Schlumberger Technology Corporation

Terry L Mayhugh

Guy P Vachon

Lloyd D Clark, Jr

Ramon Hernandez-Marti

Bart J Bombay

Marvin W Rasmussen

Jimmy Everett Neeley

Gilbert R Martinez

John A Booker

Joseph M Steiner, Jr

Heather A Campbell

Suzanne D Richardson

Terry L Mayhugh, Jr

A wireline telemetry system and method of transmitting data on multiple carrier frequencies. The system and method adjust power level and number of bits-per-carrier to optimally or near-optimally utilize the capacity of the wireline cable. Due to the nature of wireline telemetry the overall power level is restricted only by the output capability of the downhole telemetry cartridge and the input power restrictions of the uphole telemetry unit receiver. The optimal power level is determined during a training sequence and is a function of such factors as cable length, cable material, cable temperature and cable geometry. The uplink and downlink transmission are executed using different modulation techniques.

Method and apparatus for transmission of well-bore data on multiple carrier frequencies

A method and system for providing power to a wireline logging system includes a rectifier section operable to receive an AC input signal and generate a first DC power signal as an output. A converter section cascadedly coupled to the rectifier section converts the first DC power signal to a second DC power signal. An inverter section cascadedly coupled to the converter section is operable to generate an output power signal providing power to a system in response to receiving the second DC power signal. A control section is coupled to the rectifier section, the converter section, the inverter section and a communications link. The communications link is operable to receive information describing waveforms for the output power signal. The control section is operable to receive the information and control a corresponding section to generate the waveforms in response to receiving the information.

Versatile modular programmable power system for wireline logging

A method and apparatus for predicting the peak voltage at the load end of a power transmission cable having a power supply end and a load end, where direct measurement at the load end is not practical. The method samples the current and voltage waveforms at the power supply end of the cable. The current waveform is used to estimate a current function which includes a full width at half maximum and adjustments for cable reactive current, distortions, and load. The product of the current function and a peak voltage sample from the power supply end is an estimate of the peak voltage at the load end. The method and apparatus have been applied to oil well logging where one or more logging tools are lowered at the end of a transmission cable into an oil well and it is desirable to predict peak voltage at the tools to ensure proper tool performance. An important improvement is a more accurate current function which compensates for capacitive current flow in the cable and includes a quadratic term. Additional improvements are described, namely a method for predicting downhole current, adjustments for power supply distortions, and diagnostic metrics.

Method and apparatus for predicting peak voltage of a cable conveyed tool

A method and apparatus for detecting magnetic marks on a wireline logging cable and for more accurately making depth measurements during logging is described. The method uses depth-based, rather than time-based, samples and calculations. A Hall Effect sensor samples the cable at regular depth intervals approximated by an encoder mechanism. The signal values from the Hall Effect sensor are signal processed to better discriminate the precise location of the magnetic marks on the cable. The location of the magnetic marks is used to refine the depth measurements from the encoder mechanism. Depth-based sampling eliminates detection dependence on cable speed, enhances detection ability, reduces computational load, and leads to more accurate determination of the location of magnetic marks.

Magnetic mark detection

A method and apparatus for predicting the peak voltage at the load end of a power transmission cable having a power supply end and a load end, where direct measurement at the load end is not practical. The method samples the current and voltage waveforms at the power supply end of the cable. The current waveform is used to estimate a current function which includes a full width at half maximum approximation adjusted as required for load, cable type, and cable length. The product of the current function and a peak voltage sample from the power supply end is an estimate of the peak voltage at the load end. The method and apparatus have been applied to oil well logging where one or more logging tools are lowered at the end of a transmission cable into an oil well and it is desirable to predict peak voltage at the tools to ensure proper tool performance.

Growing community of inventors

Round Rock, TX, United States of America

Terry L Mayhugh