System for lowering pipes in a pipe string

Abstract

A system for controlled lowering of pipes includes a hydraulic cylinder, a hydraulic reservoir, and force transducer coupled to a first pipe and to a cable that is arranged to lower the first pipe onto a second pipe disposed within a well. The hydraulic cylinder includes a fluid chamber and a piston movably disposed within the fluid chamber, and the hydraulic reservoir is fluidly coupled to the fluid chamber of the hydraulic cylinder through a first fluid passageway. The first fluid passageway includes a first valve that controls fluid through the first fluid passageway. A controller in communication with the force transducer and the first valve is configured to operate the first valve to control flow of hydraulic fluid out of the hydraulic cylinder to lower the first pipe onto the second pipe in a controlled manner.

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 781,121, filed Mar. 31, 2025, which is incorporated herein by reference.FIELD

[0002] The present disclosure relates to a system and a method for lowering a pipe for insertion into a well.BACKGROUND

[0003] Pipes can be installed in wells to line the well borehole and, in some examples, facilitate transfer of a fluid, such as oil or water, to and from the surface. Known well configurations comprise pipe columns or strings disposed within the well, where the pipe columns can be arranged to extend between an underground reservoir, such as an aquifer, and the surface. The fluid can be conveyed through the pipe column from the underground reservoir to the surface where the fluid can be used or processed. In some examples, the fluid can be transferred from the underground reservoir to the surface. In some examples, the fluid can be transferred from the surface to the underground reservoir. Some systems comprise a plurality of pipes that are coupled end to end to form a pipe column or string extending through the borehole. The pipes and the pipe columns can vary in length, diameter, and material depending on the application, well configuration, and borehole depth.

[0004] A pipe for use in transporting fluid within a well can be delivered to a wellbore site and / or installed in the wellbore using heavy equipment, such as with masts on mobile vehicles or stationary masts. A mast can be outfitted with cables or other means configured to lift and orient the pipe over the well for insertion after which the pipe is lowered into place. However, the pipes can be heavy and cumbersome to maneuver into position. Additionally, in some cases, it can be challenging to couple a lifted pipe to a pipe installed within a wellbore when the coupling bears the weight of the lifted pipe. Accordingly, a need exists for improved systems for the lowering of pipes, for example, to improve the coupling of pipes and / or to reduce the likelihood of damage to the pipes during lowering and coupling.SUMMARY

[0005] Described herein are systems and methods for controlled lowering of a first pipe onto a second pipe in a well, for example, for coupling the first and second pipes together to form a pipe assembly or pipe string (also referred to herein as a “pipe column”). In some examples, the systems for controlled lowering described herein can be utilized with a stationary lifting structure like a mast for lifting a pipe element or pipe column. In some examples, the systems for controlled lowering can be used with a truck or other vehicle configured for lifting a pipe section or assembled pipe column.

[0006] The systems and methods described herein can be used for controlled lowering of any pipe or pipe assembly relative to a well in any industry such as, for example, for oil, gas, or water operations. For example, the systems and methods described herein can be used for controlled lowering of pipes or pipe columns / assemblies for lining a borehole (e.g., for installation of well casings). Additionally or alternatively, the systems and methods described herein can be used for controlled lowering of pipes or pipe assemblies for insertion within pipes that are already installed within a borehole. As such, the terms “borehole” and “wellbore” are used herein interchangeably, and the systems and methods described herein can be applicable to installation of well casings, as well as other pipe assemblies.

[0007] A cable can be configured to lift and suspend a first pipe over a second pipe disposed within a wellbore. A lowering system can be arranged between a lifting end portion of the cable and the first pipe. The lowering system can comprise a sensor, such as for example, a load cell or a force transducer, that is configured to detect a weight of the first pipe. A change in this weight can be used to calculate a load or force exerted on the second pipe by the first pipe as it is lowered onto and / or is coupled with the second pipe.

[0008] In some examples, a lowering system can be further configured with a hydraulic cylinder arranged between the lifting end portion of the cable and the first pipe. The lowering system of this example can comprise a hydraulic reservoir fluidly coupled to the hydraulic cylinder via a plurality of valves, where the valves are configured to control the flow of fluid between the hydraulic cylinder and the hydraulic reservoir.

[0009] The hydraulic cylinder and the hydraulic reservoir can be configured such that, as the first pipe is lowered onto the second pipe and a change in the weight of the first pipe is detected by the sensor, fluid in the hydraulic cylinder and the hydraulic reservoir can act to dampen or cushion the load exerted on the second pipe by the first pipe and facilitate controlled lowering. That is, fluid can flow from the hydraulic cylinder to the hydraulic reservoir or vice-versa to regulate lowering of the first pipe in accordance with the force (e.g., weight) detected so as not to damage end portions of the first and second pipes or couplings therebetween. The lowering system of this example can comprise a controller or control unit responsive to a detected force (e.g., weight) from the sensor and in communication with a valve of the plurality of valves to open or close the valve to vary the flow of fluid between the hydraulic cylinder and the hydraulic reservoir.

[0010] In some examples, a lowering system can comprise a sensor, such as a force transducer or a load cell, that can be arranged to communicate with a controller or control unit that operates a winch to lower or retract the cable and thus the first pipe. The sensor can be arranged to detect the weight of the first pipe. This weight can be representative of the force exerted on the second pipe by the first pipe. A rate and amount that the first pipe is lowered in relation to the second pipe can be adjusted based at least on the weight of the first pipe detected by the sensor. In this way, by raising and lowering the first pipe in relation to the second pipe, the force exerted by the first pipe on the second pipe can be managed and the first pipe can be lowered onto the second in a controlled manner.

[0011] The foregoing and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a side view schematically showing a lowering system, according to an example, where the lowering system is used with a vehicle having a mast and a cable for lowering a first pipe over a second pipe in a wellbore.

[0013] FIG. 2 is a detail view of the lowering system of FIG. 1 comprising a force sensor, hydraulic cylinder, hydraulic reservoir, and a controller configured to manage the flow of fluid between the hydraulic cylinder and the hydraulic reservoir for controlled lowering.

[0014] FIG. 3 is a schematic block diagram of a control system for controlled lowering of a first pipe over a second pipe in a well, according to an example, where the control system is used with the lowering system of FIGS. 1-2.

[0015] FIG. 4 is a process flow diagram illustrating a representative method of controlled lowering of a first pipe over a second pipe in a wellbore, according to an example, where the method is used with the lowering system of FIGS. 1-2.

[0016] FIG. 5 is a process flow diagram illustrating a method of controlled lowering of a first pipe over a second pipe in a wellbore, according to another example, where the method is used with the lowering system of FIGS. 1-2.

[0017] FIG. 6 is a side view schematically showing a lowering system, according to another example, comprising the vehicle, cable, pipes, and wellbore of FIG. 1 with a sensor and a controller configured to operate a winch to retract or extend the cable for controlled lowering.

[0018] FIG. 7 is a schematic block diagram of a control system for controlled lowering of a first pipe over a second pipe in a well, according to another example, where the control system is used with the lowering system of FIG. 6.

[0019] FIG. 8 is a process flow diagram illustrating a representative method of controlled lowering of a first pipe over a second pipe in a wellbore, according to an example, where the method is used with the lowering system of FIG. 6.

[0020] FIG. 9 is a process flow diagram illustrating a method of controlled lowering of a first pipe over a second pipe in a wellbore, according to another example, where the method is used with the lowering system of FIG. 6.

[0021] FIG. 10 is a side view schematically showing a combined lowering system, according to another example, where the combined lowering system comprises the lowering system of FIG. 1 and portions of the lowering system of FIG. 6.

[0022] FIG. 11 illustrates a computing environment in which the control systems of FIGS. 3 and 7 can operate, according to an example.DETAILED DESCRIPTIONExplanation of Terms

[0023] For purposes of this description, certain aspects, advantages, and novel features of the examples of this disclosure are described herein. The disclosed methods, apparatuses, and systems should not be construed as being limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed examples, alone and in various combinations and sub-combinations with one another. The methods, apparatuses, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed examples require that any one or more specific advantages be present or problems be solved. The scope of this disclosure includes any features disclosed herein combined with any other features disclosed herein, unless physically impossible.

[0024] Although the operations of some of the disclosed examples are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed methods can be used in conjunction with other methods.

[0025] As used in this disclosure and in the claims, the singular forms “a,”“an,” and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the term “includes” means “comprises.” Further, the terms “coupled” and “associated” generally mean electrically, electromagnetically, and / or physically (e.g., mechanically or chemically) coupled or linked and does not exclude the presence of intermediate elements between the coupled or associated items absent specific contrary language.

[0026] In the description, certain terms may be used such as “forward,”“front,”“rear,”“back,”“up,”“down,”“upper,”“lower,”“horizontal,”“vertical,”“left,”“right,”“longitudinal,”“lateral,” and the like. These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. However, these terms are not intended to imply absolute relationships, positions, and / or orientations. For example, with respect to an object, an “upper” surface can become a “lower” surface by turning the object over. Nevertheless, it is still the same object.

