US20210123311A1

US20210123311A1 - Pressure balanced ultra-short disposable setting tool

Info

Publication number: US20210123311A1
Application number: US17/066,069
Authority: US
Inventors: Wayne Rosenthal
Original assignee: Geodynamics Inc
Current assignee: Geodynamics Inc
Priority date: 2019-10-25
Filing date: 2020-10-08
Publication date: 2021-04-29

Abstract

A setting tool for setting an auxiliary tool in a well, the setting tool including an inner mandrel having an upper section and a lower section, the upper section having an internal chamber suitable for housing a power charge; an outer cylindrical piston enclosing the upper section of the inner mandrel; a slidable ring formed concentrically, and between the inner mandrel and the outer cylindrical piston; and an actuation chamber located between the outer cylindrical piston, the ring, and the inner mandrel. The slidable ring is fixedly attached with a breaking pin to the upper section of the inner mandrel.

Description

BACKGROUND

Technical Field

Embodiments of the subject matter disclosed herein generally relate to downhole tools for well operations, and more specifically, to a disposable setting tool used in a well for actuating various auxiliary tools.

Discussion of the Background

During well exploration, various tools are lowered into the well and placed at desired positions for plugging, perforating, or drilling the well. These tools are placed inside the well with the help of a conduit, as a wireline, electric line, continuous coiled tubing, threaded work string, etc. However, some of these tools need to be activated or set in place. The force needed to activate such a tool is large, for example, in excess of 15,000 lbs. Such a large force cannot be supplied by the conduit noted above.
A setting tool is commonly used in the industry to activate the tools noted above. Such a setting tool is typically activated by an explosive charge that causes a first piston to be driven within the setting tool. The movement of the first piston is transmitted to a second piston, by use of an oil located between the two pistons. The movement of the second piston activates the various tools. A traditional setting tool 100 is shown in FIG. 1 and includes a firing head 102 that is connected to a pressure chamber 104. The firing head 102 ignites a primary igniter 103 that in turn ignites a power charge 106. Note that a secondary igniter may be located between the primary igniter and the power charge to bolster the igniting effect of the primary igniter.
A mandrel 110 is connected to a housing of the pressure chamber 104 and this cylinder fluidly communicates with the pressure chamber. Thus, when the power charge 106 is ignited, the large pressure generated inside the pressure chamber 104 is guided into the mandrel 110. A floating piston 112, which is located inside the mandrel 110, is pushed by the pressure formed in the pressure chamber 104 to the right in the figure. Oil 114 stored in a first chamber 115 of the mandrel 110, is pushed through a connector 116, formed in a block 118, which is located inside the mandrel 110, to a second chamber 120. Another piston 122 is located in the second chamber 120 and under the pressure exerted by the oil 114, the piston 122 and a piston rod 124 exert a large force on a crosslink 126. Crosslink 126 can move relative to the mandrel 110 and has a setting mandrel 128 for setting a desired tool (which was discussed above). Note that mandrel 110 has the end 130 sealed with a cylinder head 132 that allows the piston rod 124 to move back and forth without being affected by the wellbore/formation pressure.
After the setting tool has been set, it needs to be raised to the surface and be reset for another use. Because the burning of the power charge 106 has created a large pressure inside the pressure chamber 104, this pressure needs to be relieved, the pressure chamber needs to be cleaned from the residual explosive and ashes, and the pistons and the oil (hydraulic fluids) need to be returned to their initial positions.
Relieving the high pressure formed in the pressure chamber 104 is not only dangerous to the health of the workers performing this task, because of the toxic gases left behind by the burning of the power charge, but is also a safety issue because the pressure in the pressure chamber is high enough to injure the workers if its release is not carefully controlled. In this regard, note that the traditional setting tool 100 has a release valve 140 that is used for releasing the pressure from inside the pressure chamber. However, when the release valve 140 is removed from cylinder 100, due to the high pressure inside the cylinder, the release valve may behave like a projectile and injure the person removing it. For this reason, a dedicated removing procedure has been put in place and also a safety sleeve is used to cover the release valve, when at the surface, for relieving the pressure from the setting tool. In addition, the oil contained inside the tool may pose a contamination danger to the environment in case that an internal seal fails.
Thus, another approach is to use a setting tool that self-vents while downhole, and/or contains no oil, to avoid the need for redressing at the surface. However, current disposable setting tools suffer from a number of drawbacks including high overall tool length, an inability to vent the tool in the event of partial or incomplete activation, and a high shock load upon activation. Thus, there is a need for a disposable setting tool that overcomes these problems.

