Callon Petroleum can call on new technologies to find old petroleum resources, employing computer-aided techniques such as enhanced 3-D surveys and horizontal drilling to explore and develop oil and gas properties. It also focuses on acquiring properties. Once a major offshore player, the firm's holdings are now primarily onshore in Texas. In 2012 Callon's estimated proved reserves stood at 14.1 million barrels of oil equivalent. About 68% of Callon's oil and gas reserves are located onshore in the Permian Basin; 77% of its proved reserve volumes are in the form of crude oil, which also accounts for the bulk of its the company's revenues.