NL2024144B1

NL2024144B1 - Cement plug tester

Info

Publication number: NL2024144B1
Application number: NL2024144A
Authority: NL
Inventors: Veenstra Feitze
Original assignee: Callidus Capital B V
Priority date: 2019-11-01
Filing date: 2019-11-01
Publication date: 2021-07-19
Also published as: AU2020372810A1; EP4051869B1; EP4051869C0; EP4051869A1; WO2021086191A1

Abstract

A device is provided for applying a load on a cement plug in a well, comprising a housing, arranged to be lowered into a well, and a clamping mechanism, arranged to fixate a position of the housing relative to the well in an engaged state. The device further comprises an actuator connected to the housing, comprising a force input for receiving an input force, a force output for exerting an output force, and a force amplification module for amplifying the input force using a mechanical advantage and transferring the amplified force to the force output. The device further comprises a load mechanism, coupled to the force output, wherein the load mechanism is arranged to apply the load on the cement plug directly or indirectly via one or more components of the device. A force of the load mechanism relative to the clamping mechanism is to exceed a load to apply.

Description

P124662NL00 Title: Cement plug tester

FIELD OF THE INVENTION The invention relates to a device for applying a load on a cement plug in a well.

BACKGROUND To ensure presence and robustness of a cement plug, a load test can be performed. To provide a sufficient load to the cement plug, which may be several hundred metres down underground, a drill pipe is lowered onto the cement plug. A drill pipe is built up from drill pipe segments, and a significant number of segments may be connected to provide sufficient weight to apply sufficient load on the cement plug for the load test. For lowering the drill pipe into the well, rig is placed above the well.

SUMMARY It is preferred to provide a device for testing a cement plug which is lighter and/or easier to use. A first aspect provides a device for applying a load on a cement plug in a well, comprising a housing, arranged to be lowered into a well, and a radial clamping mechanism, arranged to fixate a position of the housing relative to the well in an engaged state. The device further comprises an actuator connected to the housing, comprising a force input for receiving an input force, a force output for exerting an output force, and a force amplification module for amplifying the input force using a mechanical advantage and transferring the amplified force to the force output. The device further comprises a load mechanism, coupled to the force output, wherein the load mechanism is arranged to apply the load on the cement plug directly or indirectly via one or more components of the device.

For connecting the device to a wireline or another suspension member, the device may comprise a suspension member connection module. As an option, the suspension member connection module may be coupled to the force input of the actuator for providing the input force.

The device according to the first aspect may be lowered into the well using a suspension member such as a wireline, which wireline may be provided on a winch. A wireline may for example be a slick line or a woven or braided line, tube or rope, or a combination thereof. By rotating the winch and unwinding wireline from the winch, the device may be lowered further into the well. During lowering, the weight of the device puts a tension force on the wireline. When the winch is arranged to provide a force to the wireline higher than the weight of the device and the unreeled wireline combined, the device can be lifted out of the well. Using the winch, a tension force may be provided on the wireline, for example by apply a torque to the winch in the winding direction.

In embodiments, the suspension member may comprise one or more strands of wireline, one or more conduits for hydraulic fluid or pneumatic pressure, one or more conductive conduits for providing a connection for electrical power and/or data to the device, any other type of suspension member or any combination thereof.

In embodiments, the input force may be provided by a hydraulic pressure, pneumatic pressure, an electrical actuator and electrical motor in particular for converting electrical power into the input force, a tension on the suspension member, an impact and/or weight of a weighted member, any other way of providing a force or any combination thereof. The hydraulic or pneumatic pressure may be generated in the device or remote from the device; in the latter embodiment, the pressurised fluid is provided to the device via a conduit.

When the radial clamping mechanism in an engaged state fixates the position of the housing relative to the well, the radial clamping mechanism may be provide a fixation force higher than a pulling force which the winch can provide. As such, also when the maximum pulling force is applied via the wireline to the wireline connection module, the device may stay fixated to the well. In embodiments, the fixation force may be a friction force.

When the device is fixated to the well, the pulling force from the winch may be used to apply the load on the cement plug, via the load mechanism. As such, the weight of the device is not used for applying the load on the cement plug, and hence the weight of the device may be lower than the required load.

The maximum amount of pulling force may be limited by the winch, and/or by a maximum load on the wireline. When the maximum amount of pulling force is less than a desired pressing force on the cement plug, the force amplification module may comprise a mechanical advantage module used for amplifying the pulling force using a mechanical advantage.

By virtue of a mechanical advantage, the input force with a corresponding input stroke can be converted into the output force with a corresponding output stroke. If the input stroke is larger than the output stroke, the output force can be higher than the input stroke. For creating the mechanical advantage, for example gears, pistons, levers, any other mechanical, hydraulic or pneumatic component, or any combination thereof can be used.

The force amplification module may be arranged as a hydraulic force amplifier, comprising an input fluid reservoir, an output fluid reservoir, provided in fluid connection with the input fluid reservoir, a first piston, provided in the input fluid reservoir, wherein the first piston is comprised by the force input, a second piston, provided in the output fluid reservoir, wherein the second piston is comprised by the force output, wherein a first surface area of the first piston facing into the input fluid reservoir is smaller than a second surface area of the second piston facing into the output fluid reservoir. With the surface area of the first piston exposed to the input fluid reservoir being smaller than the surface area of the second piston exposed to the output fluid reservoir, and the pressure on the fluid being substantially equal, the force on the second piston may be larger than the force on the first piston. When the second piston is connected to the force output, and the first piston is connected to the force input, the input force may be amplified to the force output.