[0027] Similar components in different examples are described in the specification and illustrated in the figures with similar reference numbers for improved understanding and readability. However, it should be understood that this numbering convention is merely for convenience and is not intended to limit and / or exclude any claim scope.

[0028] Although there are alternatives for various components, parameters, operating conditions, etc., set forth herein, that does not mean that those alternatives are necessarily equivalent and / or perform equally well. Nor does it mean that the alternatives are listed in a preferred order unless stated otherwise.

[0029] As used herein, “e.g.” means “for example,” and “i.e.” means “that is.”

[0030] Where applicable, values and relationships modified by the term “substantially” mean±10% of the stated value or relationship. The term “substantially parallel” means an angle of±10° between an object and a reference. The term “substantially perpendicular” means an angle of 60° to 120° between an object and a reference.Disclosed Technology

[0031] As introduced above, pipes can be installed in a well to convey a fluid, such as water or oil, from a reservoir such as an underground aquifer to the surface or vice versa. After a borehole is drilled from the surface providing access to the reservoir, a pipe can be inserted into the borehole. Depending on the depth of the borehole, this pipe can comprise a large number of pipe segments that are coupled to each other to form a length sufficient to span the depth.

[0032] As pipes are cumulatively coupled to each other either within the borehole or above ground, the pipe column can increase in weight, necessitating the use of heavy equipment for lifting and lowering. In some examples, a stationary structure or rig comprising a mast can be used to hoist a pipe or pipe column into the air and into position over a well.

[0033] In some examples, a vehicle comprising a mast can be driven to a work or installation site for use in hoisting a pipe segment or pipe column over an opening of a well on the surface. In some examples, the vehicle can be a mobile drilling rig vehicle including a mast with a rotary head that is movable up and down along the mast. The mast can include any of a variety of additional machines including a clamp for holding a pipe string inserted in the well bore, and / or a carousel for holding pipe sections to be added to the pipe string.

[0034] As used herein, the term “mast” includes support structures such as cranes, booms, masts, towers, and derricks for the drilling, construction, maintenance, and rehabilitation of wells or boreholes. The structures may carry or include any of a variety of additional equipment, for example, winches, drive elements, clamps, coupling devices, lowering assemblies, controllers, sensors, and cutters.

[0035] To couple a first lifted pipe to a second pipe disposed within a wellbore, for example to form a pipe string, the first pipe is generally lowered over the second pipe using a cable. In some examples, first end portions of the pipes can be configured with male couplings while second end portions of the pipes can be configured with respective female couplings that are configured to engage with the male couplings. In a representative example, a first end portion of a first pipe can have male threads that are configured to engage and mate with female threads on a second end portion of a second pipe such that the pipes can be secured to each other. Although the first end portions are described herein as having male couplings and the second end portions are described as having female couplings, the coupling configurations can be reversed. That is, the first end portions can have female couplings while the second end portions can have male couplings.

[0036] When the first pipe is lowered onto the second pipe, the first end of the first pipe can contact and rest on the second end of the second pipe and the first pipe can exert a force (also referred to herein as a “load”) on the second pipe. In some examples, this load can vary based on the weight of the first pipe and the lifting support provided by the cable from which it is suspended. For example, the load exerted on the second pipe by the first pipe can vary according to the proportion of the weight of the first pipe that is supported by the mast (e.g. through the cable) and the proportion of the weight of the first pipe that is supported by the second pipe. The first pipe can be raised and lowered by the cable such that lifting aid provided by the cable to the first pipe can be varied.

[0037] As introduced above, in some instances, coupling the first and second pipes to each other can be difficult when the first pipe exerts a large load on the second pipe. For example, it can be challenging, in some cases, to maintain axial alignment between the first and second pipes when most or all of the weight of the first pipe is resting on the second pipe. For example, if the first and second pipes are misaligned by even a small amount, rotating the first pipe relative to the second pipe for a threaded coupling can damage the threads and, in some cases, result in cross-threading. It is therefore advantageous to implement a system for lowering a first pipe onto a second pipe in which the rate of the lowering is controlled, and thus the load exerted by the first pipe on the second pipe is also controlled, thereby reducing the likelihood of damage or misalignment.Example 1: Hydraulic System for Lowering Pipes

[0038] FIG. 1 schematically shows a work site system 10a for a wellbore that includes a vehicle 11 comprising a mast 12, a first pair of wheels 16 at a front portion of the vehicle, a second pair of wheels 18 at a rear portion of the vehicle 11, and optionally a third set of wheels 20 between the first and second pairs of wheels 16, 18. The mast 12 is configured to hoist a work piece, for example a pipe 22, over a pipe 23 disposed within a wellbore 24. The wellbore 24 can be utilized for the transfer of, for example, oil and gas, or for water. Although the vehicle 11 in FIG. 1 is shown lifting a pipe over a well, it is understood that any work piece can be lifted using the same system and aligned and lowered onto any structure underneath using the systems and methods described herein. Referring to FIG. 1, in some examples, the vehicle 11 can comprise one or more outriggers 14 that can be configured to extend into engagement with the ground, as shown in FIG. 1, for vehicle stability.

[0039] In some examples, the mast 12 can have a first end portion fixedly secured to the vehicle 11. That is, the mast 12 can be mounted to the vehicle 11 such that it cannot move in relation thereto. In other examples, a position of the mast 12 can be adjusted in relation to the vehicle 11.

[0040] In some examples, the vehicle 11 can be outfitted with a winch 26 coupled to a first end of a cable 28. In some examples, the cable 28 can be wound around the winch 26 and arranged over a pulley 30 or bearing surface disposed at a second end portion of the mast 12. Although FIG. 1 shows the work site system 10a as having the vehicle 11 with the winch 26, mast 12, and cable 28, it is appreciated that a stationary rig can be used to hoist the pipe 22 over the pipe 23 and the wellbore 24. In other words, a stationary rig can be configured with a winch and a cable that is couplable to a pipe for raising and / or lowering the pipe as described herein.

[0041] Referring to FIG. 1, disposed at a second end portion of the cable 28 is a coupling arrangement, such as a hook 32, to which a lowering system 100 is connected. Although a hook is shown and described herein, it is understood that any coupling arrangement can be used. The lowering system 100 is a hydraulic system, shown in detail in FIG. 2, and is further connected to an elevator 34 which is configured to couple to the pipe 22. In other words, the lowering system 100 is disposed between the hook 32 (or other coupling arrangement) of the cable 28 and the elevator 34. In some examples, the lowering system 100 can be coupled directly to a second end portion 35 of the pipe 22. The lowering system 100 will be described in more detail below in connection with FIG. 2.

[0042] To hoist the pipe 22, the winch 26 can be actuated to wind the cable 28 which pulls the cable 28 around the pulley 30. This winding action lifts the lowering system 100 and the elevator 34 which, in turn, lifts the pipe 22 into the air as shown in FIG. 1. Although the hook 32 is shown attached directly to the lowering system 100, it is possible that the hook 32 can be other attachment means attached directly or indirectly to the lowering system 100.

[0043] The pipe 22 shown in FIG. 1 can be, in some examples, a single pipe section. In other examples, the pipe 22 can be a pipe column or string comprising a plurality of coupled pipe sections. For the sake of simplicity, only one pipe section is illustrated. Additionally, the pipe 23 disposed within the wellbore 24 can be a single pipe section, or the top-most pipe section (closest to the surface) of a pipe string comprising a plurality of coupled pipe sections. For the sake of simplicity, only one pipe section is illustrated in FIG. 1. The pipe 23 can be secured within the wellbore 24 such that it does not move within the wellbore 24 while the pipe 22 is being lowered. For example, a second end portion 36 of the pipe 23 can be secured within the wellbore 24 using a clamp 37 or other support, such as a spider assembly.

[0044] A first end portion 38 of the pipe 22 can comprise a first coupling element 40 that is configured to mate and couple with a second coupling element 42 of the second end portion 36 of the pipe 23. As described above, the first and second coupling elements 40, 42 can be threaded features that, when rotated in relation to each other, screw together and secure the pipe 22 to the pipe 23. Although threaded couplings are described primarily herein, any coupling means can be used and controlled lowering of the pipe 22 onto the pipe 23 would be similarly beneficial for improved coupling therebetween.

[0045] As described above, it can be advantageous to lower the pipe 22 onto the pipe 23 in a controlled manner such that a load exerted on the pipe 23 by the pipe 22 is maintained within a specified range. FIG. 2 shows the lowering system 100 of FIG. 1, according to an example, where the lowering system 100 is disposed between the hook 32 of the cable 28 and the pipe 22 (not shown in FIG. 2). The lowering system 100 comprises a sensor 102, which can be configured as a force transducer such as a strain gauge, a load cell, etc. In some examples, the sensor 102 can comprise a case or body that is configured to be coupled between two objects, for example, between the cable 28 and a suspended pipe (e.g., the pipe 22). As such, the sensor 102 can be configured to sense a weight of the suspended pipe. In the illustrated example, a first end portion 104 of the sensor 102 is configured to be coupled to the hook 32 of the cable 28. Although the first end portion 104 of the sensor 102 is shown with a loop around which the hook 32 extends, it is appreciated that any means of connection can be implemented between the cable 28 and the sensor 102.

