A statement on the Australian's official website (www.markwebber.com) said he suffered "bruising and concussion."
Webber added: "I've got no recollection of the accident or how it happened -- the team is looking into the details to find out more.
"I'm quite sore this morning and am pretty bruised and have got a stinking headache.
"Thanks to the medical team at the track and here at the hospital who did a great job and are looking after me very well.
"On a positive note it's great that the boys in car no. 14 managed to bring home the victory which is a fantastic way to finish off the season. I'm already looking forward to getting out there again next year."
Webber was taken to hospital in Sao Paulo where he will undergo further checks before returning to the United Kingdom later this week.
The 2009 Formula One world champion and current McLaren Mercedes driver, Jenson Button, tweeted: "Glad to see @AussieGrit is OK after his shunt at Interlagos @FIAWEC, that was a big one matey."
After a 12-year career in Formula 1, former Red Bull driver Webber joined the Porsche team in the Endurance series where he finished ninth overall.
(Writing by Greg Stutchbury and Tom Hayward; Editing by Peter Rutherford and Justin Palmer)
