Schlumberger Technology Corporation

Halliburton Energy Services, Inc.

W-H Energy Systems, Inc.

Smith International, Inc.

Mark S Beattie

Caimu Tang

Ali H Abdallah

A method for receiving an encoded integer includes acquiring a digitized waveform including a first plurality of pulses distributed among a second plurality of time slots, locating each of the pulses in the digitized waveform, computing a confidence value for each of the pulses, selecting a subset of the plurality of pulses, the subset including pulses having low confidence values computed, generating a set of unique waveforms corresponding to various combinations of the subset of pulses selected, computing a cross-correlation between each of the waveforms generated and the digitized waveform acquired, and selecting the waveform having the highest cross-correlation computed.

Telemetry coding and surface detection for a mud pulser

A method for encoding a non-negative integer, for example, representative of MWD/LWD data, includes encoding at least a portion of the integer using at least a first order Fibonacci derived sequence. The remainder of the integer may be encoded using conventional Fibonacci encoding. The invention tends to improve coding efficiency, downhole and surface synchronization, and surface detection.

A method and related system for detecting mud pulse telemetry by measuring pressure fluctuations in drilling fluid by measuring mud pressure pulses at two locations. A first location is somewhat downstream of the mud pump and desurger and a second location is proximate to the mud pump and desurger. Given these two pressure signals they are subtracted to create a difference signal where the presence or absence of mud pressure pulses is determined by pressure spikes caused by the interaction of mud pressure pulses. A second method measures the mud pressure pulse at only one location.

Mud pulse telemetry

A mud pulse telemetry adaptive noise canceler (ANC) employs a primary transducer and a reference transducer downstream from a position of the primary transducer. The primary transducer receives a primary signal based on a combination of a transmitted pulse and a reflected pulse, and the reference transducer receives a reference signal based on the transmitted pulse. The ANC linearly relates the secondary signal to the primary signal by means of a fast recursive least squares algorithm and calculates a set of weighting coefficients. The finite impulse response (FIR) filter of the ANC uses the set of weighting coefficients to adaptively noise cancel correlated portions between the primary signal and the secondary signal to produce an ANC output signal based on uncorrelated portions between the primary signal and the secondary signal.

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Katy, TX, United States of America

Mark S Beattie