WELLBORE MECHANICAL CALIPER TOOL

Abstract

A wellbore caliper tool is provided for measuring a wellbore diameter without an additional wireline trip. The caliper tool includes a collar, measurement bands coupled to the collar at one end and sliding blocks on the other. The measurement bands can extend radially from the collar, which causes the sliding blocks to move within the collar. Electromagnetic sensors in the collar measure an electromagnetic field created by magnets in the sliding blocks to determine the position of the sliding blocks. The position of the sliding blocks is used to calculate the distance that the measurement bands extend and to calculate the wellbore diameter. The caliper tool includes an actuating mechanism that holds the sliding blocks in place until a differential pressure is applied by pumping fluid into the caliper tool.

Description

CROSS-REFERENCE

This application claims priority to U.S. Provisional Application Ser. No. 63/648,754, filed May 17, 2024, the complete disclosure of which is hereby incorporated by reference herein.

BACKGROUND

Downhole mechanical service tools allow for performing operations within a wellbore. When it is time to decommission the well, cement must be injected between the wellbore and casing. Accurate wellbore measurements are critical for estimating how much cement must be injected between the wellbore and the casing. However, wellbore instability can cause wash-outs and irregularities in the wellbore diameter. These irregularities make it difficult to accurately calculate the required cement volume to properly seal the wellbore.

Mechanical calipers are generally used in wireline operations to measure wellbore diameter. Current calipers, however, require an additional wireline trip to acquire the measurements. Such a wireline trip can take days, which extends the time and cost of a drilling operation.

To advance the application of well decommissioning without an additional wireline trip for measuring a wellbore diameter, a new mechanical caliper is needed.

SUMMARY

Described herein is a caliper tool for measuring wellbore diameter during Pull Out of Hole (“POOH”) operations in the wellbore drilling process. The caliper tool can be installed on a wireline assembly so that it can be used in conjunction with other drilling operations. In other words, the caliper tool does not require an additional wireline trip.

The caliper includes a collar and measurement bands coupled to the collar at one end and sliding blocks on the other. When the caliper tool is activated, the sliding blocks move axially within the collar. The measurement bands extend radially from the collar until they make contact with the inner wellbore wall. The measurement bands can extend from their inherent qualities or from an external force being applied. For example, the measurement bands can be flexible bands that arc outward from the collar when no force pulls them toward the collar. Alternatively, springs can provide a force that extends the measurement bands.

Movement of the measurement bands causes the sliding blocks to move axially within the collar. The position of a sliding block in the collar indicates how far the corresponding measurement band has extended from the collar. Electromagnetic sensors in the caliper tool measure an electromagnetic field created by magnets in the sliding blocks. These measurements are used to calculate the positions of the sliding blocks, and subsequently to calculate how far the measurement bands are extended from the caliper tool. These calculations can then be used to calculate the wellbore diameter.

The caliper tool includes an actuating mechanism that is used for activating the caliper tool. When deactivated, the measurement bands can be flush or nearly flush to the collar to protect the measurement bands while the caliper tool is lowered into the wellbore. Alternatively, the measurement bands can be positioned within helical depressions of an offset component that protects the measurement bands. The actuating mechanism can include an actuating member that applies a force on the sliding blocks to keep the measurement bands in a safe position while the caliper tool is lowered into the wellbore. The actuating member can be held in place by a dynamic member that is in turn held in place by a constraining member. The constraining member is configured to fail when fluid is pumped into the actuating mechanism and creates a differential pressure across the dynamic member above a certain threshold.

When the constraining member fails, a series of events can occur that cause the actuating member to release the sliding blocks. In one example, the high pressure can cause the dynamic member to move away axially from the actuating member. The pressure can then be lowered, and a spring coil can push the dynamic member toward the actuating member. This releases the sliding blocks and allows the measurement bands to expand until they contact the wall of the wellbore.

In another example, the dynamic member and actuating member can interlock with each other via castellations. The high differential pressure causes the dynamic member and actuating member to separate, and a cam profile in the actuating member causes the actuating member to rotate so that the dynamic member and actuating member no longer interlock. The pressure can be increased again to rotate the actuating member so that the dynamic member and actuating member again can interlock. This allows unlimited activation and deactivation of the caliper tool. Various other cam profiles and actuating mechanisms are described herein.