The device is arranged for applying a load on a cement plugin a well, but may also be suitable for applying a load on other objects next to a cement plug, on other locations next to in a well. Other locations may also be locations that are difficult to reach, where it may for example be impractical to use a weight corresponding to the required load for applying the required load. In examples, the required load may be in the order of 10 mT (metric ton), and the corresponding weight may thus also be 10 mT if no force amplification can be used.

In embodiments of the device, the first piston may be provided with a first plunger at a first side and the first piston may face the input fluid reservoir with the first side. The first plunger may be connected to the wireline connection module, or may be comprised by the wireline connection module. As such, a force may be applied to the first plunger using the wireline, which force may be used to pull the first piston into the input fluid reservoir. In use, the first piston may be pulled upwards in a direction substantially opposite to the direction of lowering the device into the well. In use, this direction may be a direction pointing away from the cement plug.

The second piston may be provided with a second plunger at a second side, and the second piston may face the output fluid reservoir with a third side, opposite to the second side. By virtue of a fluid pressure in the output reservoir, in use, the second piston may be pushed towards the cement plug and as such the load mechanism may apply the load on the cement plug.

In use, the direction of the tension force on the wireline may be opposite to the direction of the load to be applied on the cement plug. To 5 diverge the direction of the tension force, the actuator may be arranged to a receive the input force with a first force vector having a first direction, and to exert the output force with a second force vector, the second force vector having a second direction substantially opposite to the first direction. In use, the second force vector may be substantially normal to a top surface of the cement plug. In use, the first force vector may be substantially parallel to the wireline.

Embodiments of the device may further comprise a landing module comprising a landing surface, arranged to abut the cement plug. The landing module may be arranged as the first component to abut the cement plug when lowering the device into the well, and may thus in use be the component furthers down in the well.

By monitoring a tension force on the wireline, it may be determined that the landing surface has touched down on the cement plug. This tension force may drop after a certain time of lowering the device into the well, by virtue of at least a part of the weight of the device now being supported by the cement plug instead of the wireline. If part of the cement plug is still liquid and has thus not fully solidified, the gradient of the tension force may appear to be different compared to landing on a solidified cement plug, which may provide an indication to an operator that the cement plug has not fully solidified.

When the landing module has touched down on the cement plug, the full weight of the device can be applied to the cement plug by lowering sufficient length of the wireline, such that there is no tension on the wireline left from the device. This weight may be insufficient to test if the cement plug complies with requirements and regulations for cement plugs.

Such regulations may for example state that a cement plug should be able to withstand a force of 10 MT, while the weight of the device is less or even significantly less, for example 10 times less.

During the lowering of the device in the well, it may be desired to fixate the load mechanism to the landing module such that the landing module surface forms the lowest part of the device, arranged to abut the cement plug first. As such, in use, an end-plane of the load mechanism may be provided higher than the landing module surface during lowering of the device into the well.

To apply the load on the cement plug after the device has been lowered sufficiently, the load mechanism has to abut the cement plug. As such, it may be required for the fixation of the load mechanism to the landing module to be released after touching down on the cement plug.

To this end, the landing module may comprise a landing module separator, arranged to fixate position of the load mechanism relative to the landing module in a fixed state, and release the load mechanism from the landing module when the landing module separator is subjected to a force exceeding a pre-determined landing module separation force.

When the landing module separator is in the fixed state, the landing surface of the landing module may extend further away from the housing than a distal end-plane of the load mechanism. In other words, in use, the landing surface of the landing module is closer to the cement plug than the end-plane of the load mechanism to ensure that the landing module touches down on the cement plug before the load mechanism.

The force exceeding the pre-determined landing module separation force may be provided by at least part of the total weight of the device or impact load as a result of touching the hardened or cured cement during lowering. The landing module separator may be arranged as a shear pin, partially extending into the landing module, and partially extending into the load mechanism. The pre-determined landing module separation force may as such be a shear force. After the load mechanism has been released from the landing module, a distal end of the load mechanism may abut the cement plug.

After the load mechanism has been released, the radial clamping mechanism may have to be engaged. Without the radial clamping mechanism being engaged to fixate the position of the housing relative to the well, a tension force applied to the wireline may simply lift the entire device up and away from the cement plug without applying the required pressure to the cement plug.

In embodiments, the radial clamping mechanism comprises a first clamping part, resiliently connected to the housing and fixated relative to the landing module, a second clamping part, fixated to the housing with a radial clamp separator, wherein the radial clamping mechanism is arranged to engage the well by a movement, in particular a translation, of the first clamping part relative to the second clamping part.

The first clamping part may be resiliently connected to the housing by one or more springs as flexible members, arranged to change in length under influence of a force, for example the weight of the housing or a tension force of the wireline pulling the housing upwards away from the cement plug.

The flexible member may be compressed when the landing module touches down on the cement plug, and the weight of the housing presses down on the landing module via the flexible member. As such, a movement of the housing, and thus of the load mechanism fixated relative to the landing module is allowed after the load mechanism is released from the landing module by the landing module separator.

