UPDATE 1 — BP flags $3 — 4.5 billion in impairments for third quarter

(Adds details from paragraph 2) By Stephanie Kelly and Shadia Nasralla LONDON, Oct 13 (Reuters) — BP expects to report $3 billion to $4.5 billion of impairments in its third quarter results, relating to its gas and low-carbon energy segment, the oil major said on Tuesday. This is the second time in a year that the British firm has booked large write-downs in its low-carbon business, previously flagging $4 billion to $5 billion in impairments in January. BP declined on Tuesday to comment further on details of the impairment. The refining indicator margin for the quarter is due to be $46.7 per barrel, versus $29.6 per barrel in the second quarter. Realised refining margins are expected to be in the range of $1.9 billion to $2.1 billion. BP in recent years has changed its methodology for refining margins. The US-Israeli war on Iran has disrupted global oil supplies, driving up prices and helping majors book stronger profits. BP expects its gas marketing and trading result to be significantly higher in the third quarter compared with the previous quarter. It expects its upstream production to be 2.19 million to 2.24 million barrels of oil equivalent per day, versus about 2.2 million ba