The measurement bands can extend radially from the collar, which causes the sliding blocks to move within the collar. Electromagnetic sensors in the collar measure an electromagnetic field created by magnets in the sliding blocks to determine the position of the sliding blocks. The position of the sliding blocks is used to calculate the distance that the measurement bands extend and to calculate the wellbore diameter. The caliper tool includes an actuating mechanism that holds the sliding blocks in place until a differential pressure is applied by pumping fluid into the caliper tool.

A downhole deployable offset module is described for protecting other modules in a wireline assembly from damage resulting from contact with the wellbore wall. The offset module includes a piston coupled to blades or discs. The blades are coupled to angled members that convert advancement of the piston to radial deployment of the blades. When fluid pumped through the offset module creates a differential pressure above a certain threshold, the piston is activated and advances axially. This causes the blades to radially deploy. The piston stops advancing when the blades contact the inner surface of the wellbore. This centers the offset module in the wellbore. Strategically placing multiple offset modules in a wireline assembly can protect other modules by keeping them centered in the wellbore. For example, an offset module can be placed at either end of a caliper tool to protect exposed measurement bands.

The offset module can include a ratchet ring with threads that complements threads on the piston. The threads have flank angles that are biased in a single direction so that an axial force applied to the ratchet ring allows the ratchet ring to expand over the piston in the single direction. This allows the piston to advance in a single direction so that the blades can be deployed, but not retracted until manually reset. The ratchet ring can have a failure setting where it fails when a threshold pressure is applied on the piston. This can help prevent the offset module from getting stuck in the wellbore.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the embodiments, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate various embodiments and aspects of the present invention. In the drawings:

FIG. 1 is an example illustration of a cross-sectional view of a wellbore caliper tool.

FIG. 2 is an example illustration of a close-up cross-sectional view of an electrical chassis of a wellbore caliper tool.

FIGS. 3A and 3B are example illustrations of an actuating mechanism in a wellbore caliper tool.

FIG. 4 is an example illustration of an exterior perspective view of a wellbore caliper tool.

FIG. 5 is an example illustration of a cross-sectional view of a wellbore caliper tool.

FIGS. 6A-6F show the operation of an embodiment of a wellbore caliper tool, according to one or more examples of the disclosure.

FIG. 7 is an example illustration of another wellbore caliper tool.

FIGS. 8A-8I show the operation of an embodiment of a wellbore caliper tool, according to one or more examples of the disclosure.

FIG. 9 is another example illustration of an actuating mechanism in a wellbore caliper tool.

FIG. 10 is an example flow chart of a method for measuring a wellbore diameter using a wellbore caliper tool.

FIG. 11 is an example illustration of a downhole deployable offset module.

FIG. 12 is an example flow chart of a method for deploying a downhole deployable offset module.

DESCRIPTION OF THE EXAMPLES

Reference will now be made in detail to the present exemplary examples, including examples illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The described examples are non-limiting.

In the specification and appended claims: the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting” are used to mean “in direct connection with” or “in connection with via another element”; and the term “set” is used to mean “one element” or “more than one element”. As used herein, the terms “up” and “down”, “upper” and “lower”, “upwardly” and downwardly”, “upstream” and “downstream”; “above” and “below”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly described some embodiments of the invention. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or other relationship as appropriate.

A wellbore caliper tool is provided for measuring a wellbore diameter without an additional wireline trip. The caliper tool includes a collar, measurement bands coupled to the collar at one end and sliding blocks on the other. The measurement bands can extend radially from the collar, which causes the sliding blocks to move within the collar. Electromagnetic sensors in the collar measure an electromagnetic field created by magnets in the sliding blocks to determine the position of the sliding blocks. The position of the sliding blocks is used to calculate the distance that the measurement bands extend and to calculate the wellbore diameter. The caliper tool includes an actuating mechanism that holds the sliding blocks in place until a differential pressure is applied by pumping fluid into the caliper tool.

FIG. 1 is an example illustration that shows a cross-section view of an embodiment of the invention, a wellbore caliper tool 100. The caliper tool 100 includes a collar 110. The collar 110 has a cylindrical or ring-like shape and secures other parts in place. The caliper tool 100 includes one or more measurement bands 120 that are coupled to the collar 110 at a first end 122 and to a sliding block 130 at a second end 124. The measurement band 120 can be any component that can extend from the collar 110 while coupled to the collar 110 and sliding block 130. In one example, the measurement band 120 can be a flexible band that has an arc profile when no external forces act upon it. The arc profile of the measurement band 120 flattens if its ends 122, 124 are forced apart. Conversely, the ends 122, 124 are forced apart if the arc profile is flattened by an external constraint. As a result, the height of the arc can be determined based on the displacement of the ends 122, 124.

