UPDATE 1-BP's profit more than doubles to hit 5-year high

* Underlying profits rise to $3.8 billion

* Nine-month production rises thanks to field start-ups

* BHP deal to complete on Wednesday(Adds details)

By Ron Bousso

LONDON, Oct 30 (Reuters) - BP's third-quarter profitsrose to a five-year high, boosted by higher oil prices as the$10.5 billion acquisition of BHP Billiton's U.S. shale businesswas set to complete this week.

BP reported on Tuesday that profit had more than doubled inthe third quarter. Underlying replacement cost profit, thecompany's definition of net income, rose to $3.8 billion, farexceeding forecasts of $2.85 billion based on a company-providedsurvey of analysts.

That compared with a profit of $1.86 billion a year earlierand $2.8 billion in the second quarter of 2018.

"Operations are running well across BP and we're bringingnew, higher-margin barrels into production faster throughefficient project execution," Chief Executive Officer Bob Dudleysaid in a statement.

Oil and gas production for the first nine months of the yearincreased to 2.5 million barrels of oil equivalent per day(boed) and was set to rise further with the expected completionof the $10.5 acquisition of BHP's U.S. shalebusiness on Oct. 31, BP said.

In a further sign of confidence, BP said it now expected tofully fund the BHP acquisition from available cash withoutresorting to a rights issue as planned.

The rise in oil prices over the past year to their highestsince late 2014 has boosted revenue for oil companies such asBP. Coupled with deep cost cuts and stricter spending since the2014 downturn, the sector has enjoyed rapid growth in profits.

BP launched nine major oil and gas fields over the pastyear, including in Azerbaijan, Oman, Egypt and Angola that willhelp boost production by 900,000 barrels of oil equivalent perday (boed) by 2021. Most of the production will be gas.

(Reporting by Ron BoussoEditing by Edmund Blair and Louise Heavens)