Method and apparatus for bottom hole measurement
First Claim
Patent Images
1. An apparatus for use in determining drilling conditions in a borehole in the earth comprising:
- a drill string depending into a borehole;
a drill bit connected to the lower end of said drill string;
an instrument sub connected between the drill bit and drill string;
measurement means in said instrument sub to measure circumferential shear strain and axial strain at at least three circumferentially spaced locations on said instrument sub; and
means to process the measurements to obtain three force and three moment components on said instrument sub.
9 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for obtaining complete loading on a drill bit at the end of a drill string in a borehole employ at least three rosette strain gauges uniformly disposed on an instrument sub to measure torque and axial force on the sub, two bending moments in mutually perpendicular directions, and two shear forces in mutually perpendicular directions. These measurements are used to obtain torque on bit, weight on bit, two side forces on the bit normal to each other, and two bending moments on the bit normal to each other which, in turn, can be used to control the bit movement.
-
Citations
14 Claims
-
1. An apparatus for use in determining drilling conditions in a borehole in the earth comprising:
-
a drill string depending into a borehole; a drill bit connected to the lower end of said drill string; an instrument sub connected between the drill bit and drill string; measurement means in said instrument sub to measure circumferential shear strain and axial strain at at least three circumferentially spaced locations on said instrument sub; and means to process the measurements to obtain three force and three moment components on said instrument sub. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method of measuring and controlling drilling of a borehole in the earth by a drill string having a bottom hole drilling assembly including an instrument sub and drill bit connected at the lower end of the drill string, said method comprising the steps of:
-
measuring shear strain and axial strain at at least three circumferentially spaced locations on said instrument sub to obtain complete measurements to enable two shear forces and an axial force and two bending moments and one torsional moment resultant computations; and processing said computed forces and moments to obtain weight-on-bit, torque-on-bit, two bending moments and two bit side forces representing the total loading on the bit. - View Dependent Claims (13, 14)
-
Specification