OPEC document warns of uncertainty

BRUSSELS (Reuters) - OPEC faces considerable uncertainty over how much to invest in supplying oil, with crude demand seen in the range of 29 million to 38 million bpd by 2020, a document tabled at EU-OPEC talks on Tuesday showed.

"Scenarios for the call on OPEC crude oil suggest that the range of uncertainty for OPEC oil is considerable," said the document, seen by Reuters.

"This translates into an uncertainty gap for upstream investment needs in OPEC member countries of over $300 billion," it added.

The document warned the gap between supply and demand for middle distillates would grow, unless there was more investment in diesel-oriented projects.

"This evolving gap will likely drive price differentials towards a premium for diesel and could also have an impact on the absolute level of product and crude prices," it said.

(Reporting by Pete Harrison)