1. n. [Production Logging]

A type of flowmeter in which the spinner blades are collapsed to pass through the tubing and other restrictions, and then opened up below to sense the full cross section of the casing or openhole. In this way, a much larger fraction of the flow is measured. Introduced in the 1970s, the fullbore spinner gives a better average flow velocity than a conventional flowmeter, particularly at low flow rates and with simple biphasic-flow regimes. However, when the flow structure is complex, such as with multiphase flow in highly deviated wells, the average flow velocity may not be meaningful.

See related terms: diverter flowmeter,  production log,  spinner flowmeter