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* Total restarted output at Elgin field on March 9
* Elgin to reach pre-leak output capacity in 2015
* To release accident's full details in few weeks time
* Total to "kill" at least 10 wells at Elgin
By Muriel Boselli and Michel Rose
PARIS, March 11 (Reuters) - Total restartedproduction at its huge Elgin gas field in the North Sea onSaturday, almost a year after a major gas leak which cost thecompany millions of euros in lost output and even knocked UKeconomic growth.
Total said on Monday full details of what went wrong at theG4 well would not be released for the next few weeks as it isstill awaiting results of technical and scientific analysis.
The company's G4 well in the Elgin field, which spewed gasfor more than seven weeks after the leak, will return toproduction of 60,000 barrels of oil equivalent per day (boepd)by the end of the month, half its pre-leak level, two Totalexecutives said.
"We can expect that after 11 months of outage, the restartwill take place in a series of restarts and stoppages,"Yves-Louis Darricarrere, Total's head of exploration andproduction, told Reuters in a telephone interview.
The field, located 240 km off the east coast of Scotland andoperated by Total which has a 46.2 percent stake, is expected toreturn to its pre-accident production level in 2015 and reachbetween 130,000 and 140,000 boepd in 2016, a higher level thanforecast before the accident, the executives said.
"The accident has not diminished the reserves, so what wedidn't produce during the time interval (2012-2015) will meanmore production for 2016, 2017 and 2018," Darricarrere said.
Elgin and the nearby Franklin field, which startedproduction in 2001, accounted for nearly 3 percent of Britain'soutput and the shutdown registered on Britain's ailing economy,as falling oil and gas production knocked 0.2 percentage pointsoff gross domestic product last year.
Total, which is one of Britain's biggest investors, alsosaid more stringent safety rules at the field meant it wouldkill a minimum of 10 wells, out of a total of 19, over athree-year period, by injecting some 800 metres of cement perwell.
The production increase will be achieved by the developmentof two big projects: phase two of West Franklin and a revamp ofElgin, expected to be finalised this summer, Darricarrere said.
"The Elgin Franklin field has produced 700 million barrelsof oil equivalent and there is still 500 million to produce,"the executive said.
'HUMILITY LESSON'
News of the gas leak in March last year revived memories ofBP's Deepwater Horizon disaster and had an initiallysevere impact on Total shares, which fell almost a fifth in thetwo months after the initial leak.
The stock has since recovered to trade just 2 euros belowthe 41 euros seen before the accident, but is still valued atonly 7.3 times 12-month forward earnings, a 20 percent discountto its peers globally and a 10 percent discount to BP and Shell.
Darricarrere said the cost of the closure for Total hadreached 1 million pounds ($1.5 million) a day in lost revenue -suggesting a total loss in revenue between March 25, 2012, andMarch 11, 2013 of $526 million.
The company said almost all of its repair bill had beenreimbursed by insurers.
Total insisted the accident, which forced the evacuation of238 workers, was unique to the G4 well and that such an accidentcould not occur in the other Elgin Franklin wells, where bromidewas not used in the same way.
Patrice de Vivies, chairman of Total Holdings UK, said theaccident was a first in the history of the oil and gas industry,but declined to disclose the details of what made it such aspecial case.
He cited pipe corrosion due to a chemical reaction betweenbromide in the drilling fluid and grease in the pipework in ahighly pressurised and heated environment.
But de Vivies acknowledged the equipment was commonly usedin the sector and those circumstances alone were not sufficientto fully explain the accident.
De Vivies, chairman of Total Holdings UK, initially said thegroup needed the go-ahead of Britain's Health and SafetyExecutive (HSE) before it could give a full public explanationbut the regulator later on Monday said it was up to Total todisclose information.
The HSE continues to investigate the Elgin incident.
"We have nothing to hide," De Vivies said in an e-mailedstatement. "The causes of the accident have been identified.Research is still ongoing in several laboratories and we areawaiting their conclusions to communicate all the technical andscientific facts."
De Vivies said the accident had been a jolt for thefifth-largest western oil group, which had used the ElginFranklin field, one of Britain's largest, to showcase itstechnological prowess.
"This is of course a humility lesson," De Vivies said. "Wewere using the best technology there and the best teamsworldwide so it was a shock that it happened to us."
