Patent Application
20200095835
This invention is in the field of oil-bearing formation drilling and more specifically in the field of downhole plunger-style pumps and controls to allow for automated operation.
Extraction of oil from hydrocarbon bearing geological formations is a complicated and capital intensive process. Typically, once a well is drilled into an oil-bearing formation, the drilling string is extracted and a tubular or casing finalized in place in the well, through which pumping or extraction tools can be used to extract oil up the well tubular to the wellhead for transport or further processing.
In many cases, where a well is drilled substantially vertically down into the formation, vertical reciprocal pumps and “pump jacks” are used to bring extracted oil to surface. A typical arrangement of this nature comprises a downhole plunger style pump attached at the distal end of the well string, within the tubular at a pumping location at which perforations in tubular or other means allow for entry of oil from the formation into the tubular and for pumping to the surface of the tubular upon vertical reciprocating motion of the well string and operation of the pump.
This type of a pump typically also includes a travelling valve assembly and the standing assembly. Sometimes in optimizing the operating parameters of the pumping system, or to avoid the tapping of the travelling valve on the bottom of the well or otherwise by stretching or extension of the well string, it is desirable to shorten or lengthen the length of the well string within the tubular. Traditionally one way this has been done is to disassemble the well string and either shorten or lengthen it, to result in adjustment of the well string. This type of an approach requires shutdown of the well equipment during adjustment however, so pumping is interrupted, and the need to disassemble much of the equipment at the wellhead to achieve this type of a well string adjustment is also unduly complicated and carries safety and operational risks. If it were possible to come up with a method for the adjustment of the well string length within an oil well tubular without the need to shorten or lengthen the well string is believed that this would be commercially desirable and accepted.
Another approach which is often used, where it is not desired to disassemble and/or adjust the length of the well string is to shorten or lengthen the stroke of the vertical reciprocating power unit which is used to actuate the well string and the travelling valve assembly of the pump. However, shortening or lengthening the stroke of the vertical reciprocating power unit has a significant effect on the efficiency of the pumping equipment and the pumping yield at the wellhead—if the stroke is shortened, less oil is pumped with each stroke, and if the stroke is lengthened while the pumping volume is potentially increased, there are operational parameter applications to the added weight or volume of oil within the tubular, or otherwise. If it were possible to come up with a method of adjusting the well string within an oil well tubular without the need to shorten or lengthen the stroke of the vertical reciprocating power unit used, it is believed again this would be a significant commercial benefit and would be widely commercially accepted in the industry.
Any type of an approach to adjusting the well string and oil well which could be adjusted without the need to shut down pumping or oil production would also be very desirable, in order to maintain consistent output from the pump and the well and maximize commercial success.
In addition to the commercial opportunity with respect to an ability to adjust the well string within an oil well tubular during pumping operations, another previous limitation has been that by and large monitoring the need to adjust the well string has been a human or manual process. Pump system operators wishing to optimize the operation of a particular pumping system might manually decide to adjust well string, or they might determine based upon the existence of tapping or other detected problems with the operation of the pump that there was a need to adjust the well string and thus a manual adjustment could be made. If it were possible to monitor the performance of an oil well to detect the existence of a condition in which an adjustment to the well string would be desirable, in accordance with the remainder of the present invention, and automatically make the adjustment without the need for operator intervention, it is also felt that this would be a further desirable approach which would be widely commercially accepted.
As outlined above it is the object of the present invention to provide a system and method for the automatic adjustment of the well string length within an oil well tubular, upon the detection of a condition requiring the adjustment of the well string.
It is the further object of the present invention to provide a system and method for the automatic adjustment of the well string length within an oil well tubular in which the well string could be adjusted without the need to stop operation of the pump.
It is the further object of the present invention to provide a system and method for the automatic adjustment of the well string length within an oil well tubular in which the well string could be adjusted without the need to disassemble the well string and adjust its length in any way.
It is the further object of the present invention to provide a system and method for the automatic adjustment of the well string within an oil well tubular in which the stroke of the vertical reciprocal power unit used to actuate the travelling valve assembly of a typical downhole plunger-style pump would not need to be adjusted in any way while the well string was adjusted.
