The development of carbon credit markets for geologic sequestration will require a framework for accounting injected CO₂ that is based on detailed characterization data, sound engineering design, and an equitable legal and regulatory process. The monetization of CO₂ credits associated with geologic sequestration will require a streamlined process that addresses the technical aspects of a project and also considers the interests of the public and the rights of individuals who may own subsurface mineral and water rights. Such a system has already been established in the oil field unitization process under which the United States petroleum industry currently operates. Oil and gas regulatory agencies in the United States use a process commonly referred to as unitization to organize oil fields into units for the purpose of secondary and tertiary recovery operations. The process by which petroleum fields become unitized may provide a useful model for the selection of appropriate injection target formations and the governing of geologic sequestration projects. Although petroleum reservoirs, saline aquifers, and coal seams generally use different mechanisms for sequestration (for example, dissolution into oil versus dissolution into saline water versus adsorption onto coal), the unitization process may be adapted and applied to all types of geologic formations. Application of the unitization process to CO₂ sequestration may result in the establishment of geologic sequestration units.