Mechanical pump spacing adjustment system

Abstract

A well string positioner capable of actuation during the vertical reciprocal movement of a well string will increase or decrease the length of the well string within the tubular. The stroke of the vertical reciprocal power unit is not changed when the well string length within the tubular is changed, and the well string can be adjusted in operation of the well without the need to disassemble the well string. A system for retrofit to a pre-existing pump jack is disclosed, as well as a pump jack with the well string positioner and capability of the system incorporated as manufactured.

1 . A system for use in the adjustment of the well string positioning and length within the well tubular of a subterranean oil well extraction apparatus comprising:
 a) a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation;   b) a well string of circular cross-section having a lower end and a top end and extending downward inside the well tubular through a seal at the wellhead to at least a position within the tubular within the fluid-producing formation;   c) a downhole plunger-style pump located within the tubular at the lower end of the well string which will be actuated by vertical reciprocating movement of the well string to pump oil from the formation up the well tubular to the wellhead; and   d) a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string;   
       said system comprising:
 a) a powered well string positioner connecting the top end of the well string to the reciprocating power unit and which rotatably engages the well string such that the well string can be rotated along its axis within the tubular during operation of the vertical reciprocating power unit while being vertically retained in a position defining the length of the well string within the tubular; and wherein upon actuation the well string positioner will raise or lower the top end of the well string above the well string positioner resulting in the decrease or increase of the length of the well string within the tubular below the seal on the wellhead; and 
 b) a controller capable of actuation of the well string positioner by an operator;
 whereby during operation of the vertical reciprocating power unit, an operator can use the controller to actuate the well string positioner to modify the length of the well string within the tubular; and 
 wherein the length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string; 
 wherein the stroke of the vertical reciprocating power unit does not change when the length of the well string below the well string positioner is changed; and 
 wherein the well string can be rotated along its axis within the tubular during operation of the vertical reciprocating power unit without any need to deactivate the vertical reciprocating power unit, and without the need to detach the well string from the remainder of the apparatus. 
 
 
     
     
         2 . The system of  claim 1  wherein the top end of the well string is threaded, and the well string positioner comprises a rotary power source capable of engaging the threaded top end of the well string and altering the length of the well string below the seal of the wellhead by rotary power applied to the threaded portion of the top end. 
     
     
         3 . The system of  claim 2  wherein:
 a. the well string positioner comprises a carrier bar with a bar aperture therethrough through which the threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement and to the rotary power source whereby the threaded portion of the top end of the well string passes through the bar aperture and is engaged by the rotary power source; and 
 b. the rotary power source mechanically engages the threaded portion of the top end of the well string and whereby on actuation of the rotary power means during operation of the vertical reciprocating power unit, the threaded portion of the top end of the well string can be moved up or down through the bar aperture resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular. 
 
     
     
         4 . The system of  claim 3  wherein the rotary power means comprises a hydraulic or electric motor. 
     
     
         5 . The system of  claim 1  wherein the well string positioner can rotate the well string within the tubular along its axis and the controller will periodically actuate the well string positioner to incrementally rotate the well string during operation of the vertical reciprocating power unit. 
     
     
         6 . The system of  claim 1  wherein the vertical reciprocating power unit is a conventional oilfield pump jack. 
     
     
         7 . A vertical reciprocating pump jack for use in oilfield extraction being adapted to allow for adjustment of the well string positioning and length within the well tubular of a subterranean oil well extraction apparatus comprising:
 a) a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation;   b) a well string of circular cross-section having a lower end and a top end and extending downward through a seal on the wellhead inside the well tubular to at least a position within the tubular within the fluid-producing formation; and   c) a downhole plunger-style pump located within the tubular at the lower end of the well string, which will be actuated by vertical reciprocating movement of the well string to pump oil from the formation up the well tubular to the wellhead;   said pump jack comprising:   a) a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string;   b) a powered well string positioner connecting the top end of the well string to the reciprocating power unit and which rotatably engages the well string such that the well string can be rotated along its axis within the tubular during operation of the vertical reciprocating power unit while being vertically retained in a position defining the length of the well string within the tubular;
 and wherein upon actuation the well string positioner will raise or lower the top end of the well string above the well string positioner resulting in the decrease or increase of the length of the well string within the tubular below the seal on the wellhead; and 
   c) a controller capable of actuation of the well string positioner by an operator; whereby during operation of the vertical reciprocating power unit, an operator can use the controller to actuate the well string positioner to modify the length of the well string within the tubular; and   wherein the length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string;   wherein the stroke of the vertical reciprocating power unit does not change when the length of the well string below the well string positioner is changed; and   wherein the well string can be rotated along its axis within the tubular during operation of the vertical reciprocating power unit without any need to deactivate the vertical reciprocating power unit, and without the need to detach the well string from the remainder of the apparatus.   
     