There are thousands of pre-existing vertical reciprocating oil pumps in operation in oil fields around the world and if it were possible to come up with a retrofit equipment modification to implement a method and approach the present invention namely the ability to adjust the length of the well string within an oil well tubular while the pump is in operation, and without the need to disassemble the well string or to alter the stroke of the vertical power unit, such an aftermarket modification would be widely deployable, so such an invention would have aftermarket or service market utility in addition to potential as an OEM feature.
In a first embodiment of the invention, these objectives are achieved by a method of automatic adjustment of the well string length within an oil well tubular where a subterranean oil well comprises a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation; a well string having a lower end and a top end and extending downward through a seal on the wellhead inside the well tubular; and a downhole plunger-style pump located within the tubular attached to the lower end of the well string. Upon application of vertical reciprocating movement to the well string, the plunger and a travelling valve assembly will pump oil from the formation up the well tubular to the wellhead. A vertical reciprocating power unit is attached to the well string which is capable of applying vertical reciprocating motion of the desired stroke length for the plunger to the well string.
The method uses a well string positioner connecting the top end of the well string to the reciprocating power unit and capable of actuation while the reciprocating power unit is in operation, whereby on actuation of the well string positioner the top end of the well string can be moved up or down through the seal on the wellhead, resulting in the raising or lowering of the well string below the well string positioner and the decrease or increase of the length of the well string within the tubular. A controller capable of monitoring at least one well condition sensor to determine the existence of a string positioning condition within the tubular is also included—the controller will actuate the well string positioner to modify the length of the well string within the tubular on detection of a string positioning condition.
During the operation of the vertical reciprocating power unit, the controller will monitor the at least one well condition sensor to detect the existence of a string positioning condition within the tubular. A string positioning condition could either be a desire from the operator to manually trigger an adjustment to well string, or the at least one well condition sensor could determine that the positioning of the pump in the in the tubular needed to be adjusted to optimize its performance or avoid negative equipment impact.
Upon detection of a string positioning condition, the controller will actuate the well string positioner to modify the length of the length of the well string within the tubular until the string positioning condition is eliminated. The well string positioner will modify the length of the well string within the tubular while the vertical reciprocating power unit continues operation without the need to disassemble the well string, and the stroke of the vertical reciprocating power unit does not change when the length of the well string within the tubular is changed in accordance with this method.
The well string positioner could comprise a rotary power source engaging a threaded top end of the well string, which can by rotation and engagement with the threaded end effectively shorten or lengthen, dependent upon the direction of rotation, the well string between the vertical reciprocating power unit and the pump. In other embodiments of the system and method of the present invention the well string positioner could be a linear actuator, such as a hydraulic cylinder, which was capable of achieving the same objective. Both such approaches are contemplated within the scope of the present invention.
The well string positioner in some embodiments would comprise 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; load-bearing means engaging the threaded portion of the top end of the well string to the carrier bar, such that the vertical movement of the carrier bar will be translated upon the well string; and a bi-directional rotary power means capable of actuation while the reciprocating movement is in operation, whereby on actuation of the rotary power means 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.
The rotary power means used in the embodiments of the system, controller and method of the present invention could comprise hydraulic or electric motors. Any type of a rotary power means will be understood to be within the scope of the present invention in so far as they could be powered or actuated during operation of the vertical reciprocating power unit.
In certain embodiments of the system and method of the present invention, the well string positioner could also be used to rotate the well string, to provide periodic well string rotation within the tubular and the controller could periodically and incrementally rotate the well string in such embodiments.
There are many different types of string positioning conditions which might be desired to detect for use as a trigger parameter within the method of the present invention. Two specific string positioning conditions which are contemplated are where a travelling valve assembly is determined to not be optimally positioned in the downhole plunger-style pump, such that the length of the well string within the tubular needs to be increased or decreased, or upon a manual control input from operators who wish to manually adjust the well string to optimize the performance of the pump. Any number of different types of additional string positioning conditions or parameters contributing to the detection of a string positioning condition could also be considered and any type of a string positioning condition which upon its detection would result in the desire to adjust by increasing or decreasing the well string with an oil well will be understood to be within the scope of the present invention.
Where manual actuation of the well string changes is desired, at least one well condition sensor might be a human interface device allowing for an operator to select or trigger a well string change.
