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.

Claims

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.

Description

DESCRIPTION OF THE DRAWINGS

[0033] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0034] The drawings enclosed are:

[0035] FIG. 1 is a schematic drawing of a typical oil well and pumping configuration, for the purpose of demonstrating the interrelation of components in prior art or other installations;

[0036] FIG. 2 is a schematic drawing of one embodiment of the system and pump jack of the present invention; and

[0037] FIG. 3 is a detail drawing of the components of a well string positioner as otherwise outlined herein.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

[0038] The schematic drawing of FIG. 1 shows the key components of a prior art oil well. The typical well 1 comprises a well tubular 2 extending downwards from a wellhead 3 at the earth surface 4 to the bottom 5 of the well 1 in a subterranean fluid-producing formation 6. The tubular 2 is either open or perforated near its bottom end or at locations therealong where it is desired to facilitate the entry of oil into the tubular from the formation. Inside the tubular 2 is a well string 7 having a top end 10 and extending downwards through a wellhead seal 8 to a lower end 9. The lower end 9 of the well string 7 would typically be at a location within the tubular 2 that was the lowest potential location at which it was desired to position the pump 12. A downhole plunger-style pump 12 is located within the tubular.

[0039] A vertical reciprocating power unit 17 is attached to the well string 7, which is capable of applying vertical reciprocating motion of a desired stroke length for the plunger 13 to the well string 7. Upon application of vertical reciprocating movement to the well string 7, a travelling valve assembly 14 of the pump 12 will pump oil from the formation up the well tubular 2 to the wellhead 3. Typical vertical reciprocating power units 17 used with these oil well extraction apparatus are known as pump jacks. The vertical reciprocating power unit 17 shown in FIG. 1 is a conventional pump jack.

[0040] The wellhead 3 is equipped with offtake conduits and/or pumping equipment (not shown) capable of evacuating the extracted oil from the tubular/wellhead into storage or a pipeline.

System Overview

[0041] FIG. 2 is a schematic diagram of the elements of one system in accordance with the method of the present invention for the automatic adjustment of the well string and oil well. The oil well, also referred to interchangeably herein as a subterranean oil well extraction apparatus, is shown, with the key components thereof labelled similar to those of the earlier oil well demonstrated in FIG. 1. Similar to the embodiment of FIG. 1 conventional pump jack is shown as the vertical reciprocating power unit 17.

[0042] The well tubular 2 is shown with the well string 7 extending downward therethrough. The vertical reciprocating power unit 17 is shown attached to the top end 10 of the well string 7. The top end 10 of the well string is attached to the vertical reciprocating power unit 17 via a powered well string positioner 20. In the case shown, the powered well string positioner 20 comprises a rotary power unit 20A which engages a threaded upper portion 7A of the top end of the well string 7 which when actuated will rotate the top end of the well string above the wellhead seal 8 by applying threaded rotary force to the threaded upper portion 7A. By applying such rotary force to the top end of the well string 7 when actuating the powered well string positioner 20, the well string positioner 20 will raise or lower the top end of the well string 7 above the well string positioner 20 resulting in the decrease or increase of the length of the well string 7 within the tubular 2 below the wellhead seal 8.

[0043] Well string positioner 20 is attached to the controller 21 and the controller 21 can actuate the rotary power unit 20A as required to increase or decrease the length of the well string 7 below the wellhead seal 8 as desired.

[0044] The length of the threaded portion 7A will define the extreme range of added or subtracted length, which can be applied to the well string 7 below the wellhead seal 8.

By allowing for altering the length of the well string 7 within the tubular 2 by effectively moving a slacker portion up or down above or below the powered well string positioner 20, the well string can be lengthened or shortened below the wellhead seal 8 without any change in the stroke of the vertical reciprocating power unit 17.

[0045] In operation of the system, when it is desired to modify the length of the well string 7 within the tubular, or the positioning of the lower end 9 within the tubular and in relation to the pump 12, the controller 21 is used to actuate the rotary power unit 20Awhich is presumed to be a bidirectional rotary power unit such as an electric or hydraulic motor with appropriate rotational translation means for engagement of the threaded upper portion of the well string 7. By actuating the rotary power unit, which is assumed to either be bidirectional or to have a direction reversing linkage attached for optional use, rotational lifting or lowering of the well string 7 could be achieved depending upon which direction the rotary power unit 20A turns and applies rotation to the string 7.