     
         8 . The pump jack of  claim 7  wherein the top end of the well string is threaded, and the well string positioner comprises a rotary power source capable of engaging the threaded top end of the well string and altering the length of the well string below the seal of the wellhead by rotary power applied to the threaded portion of the top end. 
     
     
         9 . The pump jack of  claim 8  wherein:
 a. the well string positioner comprises a carrier bar with a bar aperture therethrough through which the threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement and to the rotary power source whereby the threaded portion of the top end of the well string passes through the bar aperture and is engaged by the rotary power source; and 
 b. the rotary power source mechanically engages the threaded portion of the top end of the well string and whereby on actuation of the rotary power means during operation of the vertical reciprocating power unit, the threaded portion of the top end of the well string can be moved up or down through the bar aperture resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular. 
 
     
     
         10 . The pump jack of  claim 9  wherein the rotary power means comprises a hydraulic or electric motor. 
     
     
         11 . The pump jack of  claim 9  wherein the well string positioner can rotate the well string within the tubular along its axis and the controller will periodically actuate the well string positioner to incrementally rotate the well string during operation of the vertical reciprocating power unit. 
     
     
         12 . A method of adjustment of the well string positioning and length within the well tubular of a subterranean oil well extraction apparatus comprising:
 a) a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation;   b) a well string of circular cross-section having a lower end and a top end and extending downward inside the well tubular through a seal at the wellhead to at least a position within the tubular within the fluid-producing formation; and   c) a downhole plunger-style pump located within the tubular at the lower end of the well string which will be actuated by vertical reciprocating movement of the well string to pump oil from the formation up the well tubular to the wellhead; and   d) a vertical reciprocating pump jack comprising:
 i. a vertical reciprocating power unit capable of applying vertical reciprocating motion of the desired stroke length for the pump to the well string; 
 ii. a powered well string positioner connecting the top end of the well string to the reciprocating power unit and which rotatably engages the well string such that the well string can be rotated along its axis within the tubular during operation of the vertical reciprocating power unit while being vertically retained in a position defining the length of the well string within the tubular; and wherein upon actuation the well string positioner will raise or lower the top end of the well string above the well string positioner resulting in the decrease or increase of the length of the well string within the tubular below the seal on the wellhead; and 
   e. a controller capable of actuation of the well string positioner by an operator;   wherein the method comprises:   a. operating the vertical reciprocating pump jack to pump oil up the tubular from the formation; and   b. during the operation of the vertical reciprocating power unit when it is desired to adjust the length of the well string within the tubular, using the controller to actuate the well string positioner to modify the length of the well string within the tubular to a desired length;
 whereby during operation of the vertical reciprocating power unit, an operator can use the controller to actuate the well string positioner to modify the length of the well string within the tubular; and 
 wherein the length of the well string within the tubular can be adjusted during operation of the vertical reciprocating power unit without the need to disassemble the well string; 
 wherein the stroke of the vertical reciprocating power unit does not change when the length of the well string below the well string positioner is changed; and 
 wherein the well string can be rotated along its axis within the tubular during operation of the vertical reciprocating power unit without any need to deactivate the vertical reciprocating power unit, and without the need to detach the well string from the remainder of the apparatus. 
   
     
     
         13 . The method of  claim 12  wherein the top end of the well string is threaded, and the well string positioner comprises a rotary power source capable of engaging the threaded section of the top end of the well string and altering the length of the well string below the seal of the wellhead by rotary power applied to the threaded section of the top end. 
     
     
         14 . The method of  claim 12  wherein:
 a. the well string positioner comprises a carrier bar with a bar aperture therethrough through which the threaded portion of the top end of the well string extends, said carrier bar being attached to the reciprocating movement and to the rotary power source whereby the threaded portion of the top end of the well string passes through the bar aperture and is engaged by the rotary power source; and 
 b. the rotary power source mechanically engages the threaded portion of the top end of the well string and whereby on actuation of the rotary power means during operation of the vertical reciprocating power unit, the threaded portion of the top end of the well string can be moved up or down through the bar aperture resulting in the raising or lowering of the well string below the carrier bar and the decrease or increase of the length of the well string within the tubular. 
 
     
     
         15 . The method of  claim 14  wherein the well string positioner can rotate the well string within the tubular along its axis and the controller will periodically actuate the well string positioner to incrementally rotate the well string during operation of the vertical reciprocating power unit.