Digital signal processing in mud pulse telemetry
AssigneeHalliburton Energy Services, Inc.
InventorsYumin Zhang, Ehud Barak
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Abstract
Digital signal processing for mud pulse telemetry utilizes a variety of “On/Off” keying based modulation schemes, such as pulse width modulation (PWM) and pulse position modulation (PPM), to encode and/or decode information. A combination of PPM and PWM is disclosed that increases a bit rate while keeping a chip rate unchanged. The combination of PPM and PWM comprises determining a drilling condition and forming a message based on the drilling condition, forming a string of symbol values comprising the message, identifying a pulse width and a pulse start for the pulse based on a symbol value, providing a first pulse at a selected chip location, providing subsequent pulses to form the pulse width, and forming a quiet period at the end of the pulse width.
Claims20
A method, comprising:
- forming a string of symbol values encoding a message that is based on a determined drilling condition;
- mapping each symbol value of the string of symbol values to a symbol waveform in a Gray code of symbol waveforms;
- selecting one or more of the mapped symbol waveforms based, at least in part, on a symbol time period;
- and
- for each of the selected one or more of the mapped symbol waveforms,
- identifying a pulse width and a pulse start,
- providing a set of one or more pulses according to the pulse width and starting at a selected chip location corresponding to the pulse start, and
- forming a quiet period at an end of the set of one or more pulses, wherein the quiet period is at least a recharging time for a battery or a capacitor in a pressure sensor or acoustic transducer.
A device, comprising:
- a memory circuit storing commands;
- and
- a processor circuit configured to execute the commands and cause the device to,
- form a string of symbol values encoding a message that is based on a determined drilling condition,
- map each symbol value of the string of symbol values to a symbol waveform in a Gray code of symbol waveforms,
- select one or more of the mapped symbol waveforms based, at least in part, on a symbol time period, and
- for each of the selected one or more of the mapped symbol waveforms,
- identify a pulse width and a pulse,
- provide a set of one or more pulses according to the pulse width and starting at a selected chip location corresponding to the pulse start, and
- form a quiet period at an end of the set of one or more pulses, wherein the quiet period is at least a recharging time for a battery or a capacitor in a pressure sensor or acoustic transducer.
One or more non-transitory machine-readable media comprising program code for signal processing in mud pulse telemetry, the program code to:
- form a string of symbol values encoding a message that is based on a determined drilling condition;
- map each symbol value of the string of symbol values to a symbol waveform in a Gray code of symbol waveforms;
- select one or more of the mapped symbol waveforms based, at least in part, on a symbol time period;
- and
- for each of the selected one or more of the mapped symbol waveforms,
- identify a pulse width and a pulse,
- provide a set of one or more pulses according to the pulse width and starting at a selected chip location corresponding to the pulse start, and
- form a quiet period at an end of the set of one or more pulses, wherein the quiet period is at least a recharging time for a battery or a capacitor in a pressure sensor or acoustic transducer.
Dependencies are inferred from the claim text.