Oil and gas condensate output from Kazakhstan’s giant Kashagan project has more than halved from early November levels due to unplanned maintenance that started last week, two industry sources told Reuters on Nov. 26.

Production at the facility stood at 184,000 barrels per day (bbl/d) as of Nov. 25, the sources said, down from 400,000 bbl/d at the start of the month.

The Kazakh energy ministry said last week that Kashagan was undergoing maintenance at a gas compressor unit, which was expected to last for seven days.

The energy ministry said on Nov. 26 that Kazakhstan’s total daily oil and gas condensate output had fallen to 240,700 tonnes from 264,000-270,000 tonnes at the start of the month, equivalent to about 1.9 million barrels per day (MMbbl/d) and 2.09-2.13 MMbbl/d, respectively.

The ministry did not respond to a request for comment about production at the Kashagan project.

Kashagan is being developed by a consortium that includes Eni, ExxonMobil Corp., China National Petroleum Corp., Royal Dutch Shell, Total, Inpex and Kazakh state energy firm KazMunayGaz.

The consortium, NCOC, confirmed that it has been producing oil at a lower than usual pace.

“We are safely working on correcting a technical issue with the gas compressors. It is not unusual for daily production to be reduced for various reasons, including maintenance and this is factored into production planning,” the consortium said in emailed comments.

“Our company is focused on safely returning the unit to normal operation as soon as possible.”