When the load mechanism has been released, the housing may be lifted up away from the cement plug using the wireline. During this lifting, the flexible member may be elongated. The landing module will rest on the cement plug by virtue of its own weight, and because the first clamping part is fixated relative to the landing module, the first clamping part stays substantially in place. The second clamping part is being lifted because it is fixated relative to the housing with the radial clamp separator. Thus, a movement of the first clamping part relative to the second clamping part may be provided and the radial clamping mechanism may be engaged to fixate the housing relative to the well.

For fixating the housing relative to the well, a friction force between the radial clamping mechanism and the well should equal the pulling force pulling on the wireline connection module. This friction force may depend on a friction coefficient and force exerted by the radial clamping mechanism on the well, for example on an inner wall of the well.

In a particular embodiment of the radial clamping mechanism, the first clamping part is arranged as a body with a tapered inner wall, and the second clamping part is arranged as a body with a tapered outer wall.

The second clamping part is at least partially provided in the first clamping part, and the tapering of the first clamping part is provided in the opposite direction than the tapering of the second clamping part. When the second clamping part in translated relative to the first clamping part the tapered outer wall of the second clamping part wedges against the tapered inner wall of the first clamping part causing the first clamping part to be pressed against the inner wall of the well.

The device may further comprise a load mechanism separator arranged to fixate the load mechanism relative to the housing in a fixed state, and release the load mechanism from the housing when the load mechanism separator is subjected to a force exceeding a pre-determined load mechanism separation force.

When the housing is fixated relative to the well, the tension force on the wireline may be increased further. With the increasing tension force — and thus increasing input force -, the output force also increases. With the increasing output force, the pre-determined load mechanism separation force may be exceeded and the load mechanism may be released from the housing. Because the load mechanism can now move relative to the housing, which is fixed relative to the well by the radial clamping mechanism, the load mechanism can be moved such that an end-plane of the load mechanism abuts the cement plug. As such, a load can be applied on the cement plug.

By monitoring a tension force on the wireline, and by knowing the force amplification provided by the force amplification module, it can be determined that the load mechanism presses on the cement plug with sufficient force to comply with regulations.

The force amplification may for example be a factor 20, wherein a tension force of five hundred KG - approximately 5 kN - applied to the wire line is amplified to a pressing force of 10 metric ton for the load mechanism.

During the pressing down of the load mechanism, the housing may be fixated relative to the well by the radial clamping mechanism. In embodiments, the housing is resiliently connected to the radial clamping mechanism by the flexible member. As such, the pulling force of the wireline is transferred from the housing to radial clamping mechanism through the flexible member. Alternatively or additionally, the housing is connected to the radial clamping mechanism by means of a clamping mechanism separator, which may be embodied as a shear pin.

When the flexible gripping member is arranged to severe under a pre-determined tension force, the flexible member or the clamping mechanism separator may be arranged to severe under a tension force higher than the required tension force to apply the required pressure on the cement plug. When the flexible member is severed, a movement of the first clamping part relative to the second clamping part is allowed again, which movement may disengage the radial clamping mechanism from the well .( When the radial clamping mechanism is disengaged, the device may be lifted out of the well again. However, when the housing is lifted out of the well, and connection between the housing and the landing module is severed, the landing module and in embodiments part of the radial clamping mechanism may be left behind.

To prevent having to leave behind the landing module and in embodiments part of the radial clamping mechanism such that they may for example be used again, a first of the load mechanism and the landing module comprises a locking mechanism and a second of the load mechanism and the landing module comprises a receiving section, wherein the locking mechanism is arranged to engage with the receiving section such that the load mechanism is coupled to the landing module when the locking mechanism engages the receiving section.

The locking mechanism and receiving section may be aligned after the load mechanism has been lifted up from the cement plug after a pre- determined distance. In embodiments, the locking mechanism is arranged as a spring activated pin, and the receiving section is a recess arranged to receive the pin. When the pin and the recess are aligned, the pin may pushed into the recess by a pre-loaded spring.

With the locking mechanism engaged with the recess, and thus with the landing module coupled to the load mechanism, with the lifting of the housing, the landing module is lifted as well.

In embodiments, the load mechanism as the first of the load mechanism and the landing module may comprise the locking mechanism. In other embodiments, the landing module as the second of the load mechanism and the landing module may comprise the locking mechanism.

The landing module may be provided coaxially relative to the load mechanism. Furthermore, the landing module may comprise a landing module bore, and the load mechanism may extend at least partially through the landing module bore.

The landing module may be provided at a distal end with a substantially thin-walled cylinder, and the landing surface is provided by a distal end of the thin-walled cylinder. Being substantially thin-walled implies that the surface area of the landing surface is relatively small and will as such sink more easily in liquid cement which has not yet solidified. The surface area may depend on an inner radius of the thin-walled cylinder and an outer radius of the thin-walled cylinder.

In embodiments, the surface area of the landing surface may be two times smaller than a surface area of the load mechanism end-plane, or may be four times smaller, ten times smaller or even 20 times smaller.

