Oil And Gas Operators
The operator of an oil or gas field is the company responsible for the field’s management and day-to-day operation. Operators in the United States are obligated to submit to EIA annual estimates of proved reserves for each field they operate. In 2009, the largest 100 operators (as determined by total operated reserves) accounted for nearly 90 percent of proved oil and natural gas reserves but less than one percent of all operators (which numbered over 14,000, based on data collected by EIA for the 2009 reporting year). The top ten accounted for 54 percent of proved oil reserves and 48 percent of proved wet natural gas reserves. EIA data release policy does not allow company-specific proved reserves estimates, as publishing these volumes could compromise proprietary data. Operators have been arranged in ten groups of ten in descending volumetric order. For comparison purposes, the operators also include the owned proved reserves estimates and production data that most of these companies submitted to the Securities and Exchange Commission (SEC). While there is some overlap, it is useful to distinguish between the proved reserves a company operates and those it actually owns.
For EIA reporting, a company estimates it’s operated proved reserves on an individual field basis, including 100 percent of each operated field’s proved reserves; fields in which it has ownership but does not operate are not included. For filings with the SEC, the company (if publicly-traded) estimates its owned proved reserves, which includes only its share of proved reserves; all fields in which it has an ownership are included (cumulatively rather than individually). EIA reporting, therefore, accounts for the entirety of a field’s proved reserves and production, while SEC filings include only those volumes owned by companies required to file with the SEC. For example, ExxonMobil currently holds an approximate one-third interest in the Prudhoe Bay Field in Alaska, the country’s largest crude oil field. Because it is not the field’s operator, ExxonMobil does not report it’s proved reserves or production to EIA. For its filing with the SEC, however, the company would include its one-third share of Prudhoe Bay’s total proved reserves. The top 100 operators include both U.S. and foreign companies; their share of total proved reserves is relatively un-concentrated by the standards of many industries. In estimating field-level proved reserves, operators add lease condensate to crude oil (as oil) and plant liquids to natural gas (as “wet” natural gas). The SEC requires companies with more than $10 million in assets whose securities are held by more than 500 owners to file annual and other periodic reports.