Abstract: 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.

Abstract: 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.

Abstract: Fluid influx in a borehole is determined by examining and monitoring the computed transfer function in the signal channel defined by the annulus between the borehole and a drillstring in the borehole.

Abstract: The present invention comprises a method and apparatus for estimating and identifying the channel filter characteristics of the drilling fluid communictions channel (e.g. standpipe) based on surface decoding of the MWD data signal. The channel filter characteristics can be mathematically defined by the transfer function of the channel. The transfer function is a mathematical model defining the input-output relationship of a physical system. The present invention may also characterize the channel filter defined by the drilling mud in the annulus between the borehole and the drillstring.