Abstract: Measurements made with at least two sensors (flow rate or pressure) during generation of a message concurrently with operation of a noise source are used to estimate a channel transfer function. The estimated transfer function is then used to attenuate pump noise in a mud pulse telemetry system. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Pump noise in a mud-pulse telemetry system is reduced based on analysis of the frequency characteristics of the noise generated by one or more pumps. Least mean-squares filtering may be done. Alternatively, the frequency domain analysis of the pump frequencies is fine-tuned in the time domain and a synthetic timing signal is used for the filtering.

Abstract: A system for transmitting information in a well comprises a tubular string disposed in the well and having a drilling fluid flowing therethrough. A pulser is disposed in the tubular string and transmits a pulse synchronization marker comprising a chirp signal. A surface controller, acting under programmed instructions, detects the chirp signal adjusts a signal decoding technique based on the detected chirp signal.

Abstract: Channel estimation and signal equalization is used in a mud-pulse telemetry system for uplink communication during drilling of wellbores.

Abstract: Measurements made with dual sensors (flow rate or pressure) are used to attenuate pump noise in a mud pulse telemetry system.

Abstract: Measurements made with dual sensors (flow rate or pressure) are used to attenuate pump noise in a mud pulse telemetry system.

Abstract: The transfer function of the communication channel in a mud pulse telemetry system is determined by sending a known signal through the channel and spectral analysis of the received signal. The known signal may be a chirp signal or a stepped frequency signal. Based on the determined transfer function, operating parameters of the pulser are adjusted.