SUMMARY

According to an embodiment, there is a setting tool for setting an auxiliary tool in a well. The setting tool includes an adaptor sub for affixing an ignitor, an inner mandrel having an upper section and a lower section, the upper section having an internal chamber configured to house a power charge, and the lower section configured to connect to an adjusted sub for affixing the auxiliary tool, an outer cylindrical piston slidably located over the inner mandrel, a slidable ring slidably located around the upper section of the inner mandrel and fixedly attached to the outer cylindrical piston, an actuation chamber located between the inner mandrel and the outer cylindrical piston, and a passage through a wall of the upper section of the inner mandrel, wherein the passage fluidly communicates the internal chamber and the actuation chamber. An activation of the power charge by the ignitor causes gas to pressurize the actuation chamber and the outer cylindrical piston to stroke downward to set the auxiliary tool in the well, after breaking a breaking pin that holds the slidable ring fixedly attached to the inner mandrel.
According to another embodiment, there is a setting tool for setting an auxiliary tool in a well, and the setting tool includes an inner mandrel having an upper section and a lower section, the upper section having an internal chamber suitable for housing a power charge, an outer cylindrical piston enclosing the upper section of the inner mandrel, a slidable ring formed concentrically, and between the inner mandrel and the outer cylindrical piston, and an actuation chamber located between the outer cylindrical piston, the ring, and the inner mandrel. The slidable ring is fixedly attached with a breaking pin to the upper section of the inner mandrel.
According to still another embodiment, there is a method for using a setting tool in a casing, and the method includes lowering the setting tool into the casing; igniting a power charge located inside an inner mandrel of the setting tool; directing a pressured gas, generated by the ignited power charge, through a passage formed through a wall of the inner mandrel, to a shoulder of an outer cylindrical piston; actuating the outer cylindrical piston with the pressured gas so that the outer cylindrical piston moves along the inner mandrel; and setting an auxiliary tool attached to the setting tool when the outer cylindrical piston is fully stroked. The lower section of the inner mandrel has a first region having a first thickness T1 and a second region having a smaller second thickness T2, the first region being separated by a shoulder from the second region.

BRIEF DESCRIPTON OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings:

FIG. 1 illustrates a traditional setting tool that needs to be retrieved to the surface for removing pressurized gas from inside;

FIG. 2 illustrates a disposable, ultra-short, setting tool, before being activated;

FIG. 3 illustrates a detail of the disposable, ultra-short, setting tool, before being activated;

FIG. 4 illustrates a passage formed between an inner mandrel and an outer cylindrical piston of the disposable, ultra-short, setting tool;

FIG. 5 illustrates the disposable, ultra-short, setting tool after being activated;

FIG. 6 illustrates a detail of the disposable, ultra-short, setting tool after being activated;

FIG. 7 illustrates a venting mechanism of the disposable, ultra-short, setting tool;

FIG. 8 illustrates the disposable, ultra-short, setting tool having two venting mechanisms, in the run-in state;

FIG. 9 illustrates the disposable, ultra-short, setting tool having two venting mechanisms, in the fully stroke state;

FIG. 10 illustrates slots formed in the upper section of the inner mandrel for the second venting mechanism; and

FIG. 11 is a flowchart of a method for using the disposable, ultra-short, setting tool.