[0046] A second end portion 106 of the sensor 102 can be coupled to a hydraulic cylinder 110 either indirectly or directly as shown in FIG. 2. The hydraulic cylinder 110 comprises a fluid chamber 112 and a piston 114 movably disposed within the fluid chamber 112. The piston 114 comprises a piston head 116 (also referred to herein as a “seal portion”) and a rod 118 attached to the piston head 116. The piston head 116 separates the fluid chamber 112 into a first chamber portion 120 and a second chamber portion 122. As shown in FIG. 2, the first chamber portion 120 is disposed on one side of the piston head 116 (e.g., below the piston head 116 in the configuration of FIG. 2) while the second chamber portion 122 is disposed on the opposite side of the piston head 116 (e.g., above the piston head 116 in the configuration of FIG. 2). The first chamber portion 120 can be filled with a hydraulic fluid 121 (also referred to herein as a “fluid”), such as oil, while the second chamber portion 122 can comprise a gas, such as air. The piston head 116 is configured such that it can be displaced within the fluid chamber 112 while maintaining a seal between the first and second chamber portions 120, 122. In this way, the respective volumes of the first and second chamber portions 120, 122 vary in size according to the location of the piston head, and the fluid and the gas do not mix. The fluid chamber 112 can further comprise a vent 123 arranged to release gas from the second chamber portion 122 when the gas pressure exceeds a selected threshold.

[0047] A spring 124 can be arranged in the first chamber portion 120 as shown in FIG. 2. In some examples, the spring 124 is a compression spring arranged to extend from an inner wall 126 of the first chamber portion 120 into abutment with the piston head 116. The spring 124 is configured to push the piston head 116 in a direction of the positive Z axis as shown in FIG. 2, which will be described in more detail below. Although the spring 124 is shown in FIG. 2 as a compression spring encircling the rod 118, it is understood that any spring configured to push the piston head 116 in the direction of the second chamber portion 122 can be used.

[0048] An end portion 128 of the rod 118 can be arranged to extend out of the fluid chamber 112 for coupling either directly to the second end portion 35 of the pipe 22 or indirectly through the elevator 34 as depicted in FIG. 2 or through other component(s). In this way, the sensor 102 and the hydraulic cylinder 110 are in-line or in series with each other, the cable 28, and the pipe 22.

[0049] Because the pipe 22 is suspended in series with the cable 28 and the sensor 102, a sensed force detected by the sensor 102 can indicate the weight of the pipe 22. A change in the sensed force (e.g., weight) can be used to calculate a portion of the weight of the pipe 22 supported by the pipe 23. For example, the sensed force can indicate a suspended or full weight of the pipe 22 when the pipe 22 is entirely supported by the cable 28 (e.g., fully suspended or hanging) and not in contact with the pipe 23. When the pipe 22 is resting on and is supported at least partially by the pipe 23, a portion of the full weight of the pipe 22 is borne by the pipe 23 underneath, resulting in a reduction of the sensed force detected by the sensor 102. That is, the sensed force detected by the sensor 102 decreases when the pipe 22 is resting on the pipe 23 compared to the sensed force when the pipe 22 is fully suspended or hanging. As such, this decrease in sensed force can be compared to the full weight of the pipe 22 and the comparison can be used to indicate the portion of the weight of the pipe 22 that is supported by the pipe 23 when the pipe 22 is resting on the pipe 23 or being coupled thereto. Stated another way, the sensed force can be used to calculate the load or force exerted by the pipe 22 on the pipe 23.

[0050] Referring to FIG. 2, the lowering system 100 further comprises a hydraulic reservoir 132 fluidly coupled to the hydraulic cylinder 110 through a first fluid passageway 134 and a second fluid passageway 136. In some examples, the hydraulic reservoir 132 can be configured as an accumulator to cushion movement of the piston 114 within the cylinder 110. In the example shown in FIG. 2, the hydraulic reservoir 132 comprises a diaphragm 138 arranged to separate a first portion 140 of the hydraulic reservoir 132 from a second portion 142 of the hydraulic reservoir 132. The first portion 140 is filled with the same hydraulic fluid that is within the first chamber portion 120 of the fluid chamber 112, while the second portion 142 can comprise gas, such as air. The diaphragm 138 is flexible but impermeable such that the fluid 121 in the first portion 140 does not mix with the gas in the second portion 142. The hydraulic reservoir 132 can have a vent 144 that releases gas from the second portion 142 when the gas pressure in the second portion 142 exceeds a selected threshold. Although the hydraulic reservoir 132 is shown and described as having the diaphragm 138, the hydraulic reservoir 132 could, in some examples, be configured with a bladder or a piston to similar effect.

[0051] The first fluid passageway 134 is configured with a valve 146 arranged to control fluid flow between the first portion 140 of the hydraulic reservoir 132 and the first chamber portion 120 of the hydraulic cylinder 110. In some examples, the valve 146 can be a solenoid valve that can be selectively opened and closed. In some examples, the valve 146 can be a solenoid valve with binary operation such that the valve 146 moves between an open state and a closed state. In some examples, the solenoid valve can be positionable at different positions between a fully open state and a fully closed state, such as 25% open, 50% open, 75% open, etc. When the valve 146 is in an open or partially open state, fluid can flow between the first chamber portion 120 of the hydraulic cylinder 110 and the hydraulic reservoir 132 through the first fluid passageway 134. Conversely, when the valve 146 is in a closed state, fluid cannot flow between the hydraulic reservoir 132 and the first chamber portion 120 of the hydraulic cylinder 110 through the first fluid passageway 134.

[0052] The second fluid passageway 136 is configured with a valve 148 arranged to control fluid flow between the first portion 140 of the hydraulic reservoir 132 and the first chamber portion 120 of the hydraulic cylinder 110. More specifically, the valve 148 is a check (one-way) valve arranged to allow flow from the first portion 140 of the hydraulic reservoir 132 to the first chamber portion 120 of the hydraulic cylinder 110 but restrict flow in the opposite direction from the first chamber portion 120 of the hydraulic cylinder 110 to the first portion 140 of the hydraulic reservoir 132.

[0053] As shown in FIG. 2, the lowering system 100 can additionally comprise a controller or control unit 156 that can be arranged to communicate with the sensor 102 and the valve 146. Although the control unit 156 is shown with a wired connection to the sensor 102 and the valve 146, it is understood that the control unit 156 can be wirelessly connected to the sensor 102 and / or the valve 146. The control unit 156 can be mounted to any component of the lowering system 100 or nearby structure. In some examples, the control unit 156 comprises a battery that can power the control unit 156 and, in some examples, the sensor 102.

[0054] The control unit 156 can be configured to receive a signal from the sensor 102 and transmit a command to the valve 146 to open or close the valve 146. Operation of the valve 146 controls the flow of fluid 121 from the hydraulic cylinder 110 to the hydraulic reservoir 132, which can result in controlled lowering of the pipe 22. As such, in response to at least a sensed force (or load) by the sensor 102, a control system can be implemented to actuate the valve 146.

[0055] For example, a control system 200 schematically illustrated in FIG. 3 can be arranged to control operation of the valve 146 depending on a difference between the sensed force detected by the sensor 102 and a selected force setting (SFS). As described above, the sensed force can be the weight of the pipe 22 and the selected force setting (SFS) can be a target force that is a threshold or selected weight of the pipe 22 that avoids damage to the pipes and / or permits alignment between the pipes.

[0056] The SFS can be manually selected by the operator, in some examples. In some examples, the SFS can be a pre-programmed value that is, for instance, based on the size and / or weight of a lifted pipe and / or the pipe or pipe column on which the lifted pipe is set. In some examples, the SFS can be constant or the same for the duration of a lowering operation. In some examples, the SFS can vary as a lifted pipe is lowered onto or coupled to a pipe underneath. For example, the SFS can increase as the lifted pipe is coupled to the pipe underneath. That is, the SFS can increase during a coupling operation such that the second pipe (e.g., the pipe underneath or pipe 23) supports increasingly more of the weight of the first pipe (e.g., the lifted pipe or pipe 22) as the pipes are coupled to each other.

[0057] Referring to FIG. 3, the lowering system 100 is represented in the control system 200 as the block 100. The control system 200 can further comprise a summing junction 202 and a valve control element or block 204. In some examples, as will be described in more detail below in connection with FIG. 11, the control unit 156 can be configured with a processor to perform the steps represented by the valve control element 204 and the summing junction 202.

[0058] With the application of an external trigger T, such as for example an operator engaged ON switch or a change in force detected by the sensor 102 (e.g., when the pipe 22 just starts to touch the pipe 23), a force signal comprising data representative of the sensed force can be provided to the summing junction 202. In some examples, the change in the sensed force can be a reduction of 1-30 percent, 1-20 percent, 1-10 percent, or 1-5 percent of the entire weight of the lifted pipe (e.g., the pipe 22).

