BP is an integrated oil and gas group based in the United Kingdom. Co. is engaged in the exploration and production of crude oil and natural gas; refining, marketing, supply and transportation; and the manufacture and marketing of petrochemicals. Co. operates globally, with business activities in Europe, the U.S., Canada, Russia, South America, Australasia, Asia and parts of Africa. Co. operates in two business segments: Exploration and Production - including oil and natural gas exploration and development and production; and Refining and Marketing- activities include the refining, manufacturing, supply and trading, marketing and transportation of crude oil, petroleum and petrochemicals.

Eni is engaged in the oil and gas exploration and production, gas marketing operations, management of gas infrastructures, power generation, petrochemicals, oil field services and engineering industries. Co.'s operations are divided into three segments; Exploration and Production (oil and natural gas exploration and field development and production, as well as LNG operations), Gas and Power (supply, trading and marketing of gas and electricity, managing gas infrastructures for transport, distribution, storage, re-gasification, and LNG supply and marketing), and Refining and Marketing (supply of crude oil, refining and marketing of refined products). Co. maintains operations in 73 countries.

Repsol is an oil and gas company. Co. is engaged in all the activities relating to the oil and gas industry, including exploration, development and production of crude oil and natural gas, transportation of oil products, liquefied petroleum gas (LPG) and natural gas, refining, the production of a wide range of oil products and the retailing of oil products, oil derivatives, petrochemicals, LPG and natural gas, as well as the generation, transportation, distribution and supply of electricity. Co. operates in more than 40 countries. Co.'s operations are divided into four segments: Upstream, Downstream, LNG and Gas Natural Fenosa.

Royal Dutch Shell is a holding company. Through its subsidiaries, Co. is engaged in the oil and gas industry. Co. reports its business through four segments: Integrated Gas, which engaged in the liquefaction and transportation of gas and the conversion of natural gas to liquids to provide fuels and other products; Upstream, which engaged in the exploration for and extraction of crude oil, natural gas and natural gas liquids; Downstream, which engaged in oil products and chemicals manufacturing and marketing activities; and Corporate, which comprising Co.'s holdings and treasury organisation, its self-insurance activities and its headquarters and central functions.

Total is an international integrated oil and gas company also active in solar and biomass energy sources. Co. engages all aspects of the petroleum industry, including Upstream operations (oil and gas exploration, development and production, and LNG (Liquefied Natural Gas)) and Downstream operations (refining, petrochemicals, specialty chemicals, marketing and marketing and trading and shipping of crude oil and petroleum products). In addition, Co. is engaged in the coal mining and power generation sectors. Co.'s worldwide operations are conducted through three business segments: Upstream, Refining & Chemicals, and Marketing & Services.