Amerisur Resources PLC (LON:AMER) shares advanced after the company unveiled flow testing results from the Pintadillo-1 discovery well.
The well produced oil at a rate of 590 barrels per date during testing and Amerisur said the water cut was below 1% and is decreasing.
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In a statement, the company said that the well will be observed for at least three further days, at which point it may run a downhole pump to optimise flow.
It now intends to remap the project before deciding future drilling options.
"This is an exciting and very positive result from Pintadillo-1, ahead of what we had expected,” said John Wardle, Amerisur chief executive.
“Indeed, at current choked production levels, the well will pay back in under a year.
“The strong natural flow from the well, together with a different oil-water contact indicates a separate structure compared to the T-sand production in the southern part of the block, which further diversifies our production base.”
Amerisur shares rose 1.82p or 15.85% to trade at 13.08p.