Inertial borehole survey system

摘要

A system and method for surveying, with accuracies better than one foot per thousand feet of depth, very deep boreholes having the attendant small diameters, high temperatures and high pressures with very high accuracy. A downhole probe is used having a small diameter, less than about four inches. Three linear type accelerometers and at least two gyros to provide three sensitive axes are fixedly mounted at points spaced along the axis of an elongated, rigid, thermally conductive support member to form an instrument cluster. Signals from these instruments are then processed and transmitted serially over a conductor of a conventional wireline to the surface unit where a surface computer continuously computes and records the current position of the instrument.