Abstract: A method and an apparatus are provided for determining an orientation of a tool with respect to a reference direction. At least one first signal is indicative of an orientation of a directional reference system with respect to the reference direction. The directional reference system is positioned spaced from the tool. At least one second signal is indicative of a relative orientation of the tool with respect to the directional reference system. The orientation of the tool at the first position is determined in response at least in part to the at least one first signal and the at least one second signal.

Abstract: A method and an apparatus are provided for determining an orientation of a wellbore survey tool at a first position with respect to a reference direction. At least one first signal is indicative of an orientation of a directional reference system with respect to the reference direction. The directional reference system is positioned at a second position spaced from the first position. At least one second signal is indicative of a relative orientation of the wellbore survey tool with respect to the directional reference system. The orientation of the wellbore survey tool at the first position is determined in response at least in part to the at least one first signal and the at least one second signal.

Abstract: A method and an apparatus are provided for determining an orientation of a wellbore survey tool at a first position with respect to a reference direction. At least one first signal is indicative of an orientation of a directional reference system with respect to the reference direction. The directional reference system is positioned at a second position spaced from the first position. At least one second signal is indicative of a relative orientation of the wellbore survey tool with respect to the directional reference system. The orientation of the wellbore survey tool at the first position is determined in response at least in part to the at least one first signal and the at least one second signal.

Abstract: A system and method for using a survey tool within a borehole is provided. The survey tool includes a plurality of rotation sensors each having a sensing axis and a direction of least acceleration sensitivity. The sensing axes of the plurality of rotation sensors are generally parallel to one another and the directions of least acceleration sensitivity of the plurality of rotation sensors are generally non-parallel to one another.

Abstract: A system and method for determining an orientation of the survey tool within a borehole utilizes a survey tool including a plurality of rotation sensors each having a sensing axis and a direction of least acceleration sensitivity. The plurality of rotation sensors are mounted in a housing with their sensing axes generally parallel to one another and with their directions of least acceleration sensitivity generally non-parallel to one another. The survey tool further includes a controller adapted to calculate a weighted average of the detected angular rotation rates from the plurality of rotation sensors. The weighted average includes the detected angular rotation rate of each rotation sensor about its sensing axis weighted by the detected acceleration along its direction of least acceleration sensitivity.

Abstract: A system and method for determining an orientation of the survey tool within a borehole utilizes a survey tool including a plurality of rotation sensors each having a sensing axis and a direction of least acceleration sensitivity. The plurality of rotation sensors are mounted in a housing with their sensing axes generally parallel to one another and with their directions of least acceleration sensitivity generally non-parallel to one another. The survey tool further includes a controller adapted to calculate a weighted average of the detected angular rotation rates from the plurality of rotation sensors. The weighted average includes the detected angular rotation rate of each rotation sensor about its sensing axis weighted by the detected acceleration along its direction of least acceleration sensitivity.

Abstract: Wellbore survey methods and apparatus for wireline and measurement-while-drilling operations are disclosed which include a gyroscope, wherein the gyroscope has a spin axis, aligned with the instrument axis, and further having two sensitive axis orthogonally related to the spin axis and to each other. In addition, the wellbore survey apparatus contains a drive means, functionally connected with the gyroscope, to rotate the gyro about the instrument axis. The wellbore survey apparatus also contains a set of accelerometers, wherein the sensitive axis are aligned orthogonally to each other, and said drive means is functionally connected to the accelerometers to rotate the accelerometers about the instrument axis. Sensors determine the azimuthal direction of inclination of the wellbore at a first location therein and while traversing from said first location.

Abstract: Wellbore survey methods and apparatus for wireline and measurement-while-drilling operations are disclosed which include a gyroscope, wherein the gyroscope has a spin axis, aligned with the instrument axis, and further having two sensitive axis orthogonally related to the spin axis and to each other. In addition, the wellbore survey apparatus contains a drive means, functionally connected with the gyroscope, to rotate the gyro about the instrument axis. The wellbore survey apparatus also contains a set of accelerometers, wherein the sensitive axis are aligned orthogonally to each other, and said drive means is functionally connected to the accelerometers to rotate the accelerometers about the instrument axis. Sensors determine the azimuthal direction of inclination of the wellbore at a first location therein and while traversing from said first location.

Abstract: A wellbore survey method and apparatus which includes a gyroscope, wherein the gyroscope has a spin axis, aligned with the instrument axis, and further having two sensitive axis orthogonally related to the spin axis and to each other. In addition, the wellbore survey apparatus contains a drive means, functionally connected with the gyroscope, to rotate the gyro about the instrument axis. The wellbore survey apparatus also contains a set of accelerometers, wherein the sensitive axis are aligned orthogonally to each other, and said drive means is functionally connected to the accelerometers to rotate the accelerometers about the instrument axis. Sensors determine the azimuthal direction of inclination of the wellbore at a first location therein and while traversing from said first location. Attitude references of the wellbore with regard to said first location are determined while the tool is continuously traversing through the wellbore.

Abstract: A method for well borehole survey is set out. A sonde supports X and Y accelerometers and X and & sensors on a rate gyro having a Z axis aligned with the sonde. On a slickline, or within a drill string, the sonde is used to measure four variables, these being G.sub.x and G.sub.y, A.sub.x and A.sub.z. This enables well azimuth and inclination to determined. Measuring depth enables a survey to be made.

Abstract: A method for well borehole survey is set out. A sonde supports X and Y accelerometers and X and & sensors on a rate gyro having a Z axis aligned with the sonde. On a slickline, or within a drill string, the sonde is used to measure four variables, these being G.sub.x and G.sub.y, A.sub.x and A.sub.z. This enables well azimuth and inclination to determined. Measuring depth enables a survey to be made.