Proved reserves are estimated volumes of hydrocarbon resources that analysis of geologic and engineering data demonstrates with reasonable certainty 1 are recoverable under existing economic and operating conditions. Reserves estimates change from year to year as new discoveries are made, existing fields are more thoroughly appraised, existing reserves are produced, and prices and technologies change. Highlights U.S. proved reserves of crude oil and lease condensate increased for the fifth year in a row in 2013, and exceeded 36 billion barrels for the first time since 1975. A sharp increase in proved natural gas reserves in 2013 more than offset the significant decline experienced in 2012, and set a new record 2 (354 trillion cubic feet) for U.S. natural gas proved reserves. An increase in natural gas prices used to characterize existing economic conditions contributed to the reported 2013 increase in proved natural gas reserves. For example, the 12-month, first-of-the-month […]