DEA Deutsche Erdoel AG was an international oil and gas company headquartered in Hamburg, Germany. It was a subsidiary of L1 Energy. In 2018, DEA owned stakes in oil and gas licenses in various countries and operated natural gas underground storage facilities in Germany. DEA is a derivation from Deutsche Erdöl-Aktiengesellschaft, the original name of the company. On 1 May 2019, DEA merged with Wintershall to form Wintershall Dea.

Wintershall Holding GmbH, based in Kassel, was Germany's largest crude oil and natural gas producer. It was a wholly owned subsidiary of BASF. The company was active in oil and gas exploration and production with operations in Europe, North Africa, South America as well as Russia and the Middle East region. Wintershall employed more than 2,000 people worldwide. In the 2018 financial year the company produced around 171 million barrels of oil equivalent (boe) of oil and gas. Revenues amounted to 4.09 billion euros.