DETAILED DESCRIPTION

The following description of the embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to a setting tool. However, the embodiments discussed herein are also applicable to any tool in which a high-pressure is generated and then that high-pressure needs to be transferred to a piston without the presence of an oil.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
According to an embodiment, a setting tool for setting an auxiliary tool (e.g., a plug) in a well includes an inner mandrel having an upper section and a lower section, the upper section having an internal chamber suitable for housing a power charge, and the lower section configured to connect to a sub for affixing an auxiliary tool, a cylindrical piston configured to slide along the inner mandrel, an annular activation chamber located between the cylindrical piston and the inner mandrel, and a gas port formed through a wall of the inner mandrel, to provide a fluid communication path between the inner mandrel internal chamber and the annular actuation chamber defined by the cylindrical piston. Activation of the power charge by the ignitor causes pressurized gas to enter the actuation chamber and the cylindrical piston to stroke downward to set the auxiliary tool in the well.
An embodiment of a setting tool 200 is shown in FIG. 2 in a preactivated state as the setting tool is run into the casing 202 (note that for simplicity, FIG. 2 shows only the bottom part of the casing, and not the upper part). The left hand side in the figure is facing the upper part of the well (i.e., the head) and the right hand side is facing the lower part of the well (i.e., the toe). In this embodiment, the setting tool 200 contains no hydraulic fluid (e.g., no oil) and thus, it may be readily disposed of after use, without a redressing operation, which is dangerous to the operator, as discussed in the Background section. Further, because the setting tool includes no oil, the disposal operation does not raise environmental issues. The term “disposable setting tool” is interpreted in this document to mean a setting tool that does not store oil (a hydraulic fluid) for acting on a piston.
In the configuration shown in FIG. 2, the setting tool 200 may be provided with an adaptor sub 210 configured to accept an S1® Ignitor 212 manufactured by the present applicant GEODynamics and described in U.S. Pat. No. 10,003,236, which is incorporated herein. Other types of ignitors 212 and firing devices may be readily accepted in the adaptor sub 210 as shown. Alternatively, the setting tool 200 is provided alone and is configured to accept common industry firing heads, devices, or subs. In this embodiment, the S1 ignitor 212 is installed into the provided adaptor sub 210 located at the uphole end of the setting tool. Note that “upper” or “uphole” end are terms used herein to mean to the left as shown in a figure and this end corresponds to a higher level in a vertical well, or towards the heel when discussing a lateral portion of a well. Conversely, “lower” or “downhole” end refer to a lower position, to the right of a figure, or further down a well towards the end or toe of the well. The adaptor sub 210 is configured to connect with appropriate threads to a casing element.
The adaptor sub 210 includes a head 214 that holds the ignitor 212 and is configured to be attached by threads 214′ to corresponding threads 223 of an inner mandrel 220. A power charge 216 is located, in this embodiment, within the inner mandrel 220 of the setting tool 200. In one embodiment, the entire power charge 216 may be located within the inner mandrel 220. The inner mandrel 220 has two sections, an upper section 222 and a lower section 224. The upper section 222 forms a power charge chamber 230, which is filled with the power charger 216, and the power charge chamber 230 terminates at a first blind end 232. In this embodiment, the power charge 216 is not located within the head 214 of the adaptor sub 210, as also shown in FIG. 2. Opposite the first blind end 232 is a wall 234 separating a second blind end 236, which defines an auxiliary chamber 238. The second blind end 236 marks the beginning of the lower section 224 of the inner mandrel 220. The lower section 224 is configured with threads 225 to accept an adjuster sub 240 for connection to a downhole auxiliary tool such as a frac or bridge plug or other device to be set within the casing (not shown). The upper section 222 is configured with threads 223 for connecting to the adaptor sub 210.
An outer cylindrical piston 250 is configured to enclose the upper section 222 of the inner mandrel 220 when the setting tool is not actuated. In one embodiment, the outer cylindrical piston 250 is placed coaxial with the power charge 216. The outer cylindrical piston 250 is formed a single piece, having an interior shoulder 256, formed at a lower end 250A, and the shoulder is configured to extend radially, toward the inner mandrel 222. In one embodiment, the interior shoulder 256 is configured to touch the inner mandrel 222 and slide along its longitudinal axis X. The outer cylindrical piston 250 forms a dampening chamber 258 with the upper section 222 of the inner mandrel 220. The dampening chamber 258 is shaped as an annulus chamber. Note that the dampening chamber 258 is filled with air at atmospheric pressure, and when the outer cylindrical piston 250 is actuated, the volume of the dampening chamber 258 decreases. With the air inside the dampening chamber 258 having no way to escape, it compresses, thus increasing its pressure, which acts as a dampening on the outer cylindrical piston 250.
