7 Liquid Measurement

Liquid hydrocarbons are produced, transported, bought and sold throughout the world in a largenetwork of pipelines, tankers and storage systems. Ownership of the liquids may change many timesfrom wellhead to final market. Each time the product changes ownership en-route to market or there is a transfer of product into another pipeline system or terminal, there is measurement of the product and custody of the product is transferred to another party. Due to the high value of liquid hydrocarbons, accurate measurement is fundamental for custody transfer facilities. Contractual arrangements between buyer and seller specify that certain measurement standards be applied to the custody transfer facilities' design, construction and operation. Typically, these standards include the American Petroleum Institute Manual of Petroleum Measurement Standards (API MPMS) and, internationally, the International Organization for Standardization (ISO).