Parameter telemetering from the bottom of a deep borehole

Claim 1

In an apparatus for pumping a liquid from a borehole in the earth, including at least a string of tubing from the surface to a selected depth in said borehole, eectric motor means and pump means supported at the bottom end of said tubing, alternating current electrical power supply means at the surface, of a first selected frequency and a multiple conductor cable that is subject to varying resistance or insulation leakage, said cable connected to said power supply means at the surface end, and to said motor means at the bottom end of said cable; apparatus for use in combination with said multiple conductor cable to measure, in said borehole, at least one well parameter indicative of a condition contiguous to said motor and pump means and transmitting to the surface a signal representative of said at least one well parameter, comprising: (a) means at the surface for generating an intermediate frequency signal; (b) electrical coupling means at the surface for connecting said intermediate frequency signal between at least one conductor in said cable and ground; (c) downhole instrument package means positioned in said borehole and connected to said at least one conductor and ground, said downhole instrument package means including; (1) power supply means energized by said intermediate frequency signal; (2) at least one non-eddy current sensor means for sensing said at least one parameter; (3) means to create a low frequency signal as a function of said parameter; (4) means to generate a high frequency carrier signal of the order of 200 KHz, (5) means to modulate said carrier signal with said low frequency signal to create a modulated carrier signal; (6) means transmitting said modulated carrier signal to said at least one conductor; and (d) means to demodulate said modulated carrier signal to reconstitute said low frequency signal; and (e) means to indicate said well parameter as a function of said reconstituted low frequency signal.

Claim 17

A method of sensing a well parameter indicative of a condition contiguous to an electric motor at a selected depth in a well by using an electrically conductive cable whose primary purpose is to carry electrical current to said motor, said cable subject to varying resistance or insulation leakage, comprising the steps of: (a) generating a first frequency signal and coupling said first frequency signal to said conductor cable; (b) conveying said first frequency signal from the surface of said well to an instrument package contiguous to said motor; (c) converting said first frequency signal to a power supply voltage in said instrument package; (d) non-eddy current sensing said well parameter and creating a second frequency signal as function thereof; (e) creating a third frequency electrical carrier signal of the order of 200 KHz; (f) modulating said carrier signal with said second frequency signal, to create a modulated carrier signal; (g) coupling said modulated carrier signal to said conductor cable; (h) receiving said modulated carrier signal; (i) demodulating said modulated carrier signal; and (j) displaying said demodulated signal as an indication of the magnitude of said parameter.

Claim 18

A method of sensing a well parameter indicative of a condition contiguous to an electric motor at a selected depth in a well by using an electrically conductive cable whose primary purpose is to carry electrical current to said motor, said cable subject to varying resistance or insulation leakage, comprising the steps of: (a) generating a first frequency signal and coupling said first frequency signal to said conductor cable; (b) conveying said first frequency signal from the surface of said well to an instrument package contiguous to said motor; (c) converting said first frequency signal to a power supply voltage in said instrument package; (d) non-eddy current sensing said well parameter and creating a second frequency signal as function thereof; (e) creating a third frequency electrical carrier signal of the order of 200 KHz; (f) modulating said carrier signal with said second frequency signal, to create a modulated carrier signal; (g) coupling said modulated carrier signal to said conductor cable; (h) receiving said modulated carrier signal; (i) demodulating said modulated carrier signal; and (j) displaying said demodulated signal as an indication of the magnitude of said parameter.