Aberdeen-based Faroe Petroleum said it expects production to average 5500-6500 barrels oil equivalent per day. In August Faroe said it expected average production to be at the lower end of the range of 7000-9000 boepd.
The cut reflects the operating challenges faced in Norway by Faroe Petroleum, which found the timetable for restoring production from a key field changed in the course of yesterday.
In its interim results announcement released at 7am yesterday Faroe Petroleum said: "As a result of the extended maintenance shut-in period on the Njord A facility, production guidance for the full year 2013 is revised down to 5500-6500 boepd. The operator Statoil has advised that resumption of production is expected around year end."
At around 1.30pm Faroe issued an update in which it said the resumption had been delayed until the second quarter of 2014.
Faroe said it had been told yesterday morning by Statoil that start-up of the Njord and Hyme fields had been delayed to allow "additional time to plan and undertake remedial works" following a structural review.
Faroe has 7.5% stakes in the Hyme and Njord assets. Hyme came onstream as satellite to Njord in March.
With shares in Faroe Petroleum closing down 9.5p at 123p, yesterday the news about production may have unsettled investors.
But in the interim results announcement chief executive Graham Stewart said the company pursues a "clear and focused strategy" that should deliver success in future.
Mr Stewart said the portfolio of producing fields amassed by Faroe generates enough cash to help fund an active drilling programme, even at reduced output rates recorded following the Njord A shut-in.
With £66.5m cash at June 30 and debt facilities confirmed, Faroe is preparing for what Mr Stewart said would be its most active exploration and appraisal drilling campaign to date. It has six Norwegian exploration wells scheduled.
Mr Stewart underlined Faroe Petroleum's enthusiasm for the UK. The company has extensive acreage west of Shetland and in the Central North Sea. It produces from the Blane field.
With £74.7m tax losses it can set against UK revenue, Faroe is keen to increase production in the country.
Production averaged 7890 boepd in the first half and 8581 boepd in the same period last year.
The company made £17.6m pre tax profit. It lost £15.9m in the same period last year, after incurring hefty exploration expenses.