The landing module may as an option comprise a spacer, and the load mechanism may as an option be arranged to apply the load on the cement plug via the spacer. The spacer may thus be provided between the end-plane of the load mechanism and the cement plug, and the required load may be provided indirectly to the cement plug - i.e. via the spacer. The spacer may be used to extend through a volume of liquid and/or slurry present on top of the cement plug.

In embodiment of the device, the radial clamping mechanism may be provided coaxially relative to load mechanism, the radial clamping mechanism may comprise a radial clamping mechanism bore, and the load mechanism may extend at least partially through the radial clamping mechanism bore. The load mechanism may thus extend at least partially through the radial clamping mechanism and the landing module.

In general, any of the housing, wireline connection module, load mechanism, radial clamping mechanism, and landing module may be provided co-axially in any combination thereof.

BRIEF DESCRIPTION OF THE FIGURES In the figures, Figs. 1-9 depict embodiments of a device for applying a pressure on a cement plug at various stages.

DETAILED DESCRIPTION OF THE FIGURES Fig. 1 shows an overview of a device 100 for applying a load on a cement plug 210, lowered into a well 200. The well 200 is provided with a cement plug 210,the plug can be placed in the tubing, the casing, or in a chamber created by removing the tubing or casing or cement prior to placing the cement plug of which the existence and/or hardness and/or load resistance and/or strength has to be ensured. The device 100 is attached to a wireline 220 as a suspension member, which is provided on a winch 221. By providing a torque to the winch 221, the wireline 220 may be unwound or a tension force may be applied on the wireline 220. In alternative embodiments, the wireline 220 may be at least partially substituted by tubing, a conduit, electrical wiring for transmitting electrical power and/or data signals, any other part from which the device 100 may be suspended or any combination thereof.

Fig. 1 is not necessarily drawn to scale. In practice, the well 200 may be several hundreds of metres deep, and the well 200 may many times deeper than the height of device 100. Furthermore, while the device 100 is shown lowered in the well 200, the device 100 may also be arranged to be lowered into the casing or tubing of a well.

The cement plug 210 may be used acting as a seal or for keeping a seal 211 in place, which seal 211 in turn is used for sealing off a production pipe 212 of the well or other leaking paths in or around the production pipe or casings installed . In Fig. 1, the well 200 is further provided with a casing 214, which may have been removed at the location of the cement plug 210, prior to placement of the plug.

The device 100 comprises a housing 102, arranged to be lowered into the well 200, in particular through the casing 214. If tubing is not removed prior to cementing, the device 100 may also be lowered into the tubing. The housing 102 may be a substantially elongated housing, optionally with a cross-sectional shape complementary to that of the casing or tubing 214, such that the housing 102 can be lowered into the casing or tubing or other conduit 214 towards cement plug 210. The device 100 further comprises a wireline connector 104 as a wireline connection module 104, connected to the wireline 220, and a press cylinder 106 as a load mechanism 106 arranged to apply a load on the cement plug 210. In the embodiment of Fig. 1, a hydraulic amplifier 108 as a force amplification module is provided between the wireline connector 104 and the pressing cylinder 106. The wireline connector 104 may in embodiments be comprised by the housing 102, the force input, the actuator, any other component of the device 100, or may be a separate component comprised by the device 100. The device 100 as depicted in Fig. 1 further comprises radial clamping mechanism 110, arranged to fixate a position of the housing 102 relative to the well 200, in particular to the casing 214, when the radial clamping mechanism 110 is in an engaged state.

In a disengaged state, the radial clamping mechanism 110 may not restrict motion of the housing relative to the well 200, in particular relative to the casing 214, or tubing when the device is lowered into tubing.

The not restricted motion may in particular be motion in a direction opposite to the load direction.

As such, when the radial clamping mechanism 110 is engaged, a closed force loop may be obtained between the cement plug, housing, and load mechanism via the radial clamping mechanism.

In the situation depicted in Fig. 1, the entire device 100 is suspended from the wireline 220, and hence the entire mass of the device 100 is suspended from the wireline 220 resulting in a tension force on the wireline 220. Fig. 2 depicts a distal end of an embodiment of the device 100 lowered in the well 200, wherein the device 100 comprises a landing cone 112 as a landing module 112. The landing cone 112 comprises at a distal end alanding surface 113 arranged to abut the cement plug 210, in particular an exposed top surface 213 of the cement plug 210. The embodiment of the device 100 further comprises a landing module shear pin 114 as a landing module separator.

The landing cone 112 is in the embodiment as shown in Fig. 2 provided coaxially relative to pressing cylinder 106. For accommodating the pressing cylinder 106 within the landing cone 112, the landing cone 112 comprises a landing module bore. By providing different components of the device 100 coaxially and at least partially accommodated in one another, a smaller form factor for the device 100 may be obtained.

The landing module is in the embodiment of Fig. 2 as an option at a distal end provided with a substantially thin-walled cylinder, and the landing surface 113 is provided by a distal end of the thin-walled cylinder.

As shown in Fig. 2, a load mechanism distal end-plane 107 is provided at a distance from the landing surface 113 and as such, when landing module shear pin 114 is in the fixed state, the landing surface 113 extends further away from the housing 102 than the distal end-plane 107 of the pressing cylinder 106. This may ensure that when the device 100 is being lowered in to the well 200, the landing surface 113 abuts the cement plug 210 first.

