Cairn said the well, which was being drilled to evaluate Upper Jurassic and Middle Jurassic objectives, reached a total depth of 3711 metres and confirmed the presence of heavy oil over a gross interval of 110 metres in the Upper Jurassic section.
Cairn said it was the same interval which was originally tested in the 1968 MO-2 well, about two kilometres away, and added it had plugged and abandoned the well without testing.
“Reservoir quality and the oil gravity in the Upper Jurassic across the Cap Juby structure require further evaluation by Cairn and its joint venture partners,” the company said.
“Work is ongoing to correlate the core and log data from JM-1 with other wells on Cap Juby to evaluate the extent of moveable hydrocarbons and how any further assessment should be conducted.”
Cairn added the Middle Jurassic objective was encountered in the well but with limited primary porosity and said it was continuing to evaluate well logs and side wall cores.
Cairn operates the Juby Maritime 3 licence with a 37.5% interest and is partnered by London-listed Genel Energy with a 37.5% interest and Moroccan state-run National Office of Hydrocarbons & Mines with a 25% stake.
JM-1 was the first of nine wells Cairn is planning this year, with its attention now turning to the Fan-1 well on the Sangomar, Sangomar Deep and Rufisque blocks off Senegal.
The well will target multiple stacked structural and stratigraphic fan closures interpreted as trapping a variety of potentially thick, high quality clastic reservoirs.