UK based independent Cairn Energy has successfully tested its SNE-2 appraisal well offshore Senegal.
The firm performed drilling, coring, logging and drill-stem testing (DST), as part of its latest, minimum three-well exploration campaign offshore Senegal, where it made one of the world's biggest offshore discoveries last year.
The results of the SNE-1 appraisal well, drilled using Ocean Rig's Athena drillship, will be used to update resource estimates for the SNE field. The well is now being plugged and abandoned.
The DST was performed over a 12m interval of high-quality pay and flowed at a maximum stabilized, but constrained rate of ~8000 b/d on a 48/64in choke, "confirming the high deliverability of the principal reservoir unit in the SNE-2 well."
Another DST over a 15m interval (~3.5m net) of relatively low quality “heterolithic” pay flowed at a maximum rate of ~1000 b/d on a 24/64in choke, "confirming that these reservoirs are able to produce at viable rates and thus make a material contribution to resource volumes," says Cairn. Flow was unstable due to the 4.5in DST tubing.
Some 216m of continuous core was taken across the entire reservoir interval with 100% recovery.
Initial indications confirm the same 32 degree API oil quality as seen in SNE-1, said Cairn.
The SNE- 2 well is in 1200m water depth and is about 100km offshore in the Sangomar Offshore block. The well reached the planned total depth (TD) of 2800m below sea level. The well has been appraising the 2014 discovery of high quality oil in the SNE-1 well, some 3km to the south.
Cairn Energy Chief Executive Simon Thomson said: "We are delighted with the results of the SNE-2 well and in particular the well tests, which are significant in demonstrating the ability of the reservoirs to flow at commercially viable rates. The results help to confirm the overall scale and extent of the resource base in Senegal and further appraisal activity is expected to lead to future revision of the estimates. We now eagerly look forward to the results of the SNE-3 well."
The three well appraisal campaign, with partner ConocoPhillips, is due also to test the Bellatrix prospect, as well as further appraisal of SNE.
Cairn operates three blocks offshore Senegal – Sangomar (containing SNE-1), Sangomar Deep (containing FAN-1) and Rufisque – under one license. The firm said in May that, to date, at least five prospects and eighteen leads have been identified and continue to be matured to drillable status across the three blocks. Development could be via an FPSO with subsea tie-backs. Production capacity would be around 100 MMb/d in order to accommodate future satellite tie-ins.
FAN-1 was drilled in 2014 in 1427m water depth, 100km offshore in the Sangomar Deep block. Shelf Edge, described as potentially the largest global oil find made last year, was drilled in 1100m water depth, 100km offshore, in the Sangomar Offshore block. Both were made in Albian aged sandstones. 2C resources on SNE are already estimated at 330 MMbbl. 2C resources on SNE are already estimated at 330 MMbbl.
Both wells were the first wells to be drilled offshore Senegal in more than 20 years and the first deepwater wells drilled.
Cairn is operator of the three licenses, holding 40% equity, alongside partners ConocoPhillips (35%), FAR (15%) and PETROSEN (10%).
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