Hawkley Oil and Gas has been investigating the rapid decline in production from a well in its Sorochynska licence in Ukraine.
The company said Well 201 had already been experiencing a measured decline in production in line with expected performance.
However the Australian-based company said it experienced a sudden “unanticipated increase” in the rate of decline from the well and suspended trading in its shares for a short time while an investigation was carried out.
The suspension of its share trading has now been lifted.
A spokesman said: “Well 201 is still producing, though at a reduced rate in the order of 40% below expectation, and investigation into the more accelerated recent decline is ongoing.
“The company has initiated a detailed technical assessment as to the reason for the well’s changed performance and its rectification.
“Preliminary information indicates that means to restore well performance are available.”