Reserves consist of oil and gas in the reservoir considered producible under existing economic and operating conditions. Proved reserves include those now developed (P1) and not yet developed (P2). Reserves where technical uncertainties prevent their classification as proved are designated probable (P3) or possible (P4) reserves, depending upon likelihood of eventual production. Oil and gas currently not producible because of economic, political, environmental, or technical conditions are considered contingent resources. As is true of reserves, contingent resources are classified as proved (P5), probable (P6), or possible (P7).