Other types of measurement bands 120 can be used. For example, the measurement band 120 can include two arm members pivotally coupled to each other. In one example, the two arm members can be pivotally coupled by a cylindrical roller that can roll when in contact with surrounding rock formations. Another component, such as a bow spring or coil spring, can apply a force on the two arm member that causes the coupling point to extend from the collar 110 unless another stronger forces prevents it from doing so.

An actuation mechanism 140 inside the collar 110 can activate and deactivate the measurement bands 120 by applying or releasing force to the sliding block 130. For example, the actuation mechanism 140 includes an actuation driver 142 and an actuation member 144. When the caliper tool 100 is deactivated, the actuation driver 142 applies a force to the actuation member 144, which in turn applies a force on the sliding block 130 that causes the sliding block 130 to pull the second ends 124 of the measurement bands 120 away from their respective first ends 122. This flattens the measurement bands 120 against the collar 110, thereby protecting the measurement bands 120 from the wellbore. To activate the caliper tool, the actuation mechanism 140 simply releases the force applied on the sliding block 130, which causes the measurement bands 120 to contract and form an arc shape outward from the collar 110.

In one example, the caliper tool 100 can include multiple measurement bands 120 that are coupled at a second end 124 to the same sliding block 130. Alternatively, each measurement band 120 can be coupled to a different sliding block 130, and the actuation mechanism can apply a force to all the sliding blocks simultaneously.

The actuation mechanism 140 can include a constraining member 146 that can mitigate unintentional activation of the actuation mechanism 140. For example, when the caliper tool 100 is deactivated, the constraining member 146 can lock the actuating member 144 in place so that the sliding block 130 remains in an axially extended position to keep the measurement bands 120 flattened against the collar 110. The constraining member 146 can unlock the actuating member 144 when the caliper tool 100 is activated.

The caliper tool 100 includes an electronics chassis 150 that contains electrical components for sensing the position of the sliding block 130 and store the measurements in digital memory. FIG. 2 is an example illustration that shows a cross-section view of the sliding block 120 and the electronics chassis 150. The sliding block 120 includes one or more magnets 210 that create a magnetic field 220. The sliding block 120 can include one magnet 210 for each measurement band 110. The electronics chassis 150 includes electronic magnetic sensors 230 that are aligned with the axis of the collar 110. The electromagnetic sensors 230 can be any sensors that can measure the magnetic field 220. The electromagnetic sensors 230 can be calibrated to determine the position of the magnets 210 based on readings of the magnetic field 220. The position of the magnets 210 indicates the position of the sliding block(s) 120, which can then be used to calculate the arc height of the measurement bands 120, and subsequently the wellbore width. This is described in more detail later herein.

In an example, the caliper tool 100 can be activated by pumping fluid through the caliper tool 100. This causes the flowrate of fluid through the caliper tool 100 to increase, which in turn causes various components of the actuation mechanism 140 to move. FIGS. 3A and 3B are example illustrations that show multiple states of the actuation mechanism 140 during the activation process. FIG. 3A shows a first state where a dynamic member 320 of the actuation driver 140 is separated from the actuation member 144. For example, the actuation driver 142 can include a static member 310 and a dynamic member 320. The increase in flowrate causes a pressure differential across the dynamic member 320 to increase. The constraining members 146 are designed to fail when a target pressure differential has been generated across the dynamic member 320. After the constraining member 146 fails, the pressure differential from the fluid flowrate causes dynamic member 144 to move away from the actuation member 144. There is also a pressure differential across the actuation member 144 during the activation operation, forcing the actuation member 144 to maintain its position during the increased flowrate stage of the activation operation.

The caliper tool 100 includes a coil spring 330 that applies a force on the actuation member 144 toward the actuation driver 142. During the water phase of the drilling operation, the coil spring 330 is not strong enough to overcome the pressure from the pumped fluid, so the actuation member 144 stays in place. However, when the water phase ends, and the flowrate is decreased or eliminated, the coil spring 330 creates sufficient force to move the actuation member 144 to the dynamic member 320, which is shown in FIG. 3B. This state of the actuation mechanism 140 removes the constraint applied to the sliding block 130 by the actuation member 144, which allows the measurement bands 120 to activate.

