Patent ID: 6631563
Filing Date: 2003-10-14
Classification: E21B

Abstract:
A method of conducting an oil well survey along a well borehole comprising the steps of:(a) moving a drill bit connected sensor having an axis coincident along a well borehole between first and second selected positions to form survey data at said first and second positions, wherein said positions are located within a non vertical section of said well borehole; (b) positioning a rate gyro in said sensor wherein said rate gyro forms rate gyro output signals indicative of measured angular rate at said first and second positions; (c) positioning in said sensor first and second accelerometers at a right angle therebetween wherein said accelerometers define a transverse plane to the axis of said sensor; and forming accelerometer output signals from said first and second accelerometers indicative of values sensed thereby at said first and second positions in said well borehole; (d) storing gyro data representative of said rate gyro output signals, relative to a reference azimuth measured by said rate gyro with said sensor stationary at said first position and second position along the well borehole; (e) forming stored accelerometer data representative of said accelerometer output signals, relative to a reference inclination measured by said accelerometers at said first position and second position along the well borehole; and (f) converting said stored rate gyro and accelerometer data into a plot of well borehole azimuth between said first and second positions.