US 4,734,860 AGranted

Simplified bore hole surveying system by kinematic navigation without gyros

AssigneeHoneywell Inc.

InventorsWerner H. Egli, Lawrence C. Vallot

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Abstract

Apparatus and method for the surveying of bore holes, for example, oil wells and the like, to permit accurate three-dimensional mapping thereof, using an accelerometer package in an instrumentation pod which is lowered into the bore hole. In one embodiment the pod is lowered on the end of a rod string where adjacent rods connected together with Hookes-joint pivots which permit two degrees of freedom of movement between adjacent rods. In another embodiment, rigid interconnections of adjacent rods are used, and the rods are isotropic for twistless flexure as the rods encounter curves in the path of the bore hole. The instrumentation pod is lowered one rod-length at a time, and accelerometer readings are taken which, together with mathematical modeling of rod motion, permits calculation of updated pod position at all depths in the hole.

Claims9

Dependent claims

Bore hole survey apparatus, comprising:

an instrumentation pod adapted for travel down a bore hole to be surveyed;
said pod including accelerometer means for sensing the Earth's gravity vector with respect to a frame of reference of the pod;
a plurality of rods, including means for attachment of said pod to one of said rods and means for interconnecting said rods to form a rod string for lowering said pod into said bore hole, said rods configured to permit limited motions thereof with respect to adjacent rods in response to turns or curves in the bore hole as the rod string is lowered;
said rod string being a continuous length of rods from the surface of the Earth to said pod;
and
computation means connected for receiving signals from said accelerometer means and responsive to said signals and to the incremental rod-by-rod lowering of said pod into said bore hole for calculating the attitude and updated position of said pod based on successive accelerometer readings and mathematically modeled motions of the rods in following curves in the bore hole as the pod is lowered in the bore hole.

3 more elements

Dependencies are inferred from the claim text.