It is primarily contemplated that the vertical reciprocating power unit of the present invention is a conventional oilfield pump jack although any other type of a vertical reciprocal power unit capable of actuation of the downhole plunger style pump such as is otherwise outlined herein is contemplated to be within the scope of the present invention.
One of the key elements of the method of the present invention which renders it novel and desirable over the current state-of-the-art is the fact that controller and well string positioner of the present invention can work together in an automatic mode to allow for automated unsupervised adjustment of the well string—this will allow for continual optimized operation of an oil pump in a well application, without the need for significant ongoing or continual human operator oversight. As well, the well string positioner of the present invention, working in conjunction with the controller, will allow for adjustment of the well string within the tubular without the need to shut down the pump or to disassemble well string, and the stroke of the vertical reciprocating power unit need not be adjusted or changed in the scope of the remainder of the operation.
In addition to the method of the present invention there is disclosed a system for use in the automatic adjustment of the well string positioning and length within an oil well tubular, the well string having a lower end and a top end; and a downhole plunger-style pump located within the tubular. Upon application of vertical reciprocating movement to the well string, a travelling valve assembly in the pump will pump oil from the formation up the well tubular to the wellhead. A vertical reciprocating power unit is attached to the well string which is capable of applying vertical reciprocating motion of a desired stroke length for the plunger to the well string.
The system comprises two key components—a well string positioner connecting the top end of the well string to the reciprocating power unit and capable of actuation while the reciprocating power unit is in operation; and a controller capable of monitoring at least one well condition sensor to determine the existence of a string positioning condition within the tubular and of actuating the well string positioner to modify the length of the well string within the tubular. The system of the present invention, namely the well string positioner and the operatively connected controller and at least one well condition sensor as outlined, can be used to practice the method of the present invention namely to adjust the well string within an oil well tubular during vertical reciprocating operation of the pump in the oil well, and without the need to adjust the stroke of the vertical reciprocating power unit.
During operation of the vertical reciprocating power unit, the controller will monitor the at least one well condition sensor to detect the existence of a string positioning condition within the tubular; and upon detection of a string positioning condition within the tubular, actuate the well string positioner to modify the length of the well string within the tubular to eliminate the string positioning condition. 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, and the stroke of the reciprocal movement does not change when the length of the well string within the tubular is changed. Many variations on the well string positioner and the controller or sensors of the present invention will be understood to those skilled in the art based upon the general scope of the invention outlined elsewhere in this document and any such modifications and permutations of the invention are contemplated within the scope of the present invention.
The top end of the well string of the well might be threaded, and the well string positioner could comprise a rotary power source capable of engaging the threaded top end of the well string and increasing or decreasing the length of the well string within the tubular when actuated. In a more specific embodiment of the well string positioner of the present invention, that component might comprise 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; load-bearing means engaging the threaded portion of the top end of the well string to the carrier bar, such that the vertical motion of the carrier bar will be translated upon the well string; and a bi-directional rotary power means capable of actuation while the reciprocating movement is in operation, whereby on actuation of the rotary power means 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.
The well string positioner might also comprise a linear actuator such as a hydraulic cylinder or the like which was configured to, on actuation, apply a linear contraction or extension of the well string resulting in the adjustment of the length of the well string within the tubular. Both such approaches are contemplated within the scope of the present invention, both in terms of rotary or linear contraction or expansion of the length of the well string.
As outlined above there are many different types of string positioning conditions which could be sought to be sensed or detected for use in conjunction with the automated adjustment method of the present invention. These could be monitored or detected using at least one well condition sensor within or in proximity to the well tubular or the pump—many types of conventional sensors will be understood to those skilled in the art and it will be understood that both in terms of the number and type of sensors, and the number and type of string positioning conditions which could be monitored, these numbers could all be anywhere from one to many and any such approach and any such equipment are contemplated within the scope of the present invention as well.
