Any upstream company – private, public or state-owned – may apply for OGP membership. Any association (regional, national or international) of two or more company members and which is directly concerned with exploration and/or production may also be admitted as a member.

Associate membership is open to companies that provide technical field services (this excludes suport services such as transport, catering and cleaning) to an oil or gas company that is qualified to be a member. For full details see the Memorandum and Articles of Association and Regulations.

Fees are based on production levels, geographical spread of upstream interests and a European supplement (where applicable). See the fee structure for details.

Starting from some 14 members in 1974, membership has grown despite industry mergers and acquisitions. Today the membership stands at 82.