* Oil price collapse further reduced need for drilling rigs
* Substantial doubt over company's future unless debt converted
* Says 10 of its rigs set to be scrapped
* Hopes to see 50 floating rigs removed from global market
* Shares fall 15% (Adds earnings call, share price)
By Nerijus Adomaitis
OSLO, June 2 (Reuters) - Seadrill announced a writedown of $1.2 billion on the value of its oil drilling rigs on Tuesday and warned its survival hinges on converting parts of its $7.4 billion in debt into equity, sending its shares tumbling.
The company plans to cut 1,400 jobs and lower costs by $130 million over the next 18 months, Chief Financial Officer Stuart Jackson told a conference call.
"Until such time that an agreement is reached to restructure our borrowing commitments, substantial doubt remains over (the) ability to continue as a going concern," Seadrill said in its first-quarter earnings report on Tuesday.
Seadrill's Oslo-listed shares traded 15% lower at 1427 GMT and are down more than 80% year-to-date.
Controlled by Norwegian-born shipping tycoon John Fredriksen, the company struggled even before the COVID-19 pandemic as low oil prices curbed demand for rigs.
Seadrill is hiring bankers and lawyers to overhaul its finances later this year, although it did not name the advisors.
"This industry has two fundamental challenges which are emphasised by recent events - there are too many rigs carrying too much debt," CEO Anton Dibowitz said. "We recognise, along with others in the sector, that a number of our assets are increasingly unlikely to return to the market and need to be scrapped."
Seadrill's impairment charge assumed that up to 10 of its 35 drilling rigs may be scrapped and the company hopes 50 floating rigs will eventually be removed from the global market, Dibowitz said.
Following the impairment, the company reported a net loss of $1.57 billion for the first quarter versus a loss of $295 million a year earlier.
The company on Monday announced its intention to delist from the New York Stock Exchange this month while maintaining an Oslo listing. (Editing by Terje Solsvik, Jason Neely and Barbara Lewis)