In a London Stock Exchange announcement, the company reported that the well, drilled into the northern part of the East EWS I field, had not encountered an oil-water transition zone.
It said oil had flowed from a zone that was 10 metres below the previously assumed oil-water contact point, which was 1872 metres subsea.
“This is likely to have a positive impact on both the production and reserves in this area of the field,” Exillon stated.
The well was spudded at the end of May and drilled in 18 days, flowing water-free oil to the surface with a combined test flow rate of 721 barrels per day on an eight millimetre choke.
The well had encountered the Jurassic P reservoir at a depth of 1857 metres, confirming 14.9 metres of effective vertical net pay, and 30 metres of effective measured net pay for production due to the angled trajectory of the wellbore.
Exillon added that EWS I-54 also hit 4.5 metres of effective vertical net pay of pre-Jurassic reservoir, which was tested separately.
This pay zone resulted in a natural flow rate to surface of 263 bpd on an eight millimetre choke.
The company stated that the well was drilled directionally 64 metres south-east of Pad 5 and was now connected to its existing production facilities.
In addition to West Siberia, Exillon holds assets in Timan-Pechora region of Russia.
The company recorded an average production rate of 12,330 barrels per day for the month of July, with the majority of production deriving from its West Siberian project (9182 bpd).