German producers include BEB Erdgas und Erdoel, Mobil Erdgas-Erdoel, DEA, formerly part of RWE and Engie E&P Deutschland.

BASF's Wintershall produces modest gas volumes at home but more abroad, and leads in domestic crude oil.

BVEG member firms had a turnover of 1.7 billion euros ($2.1 billion) in Germany last year, the same as in 2016, it said in its annual report.

German gas producers have been trying to keep up production but the government passed a law in 2016 imposing heavy limits on novel fracking technology that could potentially have helped access untapped shale gas reserves.

Germany sourced 7.1 percent of its gas demand from domestic sources last year, down from 8 percent in 2016, while importing the rest, the report showed.