Occidental Petroleum has reported preliminary worldwide proved reserves, on a consolidated basis, of 2.98 billion barrels of oil equivalent at year-end 2008, compared to 2.87 billion barrels of oil equivalent at the end of 2007.

According to the company, in 2008, its consolidated subsidiaries had proved reserve additions from all sources, before the effect of price-related revisions, of 463 million barrels of oil equivalent (boe), compared to production of 221 million boe, for a production replacement ratio of 210%.

At the end of 2008, Occidental’s consolidated reserves-to-production ratio, assuming production remained at the 2008 level, was 13.5 years. Occidental’s costs for exploration and development activities were $4.4 billion.

Additionally, Occidental incurred $3.5 billion in property acquisition costs. All of the acquisitions were domestic, mainly in the Rocky Mountains and the Permian Basin.

Excluding purchases of proved reserves and the effect of price revisions, the company added 253 million BOE of proved reserves on a consolidated basis, of which improved recovery provided 98 percent and extensions and discoveries provided 9 percent, partially offset by non-price-related negative revisions of 7 percent, said the company.

Occidental Petroleum Corporation is an international oil and gas exploration and production company, as well as a North American chemical manufacturer. The company claims to be the fourth-largest U.S. oil and gas company, based on market capitalization of $47 billion.