Wireline tool for measuring bottom-hole pressure in pumping wells

摘要

A data transmission system for use in transmitting data from a well to a surface location. The well data is converted to a voltage and used to control the frequency of an oscillator whose output frequency is transmitted to the surface. At the surface a second voltage-controlled oscillator is adjusted until its frequency and phase matches the signal transmitted from the well. The voltage required to match the frequency of the second oscillator to the frequency of the transmitted signal is then equal to the value of the well data.