The landing module shear pin 114 is in Fig. 2 depicted in a fixed state, wherein the landing module shear pin 114 fixes the pressing cylinder 106 relative to the landing module 106.

In the situation of Fig. 2, the landing surface 113 abuts the cement plug 210. As such, weight of the device 100 may be transferred from tension on the wireline 220 to a load on the cement plug 210. Weight of the device 100 may be transferred to the cement plug 210 via the pressing cylinder 106, the landing module shear pin 114 and the landing cone 112. As such, with lowering of the tension force on the wireline 220, the force on the landing module shear pin 114 may increase. If the force on the landing module shear pin 114 exceeds a pre-determined landing module separation force, the landing module shear pin 114 fails and as such the pressing cylinder 106 is released from the landing cone 112. Alternatively, the landing module shear pin 114 may be arranged to fail when impacted one or more times with the pre-determined landing module separation force.

Embodiments of the device 100 are envisioned wherein the landing cone 112 is not the first component of the device 100 to touch down on the cement plug 210 when the device 100 is lowered into the well. In such embodiments, the device 100 may be provided without a landing module. Additionally or alternatively, another component of the device 100 touches down first on the cement plug 210, for example the pressing cylinder 106, the radial clamping mechanism 110, the housing 102, any other component, or any combination thereof, which may optionally be coupled via a shear pin to be released when, after touching down one the cement plug, weight of the device is transferred from tension force on the wireline on said shear pin.

Fig. 3 depicts the device 100 wherein the landing module shear pin 114 has been severed, and the load mechanism 106, optionally with the rest of device 100, has moved relative to the landing cone 112 to now abut the top surface 213 of the cement plug with the load mechanism distal end- plane 107. The movement of the load mechanism 106 is caused by further lowering the device 100 into the well.

The landing cone 112 cannot be lowered beyond the cement plug 210 as it abuts the cement plug. However, by virtue of compression of a flexible connection provided by spring 116 as an optional flexible connection member, a movement of the pressing cylinder 106 is allowed relative to the landing cone 112. Such movement may cause the landing module shear pin 114 to fail.

Fig. 4 depicts a situation wherein the device 100 is being pulled up using the wireline 220. As such, the pressing cylinder 106 rises away from the cement plug 210. The landing cone 112 stays in place because movement of the landing cone 112 relative to the pressing cylinder 106 is allowed, due to the landing module shear pin 114 having been severed, and hence having decoupled the landing cone 112 from the pressing cylinder

106. In Fig. 4, the pressing cylinder 106 is still fixed relative to the housing 102, for example by load mechanism shear pin 144 as a load mechanism separator.

In embodiments, the load mechanism shear pin 144 can only be severed when the radial clamping mechanism 110 is activated and thus when the housing 102 is fixated relative to the well 200.

In the example of Fig. 4, the radial clamping mechanism 110 comprises an outer clamping part 141 as a first clamping part. The outer clamping part 141 is connected to the housing 102 by the spring 116, and optionally fixated relative to the landing cone 112. The radial clamping mechanism 110 further comprises an inner clamping part 142 as a second clamping part. The inner clamping part 142 is fixated relative to the housing 102 for example with a radial clamp shear pin 146 as a radial clamp separator.

A person skilled in the art will appreciated that the radial clamping mechanism can be embodied in different ways. As such, when the radial clamping mechanism comprises an inner clamping part and an outer clamping part, the outer clamping part may be connected to the inner clamping part using one or more elastic members or in any other known way. The radial clamping mechanism may be pre-tensioned in the disengaged state.

The clamping mechanism may comprise segmented cones held together by means of a resilient connection. A first of the inner clamping part 142 and the outer clamping part 141 may comprise slits, preferably narrower at the surface facing a second of the inner clamping part 142 and the outer clamping part 141. The second of the inner clamping part 142 and the outer clamping part 141 may comprise ridges or protrusions fitting in the slits, which ridges or protrusions preferably have a shape complementary to the slits. The protrusions preferably have a T-shape.

By a movement of the inner clamping part 142 relative to the outer clamping part 141, in particular the inner clamping part 142 being moved upwards relative to the outer clamping part 141, the outer clamping part 141 is pushed outwards radially to engage the casing 214 of the well

200. With this upwards movement of the inner clamping part 142, the spring 116 is stretched out to allow movement of the housing 102 relative to the outer clamping part 141. The movement of the inner clamping part 142 may be substantially coaxially relative to the outer clamping part 141.

In the embodiment of Fig. 4, the outer clamping part 141 comprises a bore, with a tapered inner wall such that the inner wall 1s tapered in a direction facing away from the landing cone 112. The inner clamping part 142 is provided with a tapered outer wall such that the tapered part of the outer wall is tapered in the same direction as the inner wall of the outer clamping part 141. The inner clamping part 142 is provided partially in the bore of the outer clamping part 141.

The inner clamping part 142 may function as a wedge pushing at least part of the outer clamping part 141 radially outwards. The outer clamping part 141 may at one end be connected to the landing cone 112. For allowing radial movement of part of the outer clamping part 141, these moving parts may be hingedly connected relative to the landing cone 112.

