Instrument for Centering Tools Within a Wellbore

Abstract

A downhole controller for aligning downhole tools including a body extending between an upstream portion and a downstream portion, wherein a longitudinal axis of the body is coincident with the longitudinal axis of a borehole. First and second springs are disposed proximate the upstream and downstream portions, respectively. A first bulkhead is disposed around the upstream portion and a second bulkhead is disposed around the downstream portion. The first bulkhead having a first plurality of ribs extending outwardly therefrom to define an upper recess spaced from a middle recess and the second bulkhead having a second plurality of ribs extending outwardly therefrom to define a bottom recess. A linkage bar system is coupled to the upper, middle, and bottom recesses disposed around the body, wherein the linkage bar system includes first through third linkage bars, a roller support plate, and a roller. A coupling is coupled to the body and adapted to suspend a tool from the body, wherein the linkage bar system is adapted to compress of at least one of the first and second springs when the roller is obstructed by an interval in a borehole.

1 . A downhole controller for aligning downhole tools:
 a body extending between an upstream portion and a downstream portion;   first and second springs disposed proximate the upstream and downstream portions, respectively;   a first bulkhead disposed around the upstream portion and a second bulkhead disposed around the downstream portion;   the first bulkhead having a first plurality of ribs extending outwardly therefrom to define an upper recess spaced from a middle recess and the second bulkhead having a second plurality of ribs extending outwardly therefrom to define a bottom recess;   a linkage bar system including first through third linkage bars, a roller support plate, and a roller;   wherein each of the first through third linkage bars extend between first and second ends;   the first end of the first linkage bar is coupled to the upper recess and the second end of the first linkage bar is coupled to an upper end of the roller support plate;   the first end of the second linkage bar is coupled to the middle recess and the second end of the second linkage bar is coupled to a lower end of the roller support plate; and   the first end of the third linkage bar is coupled to the bottom recess and the second end of the third linkage bar is coupled to the lower end of the roller support plate, wherein the linkage bar system is adapted to compress of at least one of the first and second springs when the roller is obstructed by an interval in a borehole.   
     
     
         2 . The downhole controller of  claim 1 , further including an extension coupling for attaching a tool thereto. 
     
     
         3 . The downhole controller of  claim 1 , wherein the length of the roller support plate can be varied. 
     
     
         4 . The downhole controller of  claim 1 , wherein a coupling between one of the linkage bars and the first and second collar bulkheads or the roller support plate is adapted to fail when the linkage bar system is subjected to a force greater than a threshold force. 
     
     
         5 . The downhole controller of  claim 4 , wherein the linkage bars and the first and second collar bulkheads or the roller support plate are coupled by a linkage pin. 
     
     
         6 . The downhole controller of  claim 5 , wherein the threshold force is varied by a varying the composition or size of the linkage pin 
     
     
         7 . A downhole controller for aligning downhole tools:
 a body extending between an upstream portion and a downstream portion;   first and second springs disposed proximate the upstream and downstream portions, respectively;   a first bulkhead disposed around the upstream portion and a second bulkhead disposed around the downstream portion;   the first bulkhead having a first plurality of ribs extending outwardly therefrom to define an upper recess spaced from a middle recess and the second bulkhead having a second plurality of ribs extending outwardly therefrom to define a bottom recess;   a radially extendable linkage bar system disposed around the body, wherein the linkage bar system includes first through third linkage bars, a roller support plate, and a roller; and   a coupling that is adapted to be coupled to the body, wherein the linkage bar system is adapted to compress of at least one of the first and second springs when the roller is obstructed by an interval in a borehole.   
     
     
         8 . The downhole controller of  claim 7 , wherein the length of the roller support plate is variable. 
     
     
         9 . The downhole controller of  claim 8 , wherein a coupling between one of the linkage bars and the first and second collar bulkheads or the roller support plate is adapted to fail when the linkage bar system is subjected to a force greater than a threshold force. 
     
     
         10 . The downhole controller of  claim 8 , wherein the linkage bars and the first and second collar bulkheads or the roller support plate are coupled by a linkage pin. 
     
     
         11 . The downhole controller of  claim 10 , wherein the threshold force is varied by a varying the composition or size of the linkage pin. 
     
     
         12 . A downhole controller for aligning downhole tools:
 a body extending between an upstream portion and a downstream portion, wherein a longitudinal axis of the body is coincident with the longitudinal axis of a borehole;   first and second springs disposed proximate the upstream and downstream portions, respectively;   a first bulkhead disposed around the upstream portion and a second bulkhead disposed around the downstream portion;   the first bulkhead having a first plurality of ribs extending outwardly therefrom to define an upper recess spaced from a middle recess and the second bulkhead having a second plurality of ribs extending outwardly therefrom to define a bottom recess;   a linkage bar system disposed around the body, wherein the linkage bar system includes first through third linkage bars, a roller support plate, and a roller; and   a coupling coupled to the body and adapted to suspend a tool from the body;   wherein the linkage bar system is adapted to compress of at least one of the first and second springs when the roller is obstructed by an interval in a borehole.   
     
     
         13 . The downhole controller  claim 12 , wherein the length of the roller support plate can be varied. 
     
     
         14 . The downhole controller  claim 12 , wherein the linkage bar system is coupled to the body by pivot pins. 
     
     
         15 . The downhole controller  claim 12 , wherein the linkage bar system can be disassembled by the use of handtools.