What is Gulfport Energy's 2018 Reserve Life Index for crude oil? 2018 Oil MBbls) Natural Gas (MMcf) Natural Gas Liquids (MBols) 19,157 4,825,310 75,766 Proved Reserves Beginning of the period Purchases in oil and natural gas reserves in place Extensions and discoveries Sales of oil and natural gas reserves in place Revisions of prior reserve estimates Current production End of period 5,205 622,271 9,631 (134) (43,444) (112) (377) (2.801) 21,050 (826,506) (443,742) 4,133,889 1,228 (5,993) 80,520