Watercut meter
A water cut meter measures the water content (cut) of crude oil and hydrocarbons as they flow through a pipeline. While the title "Water cut" has been traditionally used, the API released a technical report using the title/term OWD or On-Line Water Determination, however as these were trademarked by a manufacturer they have been superseded in current dialogue by the term WCA or Water Content Analyser. The API is in processes of developing a standard (API MPMS Chapter 10.10) in conjunction with the EI, the ISO committee has not yet developed an international standard for these  devices though the EI has a published standard based upon the original content of the original API technical report. There are however standards in place for fiscal automatic sampling of crude oil that are used for determination of quality and water content namely API 8.2, EI 476 and ISO 3171. Water cut meters are typically used in the petroleum industry to measure the water cut of oil flowing from a well, produced oil from a separator, crude oil transfer in pipelines and in loading tankers. There are several technologies used. The main technologies are dielectric measurements using capacitance, radio or  microwave frequency and NIR measurements, guided radar, optical and less common are gamma ray based instruments. Each of these technologies currently have limitations rendering them extremely valuable for trending applications but they are currently not acceptable for fiscal transfer accounting. The water cut is the ratio of water produced compared to the volume of total liquids produced from an oil well. The water cut in waterdrive reservoirs can reach very high values.