Cairn Energy did not get the results the company was hoping for after drilling deeper at the Vega-Regulus (VR-1) well offshore Senegal, following its winning streak in the area.
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The Stena DrillMAX is mobilizing to the SNE-6 appraisal and interference test well. Image from Stena. |
Upon encountering the deeper carbonate exploration targets at 3899m to the Albian sandstone reservoir, Cairn says the well showed indications of hydrocarbons at the base of the well in tight formation that is not currently viewed as commercial.
A significant amount of new stratigraphic and log data has been recorded, which Cairn says will be incorporated into the regional geological model.
“VR-1 is the sixth successful appraisal well on the SNE field and has encountered some of the best quality reservoirs found to date, some 5km from the original SNE-1 discovery well,” says Simon Thomson, Cairn Energy chief executive. “The drilling program is currently ahead of schedule and significantly under budget. We look forward to commencing operations on SNE-6.”
Joint venture partner FAR Ltd. says that its preliminary assessment of the data indicates that the hydrocarbons are not commercially significant.
“The results of the VR-1 well have been an overall success as the objectives of the appraisal of the SNE field at this location were met and in some cases exceeded,” says Cath Norman, FAR managing director. “We see evidence at this stage of hydrocarbons in the secondary target in the limestones but at this stage, FAR’s interpretation is that these are more than likely not of economic significance although interpretation of the wireline logs and samples taken has not been completed.”
“The limestone target was high risk with FAR carrying a 10% chance of success and we look forward now to completing the SNE-6 well and the connectivity measurements across the SNE field as planned. Because of the efficient drilling in VR-1 and SNE-5 to date, the drilling program is significantly under budget which is a very pleasing achievement by the operations team,” says Norman.
Over at the VR-1 appraisal target, the well encountered the targeted lower (500 series) reservoirs within the oil column as anticipated, confirming the reservoir presence, fluid contacts and fluid quality in line with the results from the previous wells, says Cairn. Preliminary analysis indicates the lower (500 series) reservoir quality is better and slightly thicker than previously encountered.
“The appraisal results from VR-1 are very encouraging, as the well is a significant step out, some 5km west from the line of wells drilled to date, including the SNE-1 discovery,” says Cairn. “The results will be useful for the planning of the first phase of development – the lower 500 series reservoirs are the better connected, more tabular, highly productive sands, where water-flooding should yield recovery factors of 30% or more. The well result confirms the predictability of the mapped reservoir over a wide area giving confidence to the reservoir engineering models. A resource update will be provided later this year following completion of the appraisal program, however VR-1 has confirmed the 1C proven resources for the field.”
The well is being plugged and abandoned and the Stena DrillMAX drillship is mobilizing to begin operations shortly on the SNE-6 appraisal and interference test well, about 2km to the south of the SNE-1 discovery well.
Last week, Cairn discovered a 97m oil column at VR-1, with greater than expected net pay, and the thickest net pay of all appraisal wells drilled in the SNE oil field to date.
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