Patent ID: 6427124
Filing Date: 2002-07-30
Classification: E21B,G01V

Abstract:
A downhole tool for determination of the position and orientation of a bed boundary in a formation surrounding a wellbore during drilling of the wellbore, the downhole tool comprising:(a) a transmitter for transmitting acoustic signals at at least one position in the wellbore during drilling of the wellbore, said acoustic signals having an acoustic velocity; (b) a plurality of spaced apart receivers for detecting signals including reflected signals from the bed boundary; and (c) a processor for prefiltering the detected signals using a prefilter based upon a threshold determination for selectively attenuating unwanted signal components traveling between the transmitter and the plurality of receivers and providing prefiltered signals, the processor further using said acoustic velocity and the prefiltered signals for determining a distance and orientation of the bed boundary relative to the tool.