Oil prices were down in Asia Wednesday as investors weighed US petroleum industry data showing a build-up in crude stockpiles and news that shipments from a Libyan port were halted due to tensions. US benchmark West Texas Intermediate for delivery in December was down 15 cents at $47.75 and Brent crude for December was trading 14 cents lower at $50.40 at 0600 GMT.–AFP

The industry-funded American Petroleum Institute said US crude inventories rose by 2.8 million barrels in the week to October 30, according to Bloomberg News.

The industry report comes ahead of the release later Wednesday of the official US Department of Energy data on commercial crude stockpiles which is also expected to show an increase.

A build-up in the stockpiles indicates softer demand in the world's top oil consumer and is negative for prices.

Libya's Petroleum Facilities Guard meanwhile halted crude shipments from Zueitina port indefinitely due to the widening conflict between the strife-torn nation's rival governments, Bloomberg News said.

Tankers seeking to load crude at the port must register with the National Oil Corp. administration loyal to the internationally recognised government in the country's eastern region, Bloomberg quoted Petroleum Guard spokesman Ali al-Hasy as saying.

"Supply is still the story," Jonathan Barratt, chief investment officer at Ayers Alliance Securities in Sydney, told Bloomberg.

"Geopolitical issues will always put a base under prices and there is a solid range for oil."

Oil prices have fallen by more than half from peaks of over $100 a barrel in June last year.

A global economic slowdown led by top energy guzzler China has led to demand not keeping pace with the crude supply glut which is expected to persist well into next year.