Sunrise PLC () told investors that it is flowing oil from Deep Well A5 at the BNG project, in Kazakhstan.

Deep Well A5 was previously completed, extensively cleaned and more than 63 metres of reservoir was perforated. The company detailed that the well has now flowed without artificial stimulation for 4 days, without interruption. Over that period the volumes of produced oil increased, it added.

At the most recent measure, production reached 1,500 barrels of oil per day and Sunrise said that further increases in volumes are expected.

shares shot up 22.3% in Thursday’s early deals.

The result is significant, albeit it is too early to predict consistent production volumes, as at present rates Deep Well A5 more than doubles the company’s oil output.

A 90-day production test is being planned, which will also aid a new third-party review of the project’s reserves.

Meanwhile, work continues on other deep wells which have already been drilled to bring them into production in due course.

“While we need to be careful not to get over excited, as it is possible the continuous flows exhibited over the past 4 days might be interrupted or reduced as happened before, the strength of the flows and the uninterrupted 3 day period lead are extremely encouraging,” said Clive Carter, Caspian executive chairman.

“They lead the company’s management to believe Deep Well A5 will be a mainstay of the production expected over the coming years from the large quantities of deep oil believed to be present on the Airshagyl structure.”