In the petroleum industry, valid green economic accounting magnitudes are influenced by natural and other constraints on production, by non-convexity of technology and by non-optimality of output. The paper undertakes an economic analysis of oil extraction that explicitly represents the conditions and constraints that influence the decisions of a firm. This microeconomic analysis diverges from conventional, "Hotelling" macroeconomic models of nonrenewable-resource extraction and has substantially different findings. Optimality conditions such as Hotelling's rule or first-order conditions are not utilized in defining accounting statistics. Contrary to the findings of many studies, it is found that traditional (non-green) accounting practice for commercial natural resources such as petroleum sensibly balances the aims of economic accounting. Instead, adjustments to practice are most needed for non-commercial values such as pollution or amenities.