The Echometer Model M is used in conjunction with an acoustic gas gun to determine the distance to the liquid level in the casing annulus or tubing of a well. A pressure pulse is generated from a gas-gun wellhead attachment that is connected to the surface casing annulus valve. The pressure pulse travels down the casing annulus gas and is reflected by collars, the liquid level and other obstructions. A microphone in the wellhead attachment converts the pressure pulses into electrical signals that are amplified, filtered and recorded on a strip of paper. The record displays the tubing collars from the surface to the liquid level and hence the liquid level depth can be determined by counting the number of tubing collar reflections to the liquid level reflection.
The Model M instrument consists of an analog/digital amplifier-recorder and a dual-channel paper chart recorder. One channel (Liquid Level) is used to optimize the reflection from the liquid level and other large downhole anomalies. The second channel (Collars) is used to optimize the response from the tubing collars and other small downhole anomalies.
Senior Tech (now Hamdon Energy Solutions) carries these units in stock and can usually ship within 24 hours.