US oil major Chevron has replaced BP as the third-largest non-government controlled oil company in the world, as problems in Russia and currency weakness have hit BP.

BP's market capitalisation was €105 billion as measured by Friday's closing prices, compared with €105.02 billion for Chevron.

BP was the industry's number two until it was overtaken by Royal Dutch Shell after BP's valuation was hit by the Texas City refinery explosion in 2005, which killed 15 workers, and by big project delays.

Exxon Mobil is the largest listed international oil company, with a market capitalisation of €286.6 billion.

Chevron Corp. manages its investments in subsidiaries and affiliates, and provides administrative, financial, management and technology support to the US and international subsidiaries that engage in fully integrated petroleum operations, chemicals operations, mining operations of coal and other minerals, power generation and energy services.

Exploration and production (upstream) operations consist of exploring for, developing and producing crude oil and natural gas, and also marketing natural gas.

Refining, marketing and transportation (downstream) operations relate to refining crude oil into finished petroleum products; marketing crude oil and the many products derived from petroleum, and transporting crude oil, natural gas and petroleum products by pipeline, marine vessel, motor equipment and rail car.

Chemical operations include the manufacture and marketing of commodity petrochemicals, plastics for industrial uses, and fuel and lubricant oil additives.