Echometer Company
Model – M Manual
Phone: (940) 767-4334
5001 Ditto Lane
Page
7
Fax: (940) 723-7507
Wichita Falls, Texas 76302, U.S.A.
E-Mail:3 – General Description – Model M
The Echometer Model M is a dual channel, microprocessor controlled amplifier/recorder. It permits better
interpretation of reflections from downhole anomalies since two different filters are used to improve the signal.
Processing and simultaneously recording reflected signal using two separate amplifiers having different frequency
response, improve the ability of the operator to distinguish downhole obstructions from enlargements. The
response from the liquid level (orreduction in annulus area) is opposite to the response from an enlargement such
as a hole in the casing. The Model M uses modern electronics, integrated circuits, chart drive system and a thermal
printhead, which result in a very compact and lightweight system.
The dual channel Model M accents and records collars on one channel, and the liquid level response on a second
channel. The collar channel can be set to record sharp upper collars or deep collars. Selecting the proper collar
filter will result in more accurate determination of the number of tubing collar reflections from the surface to the
liquid level. The lower trace accents the signals from the liquid level, tubing anchor, gas-lift mandrels, casing
perforations and other major anomalies.
A microprocessor is used with an analog to digital converter, memory chip, amplifiers, clock, timing circuit and
other electronic components to improve the performance and utility of the instrument. When an acoustic pulse is
generated in the well, the signals reflected from the collars at the top of the well are large but rapidly attenuate.
The microprocessor is programmed to evaluate the signal level and increase or decrease the collar amplifier gain as
necessary to optimize the quality of the recording. The collar and other signals will be recorded at a width of
approximately 0.6-inch (12-mm), which simplifies the manual counting of the collars since the amplitude of the
collar signal is maintained automatically. The automatic control of the recording level is called automatic gain
control.
The microprocessor is used in conjunction with a timer. Since these instruments are used throughout the world, the
universal coordinated time and date are printed on the strip chart. Also, the timing capabilities of the
microprocessor, clock and timing circuit are used to place labeled markers at one-second intervals beginning from
the instant the acoustic pulse is generated. This allows the operator to determine the round trip travel time very
accurately. The travel time and the distance to the liquid level are used to compute the acoustic velocity of the gas
in the annulus. The acoustic velocity the casing pressure and average temperature can be input to the utility
program AWP for Windows to compute the gas gravity and the pressure distribution in the well, including the
pump intake pressure and the pressure at the perforations.
In addition to recording both collar and liquid level signals simultaneously, the digital printhead generates a
header, an analysis form, and prints the values of background noise, battery voltage and special instructions on the
strip chart.
The entire instrument is contained in a waterproof, dustproof plastic housing having dimensions of 11 by 10 by 5
inches and weighs 11 pounds (5 kg). The following section describes the instrument panel and the function of the
various controls.