Total plans to buy back $1.5 billion (1.1 billion pounds) of shares by the end of 2018 after purchasing around $600 million in shares during the first half of the year as part of its $5 billion 2018-2020 share buyback programme announced in February.

"We will realise the $1.5 billion in 2018 on top of the 2 billion scrip share buyback," Chief Executive Officer Patrick Pouyanne told investors in New York.

"The share buyback is a way to share additional revenues with our investors. In February, we said up to 5 billion because oil was still at around $60, this time I can confirm that the $5 billion will be bought back in 2018-2020," Pouyanne said.

Crude oil prices rose to a fresh four-year high on Tuesday. Brent crude futures were up nearly 1 percent at $81.95 by 1513 GMT. [O/R]

Although Total was benefiting from the high oil prices, which has enabled it to generate strong cash flow, and launched new projects, Pouyanne said the oil market was expected to remain volatile in the long-term.

He added that oil demand was strong, supported by fundamentals, but it was sensitive to uncertainty over global economic growth.

Pouyanne said oil companies were still prudent on investments and this could have an impact in the next three to four years, which could support oil prices.

Total kept its production growth target of 6 to 7 percent per year from 2017 to 2020, and capital investments for the same period at $15 billion to $17 billion.

It also maintained coats savings target of $5 billion per year by 2020 compared to the 2014 base.

Pouyanne said that although Total will maintain discipline on costs, it will continue to give the go-ahead to projects in its portfolio with a low break-even point.

Following a recent string of acquisitions and discoveries, Total has a pipeline of major, and short-cycle projects to be approved by 2020 which should add more than 700,000 barrels of oil equivalent per day (kboe/d) of production.

This will contribute to 5 percent average growth in production from 2017 to 2022.

"Over the past three years, Total has demonstrated a track record of delivering on its objectives including production growth, cost reduction, capital discipline, and asset sales," the French company said in a statement.

It added that with Brent oil prices at $60 per barrel, its cash flow was expected to increase by $7 billion from 2017 to 2020 and return on equity to increase to 12 percent, which would enable it to continue to reward shareholders.

Total's shares closed up 1.2 percent, among the top gainers in France's CAC 40 <.FCHI> index, which was up 0.05 percent.

(Reporting by Bate Felix; Editing by Sudip Kar-Gupta and Adrian Croft)

By Bate Felix