[0046] The controller 21 could simply be a switch or other human interface actuator which an operator of the well could use to activate the rotary power unit 20A in one direction or the other, or in other embodiments of the invention, the controller 21 could be an electronically actuated control which would allow for local or remote computerized control of the system of the present invention. Both such approaches are contemplated within the scope of the present invention and many different types of specific embodiments of the controller 21, all of which are intended to be covered herein, will be understood to those skilled in the art of system controls and oilfield maintenance. Many types of controllers, as outlined herein, could be used from basic locally operated manual operator controls, through to more elaborate either remotely or locally controlled by operators or automatic control systems.

[0047] It is explicitly contemplated that the system comprising the well string positioner for connection between the well string and the pump jack, along with the controller, or a pump jack with the well string positioner and controller manufacturer or attached, are both encompassed herein.

Well String Positioner

[0048] As discussed throughout, a key component of the system of the present invention is a well string positioner 20 which is operatively connected to the well string 7 and the vertical reciprocating power unit 17 which will allow for shortening or lengthening the length of the well string 7 below the well string positioner 20, resulting in the adjustment of the well string 7 without changing the stroke of the vertical reciprocating power unit 17. FIG. 3 demonstrates a sample of a rotary well string positioner 20 in accordance with the invention.

[0049] Either a rotary powered or linear actuated well string positioner 20, connected to the controller 21 such that it could be activated to allow for the shortening or lengthening of the well string 7 below the wellhead seal 8 as required, is contemplated within the scope of the present invention. In the case of a rotary powered well string positioner 20, the typical method of attachment of the rotary powered well string positioner 20 might comprise a yoke 23 and carrier bar 22 attachment system which is attachable to the pump jack 18 and has a bar aperture 22A extending therethrough. In addition to being attached to the reciprocating movement 18, the carrier bar 22 system could have the rotary power source 20Aattached to the top of the carrier bar 22 above the bar aperture 22A so that the threaded upper portion 7A of the well string 7 is engaged by the rotary power source 20A after passing through the bar aperture 22A. This would allow for the rotary power means 20A when turned on to raise or lower the well string 7 and result in an attendant adjustment of the length of the well string below the wellhead seal 8. Effectively, rotary movement of the motor 20A would be translated into a raising or lowering motion applied to the well string 7.

[0050] It will be understood to those skilled in the art of mechanical system design that in some cases it may be desired to create a means of attachment between a threaded upper portion of the well string and rotary power means that would result in the rotation of the well string when it was lifted or lowered, and other modified approaches could be taken in which the threaded engagement of the two systems would simply result in the lifting or lowering of the well string within the tubular without a rotary motion being applied to string. In some embodiments, the rotational power of the rotary power means 20A could be translated directly onto the threaded upper portion of the well string 7 whereby rotations of the rotary power means 20A would be directly translated into rotations of the well strata 7 in other embodiments it is contemplated that the rotary power means 20A might include a threaded collar sized and threaded for coordinated engagement of the threaded portion of the well string 7, to which the rotary power of the motor 20A would be directly applied in which would potentially result in the application of a direct raising or lowering of the well string 7 without necessarily rotation. However, insofar as it is explicitly contemplated that the system and method of the present invention will permit for incremental well string rotation in certain embodiments, those embodiments would either need to use the first approach whereby rotation of the power means 20A would actually directly rotate the well string 7 resulting in the ability to apply incremental rotation, or in the case of the threaded collar it would be necessary to include a locking mechanism which could lock the threaded collar to the well string and result in the ability for incremental rotation to be applied by the motor 20A. Both such approaches will be understood to those skilled in the art and are all contemplated with the necessary modifications to be within the scope of the present invention.

[0051] FIG. 3 shows a detailed schematic view of one embodiment of a well string positioner 20 within the scope of the present inventionwhere the rotary power means 20A is a hydraulic motor. Referring to that Figure, a carrier bar 22 and related yoke assembly can be seen which would be assembled between the well string 7 and the vertical reciprocating pump assembly 18, The rotary power means 20A is attached on top of the carrier bar 22 such that the carrier bar 22 will assist in the application of reciprocating vertical power from the yoke to the well string 7. The range of pump spacing adjustment defined by the threaded upper end of the well string 7 is also shownthe yoke 23 would be of sufficient length to allow for the entirety of the pump spacing adjustment and threaded portion of the well string 7 to move above the carrier bar 22 during operation of the pump jack without the need for stopping the application of vertical power and/or without the need to disassemble the well string.

