Abstract: A method and apparatus for data communication in an oil well environment, wherein the method comprises detecting an acoustic signal transmitted along an acoustic channel, the acoustic signal being distorted from transmission through the acoustic channel, generating a transmitted data signal in response to the acoustic signal, inputting the transmitted data signal to an adaptive equalizer and adaptively equalizing the transmitted data signal to produce an equalized data signal related to the transmitted data signal by a mathematical function. The detecting step may include positioning an acoustic receiver in a communication unit along the acoustic channel. The communication unit may be positioned downhole and the adaptive equalizer may be positioned remotely relative to the communication unit or may be placed in the communication unit. The adaptive equalizer may be a frequency domain filter, a neural net adaptive equalizer or a nonlinear recurrent neural net equalizer.

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: Communicating relative to a subterranean well includes encoding information in an amplitude and a duration for a pulse. A detectable change in response to both the amplitude and duration communicates the information. Two distinct items of information can be encoded wherein the information encoded in the amplitude is distinct from the information encoded in the duration. A single, more highly resolved, item of information can be defined in that the amplitude and the duration can together represent one aspect of the information to be communicated. Particular application is found in a subterranean well having three-phase power conductors connected to a three-phase motor in the well with the amplitude and duration being communicated through the power conductors.

Abstract: A reliable, high data rate, downhole acoustic telemetry system is disclosed. In one embodiment, the acoustic telemetry system includes a tubing string with an acoustic transmitter and an acoustic receiver mounted on it. The acoustic transmitter transmits telemetry information by modulating an acoustic carrier frequency that propagates along the walls of the tubing string. The transmitter is preferably mounted at a selected position relative to the end of the tubing string. The selected position is preferably less than &lgr;/4 from the end or approximately n&lgr;/2 from the end, where &lgr; is the wavelength of the carrier frequency in the tubing string, and n is a positive integer. In a more preferred embodiment, n may be the lesser of 4 times the number of cycles in the modulating toneburst and 40. The receiver is preferably mounted at approximately (2n−1)&lgr;/4 relative to the end of the tubing string, where n is a positive integer.

Abstract: A system for use with a well includes a surface device, a communications link coupled to the surface device and extending into the well, and a plurality of downhole devices coupled to different points on the communications link in the well. The surface device and the plurality of devices are adapted to determine distortions of different portions of the communications link coupling the surface device and downhole devices and to compensate for the distortions when communicating. Transfer characteristics of the communications link portions may be determined, from which equalization parameters may be determined to compensate for distortions caused by communications link portions.