In other embodiments of the device 100, the radial clamping mechanism 110 may be engaged using a rotation of two parts relative to each other, for example using engaging threads. As other options, radial clamping mechanism 110 may be engaged using an external power source, such as electrical energy being provided to a electric motor, or hydraulic or pneumatic pressure being provided to a hydraulic or pneumatic actuator. In examples, hydraulic or pneumatic pressure may be provided by a tension force on the wireline.

Fig. 5 shows part of an embodiment of the device 200, comprising force transmission module 108 as an actuator . The force transmission module 108 comprises an upper plunger 150 as a force input. The upper plunger 150 is connected to the wireline connector 104, and as such a tension force on the wireline may be transferred to the upper plunger 150. In use, a tension force on the wireline will try to pull the upper plunger 150 up away from the cement plug. Alternatively, a weight can be lowered to actuate the upper plunger 150 such that fluid is transferred from the input fluid reservoir 155 to the output fluid reservoir 156. The gravitational force acting on the upper plunger 150 is amplified as discussed above. the mass of the weight is preferably in the order of five hundred kilograms.

The force transmission module 108 further comprises a lower plunger 152 as a force output. In embodiments, the lower plunger 152 is coupled to the pressing cylinder 106, and the pressing cylinder 106 may be a part of the lower plunger 152.

In Fig. 5, the arrow 301 depicts a tension force vector as a first force vector of the input force, representing the tension force on the wireline. In use, the tension force vector may be directed substantially opposite to gravity. The arrow 302 depicts a load vector as a second force vector of the output force having a substantially opposite direction relative to the tension force vector, and may in use be directed substantially in the same direction as the gravity. Hence, the direction of the tension force may be substantially reversed by virtue of the force transmission module 108 as shown in Fig. 5.

In the embodiment of Fig. 5, as an example, the force amplification module is arranged as a hydraulic amplifier. As such, the hydraulic amplifier 108 comprises an input fluid reservoir 155, which in Fig. 5 is surrounding upper plunger 150. The hydraulic amplifier 108 further comprises an output fluid reservoir 156, provided in fluid connection with the input fluid reservoir via fluid conduit 157 as a part of the force transmission module. Via the fluid conduit 157, fluid may be transferred between the input fluid reservoir 155 and the output fluid reservoir 156. As such, a fluid pressure in the input fluid reservoir 155 may be substantially equal to a fluid pressure in the output fluid reservoir 156 and the input force may be coupled to the output force.

At least one of the input fluid reservoir 155 and the output fluid reservoir 156 may be provided with a pressure sensor for sensing pressure of fluid in the applicable reservoir. One or more signal from the pressure sensors indicative of pressure in the applicable reservoir may be provided to a vessel or other base station at the surface. The signal or signals received may in that way provide a verification whether the appropriate load has been applied to the plug 210. In particular the pressure in the output fluid reservoir 156 may provide an input to a load verification process.

Additionally or alternatively, the pressure signal or pressure signals may be used for safety control in the device itself - shutting it down if pressure is above a first limit and/or below a second limit - or for controlling operation of the device. As discussed below, certain parts of the device may be coupled or decoupled based on certain forces between the applicable parts. In addition to the way of working discussed below, actuators may be used controlled based on at least one pressure sensed in at least one of the input fluid reservoir 155 and the output fluid reservoir 156. Such actuators may be (electrical) solenoid driven, otherwise electrically driven, hydraulically or pneumatically driven or mechanically driven.

Additionally or alternatively, strain gauges may be applied to various parts of the device 100 to verify an applied load. For example, strain gauges may be applied to the lower piston 159 and/or to the pressing cylinder 106. Values read out may be stored locally in the device and/or communicated to the surface by means of a communication line between the device 100 and further processing means at the surface, like a computer.

The device 100 as shown in Fig. 5 is further provided with an upper piston 158 as a first piston, provided in the input fluid reservoir 155,

wherein the upper piston 158 is coupled to the force input via the upper plunger 150 and the wireline connection module. Also provided is a lower piston 159 as a second piston, provided in the output fluid reservoir 156, wherein the lower piston 159 is coupled to the pressing cylinder 106 via the lower plunger 152.

To provide a mechanical advantage, the surface area of the upper piston 158 facing into the input fluid reservoir 155 is smaller than a surface area of the lower piston 159 facing into the output fluid reservoir 156. In particular, the ratio between these two surface areas may determine the force amplification factor. For example, the surface area of the upper piston 158 facing into the input fluid reservoir 155 may be smaller than the surface area of the lower piston 159 facing into the output fluid reservoir 156 by a factor 2, 5, 10, fifteen, twenty, thirty, or even more than forty.

In use, when the upper plunger 158 is pulled upwards relative to the housing 102 by virtue the tension force on the force input, the lower plunger 159 may be pushed downwards due to lower piston 159 being exposed to the output fluid reservoir 156 at a side opposite to the lower piston side at which the lower plunger 152 is provided. As such, a tension force on the wireline 220, for example provided by the winch 212 as shown in Fig. 1, may be converted into a load on the cement plug for testing the cement plug, for example on existence and hardness.

In Fig. 6, the device 100 is shown in a position wherein the cement plug 210 is tested by a load. The desired load for testing may be a pre-determined load, for example laid down in a standard, such as the Nogepa standard 45 or Norsok.