Another embodiment of the present invention is a controller for use in the automatic adjustment well string within an oil well tubular where the well comprises a well tubular extending downwards from a wellhead at the earth surface to the bottom of the well in a subterranean fluid-producing formation; a well string having a lower end and a top end; and a downhole plunger-style pump located within the tubular. Upon application of vertical reciprocating movement to the well string, a travelling valve assembly in the pump will pump oil from the formation of the well tubular to the wellhead. A vertical reciprocating power unit is attached to the well string which is capable of applying vertical reciprocating motion of a desired stroke length for the plunger to the well string.
The oil well and pump would also be fitted with a well string positioner connecting the top end of the well string to the reciprocating power unit and capable of actuation while the reciprocating power unit is in operation, whereby on actuation of the well string positioner the top end of the well string can be moved up or down through the seal on the wellhead, resulting in the raising or lowering of the well string below the well string positioner and the decrease or increase of the length of the well string within the tubular. The well would also comprise at least one well condition sensor to determine the existence of a string positioning condition within the tubular.
The controller itself comprises an electronic controller capable of monitoring at least one well condition sensor to determine the existence of a string positioning condition within the tubular, and of actuating the well string positioner to modify the length of the well string within the tubular; whereby during operation of the vertical reciprocating power unit, the controller will monitor the at least one well condition sensor to detect the existence of a string positioning condition within the tubular; and upon detection of a string positioning condition within the tubular, actuate the well string positioner to modify the length of the well string within the tubular to eliminate the string positioning condition. The controller could comprise a controller specifically manufactured to actuate and control a well string positioner in accordance with the remainder of the present invention, or any other type of a well string positioner to which it was desired to apply the automated monitoring and adjustment methodology of the present invention.
It will be understood that there are many variations on the method, system and controller of the present invention as will be obvious to those skilled in the art of oilfield production and control and instrumentation design and any such modifications and variations are intended to be within the scope of the present invention as claimed and outlined herein.
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. The drawings enclosed are:
The schematic drawing of
During operation of the vertical reciprocating power unit 17, the at least one well condition sensor will be monitored by a controller to detect the existence of a string positioning condition. The monitoring step is shown at 2-2. A detection decision step within the monitoring loop is shown at 2-3, wherein if a string positioning condition is determined to exist, the well string positioner operatively connected to the controller would be actuated, at step 2-4, to alter the length of the well string within the tubular until the well string condition was alleviated or eliminated—the determination of the completion of the well string adjustment is shown at step 2-5. Following the adjustment of the well string within the tubular in response to the detection of a string positioning condition, or in continuing the monitoring loop where no string positioning condition is determined to exist (2-6) the pump would continue to operate, and the controller would continue to monitor for the existence of string positioning conditions and would adjust the well string within the tubular on detection of any such condition as required. By operating the controller and related at least one sensor during operation of the pump, the method of this Figure will allow for automated well string adjustment in the related oil well. As outlined elsewhere above, one of the well string adjustment conditions which could be detected would actually be a selection by an operator of a manual control input to allow for manual well string adjustment, in addition to the determination or detection of trigger parameters within our in relation to the well which would result in an automatic string positioning condition.
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 is attached to the vertical reciprocating power unit 17 via a well string positioner 20. In the case shown, the well string positioner 20 comprises a rotary power unit 20A which engages a threaded upper portion of the well string 7 which when actuated will allow for the expansion or contraction of the well string without any change in the stroke of the vertical reciprocating power unit 17. 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 well string in the oil well as desired. One downhole well condition sensor 22 is shown which is also connected to the controller 21.
One 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 the adjustment of the well string 16 by shortening or lengthening the well string 7 or the connector portion above the well string 7 and below the vertical reciprocating 17, resulting in the adjustment of the well string 16 without changing the stroke of the vertical reciprocating power unit 17. As outlined elsewhere herein, there are many different types of the well string positioners 20 which could operate within these parameters and which are contemplated within the scope of the present invention. It is for example specifically contemplated that 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 extension or contraction of the well string 16 as required, is contemplated within the scope of the present invention. A rotary power well string positioner 20 might comprise a rotary power means engaging a threaded upper portion of the well string 7, with the appropriate yoke or attachment system at the upper end thereof, which would allow for the rotary power means on its engagement to raise or lower the well string 7 and result in an attendant adjustment of the well spacing 16. In other embodiments, the well string positioner 20 might be a linear actuator such as a hydraulic cylinder or the like which was capable of effecting the same type of a movement upon the well string 7. Both linear and rotary equipment of this nature is contemplated within the scope hereof.