The upper end 250B of the outer cylindrical piston 250, which is shown in more detail in FIG. 3, has threads 252 that are configured to engage corresponding threads 262 of a slidable ring 260, which is configured to fully encircle a portion of the upper section 222 of the inner mandrel 220. The slidable ring 260 is sandwiched between the upper section 222 of the inner mandrel 220 and the upper end 250B of the outer cylindrical piston 250 as shown in FIGS. 2 and 3. Because of the mating threads 252 and 262, the outer cylindrical piston 250 is fixedly attached to the slidable ring 260, and they move in tandem when the setting tool is activated.
Those skilled in the field will know that when the setting tool is lowered into the casing, the outer cylindrical piston 250 may touch the casing 202, which may result in accidentally moving the piston relative to the inner mandrel. To prevent the outer cylindrical piston 250 from moving while the setting tool is lowered into the casing, the slidable ring 260 is fixed with a breakable pin 264 to the upper section 222 of the inner mandrel 220. In this regard, FIG. 3 shows that a through hole 254 is formed at the upper end 250B of the outer cylindrical piston 250, and a receiving hole 226 is formed into the upper section 222. The through hole 254 is aligned with the receiving hole 226 so that the breakable pin 264 can be inserted from outside the outer cylindrical piston 250, into the upper end 250B and into the receiving hole 226, so that the slidable ring 264 is fixed relative to the upper section 222. A strength of the breakable pin 264 is selected so that a pressured gas formed as a consequence of the ignition of the power charge 216 is capable to break the pin 264 and actuate the outer cylindrical piston 250, as discussed later.
FIG. 3 also shows first and second seals 265 and 267 placed at interfaces between the slidable ring 264 and the upper end 250B of the outer cylindrical piston 250, and the slidable ring 264 and the upper section 222 of the inner mandrel 220, to prevent the pressured gas to escape from the setting tool.
The lower end 250A of the outer cylindrical piston 250 and the corresponding part of the upper section 222 that faces the outer cylindrical piston 250, are shown in more detail in FIG. 4. One or more passages 402 are formed between the power charge chamber 230 and an actuation chamber 410 formed between the outer cylindrical piston 250 and the upper section 222 of the inner mandrel 220. The actuation chamber 410 is closed along the X axis by the shoulder 256 of the outer cylindrical piston 250, at the lower end, and by a shoulder 228 formed into the upper section 222 of the inner mandrel 220, at the upper end. The shoulder 228 of the upper section 222 extends radially, toward the outer cylindrical piston 250, and touches the outer cylindrical piston 250. One or more seals 229 are placed between the shoulder 228 and the outer cylindrical piston 250 to prevent a pressured gas from the actuation chamber 410 to escape. Similarly, the shoulder 256 may have one or more seals 257 facing the upper section 222 to prevent the pressured gas from the actuation chamber 410 to escape.
In its run-in state shown in FIG. 2, the inner mandrel's upper portion 222 and the outer cylindrical piston 250 are nested with each other, thus reducing the overall setting tool length L. The term “nest” herein refers to the concentric, coaxial arrangement of the outer cylindrical piston 250 and the upper section of the setting tool in their pre-activated state. The more concentrically arranged these sections initially results in a shorter setting tool, thus reducing the overall tool string length, which aids in the ability to run the string (having the setting tool) into the casing and maneuver the string through bends and other deviations in the wellbore trajectory. For example, in this embodiment, the length L of the setting tool is about 20″ and a length I from the top part of the outer cylindrical piston 250 to the top part of the adaptor sub 210 is about 6″.
In one or more embodiments, the power charge 216 may be comprised of a compact power charge that when used with the disclosed tool further nests the mandrel and piston, which results in a setting tool of significantly reduced length. In this embodiment, the length L as measured from the upper most end of the inner mandrel 220 to the lowermost end that accepts the adjuster sub 240 measures approximately 20 inches. Other reductions in length are readily contemplated by those skilled in the art having the benefit of the present disclosure and may include tools of 20 inches or less. Depending upon the setting force required for the given tool to be set, a shorter stroke may be required and or less force and thus the power charge requirements may be reduced, thus shortening the tool's length depending upon specific applications.
FIG. 5 shows the setting tool 200 in its fully stroked state following the activation of the power charge. Ignitor 212 ignites the power charge 216, which results in a pressurized gas being formed within the power charge chamber 230. The pressurized gas exits the power charge chamber 230 along the passage 402 and enters into the actuation chamber 410, which is located outside the inner mandrel 220 and within the outer cylindrical piston 250, as illustrated in FIG. 5. The pressured gas directly strikes the shoulder 256 at the lower end 250A of the outer cylindrical piston 250 when entering the actuation chamber 410, which results in the downward movement of the outer cylindrical piston 250. Thus, there is no need for any oil to activate the outer cylindrical piston 250. The path of the pressured gas, from the power charge chamber 230 to the actuation chamber 310 is illustrated by arrows in FIG. 5.
