JKX, which has headquarters in London, said it averaged a production rate of 11,100 barrels of oil equivalent per day, in line with its previous estimates.
The company said second quarter production was split between Ukraine and Russia, with the latter accounting for the bulk of the gains. JXK said a "small contribution" came from its operations in Hungary.
JKX Chief Executive Officer Paul Davies said in a statement Monday the production during the second quarter was boosted in part because of its increased activity in Ukraine.
JKX Oil & Gas said last week it started a multi-stage hydraulic fracturing operation at its Rudenkovskoye license area in eastern Ukraine. The company said a nine-stage hydraulic fracturing campaign in Ukraine was "probably the largest" campaign of its kind in Europe to date.
JKX gave no indication of the reserve potential for the eastern Ukrainian field.
Russia is the world's largest natural gas producer. The Ukrainian government said there may be enough natural gas in shale plays to meet the country's needs without imports.