During testing, the inner clamping part 142 is fixed to the housing 102 via radial clamp shear pin 146, and the load may be transferred through the radial clamp shear pin 146. The pre-determined radial clamp separation force required to severe the radial clamp shear pin 146 may be a factor higher than the desired load for testing. For example, the radial clamp shear pin 146 may be designed to severe when subjected to at least 105% of the desired load, at least 110%, at least 120%, or for example more than 130%. As such, it may be ensured that the desire load has been applied when the radial clamp shear pin 146 severs. If the device 100 has been brought back to the surface, a severed radial clamp shear pin 146 - or equivalent separator connecting the clamping mechanism to the rest of the device 100 or at least to the housing 102 - it may provide proof that the desired load has been applied.

In the situation depicted in Fig. 6, the radial clamping mechanism is engaged, which in this particular embodiment implies that at least part of an outer wall of the outer clamp part 141 engages the casing 214 of the well

200.

To improve the friction between the outer clamp part 141 and the casing 214, at least part of the outer wall of the outer clamp part 141 is provided with teeth 143 which may at least partially be pushed into the casing 214 and/or any other part of a well 200 when the radial clamping mechanism is engaged. Alternatively or additionally, at least part of the outer wall of the outer clamp part 141 may be serrated, provided with one or more protrusions, may be embossed, may be provided with any other shape, structure, form and/or material to enhance friction and/or a friction coefficient, or may be provided with any combination thereof.

In Fig. 7, a situation is depicted wherein the radial clamp shear pin 146 is severed, because the radial clamp shear pin 146 has been subjected to a force exceeding the pre-determined radial clamp separation force. Furthermore, the spring 116 has been severed or otherwise released from either the outer clamp part 141, the housing 102 or both, because it has been subjected to a force exceeding a pre-determined tension force. With the severing of the radial clamp shear pin 146, the inner clamping part 142 is released from being fixed relative to the housing 102. As such, the inner clamping part 142 1s again allowed to moved relative to the outer clamping part 141. With this, for example downward, movement of the inner clamping part 142 relative to the outer clamping part 142the radial clamping mechanism 110 may be disengaged. This may in use be caused by gravity pulling the inner clamping part 142 downwards and/or or a spring element pushing or pulling it downwards, As such, the housing 102 is released from the well 200 and may now be moved relative to the well 200, for example by pulling the housing 102 upwards away from the cement plug 210 using the wireline.

In the situation depicted in Fig. 7, the housing 102 can be moved relative to the landing cone 112, the inner clamping part 142 and the outer clamping part 141 . Due to their weight, they may remain on the cement plug 210 when the housing 102 and the pressing cylinder 106 are lifted up. The lower piston 159 may act as a stop to prevent the pressing cylinder 106 from falling out of the housing 102.

To connect the pressing cylinder 106 to the landing cone 112, in the embodiment of the device 100 as shown in Fig. 7, the pressing cylinder 106 as a first of the pressing cylinder 106 and the landing cone 112 comprises a spring-loaded protrusion 172 as a locking mechanism. The landing cone 112 as a second of the pressing cylinder 106 and the landing cone 112 comprises a recess 171 as a receiving section.

When the pressing cylinder 106 is moved relative to the landing cone 112, the spring-loaded protrusion 172 may be aligned with the recess 171, for example by pulling the housing 102 with the pressing cylinder 106 up, while the landing cone 112 substantially remains at the same height standing on the cement plug 120.

In Fig. 8, an embodiment of the device 100 is shown being pulled up and away from the cement plug 210, for example after the testing of the cement plug 210 has been completed. The device 100 may be arranged to be used again, and as such it may be preferred to lift all the components of the device 100 up and out of the well 200. The spring-loaded protrusion 172 1s locked into the recess 171, and as such the landing cone 112 is pulled away from the cement plug 210 as well.

When an embodiment of a device 100 does not comprise a landing module, the receiving section or locking mechanism may be provided by another component, for example the radial clamping mechanism or the housing.

For example, when the device 100 does not comprise a landing cone 112, it may be detected when the pressing cylinder 106 has landed on the cement plug 210, for example by monitoring a tension on the wireline from which the device 100 is suspended. When it is detected that at least part of the weight of the device 100 has been transferred from a tension force on the wireline to being supported by the cement plug 210, a radial clamping mechanism may be engaged for fixating a component of the device 100, for example the housing 102, relative to the well.

In embodiments, the radial clamping mechanism may be engaged using an energy input, for example providing electrical energy to a motor arranged to engage the radial clamping mechanism, providing hydraulic or pneumatic pressure to engage the radial clamping mechanism, and/or using at least part of the weight of the device and/or a tension force on the wireline for engaging the radial clamping mechanism.

When only the weight of the device and/or a tension force on the wireline is used for engaging the radial clamping mechanism, it may not be necessary to provide the device an additional energy input, and hence the device may for example be lighter and/or less complex.

In Fig. 9, a particular embodiment of the device 100 is depicted, wherein the landing cone 112 as the landing module comprises an extended section 910 as a spacer. In the embodiment of Fig. 9, the extended section 910 provides the landing surface 113. As such, when the device 100 is lowered into the well 200, the extended section 910 with its landing surface 113 may be the first and optionally only component of the device 100 to abut the cement plug 210. The load to be applied by the pressing cylinder 106 as the load mechanism is now to be applied via the extended section 910. The pressing cylinder 106 is now arranged to engage the extended section 910, for example with the load mechanism distal end-plane 107 engaging an abutment surface 912 of the extended section 910. In the state of the device 100 as depicted in Fig. 9, a distance between the load mechanism distal end-plane 107 and the abutment surface 912 of the extended section 910 is greater than a thickness of the landing module shear pin 114. This allows the landing module shear pin 114 to shear when the pre-determined landing module separation force on the landing module shear pin 114 is exceeded — statically or by one or more impacts on the landing module shear pin 114.