[0059] The sensed force (e.g., the weight of the pipe 22) can be compared to (e.g., subtracted from as shown in FIG. 3) the selected force setting SFS at the summing junction 202, where the SFS in this example can be a threshold or selected weight of the pipe 22 that, in some examples, avoids damage to the pipes and / or permits alignment between the pipes.

[0060] Comparison (e.g., subtraction) of the sensed force with the selected force setting (SFS) can yield a signal indicative of a force difference or force error relative to the SFS. This force difference signal can be provided to the valve control element 204. Using this force difference signal, the valve control element 204 can determine a valve command a1 for transmission to the lowering system 100. In some examples, the valve control element 204 can determine whether to open the valve 146, close the valve 146, or make no change to a position of the valve 146.

[0061] In operation, an operator can lower the pipe 22 manually by unwinding the cable 28 from the winch 26 until a first end of the pipe 22 is in close proximity to a second end of the pipe 23. For example, the first end of the pipe 22 can be within 2 -12 inches of the second end of the second pipe, such as 2-8 inches, or 2-6 inches from the second end of the pipe 23. In some examples, as will be described in more detail below in connection with FIGS. 6-10, when the first end of the pipe 22 is in close proximity to the second end of the pipe 23 as described above, an automated system of lowering (for example, systems 500, 900) can be triggered to automatically actuate the winch 26 to release the cable 28 at a set rate to lower the pipe 22 until the pipe 22 contacts the pipe 23 underneath.

[0062] Alternatively, the operator can lower the pipe 22 manually by unwinding the cable 28 from the winch 26 until the first end of the pipe 22 contacts the second end of the pipe 23. When the pipe 22 contacts the pipe 23, a change in load or force is detected by the sensor 102. In this example, as the pipe 22 is lowered in a suspended state over the pipe 23, the sensor 102 detects a force representative of the full weight of the pipe 22 suspended by the cable 28, as described above. When the pipe 22 starts to touch the pipe 23, the force detected by the sensor 102 changes (e.g., the detected force is reduced). That is, as the pipe 22 begins resting on the pipe 23, the force change detected by the sensor 102 reflects support provided by the pipe 23 to the pipe 22. The change in force sensed by the sensor 102 represents the portion of the weight of the pipe 22 that is being supported by the pipe 23 (e.g., the load exerted by the pipe 22 on the pipe 23).

[0063] Referring to FIG. 2, sensed force data is received by the control unit 156 from the sensor 102. The sensed force is compared with the selected force setting (SFS) as described above to determine if the force is greater than the SFS, less than the SFS, or at the SFS. In response to a difference between the sensed force and the SFS, a state of the valve 146 can be calculated to reduce the difference (e.g., the load or force error) and a control signal can be transmitted to the valve 146 to move the valve to the calculated state.

[0064] For example, if the force is less than the target force (e.g., the SFS) and the valve 146 is closed, no change command is sent to the valve 146 and the valve 146 remains closed. Alternatively, if the force is less than the target and the valve 146 is open, the control unit 156 sends a signal to the valve 146 to close (for example, valve command a1 from the valve control block 204 in FIG. 3).

[0065] In another example, if the force is greater than the target force (e.g., the SFS) and the valve 146 is open, no change command is sent to the valve 146 and the valve 146 remains open. Alternatively, if the force is greater than the target force and the valve 146 is closed, the control unit 156 sends a signal to the valve 146 to open (for example, valve command a1 from the valve control block 204 in FIG. 3). With the valve 146 open, the fluid 121 can flow from the first chamber portion 120 in the cylinder 110 to the first portion 140 of the hydraulic reservoir 132. The piston head 116 can move in a direction of the negative Z axis (e.g., downward in the configuration of FIG. 2) due to the weight of the pipe 22 on the rod 118. This displacement of the piston head 116 due to the weight of the pipe 22 can apply a compressive force on the fluid 121 in the first chamber portion 120. The fluid 121 is generally non-compressible and, as such, is forced to flow through the open valve 146 and into the first portion 140 of the hydraulic reservoir 132 under the compressive force of the piston head 116.

[0066] As the fluid 121 flows into the first portion 140 of the hydraulic reservoir 132, the diaphragm 138 can deflect in the direction of the positive Z axis (e.g., upward in the configuration shown in FIG. 2) as a volume of the fluid 121 in the first portion 140 of the hydraulic reservoir 132 increases. Movement of the diaphragm 138 due to an increase in volume within the first portion 140 of the hydraulic reservoir 132 is limited by the shape and size of the diaphragm 138 and the gas pressure in the second portion 142 of the hydraulic reservoir 132. In other words, the diaphragm 138 and the gas in the second portion 142 of the hydraulic reservoir 132 push back on the fluid 121 in the first portion 140 of the hydraulic reservoir 132 and act to resist the flow of the fluid 121 into the hydraulic reservoir 132 after a select volume of fluid 121 has moved into the hydraulic reservoir 132.

[0067] After the select volume of fluid 121 has moved into the hydraulic reservoir 132, additional fluid 121 is prevented from moving from the first chamber portion 120 of the fluid chamber 112 into the first portion 140 of the hydraulic reservoir 132 by virtue of the diaphragm 138 and gas in the second portion 142 of the hydraulic reservoir 132 as described above. By restricting movement of additional fluid into the hydraulic reservoir 132, further displacement of the piston head 116 in the direction of the negative Z axis under the weight of the pipe 22 is likewise limited. Thus, an equilibrium state is reached in which the fluid 121 in the hydraulic reservoir 132 controls or minimizes movement of the piston head 116 due to the weight of the pipe 22. In this way, the hydraulic reservoir 132 acts to damp or cushion downward displacement of the piston 114 under the weight of the pipe 22. This cushioned downward displacement, in turn, can result in controlled lowering of the pipe 22 and a controlled application of force on the pipe 23.

[0068] In this way, the diaphragm 138 is arranged to limit change in a volume of fluid 121 in the first chamber portion 120 of the hydraulic cylinder 110. The configuration of the diaphragm 138 and pressure of the gas in the second portion 142 of the hydraulic reservoir 132 can be selected to yield a specified equilibrium state in which the piston 114 is displaced in a controlled manner and the load exerted on the pipe 23 is increased at a specified rate.

[0069] When the sensed force is equal to the target (e.g., the SFS) such that the force error is zero, the control unit 156 sends a signal to the valve 146 to close. When the valve 146 is closed, fluid 121 can no longer flow from the first chamber portion 120 of the fluid chamber 112 into the hydraulic reservoir 132. By restricting flow from the first chamber portion 120 of the fluid chamber 112 into the hydraulic reservoir 132, the fluid 121 is maintained in place and the piston 114 and the pipe 22 are held steady on the pipe 23 without any movement in the Z axis.

[0070] When the pipe 22 is coupled to the pipe 23, for example by screwing male threads on the first end portion 38 of the pipe 22 to female threads on the second end portion 36 of the pipe 23, the pipe 22 displaces in a direction of the negative Z axis (e.g., downward in the configuration shown in FIG. 2) as the threads are engaged. That is, the pipe 22 displaces axially downward when it is threaded onto the pipe 23. With the cable 28 held fixed such that it does not release or extend, the axial displacement of the pipe 22 due to coupling can result in an increase in pulling force on the piston 114 and / or tension on the sensor 102. This increase in tension on the sensor 102 can result in an increase in sensed force relative to the target force (e.g., the SFS).

[0071] As described above, during coupling of the pipes 22 and 23, when the sensed force is greater than the target force, the control unit 156 sends a signal to the valve 146 to open. With the valve 146 open, the fluid 121 can flow from the first chamber portion 120 in the cylinder 110 to the first portion 140 of the hydraulic reservoir 132 due to the pulling force on the piston 114. The piston 114 pushes on the fluid 121 as the pipes are threaded together and the piston 114 is displaced in the first chamber portion 120. This results in fluid flow out of the first chamber portion 120. Flow of the fluid 121 out of the cylinder 110 can continue until the controller transmits a signal to close the valve 146, or the diaphragm 138 reaches its maximum displacement at which time additional fluid 121 is prevented from flowing into the hydraulic reservoir 132 as described above. Lowering of the pipe 22 onto the pipe 23 during coupling is thus controlled.

[0072] After the pipes 22 and 23 are coupled together, the pipe 22 can be released from the lowering system 100. When the pipe 22 (and the weight of the pipe 22) is decoupled from the piston 114, the spring 124 can act to displace the piston head 116 upwards in the direction of the positive Z axis. That is, without the weight of the suspended pipe 22, the sensed force is zero and the force of the spring 124 acts to reset the cylinder 110 for another lowering operation. When the piston head 116 is displaced upward by the spring 124 as described, fluid 121 is drawn through the check valve 148 in the second fluid passageway 136 from the first portion 140 of the hydraulic reservoir 132 and into the first chamber portion 120 of the fluid chamber 112. The amount of fluid 121 that flows through the check valve 148 and into the first chamber portion 120 of the fluid chamber 112 can depend on a variety of factors including displacement of the spring 124 and the piston head 116, a total volume of the fluid 121 in the system, a maximum displacement of the diaphragm 138, etc.

