* Impossible to say when Wafa will restart - CEO
* Its Libyan production 180,000-200,000 boed -analyst
* Eni to report Q3 results on Oct. 30 (Recasts, adds analyst, background)
ROME, Oct 23 (Reuters) - Disruptions to oil production in Libya are "very worrying" to Italian oil and gas group Eni , its chief executive said on Wednesday, as losses there continue to weigh on its prospects for output and profit.
A combination of strikes, militias and political activists have disrupted production at the majority of Libya's oilfields and ports since the end of July.
Eni, the world's seventh-biggest oil major, is the largest foreign operator in Libya in terms of volume. Production disruptions there prompted the company in August to cut its yearly projections.
"The Wafa field is shut, while gas is only produced for power generation inside the country," Eni Chief Executive Paolo Scaroni said on the sidelines of a conference.
Wafa is one of four major oil and gas areas that Eni operates in Libya in a joint venture with the National Oil Company.
It is impossible to say when Wafa would return to production, Scaroni said. "I wish we could know; it's impossible."
Before Libya's 2011 revolution, the Italian state-owned group produced around 270,000 barrels of oil equivalent per day. It has oil and gas contracts that run to 2042 and 2047, respectively.
"With Wafa shut, I'm estimating Eni's production at around 180,000-200,000 barrels per day," a Milan-based oil analyst said.
Disruptions in Libya have already cost majors including Eni and Marathon Oil billions of dollars in lost revenue, while sending global prices higher.
NOC said on Tuesday that Libya's oil production was stable at around 600,000 barrels per day, where it has been for about a month, as the government worked to end protests.
Eni's net profit in the second quarter fell 55 percent, partly due to problems in Libya. It is due to report third-quarter results on Oct. 30. (Reporting by Alberto Sisto and Stephen Jewkes; editing by Jane Baird)