To be able to actuate the outer cylindrical piston 250, the pressured gas needs to generate a force large enough to break the breaking pin 264. FIG. 5 shows that the breaking pin 264 has been broken, with one piece 264A still seen inside the receiving hole 226 and with another piece 264B still inside the hole 254 of the upper end 250B of the outer cylindrical piston 250. FIG. 5 further shows that the slidable ring 260 moves in tandem with the outer cylindrical piston 250, in a downward direction, until the slidable ring 260 is stopped by the shoulder 228 of the upper section 222 of the inner mandrel 220. The air trapped inside the dampening chamber 258 is compressed during the actuation of the setting tool, which may act as a dampening mechanism so that the outer cylindrical piston 250 does not slam violently the shoulder 228 of the upper section 222 of the inner mandrel 220.
In one embodiment, a damping element 270 may be placed between (1) the slidable ring 260 and the shoulder 228, and/or (2) the shoulder 256 and the upper end of the adjuster sub 240. For simplicity, FIG. 5 shows the damping element 270 placed at the later position. However, the damping element 270 is optional.
As mentioned above, the setting tool 200 has the ability to self-vent the pressurized gases while still downhole, following activation. This is achieved by the venting mechanism 500, which is partially implemented at the shoulder 256 as now discussed with regard to FIG. 6. In this implementation, as illustrated in FIG. 6, the venting mechanism 500 includes a step down in the thickness of the lower section 224 of the inner mandrel 220, from a first thickness T1 to a smaller thickness T2, so that a passage 510 (or annulus) is formed between the shoulder 256 of the outer cylindrical piston 250 and the outer surface of the lower section 224 of the inner mandrel 220. A shoulder 502 defines the reduction in thickness of the lower section 224 of the inner mandrel 220. When the face of the shoulder 256, which fits tightly to the upper section 224 of the inner mandrel 220 prior to passing the shoulder 502, moves downward past the shoulder 502, the passage 510 is formed. At this time, the actuation chamber 410 automatically becomes fluidly connected, through the passage 510, to an unsealed chamber 520, which is not sealed from an exterior of the setting tool. As shown in FIG. 6, the unsealed chamber 520 is defined by the lower end 250A of the outer cylindrical piston 250, the lower section 224 of the inner mandrel 220, and an end of the adjuster sub 240. An interface 530 between the lower end 250A of the outer cylindrical piston 250 and the adjuster sub 240 (shown in the figure having an exaggerated large gap for illustration) is not sealed so that the pressured gas from the unsealed chamber 520 can escape outside the setting tool, as indicated by the arrows in FIG. 6. The venting mechanism 500 may also be implemented as one or a combination of a slot, channel or a step down in the diameter of the cylindrical body of the barrel piston. Note that the location of the thinner thickness T2 of the lower section 224 of the inner mandrel 220 is selected such that when the shoulder 256 of the outer cylindrical piston 250 fully strokes past the shoulder 502 of the lower section 224 of the inner mandrel 220, the gas pressure may thus escape between the two sections and external to the setting tool. This self-venting is accomplished downhole as part of the activation sequence and thus removes the need to depressurize the setting tool at the surface.
Returning to FIG. 5, the adaptor sub 212 may include a gas passage 520, which is closed by a cap 522, that allows a secondary manual bleed or vent capability. As discussed above, the setting tool will self-vent (“self-bleed”) gas pressure downhole as part of the activation sequence. However, in certain scenarios, a setting tool may jam or otherwise not fully complete its activation as defined by full extension of its normal stroke. An incomplete stroke thus does not allow a piston or mandrel to fully extend past the point at which the bleed port of valve opens, thus leaving the setting tool in a pressurized state. In that event, the setting tool must be withdrawn from the well and depressurized for safety. The present adaptor sub gas passage 520 allow that venting to be safely and readily conducted at the surface in the event of a faulty or incomplete activation.
In one application, the inner mandrel 220 is configured in such a way that a differential pressure applied on the outer cylindrical piston 250, along the longitudinal axis X, by the fluid present inside the casing is zero or near zero, i.e., the setting tool is pressure balanced. Note that the differential pressure results because of the hydrostatic pressure that exists in the well and because the traditional setting tool has ends having different cross-section areas, which results in different forces acting on these ends. Also note that if this differential pressure is not near zero, then the pressured gas in the actuation chamber 410 needs to overcome this differential pressure, which would render the setting tool less efficient. To achieve this near zero differential pressure, in one embodiment, an external diameter D1 of the upper section 222 of the inner mandrel 220 is made to be equal to an external diameter D2 of the