The measurement bands 120 can be deactivated by increasing the flowrate through the caliper tool 100 again. However, the target flowrate is lower than the flowrate required to fail the constraining members 146. This increased flowrate causes the actuation mechanism 140 to return to second state illustrated in FIG. 3A, and constrain the measurement bands 120 to the deactivated position.

In an embodiment, the caliper tool 100 can be positioned in a wireline assembly between (a coupled to) deployable offset modules that protect and centralize the caliper tool 100. The deployable offset modules can include offset features that expand to a predetermined dimension under-gauge to protect the measurement bands 120. For example, while the wireline assembly is inside a wellbore, the offset features contact the surrounding rock formation, thereby preventing the measurement bands 120 from doing so.

Although the caliper tool 100 shows the measurement bands 120 being axially aligned with the collar 110, other configurations are possible. For example, FIG. 4 is an example illustration that shows another embodiment, a caliper tool 400, with measurement bands 420 that are helically aligned with the collar 410. The collar 410, measurement bands 420, and sliding blocks 430 correspond to the like-named components of FIG. 1. For example, the collar 410 corresponds to the collar 110, the measurement bands 420 to the measurement bands 120, and sliding blocks 430 to the sliding blocks 130. The caliper tool 400 includes an offset component 440 that includes helical depressions 442 that match the helical profile of the measurement bands 420 rest in. An offset component 440 with a helical profile produces less vibration than a straight profile if the offset component 440 contacts the wellbore while drilling.

While the caliper tool 400 is deactivated, the measurement bands 420 are stretched by the sliding blocks 430 so that they pass through the depressions 442 beneath the outer annular surface of the offset component 440. This maintains the helical arc profile of the measurement bands 420 when deactivated. While the caliper tool 400 is lowered into a wellbore, and while any other drilling operations are being performed, the offset component 440 makes contact with the surrounding rock formation, thereby protecting the measurement bands 420. Also, when deactivated, the measurement bands 420 need not be flush, or nearly flush, with the collar 410, thereby reducing stress on the measurement bands 420.

FIG. 5 is an example illustration of a cross-section view of the caliper tool 400. The caliper tool 400 includes the same components as the caliper tool 100, but in a different configuration. The actuation driver 542, actuation member 544, constraining member 546, and electronics chassis 550 correspond to the like-named components of FIG. 1. For example, the actuation driver 542 corresponds to the actuation driver 142, the actuation member 544 to the actuation member 544, the constraining member 546 to the constraining member 546, and the electronics chassis 550 to the electronics chassis 550.

FIGS. 6A-6F show the operation of an embodiment of a wellbore caliper tool. The initial position of the actuation driver 542 and the actuation member 544 is shown in FIG. 6A, with a collar pin 602 movable within the recess of a cam profile 604 being in an end of a straight portion. In this position, the differential pressure can vary within the typical drilling operating range without activating the measurement units. These changes in differential pressure will only vary the position of the actuation driver 542 axially, as the collar pin 602 moves in the straight portion. This decoupling between the motion of the actuation driver 542 and the actuation member 544 is critical to this embodiment.

To transition into activation mode, differential pressure is increased which causes the collar pin 602 to engage a ramp in the other end of the cam profile 604 and rotate the actuation driver 542. Motion of the actuation driver 542 is inhibited by the collar pin 602 after sufficient differential pressure has been applied. This is shown in FIG. 6B.

At this position, the differential pressure is reduced, and the coil spring 560 returns the actuation driver 542 to its original position. When the actuation driver 542 is returning to its original position, the collar pin 602 engages a ramp opposing the previous straight portion of the cam profile 604, further rotating the actuation driver 542 as shown in FIG. 6C.

As the actuation driver 542 returns to its original position, the extended portions of the actuation driver 542 and the actuation member 544 are in contact, as shown in FIG. 6D. This transfers force from the coil spring 560 to the actuation member 544, which moves the actuation member 544, thereby activating the measurement units.

To deactivate the measurement units, high differential pressure is required again. Increased differential pressure causes the collar pin 602 to move to the other end of the cam profile 604 again, which engages the ramp in the other end and rotating the actuation driver 542, misaligning the extended sections of the actuation driver 542 and the actuation member 544. This is shown in FIG. 6E.