Claims

Conclusions

An apparatus for applying a load to a cement plug in a well, comprising: - a housing adapted to be lowered into the well; - a clamping mechanism arranged to fix a position of the housing relative to the well in an activated state; - an actuator connected to the housing, comprising: - a power input for receiving an input signal; - a force output for applying an output force in response to the input signal; and - a load mechanism coupled to the power output; wherein the load mechanism is adapted to apply the load to the cement plug.

The apparatus of claim 1, further comprising a pendant link module coupled to the force input of the actuator for providing an input force as the input signal.

An apparatus according to claim 1 or 2, wherein the actuator is arranged to receive an input force with a first force vector having a first direction as the input signal, and to apply the output force with a second force vector, wherein the second force vector has a second direction substantially opposite to the first direction.

Apparatus according to any one of the preceding claims, further comprising a force amplification module for amplifying the input force using a mechanical advantage and transferring the amplified force to the force output, wherein the force amplification module is configured as a hydraulic force amplifying device, comprising: a feed fluid reservoir ;

- an output liquid reservoir provided in fluid communication with the input liquid reservoir; - a first piston provided in the input liquid reservoir, wherein the first piston is contained by the force input; - a second piston provided in the output liquid reservoir, wherein the second piston comprises 1s by the power output; wherein a first area of the first piston directed into the input liquid reservoir is smaller than a second area of the second piston directed into the output liquid reservoir.

The apparatus of claim 4, wherein the first piston includes a first plunger on a first side and the first piston faces the input liquid reservoir with the first side.

An apparatus according to claim 4 or 5, wherein the second piston includes a second plunger on a second side, and the second piston faces the discharge liquid reservoir on a third side opposite the second side.

Apparatus according to any preceding claim, further comprising a landing module including a landing surface adapted to abut the cement plug.

Apparatus according to claim 7, wherein the landing module comprises a landing module separator arranged to: - fix the position of the load mechanism with respect to the landing module in a fixed state; and - releasing the load mechanism from the landing module when the landing module separator is subjected to a force exceeding a predetermined landing module separation force.

The apparatus of claim 8, wherein when the landing module separator is in the fixed state, the landing module landing surface extends further away from the housing than a distal end face of the load mechanism.

Apparatus according to any one of the preceding claims, the radial clamping mechanism comprising: - a first clamping part connected to the housing; - a second clamping part, wherein the radial clamping mechanism is adapted to engage the well by means of a movement of the second clamping part relative to the first clamping part such that a diameter of at least one of the first clamping part and the second clamping part is larger is becoming.

Apparatus according to any one of the preceding claims, wherein the radial clamping mechanism is connected to the housing with a radial clamp separator adapted to release the second clamp member from the housing when the radial clamp separator is subjected to a force exceeding a predetermined radial clamping force. exceeds separation force

Apparatus according to any one of the preceding claims, further comprising a load mechanism separator arranged to: - fix the load mechanism relative to the housing in a fixed position; and - releasing the load mechanism from the housing when the load mechanism separator is subjected to a force exceeding a predetermined load mechanism separation force.

Apparatus according to claim 12, wherein: - a first one of the loading mechanism and the landing module comprises a closing mechanism; and - a second of the load mechanism and the landing module comprises a receiving part;

wherein the locking mechanism is adapted to engage the receiving member such that the load mechanism is coupled to the landing module when the locking mechanism engages the receiving member.

Apparatus according to any one of claims 7-13, when dependent on claim 7, wherein: - the landing module is provided coaxially with the load mechanism; - the landing module comprises a landing module bore; and - the load mechanism extends at least partially through the landing module bore.

An apparatus according to any one of claims 7-14 when dependent on claim 7, wherein the landing module comprises a substantially thin-walled cylinder at a distal end, and the landing surface is provided by a distal end of the thin-walled cylinder.

Apparatus according to any one of claims 7-14, when dependent on claim 7, wherein the landing module comprises a spacer, and the load mechanism is arranged to apply the load to the cement plug via the spacer.

Apparatus according to any one of the preceding claims, wherein: - the radial clamping mechanism is provided coaxially with the load mechanism; - the radial clamping mechanism comprises a radial clamping mechanism bore; and - the load mechanism extends at least partly through the radial clamping mechanism bore.

An apparatus according to any one of the preceding claims, wherein the actuator comprises an output liquid reservoir and a second piston provided in the output liquid reservoir, wherein the second piston is contained by the power output and wherein the output liquid reservoir is adapted to receive a pressurized liquid as the output fluid. input signal for actuating the second piston.

Apparatus according to any one of the preceding claims 1-17, wherein the actuator comprises an electric actuator and an electric motor in particular adapted to convert electric power to an input force which is adapted to be controlled by at least one of an electric , mechanical or optical signal as the input signal.