lower section 224 of the inner mandrel 220, as shown in FIG. 7. Further, the cross-section area 250-1 of the outer cylindrical piston 250 and the cross-section area 260-1 of the ring 260, which are perpendicular to the longitudinal axis X, and on which the fluid from the casing acts along the longitudinal axis X, are made to be equal. In this way, the net force exerted along the longitudinal direction X on the outer cylindrical piston 250, by the fluid present inside the casing, is near zero and thus, the outer cylindrical piston 250 is pressured balanced. In one application, a balanced setting tool is achieved if (i) the cross-sectional areas of the opposite ends of the outer cylindrical piston 250 are equal or (ii) the external diameters D1 and D2 of the upper and lower sections of the setting tool are equal. In still another application, both (i) and (ii) need to happen. In yet another application, the near zero differential pressure may be achieved only if the interface 280 between the ring 260 and the outer surface of the upper section 222 of the inner mandrel 220 is coplanar with the interface 282 between the shoulder 256 of the outer cylindrical piston 250 and the outer surface of the upper section 222 of the inner mandrel 220, as also shown in FIG. 7. When the pressure balanced setting tool is actuated, and the setting tool is connected to a plug, while the setting tool is dangling on a wireline, the outer cylindrical piston can do nothing but move down and compress the slips and packing of the plug. Then, as soon as the plug firmly anchors itself to the wellbore casing, the outside movement of the outer cylindrical piston ceases and the inner mandrel can move (pull) back up until the connection between the setting tool and the plug shears and releases the setting tool from the plug.
Returning to the damping element 270 discussed above with regard to FIG. 5, it may be, for example, an elastomeric grommet, bushing, sleeve, O-ring or a combination of these or other elastomeric elements, that is configured to dampen the shock that occurs during the setting tool activation process. As shown in FIG. 5, for example, the damping element 270 is placed concentric to the upper section 222 of the inner mandrel 220, so that the ring 260 and the outer cylindrical piston 250 are stopped by the damping element 270 when fully stroked by the pressurized gas. Alternatively, the damping element 270 may be attached to the lower end 250B of outer cylindrical piston 250, to strike the adjusted sub 240.
If the pressure increase in the damping chamber 258 is considered to be too high when the outer cylindrical piston 250 is stroke, so that it might hinder the piston to fully stroke, it is possible to implement a second venting mechanism 800, as illustrated in FIG. 8. For this embodiment, the setting tool 200 is modified to have notches 810 formed in the downhole end of the slidable ring 260 and corresponding slots 820 formed in the upper section 222 of the inner mandrel 220, close to the shoulder 228. The slots 820 extend along the axis X and a length of the slots is larger than a length of the slidable ring 260 for the reasons to be discussed next. In addition, the upper end of the upper section 222 has an undercut are 830, such that the inner diameter of this portion of the upper section is larger than the inner diameter of the remaining of the upper section.
When the outer cylindrical piston 250 is fully stroke as illustrated in FIG. 9, the undercut area 830 fits around the shoulder 228 of the upper section 222 of the inner mandrel 220. Because of the undercut area 830, a passage 840 is now formed between the actuation chamber 410 and the slots 820, so that the air from the dampening chamber 258 and the pressurized gas existing in the actuation chamber 410 can escape along slots 820, outside the setting tool, as illustrated by arrows 850. Therefore, the second venting mechanism 800, which includes the notches 810, slots 820, undercut area 830, and passage 840 allows the pressurized gas from the actuation chamber 410 to also escape outside the setting tool, in addition to the first venting mechanism 500. FIG. 10 shows in more detail the position of the slots 820 along the upper section 222 of the inner mandrel, and also the position of the sliding ring 260 relative to the slots 820 when the piston 250 is fully stroke.
A method for setting the setting tool is now discussed with regard to FIG. 11. The method starts in step 1100 by lowering the setting tool 200 into the casing 202. The setting tool 200 has an outer cylindrical piston 250 located over an upper section 222 of an inner mandrel 220. After the setting tool 200 arrives at its final position inside the well, the power charge 216 stored in the power charge chamber 230 is ignited in step 1102. Pressured gas formed within the power charger chamber 230, as a consequence of the ignition step, is directed in step 1104, along the passage 402, to the actuation chamber 410, formed between the inner mandrel 220 and the outer cylindrical piston 250, and actuates in step 1106 the outer cylindrical piston 250 to fully stroke. Then, in step 1108, the auxiliary tool (e.g., plug) attached to the setting tool 200 is set inside the casing.
The disclosed embodiments provide methods and an ultra-short setting tool for well operations in which the setting tool is disposable, i.e., does not use oil for activating an auxiliary tool. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.
Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.
This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.