[0073] FIG. 4 is a process flow diagram illustrating a representative method 300 of controlled lowering of a pipe using a control system, such as the control system 200, according to an example. Step 302 comprises determining a sensed force, where the sensed force is detected by a sensor coupled to a cable arranged to lift a first pipe (e.g., pipe 22). In some examples, the sensed force is the weight of the first pipe (e.g., the pipe 22) and the sensed force can be compared to a SFS that is a threshold or selected weight of the pipe 22. In some examples, as will be described in more detail below, the sensed force can be used to calculate a force exerted by a first pipe (e.g., pipe 22) on a second pipe (e.g., pipe 23) disposed within a well when the first pipe is lowered onto the second pipe.

[0074] The control system 200 can continue determining a load difference, calculating a state of the valve, and sending the valve command a1 until the control system 200 is suspended, for example, by the operator. Alternatively, the control system 200 can cease operation when the sensed load is zero, indicating that the lifted pipe is decoupled from the controlled lowering system 100 or fully supported by the second pipe, at which time the spring 124 can reset the cylinder 110 for another lowering operation.

[0075] Step 304 comprises determining a difference between the sensed force and a selected force setting (e.g., SFS).

[0076] Step 306 comprises actuating a valve (e.g., the valve 146) to open or close based at least in part on the difference between the sensed force and the selected force setting.

[0077] The process flow continues iteratively in a loop as shown in FIG. 4, each time determining a sensed force exerted by the first pipe on the sensor, a difference between the sensed force and a selected force setting in step 304 and accordingly actuating the valve to open or close in step 306. This iterative loop continues until the control system ascertains that the sensed force is zero in step 302 or the system has been discontinued by the operator at any point.

[0078] FIG. 5 is a process flow diagram illustrating a representative method 400 of controlled lowering of a pipe using a control system, such as the control system 200, according to another example. The method begins in step 402 by lowering a first pipe onto a second pipe, such as for example, the pipe 22 being lowered onto the pipe 23 as shown in FIG. 1. In step 404, the method 400 includes determining a sensed force indicating the weight of the pipe 22. If the sensed force is zero, the first pipe is deemed decoupled from the lowering system and the process ends. If the sensed force is non-zero, in step 406 the method includes determining a difference between the sensed force and a selected force setting. If the sensed force equals the selected force setting, the method includes closing the solenoid valve in step 408. If the sensed force is greater than the force setting, in step 410, the method includes opening the solenoid valve. After the solenoid valve is either opened or closed, the method continues at step 404 in determining a sensed force.

[0079] The process flow continues iteratively in a loop as shown in FIG. 5, each time determining a sensed force in step 404, a difference between the sensed force and a selected force setting in step 406 and accordingly actuating the valve to open or close in steps 408, 410. This iterative loop continues until the control system ascertains that the sensed force is zero in step 404 or the system has been discontinued by the operator at any point.

[0080] In some examples, as described in the example above, the sensed force can be the weight of the pipe 22 and the selected force setting (SFS) can be a target force that is a threshold or selected weight of the pipe 22 that can, for example, avoid damage to the pipes and / or permit alignment between the pipes. Alternatively, the sensed force detected by the sensor 102 can be used to calculate the force exerted by the pipe 22 on the pipe 23 and the selected force setting (SFS) can be a target force that is a threshold or selected force exerted on the pipe 23 by the pipe 22. For example, the SFS can be a selected or threshold force exerted on the pipe 23 by the pipe 22 that avoids damage to the pipes and / or permits alignment between the pipes. Determination of the force exerted on the pipe 23 by the pipe 22 can be calculated by the sensor 102 and / or the control unit 156. This force can be compared to (e.g., subtracted from as shown in FIG. 3) the selected force setting SFS of this example at the summing junction.

[0081] Comparison (e.g., subtraction) of the sensed force with the selected force setting (SFS) in this example can yield a signal indicative of a force difference or force error relative to the SFS. This force difference signal can be provided to the valve control element 204. Using this force difference signal, the valve control element 204 can determine a valve command a1 for transmission to the lowering system 100 to control lowering per the control system 200 and the methods 300, 400. In some examples, the valve control element 204 can determine whether to open the valve 146, close the valve 146, or make no change to a position of the valve 146.Example 2: Cable Control System for Lowering Pipes

[0082] In some examples, a lowering system can sense a weight of a first pipe, determine a load exerted by the first pipe on a second pipe, and automatically adjust extension or retraction of a cable to which the first pipe is coupled to adjust the weight and / or load. FIG. 6 schematically shows a work site system 10b for a wellbore, according to an example, with a similar arrangement as the work site system 10a shown in FIG. 1, except for the inclusion of a lowering system 500 instead of the lowering system 100. As such, the description of the work site system 10a other than the controlled lowering system 100 applies to the description for the work site system 10b and is incorporated herein accordingly. For example, the description of the vehicle 11, the mast 12, the cable 28, and the pipes 22, 23 apply to the work site system 10b, and so on.

[0083] Unlike the lowering system 100 described above in connection with FIGS. 1-3, the lowering system 500 extends and retracts the cable 28 and comprises a sensor 502 which can be configured as a dynamometer, a force transducer such as a strain gauge, a load cell, etc. The sensor 502 can be in communication with a controller or control unit 504 which is in communication with a valve 506 (for example, a spool valve) that operates a motor (e.g., a hydraulic motor) 508 on the winch 26. Although the motor 508 is shown in FIG. 6 and described herein as being operated by the valve 506, it is appreciated that the motor can be operated by any means. For example, the control unit 504 can communicate directly with the motor 508 to operate the winch 26.

[0084] In some examples, the sensor 502 can be disposed between a coupling arrangement on the cable 28, such as the hook 32, and the pipe 22. In some examples, the sensor 502 can be coupled directly to the second end portion 35 of the pipe 22. In some examples, the sensor 502 can be coupled to the elevator 34 as shown in FIG. 6. In this way, the sensor 502 is disposed in-line or in series with the cable 28 and the pipe 22.

[0085] In some examples, the sensor 502 can be configured to measure or sense the weight of the pipe 22 which, as described above, can be indicative of the force exerted on the pipe 23 by the pipe 22. The sensed force can be transmitted to the controller 504 as a force signal. Although the control unit 504 is shown with a wired connection to the sensor 502 and the valve 506, it is understood that the control unit 504 can be wirelessly connected to the sensor 502 and / or the valve 506. The control unit 504 can be configured to receive a signal from the sensor 502 and transmit a command to the valve 506 which, in turn, operates the valve 506 to control the motor 508 to retract or extend the cable 28 based at least in part on the force signal. The control unit 504 can be mounted to any portion of the vehicle 11, mast 12, or nearby structure.

[0086] To achieve controlled lowering of the pipe 22 onto the pipe 23 in accordance with the lowering system 500, a control system 600, according to an example as illustrated in the block diagram of FIG. 7, can be implemented to determine a difference between a sensed force and / or a change in force detected by the sensor 502 in relation to a selected force setting (SFS) or target force. The selected force setting (SFS) according to the example shown in FIGS. 6-7, can comprise a force and / or a rate of change in the force.

[0087] The selected force setting (SFS) can be manually selected by the operator, in some examples. In some examples, the SFS can be an auto-generated value that is a function of the size and / or weight of a lifted pipe and / or the pipe or pipe column on which the lifted pipe is set. In some examples, the selected force setting can indicate a threshold or acceptable force within which damage and / or misalignment is minimized. In some examples, the selected force setting can be constant during a lowering operation. In some examples, the selected force setting can vary as a lifted pipe is lowered and / or as the lifted pipe is coupled to the pipe underneath. For example, a selected force setting and / or a rate of change of the force can be increased as the lifted pipe is coupled to the pipe below. In other words, the selected force setting and rate of change of the force can be reduced as the pipes initially contact each other such that a minimal load is slowly applied to the pipe underneath. This load and rate of change thereof can be increased thereafter, for example, as the pipes are coupled to each other.

[0088] The valve 506 can be configured to vary operation of the motor 508 which can act to wind or unwind the cable 28 on the winch 26 until the selected force setting is achieved or a selected threshold force occurs. The lowering system 500 is represented in the control system 600 as the block 500 in FIG. 7. The control system 600 can further comprise a summing junction 602 and a valve control element or block 604. In some examples, the control unit 504 can be configured in accordance with the computing environment 1000 described in FIG. 11 and can perform the steps represented by the valve control element 604 and the summing junction 602.

[0089] With the application of an external trigger T, such as for example an operator engaged ON switch, a force signal representative of sensed force data can be provided to the summing junction 602. The sensed force data can be compared to (e.g., subtracted from as shown in FIG. 7) the selected force setting (SFS) at the summing junction 602. As described above, the selected force setting can vary depending on operator input and / or a pre-programmed setting.

[0090] Comparison (e.g., subtraction) of the sensed force data with the selected force setting (SFS) can yield a force difference signal indicative of a difference or force error between the sensed force data and the SFS. This force difference signal can be provided to the valve control element 604. Using this force difference signal, the valve control element 604 can determine a valve command a2 for transmission to the controlled lowering system 500 that can reduce or eliminate the force error such that the sensed force is the same or substantially the same (within, for example, 5%) of the SFS.

