* Santos to writedown $1.24 billion in assets as oil price sinks
* Excludes Gladstone LNG stake from the non-cash charges
* Stock tumbles more than 4 pct, before partial recovery (Updates with details of Gladstone stake, share price)
SYDNEY, Feb 12 (Reuters) - Santos Ltd will write off A$1.6 billion ($1.24 billion) in impairments on a host of assets as lower oil prices take a toll on operations, the Australian oil and gas company said on Thursday.
"This is a reflection of the current oil price environment. The non-cash impairment charges are not expected to impact Santos' investment grade credit rating or debt facilities," Chief Financial Officer Andrew Seaton said in a statement.
Santos stock dropped more than 4 percent in early trade, before recovering to trade 2-percent down at A$7.56 by 0040 GMT.
Excluded from the impairments was Santos' 30 percent-owned Gladstone liquefied natural gas project in eastern Australia, costing $18.5 billion and on track to start up in the second half of 2015, according to the company.
Analysts, expecting Santos to report about a 6-percent rise in underlying net profit of around A$535 million for 2014, were divided on whether Gladstone would be included in any impairments, foreshadowed last month.
Santos warned in January that guidance on costs, royalties and spending was subject to finalisation of its accounts, which included an impairment review.
It confirmed at the time that it met its production guidance in 2014 with 54.1 million barrels of oil equivalent (mmboe), while the average oil price during the quarter fell 20 percent to A$92 per barrel.
Santos reports its 2014 financial results on Feb. 20.
The firm has resisted calls to sell new shares to protect its credit rating, already cut by one notch in December, and instead pared planned capital spending for 2015 by a quarter to $2 billion and lined up an extra $1 billion loan in December.[ID:nL4N0V02Q4} ($1 = 1.2953 Australian dollars) (Reporting by James Regan and Colin Packham; Editing by Joseph Radford)