Patent ID: 8302685
Filing Date: 2012-11-06
Classification: E21B

Abstract:
1. A mud pulse telemetry system comprising: a pressure pulse generator disposed in a wellbore, the pressure pulse generator configured to generate a pressure wave in a drilling fluid disposed in the wellbore; and a data encoder disposed in the wellbore, the data encoder configured to receive digital data from a data source, to group data bits of the digital data into groups having one or more data bits, and to vary the phase of the pressure wave based on bit patterns of respective groups of data bits such that the phase of the pressure wave simultaneously encodes the one or more data bits of a group of data bits, and wherein the encoder is configured to perform a smooth phase PSK modulation according to where the Es value is an energy per symbol, the t value is time, the T value is a symbol period, the fc value is a carrier frequency the q value is a transition function, the σ(n) value is a state of a modulator at time nT and Θ wherein the pressure pulse generator is configured to modulate the pressure wave from a first phase encoding a first group of data bits of the digital data to a second phase encoding a second group of data bits of the digital data, and to modulate the pressure wave such that the pressure wave includes a smooth phase transition between the first phase and the second phase.