[0091] In operation, the pipe 22 can be lowered manually (e.g., by an operator) until a first end of the pipe 22 is within a selected distance from a first end of the pipe 23. For example, the pipe 22 can be lowered by releasing and extending the cable 28 until there is a space between the first and second pipes of 2 -12 inches, such as 2-8 inches, or 2-6 inches. In other words, the pipe 22 can be lowered until it is suspended just above the pipe 23 at which point a control system 600 for controlled lowering can be triggered by the operator. When the pipe 22 is in a suspended state above the pipe 23, the sensor 502 detects a force representative of the full weight of the pipe 22 suspended by the cable 28. When the control system 600 is engaged, the pipe 22 is automatically lowered until a force change is detected.

[0092] When the pipe 22 starts to touch the pipe 23, the force (weight) detected by the sensor 502 changes. That is, as the pipe 22 begins resting on the pipe 23, the force change detected by the sensor 502 reflects support provided by the pipe 23 on the pipe 22. The change in force sensed represents the weight of the pipe 22 on the pipe 23, or, stated differently, the force exerted by the pipe 22 on the pipe 23.

[0093] Referring to FIG. 6, sensed force data is received by the control unit 504 from the sensor 502. In some examples, the sensed force is non-zero. In other examples, the sensed force can be zero corresponding to a state in which no lifted pipe is suspended (e.g., the pipe 22 is removed from the elevator 34 or the cable 28).

[0094] When the sensed force is non-zero, the sensed force data is compared with the selected force setting (SFS) as described above to determine the force difference or force error (for example, at the summing junction 602 in FIG. 7). That is, the weight of the pipe 22 is compared to a target force to determine if the weight of the pipe 22 is greater than the target, less than the target, or at the target force and if the rate at which the force is changing is in accordance with the rate setting. If the sensed force and / or the change in force is greater than the target, the control unit 504 sends a signal to the valve 506 to operate the motor 508 to rotate the winch 26 to wind or retract the cable 28 to pull up the pipe 22. Conversely, if the sensed force and / or the change in force is less than the target, the control unit 504 sends a signal to the valve 506 to operate the motor 508 to rotate the winch 26 to extend the cable 28 to lower the pipe 22. A speed and displacement of the winding of the cable 28 can be specified such that the pipe 22 is retracted or lowered by a displacement and speed commensurate with the error to reduce or eliminate the error.

[0095] In some examples, the cable 28 can be extended or retracted such that 10 percent, 20 percent, or another percentage (proportion) of the weight of the pipe 22 is exerted on the pipe 23 during early stages of lowering or coupling.

[0096] In some examples, the cable 28 can be extended or retracted such that 50 percent, 60-80 percent, or another percentage (proportion) of the weight of the pipe 22 is exerted on the pipe 23 during later stages of lowering or coupling. The proportion of the weight of the pipe 22 exerted on the pipe 23 can be selected to minimize damage to the couplings and misalignment.

[0097] FIG. 8 is a process flow diagram illustrating a representative method 700 of controlled lowering of a pipe using a control system, such as the control system 600, according to an example. Step 702 comprises determining a sensed force indicating a weight of a first or lifted pipe (e.g., the pipe 22) when the first pipe is lowered onto a second pipe (e.g., the pipe 23) disposed within a well, where the sensed force is detected by a sensor coupled to a cable arranged to lift the first pipe.

[0098] Step 704 comprises determining a difference between the sensed force (e.g., the weight of the first pipe) and a selected force setting.

[0099] Step 706 comprises actuating a winch (e.g., the winch 26), for example by actuating a valve (e.g., the valve 506), to wind or unwind a cable (e.g., the cable 28) based at least in part on the difference between the sensed force and the selected force setting.

[0100] The process flow continues iteratively in a loop as shown in FIG. 8, each time determining a sensed force in step 702, a difference between the sensed force and a selected force setting in step 704 and accordingly actuating the winch in step 706. This iterative loop continues until the control system ascertains that the sensed force is zero in step 702 or the system has been discontinued by the operator at any point.

[0101] FIG. 9 is a process flow diagram illustrating a representative method 800 of controlled lowering of a pipe using a control system, such as the control system 600, according to another example. The method begins in step 802 by lowering a first pipe into proximity of a second pipe, such as for example, the pipe 22 being lowered above the pipe 23 as shown in FIG. 6. In step 804, the controlled lowering system is engaged by the operator and the system automatically lowers the first pipe by extending the cable 28 until the first pipe just begins to touch the second pipe. In step 806, the method 800 includes determining a sensed force (e.g., a weight of the first pipe) and change in force exerted by the first pipe on the second pipe. If the sensed force is zero, the first pipe is deemed decoupled from the lowering system and the process ends. If the sensed force is non-zero, in step 808 the method includes determining a difference between the sensed force and rate of change in force and a selected force setting. If the sensed force and rate of change in force equals the selected force setting, the method continues to step 806 and is repeated. If the force and / or rate of change in force are greater or less than the force setting, the method includes operating the winch to retract or extend the cable in step 810, after which the method continues at step 806 in determining a sensed force and rate of change in force exerted by the first pipe on the second pipe.

[0102] The process flow continues iteratively in a loop as shown in FIG. 8, each time determining a force and rate of change in force in step 806, a difference between the force and rate of change in force and a selected force setting in step 808 and accordingly actuating the winch in step 810. This iterative loop continues until the control system ascertains that the sensed force is zero in step 806 or the system has been discontinued by the operator at any point.

[0103] Although the example described herein in connection with FIGS. 6-9 uses a sensed force that is the weight of the lifted pipe and an SFS that is a threshold or selected weight of the pipe 22 that, for example, minimizes damage, the sensed force detected by the sensor 502 can be alternatively used to calculate a force exerted by the pipe 22 on the pipe 23. As described above in connection with the example of FIGS. 1-5, the selected force setting (SFS) can be a target force that is a threshold or selected force exerted on the pipe 23 by the pipe 22 and this SFS can be compared to a calculated force exerted by the pipe 22 on the pipe 23 to control lowering per the control system 600 and the methods 700, 800. The sensor 502 and / or the controller 504 can be configured to calculate the force exerted by the pipe 22 on the pipe 23 based at least on the weight detected by the sensor 502.Example 3: Combined System for Lowering Pipes

[0104] As introduced above, in some examples, a lowering system for controlled lowering of a first pipe onto a second pipe can comprise means for both automatically adjusting extension or retraction of a cable to which the first pipe is coupled for suspension (e.g., the Cable Control system of FIGS. 6-9) as well as means for cushioned downward displacement resulting in controlled lowering (e.g., the Hydraulic System of FIGS. 1-5). In some examples, a lowering system can comprise one or more elements of either of the Hydraulic System and / or the Cable Control system.

[0105] FIG. 10 schematically shows a work site system 10c for a wellbore, according to an example, with a similar arrangement as the work site systems 10a, 10b shown in FIGS. 1 and 6. The description of the work site systems 10a, 10b applies to the work site system 10c and is incorporated herein accordingly. For example, the description of the vehicle 11, the mast 12, the cable 28, and the pipes 22, 23 apply to the work site system 10c, and so on.

[0106] Unlike the work site systems 10a, 10b, FIG. 10 shows a combined lowering system 900 comprising the lowering system 100 and at least portions of the lowering system 500. In other words, portions of the lowering systems 100, 500 can be integrated with each other to control different aspects of pipe lowering in a varied and automated manner.

[0107] In the example shown in FIG. 10, the lowering system 100 can be in communication with the control unit 504 of the lowering system 500, which is in communication with the valve 506 that operates the motor (e.g., a hydraulic motor) 508 on the winch 26. For example, the sensor 102 and / or the control unit 156 can be configured to communicate with the control unit 504. When the first end of the pipe 22 is in close proximity to the second end of the pipe 23, the combined lowering system 900 can be triggered to automatically actuate the winch 26 in a controlled manner to release the cable 28 and lower the pipe 22 until the pipe 22 contacts the pipe 23 underneath. Upon contact, the Hydraulic System of the lowering system 100 is engaged to cushion and lower the pipe 22 as the pipe 22 is coupled to the pipe 23 as described above in connection with FIGS. 1-5.

[0108] As described above in connection with FIG. 6, the motor 508 can be operated by any means. For example, the control unit 504 can communicate directly with the motor 508 to operate the winch 26. In other examples, in lieu of the control unit 504, the control unit 156 in the lowering system 100 can communicate directly with the motor 508 or the valve 506 to operate and control the winch 26 based at least on force data received from the sensor 102 instead of the sensor 502. The Cable Control system of the lowering system 500 is engaged to wind and unwind the cable 28 to lower or retract the pipe 22 as described above in connection with FIGS. 6-9. Although a wired connection is shown extending from the lowering system 100 to the control unit 504, the control unit 156 and / or the sensor 102 of the lowering system 100 can be in wireless communication with the control unit 504, the valve 506, and / or the motor 508.

