The company didn't provide the name of the buyer nor the price received.
Nostrum acquired Rostoshinskoye in 2013 along with 2 other fields near its flagship Chinarevskoye field.
The exploration period under Nostrum's contract for Rostoshinskoye had been due to end in August 2022.
The field's contingent resources were assessed at 31.3 millionbarrels of oil equivalent at the end of last year.In October 2020, Nostrum sold its rights for the Darinskoye and Yuzhno-Gremyachenskoye fields in the pre-Caspian basin.
Nostrum has endured a difficult few years, amid production setbacks, the delayed completion of a gas treatment unit and low oil prices.
Its revenues were almost unchanged year on year in the 1st half at $92.3 million, as a slide in production to 18,107 barrels of oil equivalent/day from 23,528 boe/d more than offset the gain from higher oil prices.
Nostrum has invested over $1 billion into its infrastructure in North-western Kazakhstan.
