Regarding the Red Line Agreement:

From Wikipedia (Beware using Wikipedia.  Who writes it?) Page [Article is accurate but doesn't tell much.]

    Turkish Petroleum, changed to Iraqi Petroleum Company.

None of the partners to the Red Line Agreement of 1928 can seek oil in the former territory of the Ottoman Empire (sic: the Red Line was somewhat inaccurate) without permission of the other partners.  It created a sort of cartel: by limiting exploration, one limits production later.

From Helen Chapin Metz, ed. Iraq: A Country Study. Washington: GPO for the Library of Congress, 1988. Page

The discovery of oil hastened negotiations over the composition and the functions of TPC. The shareholders signed a formal agreement in July 1928. The Anglo-Persian Oil Company, the Dutch Shell Group, the CFP, and the Near East Development Corporation (which represented the interests of five large American oil companies) each held 23.7 percent of the shares, and Gulbenkian the remaining, but nonvoting, 5 percent. TPC was organized as a nonprofit company registered in Britain that produced crude oil for a fee for its parent companies, based on their shares. TPC was limited to refining and marketing for Iraq's internal needs to prevent any competition with the parent companies. The Anglo-Persian Oil Company was awarded a 10 percent royalty on the oil produced, as compensation for its reduced share in TPC.