US independent Cobalt has taken the wraps off two deepwater pre-salt discoveries offshore Angola – Lontra and Mavinga.
On block 20, Lontra-1 has reached total depth, and the drilling and evaluation results confirm an oil and gas discovery. Further evaluation, including a drill-stem test, is required to assess Lontra’s potential.
Cobalt said it expects to be able to provide more information on the well prior to year end.
Once testing is complete, the company plans to mobilise the Petroserv SSV Catarina drilling rig to the Orca-1 Pre-salt exploratory well (formerly the Baleia prospect), located about 25km north-east of Lontra, also on block 20.
Turning to Mavinga-1 on block 21 the well is located some 12.5km north-west of Cobalt’s 2012 Cameia discovery. The drill-bit encountered around 30m of net oil pay.
This discovery was confirmed by the successful production of oil from mini drill stem tests, direct pressure and permeability measurements, and log and core analyses.
However, efforts to establish a sustained flow rate from a full drill stem test were not successful. Cobalt is in the early stages of determining what operational issues may have prevented the production from the oil reservoir during the drill stem test.
The company estimates a gross oil column of up to 200m at the crest of the Mavinga structure up-dip of the Mavinga-1 well.
Additional drilling will be required to confirm the ultimate gross thickness of the mound and its reservoir quality; however, the Mavinga discovery is expected to be tied-back to and become part of the planned Cameia development complex in Block 21.
Following the temporary abandonment of Mavinga-1, Cobalt moved the rig Ocean Confidence to drill the Bicuar-1A pre-salt exploratory well located south of the Cameia and Mavinga discoveries.