Abu Dhabi: US-based Occidental Petroleum Corporation has said it will invest about $500 million over the next three to four years to appraise and develop Jarn Yaphour and Ramhan oil and natural gas fields in Abu Dhabi, according to a statement the company made available on its website.

Occidental said it had signed a preliminary agreement with the Abu Dhabi National Oil Company (Adnoc) to appraise and develop the fields.

An official for Adnoc reached by Gulf News on Thursday declined to comment.

Under the terms of the agreement, Occidental said it will operate both fields and hold a 100 per cent interest in the newly created concessions.

Dr Ray R. Irani, chairman and CEO of Occidental, said: "This is an important step in the implementation of our growth strategy and in our relationship with the emirate of Abu Dhabi. The development of these two fields provides an exciting opportunity to create value for the people of Abu Dhabi and for our stockholders."

The Jarn Yaphour field is located onshore near Abu Dhabi city. Occidental said development activities at the field will commence immediately and first production is expected next year.

"Gross production from the initial development is anticipated to be around 10,000 barrels of oil equivalent per day," said the US company.

Appraisal activities at the Ramhan field will commence immediately and, if technically and commercially successful, production from the Ramhan initial development is also expected to be in the 10,000 barrels of oil equivalent per day range, Occidental added.

"First production from the field could commence as early as 2011," it said.

Abu Dhabi's production accounts for nearly 94 per cent of the UAE's crude output.

The country's oil will last 92 years at current production levels, recent estimates by global energy major BP show.

The UAE's output currently is about 2.66 million barrels per day.

Its proven oil reserves of 97.8 billion barrels make up 7.9 per cent of the world's total.