MOSCOW, Feb 25 (Reuters) - Kazakhstan's vast Tengiz oil field is restoring production more slowly than planned due to loading disruption at the Caspian Pipeline Consortium (CPC) marine terminal near Novorossiysk, Russia, caused by bad weather and drone alerts, two industry sources told Reuters.

Kazakhstan has faced a perfect storm of disruption to its oil sector due to Ukrainian drone attacks on the CPC, which pumps 80% of its exports, and power outage which halted production at Tengiz, which accounts for 40% of Kazakhstan's output.

After the transformer fires at Tengiz, Kazakhstan has been restoring production at the world’s deepest producing supergiant oil field but is coming up against constraints on the CPC which pumps oil to the Black Sea.

Two sources who spoke on condition of anonymity due to the sensitivity of the situation said oil production at Tengiz increased to 790,000 barrels per day (bpd) on February 24, up from 660,000 bpd the previous day.

But that was still short of the previously planned level of 950,000 bpd, the sources said. According to Reuters calculations, the current output level at Tengiz is 17% below the forecast.

TCO's press service did not immediately respond to Reuters' request for comment. CPC's press service declined to comment.

The Tengiz field, in western Kazakhstan along the shore of the Caspian Sea, along with the Korolev field, is estimated to have recoverable crude of around 11.5 billion barrels.

TENGIZ

Tengiz operator Tengizchevroil $(TCO)$, led by US-based Chevron, last week said output at the field was being ramped up in stages.

One of the sources noted that Tengiz was technically ready to meet this schedule, but oil intake into the CPC system was restricted due to delays with tanker loading at the consortium's Black Sea terminal in Yuzhnaya Ozereyevka near Novorossiysk.

"The schedule for shipments at Yuzhnaya Ozereyevka was delayed by about five days," the source said. "There was not enough tank storage to compensate for the delay, so oil intake was limited."

Last week, the CPC terminal was closed for at least three days, according to a source with the grade's exporter. He added that loadings have been regularly disrupted recently due to weather or drone danger alerts.

According to another industry source, stormy weather hampered both the mooring and loading of tankers at the CPC terminal, as well as underwater vessel inspections, which became mandatory at Russian ports in 2025 as a safety measure.

Discounts for February CPC Blend widened to the deepest levels against dated Brent since late 2022 as buyers turned away from the market frustrated by export instability, Reuters reported.

CPC restricted oil transshipment in December after a Ukrainian drone strike damaged one of its berths, restoring full capacity only by the end of January. Production at Tengiz was halted on January 18 following a power outage and began gradually returning to normal on January 31.

TCO exports most of its crude via the CPC system, while some volumes are redirected through alternative routes including the Baku-Tbilisi-Ceyhan $(BTC)$ pipeline and to Germany via the Druzhba pipeline.

(Reporting by Reuters; editing by Guy Faulconbridge, Alexandra Hudson)