[0109] By combining one or more elements of each the lowering systems 100, 500 into an integrated lowering system, the combined lowering system 900 can benefit from automated cable winding as well as controlled, hydraulic cushioning during coupling.Example 4: Representative Computing Environment

[0110] FIG. 11 illustrates a generalized example of a computing environment 1000 in which software and control algorithms for the described examples can be implemented. For example, software and / or hardware for implementing the various control systems and methods described herein (such as, for example, the control systems 200, 600) can be configured similarly to the computing environment 1000 and can be a local computing system integrated as part of the control units 156, 504 or can be a remote computing system as described herein.

[0111] The computing environment 1000 is not intended to suggest any limitation as to scope of use or functionality of the technology, as the technology may be implemented in diverse general-purpose or special-purpose computing environments. For example, the disclosed technology may be implemented with other computer system configurations, including programmable automation controllers, programmable logic controllers, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), hand held devices, multi-processor systems, programmable consumer electronics, network PCs, minicomputers, and the like. The disclosed control methodology may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

[0112] With reference to FIG. 11, the computing environment 1000 includes at least one processing unit 1010 and memory 1020. In FIG. 11, this most basic configuration 1030 is included within a dashed line. The processing unit 1010 executes computer-executable instructions and may be a real or a virtual processor. In a multi-processing system, multiple processing units execute computer-executable instructions to increase processing power and as such, multiple processors can be running simultaneously. The memory 1020 may be volatile memory (e.g., registers, cache, RAM), non-volatile memory (e.g., ROM, EEPROM, flash memory, etc.), or some combination of the two. The memory 1020 stores software 1080 that can, for example, implement the technologies described herein. A computing environment may have additional features. For example, the computing environment 1000 includes storage 1040, one or more input devices 1050, one or more output devices 1060, and one or more communication connections 1070. An interconnection mechanism (not shown) such as a bus, a controller, or a network, interconnects the components of the computing environment 1000. Typically, operating system software (not shown) provides an operating environment for other software executing in the computing environment 1000, and coordinates activities of the components of the computing environment 1000.

[0113] The storage 1040 may be removable or non-removable, and includes non-volatile solid state memory, magnetic disks, or any other medium which can be used to store information and that can be accessed within the computing environment 1000. The storage 1040 stores instructions for the software 1080, plugin data, and messages, which can be used to implement technologies described herein.

[0114] The input device(s) 1050 may be, for example, a dynamometer, a force transducer, a load cell, an accelerometer, a position sensor such as an optical time-of-flight sensor, a temperature sensor, a position encoder, or a touch input device such as a switch, keyboard, keypad, mouse, touch screen display, pen, or trackball, a voice input device, a scanning device, or another device, that provides input to the computing environment 1000. The output device(s) 1060 may be a wired or wireless signal transmitter, a display, or another device that provides output from the computing environment 1000.

[0115] The communication connection(s) 1070 enable communication over a communication medium (e.g., a connecting network) to devices or computing entities. The communication medium conveys information such as control signals, computer-executable instructions, sensor inputs or outputs, or other data in a modulated data signal. The communication connection(s) 1070 are not limited to wired connections (e.g., megabit or gigabit Ethernet, Infiniband, Fibre Channel over electrical or fiber optic connections) but also include wireless technologies (e.g., RF connections via Bluetooth, WiFi (IEEE 802.11a / b / n), WiMax, cellular, satellite, laser, infrared) and other suitable communication connections for providing a network connection for the disclosed controlled devices.

[0116] Some examples of the disclosed methods can be performed using computer-executable instructions implementing all or a portion of the disclosed technology in a computing cloud 1090 or other remote computing system. For example, the disclosed methods can be executed on processing units 1010 located in the computing environment 1030, or the disclosed methods can be executed on servers located in the computing cloud 1090.

[0117] Computer-readable media are any available media that can be accessed within a computing environment 1000. By way of example, and not limitation, with the computing environment 1000, computer-readable media include memory 1020 and / or storage 1040. As should be readily understood, the term computer-readable storage media includes the media for data storage such as memory 1020 and storage 1040, and not transmission media such as modulated data signals.Additional Examples of the Disclosed Technology

[0118] In view of the above-described implementations of the disclosed subject matter, this application discloses the additional examples enumerated below. It should be noted that one feature of an example in isolation or more than one feature of the example taken in combination and, optionally, in combination with one or more features of one or more further examples are further examples also falling within the disclosure of this application.

[0119] Example 1. A system for lowering pipes, the system comprising: a force transducer comprising a first end portion and a second end portion, the first end portion configured to be coupled to a cable that is arranged to lower a first pipe onto a second pipe disposed within a well; a hydraulic cylinder coupled to the second end portion of the force transducer, wherein the hydraulic cylinder comprises a fluid chamber and a piston movably disposed within the fluid chamber, and wherein a rod of the piston is configured to be coupled to a second end portion of the first pipe; a hydraulic reservoir fluidly coupled to the fluid chamber of the hydraulic cylinder through a first fluid passageway comprising a first valve and a second fluid passageway comprising a second valve; and a controller in communication with the force transducer and with the first valve, the controller configured to operate the first valve to control flow of hydraulic fluid out of the hydraulic cylinder to lower the first pipe onto the second pipe based at least in part on data from the force transducer.

[0120] Example 2. The system of any example herein, particularly example 1, wherein the data from the force transducer indicates a load exerted on the second pipe by the first pipe or a weight of the first pipe.

[0121] Example 3. The system of any example herein, particularly example 1, wherein the first valve is a solenoid valve configured to open and close in response to the controller.

[0122] Example 4. The system of any example herein, particularly example 1, wherein the fluid chamber comprises a spring configured to displace the piston within the fluid chamber to draw fluid through the second fluid passageway from the hydraulic reservoir to the fluid chamber when the first pipe is decoupled from the rod of the piston.

[0123] Example 5. The system of any example herein, particularly example 1, wherein the second valve is a one-way valve configured to allow fluid flow from the hydraulic reservoir into the fluid chamber and prevent fluid flow from the fluid chamber to the hydraulic reservoir.

[0124] Example 6. The system of any example herein, particularly example 1, wherein the hydraulic reservoir comprises a diaphragm arranged to separate a first portion of the hydraulic reservoir from a second portion of the hydraulic reservoir, wherein the first portion comprises fluid and the second portion comprises air.

[0125] Example 7. The system of any example herein, particularly example 6, wherein the diaphragm is movable within the hydraulic reservoir in response to changes in a volume of fluid in the first portion of the hydraulic reservoir and a pressure of the air in the second portion of the hydraulic reservoir.

[0126] Example 8. A system comprising: a sensor comprising a first end portion and a second end portion, the first end portion configured to be coupled to a cable that is arranged to lower a first pipe onto a second pipe disposed within a well, wherein the sensor is configured to sense a sensed force indicative of a weight of the first pipe; a hydraulic cylinder coupled to a second end portion of the sensor, wherein the hydraulic cylinder comprises a fluid chamber and a piston movably disposed within the fluid chamber, and wherein a rod of the piston is configured to be coupled to a second end portion of the first pipe; and a hydraulic reservoir fluidly coupled to the fluid chamber of the hydraulic cylinder via a valve that is configured to be movable between an open state and a closed state; and a control system configured to: receive a sensed force from the sensor; determine a difference between the sensed force and a selected force setting, the difference being a force error; calculate a state of the valve to reduce the force error; and transmit a control signal to the valve to move the valve to the calculated state.

[0127] Example 9. The system of any example herein, particularly example 8, wherein, when the force error is zero, the control system is configured to transmit control signals to the valve to move to the closed state.

[0128] Example 10. The system of any example herein, particularly example 8, wherein, when the force error is non-zero, the control system is configured to transmit control signals to the valve to move to the open state.

[0129] Example 11. The system of any example herein, particularly example 8, wherein, when the sensed force is zero, the control system is configured to transmit control signals to the valve to move to the closed state such that fluid can flow from the hydraulic reservoir into the fluid chamber of the hydraulic cylinder.

[0130] Example 12. The system of any example herein, particularly example 8, wherein the fluid chamber comprises a spring arranged in abutment with a seal portion of the piston and configured to return the piston to an equilibrium state within the fluid chamber when the second end portion of the first pipe is decoupled from the piston.

[0131] Example 13. The system of any example herein, particularly example 8, wherein the hydraulic reservoir comprises a first portion and a second portion separated by a diaphragm, wherein the first portion comprises fluid and the second portion comprises air, and wherein a displacement of the diaphragm varies based at least on a volume of fluid in the first portion of the hydraulic reservoir and an air pressure in the second portion of the hydraulic reservoir.

[0132] Example 14. The system of any example herein, particularly example 13, wherein the diaphragm is arranged to limit change in a volume of fluid in the fluid chamber of the hydraulic cylinder.

[0133] Example 15. The system of any example herein, particularly example 8, wherein the control system is configured to receive a sensed force, determine the force error, calculate the state of the valve, and transmit a control signal to the valve until the sensed force is zero or an off trigger is actuated.