[0052] The well string positioner 20 along with a controller 21 capable of actuating same is contemplated to comprise one set of embodiments of the present invention, along with another set of embodiments of the present invention comprising the well string positioner 20 of the present invention pre-manufactured or attached to a vertical reciprocating power assembly 18 for use with a well string 7 within a tubular 2 i.e. both retrofit of the equipment of the present invention as well as OEM incorporation of the device are contemplated within the scope of the present invention.

Controller

[0053] As outlined above, the controller 21 in its simplest embodiments might comprise a control by which the application of bidirectional rotary motion to the threaded upper portion of the well string [in embodiments using a rotary power means in the well string positioner] for actuating the bidirectional linear contraction or expansion of the length of the well string [in embodiments using a linear well string positioner and movement means] could be activated or deactivatedsomething as simple as a switch, or local electrical control for the power device used to effect movement and contraction or expansion below the well string positioner to the well string, are all contemplated within the scope of the present invention. An operator could simply actuate the power means within the well string positioner until the desired alteration of the length of the well string below the well string positioner was effected, with or without the use of sensors or other downhole measurements to determine the appropriate position of the lower end of the well string.

[0054] In the embodiment of the well string positioner 20 shown in detail in FIG. 3, it is contemplated that the rotary power source 20A would be a hydraulic motor. Hydraulic connectors 20B are shownin its simplest embodiment, the controller 21 would be a hydraulic valve capable of providing the necessary hydraulic fluid function to the rotary power source 20A to lift or lower the well string within the tubular. In cases where an electric motor was used in the place of a hydraulic motor, rather than a hydraulic valve, the controller 21 could simply be a electrical switch capable of applying the necessary power and polarity to the motor to raise or lower the well string within the tubular. Any such type of a straightforward manually actuated controller for use by an operator will be contemplated to be within the scope of the present invention.

[0055] It will also be understood that remote controlled embodiments of the controller 21 could be used, whereby the length of the well string within the tubular could be adjusted remotely by an operator without the need for site attendance, or could even be automatically adjusted by a monitoring system capable of automatically actuating the control 21 as required. All such approaches again are contemplated within the scope hereof.

[0056] As outlined some embodiments of the controller 21 might also include a network interface whereby the controller 21 could be accessed either locally or remotely via a local or wide area network to provide control inputs, monitor its performance and otherwise, and the addition of such additional components will be understood to be within the scope of the present invention. As well as outlined above, it is specifically contemplated that the hardware of the controller 21 could either be a software enabled configuration of a standard computer at the oil well site, or a purpose built or purpose programmed programmable logic controller or the like could be used as well. Any type of a combination of software and hardware which is capable of achieving the desired and needed steps of the method of the present invention outlined herein will be understood to be contemplated within the scope of the present invention from the perspective of the broadest enablement of the controller element.

[0057] In some embodiments of the present invention, where the well string positioner 20 would apply rotary power to the well string to adjust its length within the tubular, the controller 21 and the well string positioner 20 could also be modified to allow for periodically applied rotation to the well string. In some extraction methodologies it is desired to modestly rotate the well string 7 from time to time within the tubular and with a rotary power source being used within the well string positioner 20 this could be affected as outlined elsewhere herein and will be understood to again be contemplated within the scope of the present invention.

Method

[0058] The method of use of the system of the present invention is fairly straightforward. A well as outlined equipped with a vertical reciprocating power unit and a downhole plunger pump would have the well string positioner 20 of the present invention connected between the well string 7 and the reciprocating power means.

[0059] In an operational step of the method of the present invention, when it was desired to modify the length of the well string 7 within the tubular or to adjust the positioning of the lower end of the well string 7 within the tubular, the well string positioner 20 would be actuated to apply linear or rotary power to the upper end of the well string, resulting in the increase or decrease of length downhole within the tubular. The method of operation of the present invention is also contemplated and claimed within the scope hereof.

[0060] It will be apparent to those of skill in the art that by routine modification the present invention can be optimized for use in a wide range of conditions and application. It will also be obvious to those of skill in the art that there are various ways and designs with which to produce the apparatus and methods of the present invention. The illustrated embodiments are therefore not intended to limit the scope of the invention, but to provide examples of the apparatus and method to enable those of skill in the art to appreciate the inventive concept.

[0061] Those skilled in the art will recognize that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the scope of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms comprises and comprising should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.