 2011.
The well will now be plugged and abandoned as planned. The Ocean Guardian semisubmersible will proceed to drill the Ninky prospect, in which Rockhopper has a nonoperated 7.5% working interest.
Map from Petrobras.
Photo from Borealis AG.