[0134] Example 16. A method comprising: determining a sensed force indicative of a weight of a first pipe, wherein the sensed force is detected by a sensor coupled to a cable arranged to lift the first pipe and lower the first pipe onto a second pipe; determining a difference between the sensed force and a selected force setting; and actuating a valve to open or close based at least in part on the difference between the sensed force and the selected force setting, wherein the valve is arranged between a hydraulic reservoir and a hydraulic cylinder, the hydraulic cylinder being disposed between the sensor and the first pipe and, wherein, when the valve is open, fluid flows from the hydraulic reservoir to the hydraulic cylinder, and when the valve is closed, fluid flows from the hydraulic reservoir to the hydraulic cylinder.

[0135] Example 17. The method of any example herein, particularly example 16, wherein the hydraulic reservoir comprises a first portion and second portion separated from the first portion by a diaphragm, wherein the first portion comprises the fluid and the second portion comprises pressurized air, and wherein the diaphragm is configured to move within the reservoir to control lowering of the first pipe onto the second pipe.

[0136] Example 18. The method of any example herein, particularly example 16, wherein the hydraulic cylinder comprises a fluid chamber and a piston movably disposed within the fluid chamber, and wherein the method further comprises returning the piston to an equilibrium state within the fluid chamber when the sensed force is zero.

[0137] Example 19. The method of any example herein, particularly example 16, further comprising coupling a first end portion of the first pipe to a first end portion of the second pipe.

[0138] Example 20. A method comprising lowering a first pipe onto a second pipe using the system of any example herein, particularly example 1.

[0139] Example 21. A system, comprising: a force transducer, the force transducer comprising a first end portion and a second end portion; a hydraulic lowering apparatus comprising a hydraulic cylinder, a piston movably disposed in the hydraulic cylinder, and a hydraulic reservoir, wherein the hydraulic cylinder is in fluid communication with the hydraulic reservoir through a first flow path comprising a first valve and through a second flow path comprising a second valve; and a controller configured to operate the first valve to control a flow of hydraulic fluid from the hydraulic cylinder to the hydraulic reservoir based at least in part on force data received from the force transducer; wherein the first end portion of the force transducer is configured to be coupled to a cable configured to lift a pipe, the second end portion of the force transducer is configured to be coupled to the hydraulic cylinder, and a rod of the piston is configured to be coupled to the pipe such that when the pipe is lifted by the cable, the force transducer senses a weight of the pipe.

[0140] Example 22. The system of any example herein, particularly example 1, wherein controller is configured to receive force data indicative of a weight of the first pipe, determine a force error that is a difference between the weight and a selected force setting, calculate a positional state of the first valve to reduce the force error, and transmit control signals to the first valve to move the first valve to the calculated positional state.

[0141] The features described herein with regard to any example can be combined with other features described in any one or more of the other examples, unless otherwise stated. For example, any one or more of the features of one system for lowering pipes can be combined with any one or more features of another system for lowering pipes. As another example, any one or more steps of one method of lowering pipes can be combined with any one or more steps of another method of lowering pipes.

[0142] In view of the many possible examples to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are only examples and should not be taken as limiting the scope of the disclosure. Rather, the scope of the disclosure is at least as broad as the following claims and equivalents of the recited features. We therefore claim all that comes within the scope and spirit of these claims.

Claims

1. A system for lowering pipes, the system comprising:a force transducer comprising a first end portion and a second end portion, the first end portion configured to be coupled to a cable that is arranged to lower a first pipe onto a second pipe disposed within a well;a hydraulic cylinder coupled to the second end portion of the force transducer, wherein the hydraulic cylinder comprises a fluid chamber and a piston movably disposed within the fluid chamber, and wherein a rod of the piston is configured to be coupled to a second end portion of the first pipe;a hydraulic reservoir fluidly coupled to the fluid chamber of the hydraulic cylinder through a first fluid passageway comprising a first valve and a second fluid passageway comprising a second valve; anda controller in communication with the force transducer and with the first valve, the controller configured to operate the first valve to control flow of hydraulic fluid out of the hydraulic cylinder to lower the first pipe onto the second pipe based at least in part on data from the force transducer.

2. The system of claim 1, wherein the data from the force transducer indicates a load exerted on the second pipe by the first pipe or a weight of the first pipe.

3. The system of claim 1, wherein the first valve is a solenoid valve configured to open and close in response to the controller.

4. The system of claim 1, wherein the fluid chamber comprises a spring configured to displace the piston within the fluid chamber to draw fluid through the second fluid passageway from the hydraulic reservoir to the fluid chamber when the first pipe is decoupled from the rod of the piston.

5. The system of claim 1, wherein the second valve is a one-way valve configured to allow fluid flow from the hydraulic reservoir into the fluid chamber and prevent fluid flow from the fluid chamber to the hydraulic reservoir.

6. The system of claim 1, wherein the hydraulic reservoir comprises a diaphragm arranged to separate a first portion of the hydraulic reservoir from a second portion of the hydraulic reservoir, wherein the first portion comprises fluid and the second portion comprises air.

7. The system of claim 6, wherein the diaphragm is movable within the hydraulic reservoir in response to changes in a volume of fluid in the first portion of the hydraulic reservoir and a pressure of the air in the second portion of the hydraulic reservoir.

8. The system of claim 1, wherein controller is configured to receive force data indicative of a weight of the first pipe, determine a force error that is a difference between the weight and a selected force setting, calculate a positional state of the first valve to reduce the force error, and transmit control signals to the first valve to move the first valve to the calculated positional state.

9. A system comprising:a sensor comprising a first end portion and a second end portion, the first end portion configured to be coupled to a cable that is arranged to lower a first pipe onto a second pipe disposed within a well, wherein the sensor is configured to sense a sensed force indicative of a weight of the first pipe;a hydraulic cylinder coupled to the second end portion of the sensor, wherein the hydraulic cylinder comprises a fluid chamber and a piston movably disposed within the fluid chamber, and wherein a rod of the piston is configured to be coupled to a second end portion of the first pipe; anda hydraulic reservoir fluidly coupled to the fluid chamber of the hydraulic cylinder via a valve that is configured to be movable between an open state and a closed state; anda control system configured to:receive a sensed force from the sensor;determine a difference between the sensed force and a selected force setting, the difference being a force error;calculate a state of the valve to reduce the force error; andtransmit a control signal to the valve to move the valve to the calculated state.

10. The system of claim 9, wherein, when the force error is zero, the control system is configured to transmit control signals to the valve to move to the closed state, and when the force error is non-zero, the control system is configured to transmit control signals to the valve to move to the open state.

11. The system of claim 9, wherein, when the sensed force is zero, the control system is configured to transmit control signals to the valve to move to the closed state such that fluid can flow from the hydraulic reservoir into the fluid chamber of the hydraulic cylinder.

12. The system of claim 9, wherein the fluid chamber comprises a spring arranged in abutment with a seal portion of the piston and configured to return the piston to an equilibrium state within the fluid chamber when the second end portion of the first pipe is decoupled from the piston.

13. The system of claim 9, wherein the hydraulic reservoir comprises a first portion and a second portion separated by a diaphragm, wherein the first portion comprises fluid and the second portion comprises air, and wherein a displacement of the diaphragm varies based at least on a volume of fluid in the first portion of the hydraulic reservoir and an air pressure in the second portion of the hydraulic reservoir.

14. The system of claim 13, wherein the diaphragm is arranged to limit change in a volume of fluid in the fluid chamber of the hydraulic cylinder.

15. The system of claim 9, wherein the control system is configured to receive a sensed force, determine the force error, calculate the state of the valve, and transmit a control signal to the valve until the sensed force is zero or an off trigger is actuated.

16. A method comprising:determining a sensed force indicative of a weight of a first pipe, wherein the sensed force is detected by a sensor coupled to a cable arranged to lift the first pipe and lower the first pipe onto a second pipe;determining a difference between the sensed force and a selected force setting; andactuating a valve to open or close based at least in part on the difference between the sensed force and the selected force setting,wherein the valve is arranged between a hydraulic reservoir and a hydraulic cylinder, the hydraulic cylinder being disposed between the sensor and the first pipe and,wherein, when the valve is open, fluid flows from the hydraulic reservoir to the hydraulic cylinder, and when the valve is closed, fluid flows from the hydraulic reservoir to the hydraulic cylinder.

17. The method of claim 16, wherein the hydraulic reservoir comprises a first portion and second portion separated from the first portion by a diaphragm, wherein the first portion comprises the fluid and the second portion comprises pressurized air, and wherein the diaphragm is configured to move within the reservoir to control lowering of the first pipe onto the second pipe.

18. The method of claim 16, wherein the hydraulic cylinder comprises a fluid chamber and a piston movably disposed within the fluid chamber, and wherein the method further comprises returning the piston to an equilibrium state within the fluid chamber when the sensed force is zero.

19. The method of claim 16, further comprising coupling a first end portion of the first pipe to a first end portion of the second pipe.

20. A method comprising lowering a first pipe onto a second pipe using the system of claim 1.

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