The controller 21 could be any type of a computer, programmable logic controller or other electronic system capable of monitoring and/or sampling inputs from the at least one well condition sensor 22 and/or communicating with and actuating the well string positioner 20. Key elements of the controller 21 in addition to the necessary memory and electronic components for basic operation include a communications bus 30 by which the controller 21 could communicate with the at least one well condition sensor 22. The controller 21 also needs to be able to actuate the well string positioner 20 by a connection thereto, this could be either by the same communications bus 30 used to communicate with the at least one well condition sensor 22 or by some additional connection—both such approaches will be understood to those skilled in the art. The controller 21 may also include a computer network connection, where the at least one well condition sensor 22 might comprise a remote software application reliant upon a wide area network connection to the controller 21.
Referring to
The controller 21 shown in this figure also shows one or more input and output devices 34 by which an operator of the controller 21 could interact with and enter information for capture. In some implementations, the controller 21 might also include a clock, location sensor or the like. Also present in the controller 21 would be a sensor bus 35 by which the controller 21 could communicate with the sensors 22 for the capture of well condition sensor readings. The controller 21 would also include either a separate or combined communication interface 36 by which the controller 21 could communicate with and actuate the well string positioner.
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.
Any number of different types of well condition sensors 22 could be used in the system of the present invention where it was desired to implement an automated well string adjustment methodology within an oil well tubular driven by a traditional vertical reciprocating power unit. Many different types of sensors will be understood to those with expertise in this area—any type of a sensor which was capable of detecting, either from monitoring the above surface equipment or in a downhole fashion, the need to adjust the well string to optimize its performance or avoid equipment damage is understood to be contemplated within the scope of the present invention. As discussed and outlined, the at least one well condition sensor could be a downhole sensor, a sensor connected to the aboveground equipment, or some combination thereof—any type of a sensor which could be monitored by the controller in accordance with the remainder of the present invention will be understood to be contemplated within the scope hereof.
As also described elsewhere herein, more than one well condition sensor could be used if it was desired to detect either redundantly a single type of a well condition requiring a well string adjustment or alternatively if it was desired to monitor more than one parameter which might indicate the existence of a well string positioning condition and again any number of well condition sensors will be understood to be within the scope of the present invention.
The controller 21 of the present invention would be modified or would contain the necessary communications bus to sample readings from the at least one well condition sensor 22.
It is explicitly contemplated that at least one well condition sensor 22 for use in conjunction with the remainder of the system and method of the present invention could be a human interface operatively connected to the controller, whereby an operator could manually select a well string adjustment or indicate to the remainder of the system the existence of a string positioning condition requiring an adjustment downhole. It will be understood that any combination of sensors 22 could include at least one human interface device 22 along with one or more automated sensors 22 all of which could be connected to the controller 21 for individual or combined reading and operation in accordance with the remainder of the method of the present invention and any such type of a human interface device, including an analog or digital input, computer interface to a local or wide area network or the like are all contemplated within the scope of the present invention. It is explicitly contemplated that one type of a human interface device which could be used as a well condition sensor 22 would actually be a interface on a computer network by which an operator could remotely adjust the well string in the oil well—for example by way of a smart phone app, remote monitoring software application and the like—wherein a well string adjustment and the related existence of a condition could be communicated to the controller 21 remotely via the human interface 22 of a client device on a computer network operatively connected to the controller 21. A remote control application such as this will be understood to be explicitly contemplated within the scope of human interface well condition sensors 22 which are contemplated within the scope of the present invention and that the existence of the string positioning condition could be indicated to the controller 21 via a remote human interface software input from an operator.
It will also be understood that the controller 21 might facilitate additional instrumentation or additional viewing or reporting of the values sensed from the at least one well condition sensor 22—while beyond the general or necessary scope of the present invention certain embodiments of the system outlined herein may include an ability for a user via a remote client device operatively connected via a wide area computer network to the controller 21 to read certain values therefrom in addition to allowing in certain cases for the selection of manual control inputs to adjust well string. It will be understood that such alterations are contemplated within the scope of the present invention as well.
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.
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.