Claims

What is claimed is:

1. A setting tool for setting an auxiliary tool in a well, the setting tool comprising:

an adaptor sub for affixing an ignitor;

an inner mandrel having an upper section and a lower section, the upper section having an internal chamber configured to house a power charge, and the lower section configured to connect to an adjusted sub for affixing the auxiliary tool;

an outer cylindrical piston slidably located over the inner mandrel;

a slidable ring slidably located around the upper section of the inner mandrel and fixedly attached to the outer cylindrical piston;

an actuation chamber located between the inner mandrel and the outer cylindrical piston; and

a passage through a wall of the upper section of the inner mandrel, wherein the passage fluidly communicates the internal chamber and the actuation chamber,

wherein activation of the power charge by the ignitor causes gas to pressurize the actuation chamber and the outer cylindrical piston to stroke downward to set the auxiliary tool in the well, after breaking a breaking pin that holds the slidable ring fixedly attached to the inner mandrel.

2. The setting tool of claim 1, wherein the inner mandrel, the slidable ring, and the outer cylindrical piston are concentrically positioned, in this order, prior to activation.

3. The setting tool of claim 1, wherein the setting tool contains no hydraulic fluid.

4. The setting tool of claim 1, wherein the adaptor sub further comprises a manual back-off for gas bleeding.

5. The setting tool of claim 1, wherein the setting tool is self-venting through a venting mechanism.

6. The setting tool of claim 1, wherein the lower section of the inner mandrel has a first region having a first thickness T1 and a second region having a smaller second thickness T2, the first region being separated by a shoulder from the second region.

7. The setting tool of claim 6, wherein the outer cylindrical piston (250) has a shoulder that extends radially toward the inner mandrel.

8. The setting tool of claim 7, wherein the shoulder of the outer cylindrical piston is configured to contact the first region of the lower section when the outer cylindrical piston is sliding along the first region, and to not contact the second region of the lower section when the outer cylindrical piston is sliding along the second region.

9. The setting tool of claim 8, wherein the pressured gas from the actuation chamber is (1) prevented to escape when the shoulder of the outer cylindrical piston is in contact with the first region of the lower section of the inner mandrel, and (2) allowed to escape from the actuation chamber, through a passage, when the shoulder of the outer cylindrical piston is not in contact with the second region of the lower section of the inner mandrel.

10. The setting tool of claim 1, further comprising a first venting mechanism located at an interface between the outer cylindrical piston and an adjuster sub, which is attached at the lower section of the inner mandrel,

wherein the first venting mechanism is closed when the outer cylindrical piston is not actuated, and the first venting mechanism is open when the outer cylindrical piston is fully stroked.

