pay (geology)

Pay is an expression used in hydrocarbon mining. It denotes a portion of a reservoir that contains economically recoverable hydrocarbons. The term derives from the possibility of "paying" an income surpassing the costs. Equivalent terms are pay sand or pay zone. Overall interval in which pay volumes occur is the gross pay; smaller portions of the reservoir that meet further criteria for pay (such as permeability and hydrocarbon saturation) are net pay.