Multi-arm well diameter imager

The utility model discloses an imager for monitoring a well diameter, and particularly relates to a multi-arm well diameter imager that can work normally when a well wall deforms. The multi-arm well diameter imager comprises a cable sealing head, an upper centering device, a control piece, an imaging arm sensor, a lower centering device and a counterweight joint, wherein the cable sealing head is connected with one end of the upper centering device; the other end of the upper centering device is connected with the control piece through telescopic arms; the control piece is connected with the imaging arm sensor; the imaging arm sensor is connected with one end of the lower centering device; the other end of the lower centering device is connected with the counterweight joint through telescopic arms; and 1-40 monitoring arms are arranged around the imaging arm sensor. The multi-arm well diameter imager can measure parameters such as the internal diameter of a petroleum casing, a casing coupling, a well temperature and natural gamma (optional) in real time accurately, and is faster in data processing, lower in power consumption, better in test passing property, and wider in application scope, and the external diameter of the imager is reduced greatly.