11. The setting tool of claim 10, further comprising a second venting mechanism located at an interface between the outer cylindrical piston, the slidable ring, and the upper section of the inner mandrel,

wherein the second venting mechanism is closed when the outer cylindrical piston is not actuated, and the second venting mechanism is open when the outer cylindrical piston is fully stroked.

12. The setting tool of claim 1, further comprising:

a dampening element located between the slidable ring and the inner mandrel so that when the outer cylindrical piston is fully stroked, the slidable ring squeezes the dampening element against a shoulder of the inner mandrel.

13. A setting tool for setting an auxiliary tool in a well, the setting tool comprising:

an inner mandrel having an upper section and a lower section, the upper section having an internal chamber suitable for housing a power charge;

an outer cylindrical piston enclosing the upper section of the inner mandrel;

a slidable ring formed concentrically, and between the inner mandrel and the outer cylindrical piston; and

an actuation chamber located between the outer cylindrical piston, the ring, and the inner mandrel,

wherein the setting tool is sized to be pressure balanced when placed in the well.

14. The setting tool of claim 13, wherein the setting tool is pressure balanced when (i) the outer cylindrical piston is sized so that cross-sectional areas of opposite ends are equal, or (ii) an outer diameter of the upper section of the inner mandrel is equal to an outer diameter of the lower section of the inner mandrel, or (iii) the outer cylindrical piston is sized so that cross-sectional areas of opposite ends are equal, and an outer diameter of the upper section of the inner mandrel is equal to an outer diameter of the lower section of the inner mandrel.

15. The setting tool of claim 13, further comprising:

a passage formed through a wall of the upper section of the inner mandrel, wherein the passage is fluidly connected to the actuation chamber.

16. The setting tool of claim 13, wherein the lower section of the inner mandrel has a first region having a first thickness T1 and a second region having a smaller second thickness T2, the first region being separated by a shoulder from the second region.

17. The setting tool of claim 16, wherein the outer cylindrical piston has a shoulder that extends radially toward the inner mandrel, and the shoulder of the outer cylindrical piston is configured to contact the first region of the lower section when the outer cylindrical piston is sliding along the first region, and to not contact the second region of the lower section when the outer cylindrical piston is sliding along the second region.

18. The setting tool of claim 17, wherein the pressured gas from the actuation chamber is (1) prevented to escape when the shoulder of the outer cylindrical piston is in contact with the first region of the lower section of the inner mandrel, and (2) allowed to escape from the actuation chamber, through a passage, when the shoulder of the outer cylindrical piston is located over the second region of the lower section of the inner mandrel.

19. The setting tool of claim 13, further comprising:

an adaptor sub attached to the tread of the inner mandrel; and

an adjuster sub attached to a lower end of the inner mandrel.

20. The setting tool of claim 19, further comprising:

an ignitor located in the adaptor sub; and

the power charge located within the internal chamber,

wherein activation of the power charge by the ignitor causes gas to pressurize the actuation chamber and the outer cylindrical piston to stroke downward to set the auxiliary tool in the well.

21. The setting tool of claim 13, further comprising:

a dampening element located between the slidable ring and a shoulder of the inner mandrel so that when the outer cylindrical piston is fully stroked, the slidable ring squeezes the dampening element against the shoulder of the inner mandrel.

22. The setting tool of claim 13, further comprising:

a first venting mechanism located at an interface between the outer cylindrical piston and an adjuster sub attached to the lower section of the inner mandrel, the first venting mechanism being configured to allow the pressured gas from the activation chamber to escape from the setting tool,

23. The setting tool of claim 21, further comprising:

a second venting mechanism located at an interface between the outer cylindrical piston, the slidable ring, and the upper section of the inner mandrel,

24. A method for using a setting tool in a casing, the method comprising:

lowering the setting tool into the casing;

igniting a power charge located inside an inner mandrel of the setting tool;

directing a pressured gas, generated by the ignited power charge, through a passage formed through a wall of the inner mandrel, to a shoulder of an outer cylindrical piston;

actuating the outer cylindrical piston with the pressured gas so that the outer cylindrical piston moves along the inner mandrel; and

setting an auxiliary tool attached to the setting tool when the outer cylindrical piston is fully stroked,

wherein the lower section of the inner mandrel has a first region having a first thickness T1 and a second region having a smaller second thickness T2, the first region being separated by a shoulder from the second region.