The motion of the actuation driver 542 is inhibited by the collar pin 602 after sufficient differential pressure has been applied. At this position, the differential pressure is reduced, and the coil spring 560 returns the actuation driver 542 to its original position. When the actuation driver 542 is returning to its original position, the collar pin 602 engages a ramp opposing the previous straight portion of the cam profile 604, further rotating the actuation driver 542 as shown in FIG. 6F. Once the actuation driver 542 returns to its original position, the extended portion of the actuation driver 542 engages the depressed portion of the actuation member 544 as shown in FIG. 6A, resetting the sequence.

FIG. 7 is an illustration of a cross-section view of another embodiment, a caliper tool 700. Like other embodiments described previously, the caliper tool 700 includes a collar 710, measurement band 720, sliding block 730, actuation driver 742, actuation member 744, and electronic chassis 750. The caliper tool 700 also includes a tattle-tale apparatus 770. The tattle-tale apparatus 770 provides a pressure signal to the operator when the actuation member 744 changes position from the deactivated state to activated state.

FIGS. 8A-8I show the operation of an embodiment of a wellbore caliper tool similar to the embodiment illustrated in FIGS. 6A-6F, other than, as shown in FIG. 8A, the absence of castellations, and the addition of an insert 866 in the internal bore of the actuation member 744 and a tooth 864 in the external bore of the actuation driver 742, with the actuation member 744 housing a portion of the actuation driver 742. The actuation driver 742 drives the actuation member 744 via contact of the insert 866 and the tooth 864.

After maintaining the differential pressure with the upper operational magnitude, the differential pressure is decreased, and a coil spring 760 returns the actuation driver 742 to its original position via the path shown in FIG. 8B and FIG. 8C. It should be noted that the insert of the actuation member 744 does not contact the tooth 864 of the actuation driver 742 when the actuation driver 742 returns to its original position in this profile.

To engage the second profile, an intermediate differential pressure is maintained across the actuation driver 742. This positions the collar pin 862 midway along the cam profile 860 as shown in FIG. 8D. When the differential pressure is decreased at this point, the coil spring 760 returns the actuation driver 742 back to its original position, however the collar pin 862 will move to an alternate path in the cam profile 860 as shown in FIG. 8E, thereby entering the path of the second profile shown in FIG. 8E.

From this position, the differential pressure is increased to begin the activation of the measurement units. This causes the collar pin 862 to move to an upper stop different from the previous upper stop in the cam profile 860, as shown in FIG. 8F. When the collar pin 862 travels along this path, the tooth 864 of the actuation driver engages the insert of the actuation member 744.

When the collar pin 862 reaches this point, the differential pressure is decreased which causes the coil spring 760 to return the actuation driver 742 to its original position, as shown in FIG. 8G. At this point, the measurement units are activated and no further energization is required to obtain measurements.

To deactivate the measurement units, the differential pressure is increased to a high magnitude which causes the collar pin 862 of the actuation driver 742 to move to an upper stop different from the previous upper stops in the cam profile 860, as shown in FIG. 8H.

After maintaining the differential pressure, the differential pressure is decreased, and the coil spring returns the actuation driver 742 to its original position, as shown in FIG. 8I. The insert of the actuation member 744 disengages from the tooth 866 of the actuation driver 742 during the movement of the actuation driver.

FIG. 9 is an example illustration of an actuation mechanism 900 that can be used in conjunction with some of the embodiments described herein. The actuation mechanism 900 uses cam profiles (not shown) and resettable locking features 980 for when greater actuation force is required. This can be advantageous compared to the caliper tool 400 because the differential pressure across the actuation driver 942 supplies the force required to open the actuation member 944, rather than coil spring force. Compared to the caliper tool 700, the cam profile of this alternative actuation mechanism 900 can be designed to follow a similar operating philosophy, but with simpler cam profiles. The specific cam profile of this design is not explored in detail. The focus is on the behavior of the latching feature.

The actuation driver 942 includes castellations at one end. These castellations interface with protruding features from the actuation member 944. When the caliper is being activated, a high magnitude differential pressure is applied across the actuation driver 942. This causes the actuation driver 942 castellation flats and the actuation member 944 protruding flats to contact. This allows the actuation member 944 to be moved axially. Sufficient axial movement causes the locking features 980 in the actuation member 944 and collar 910 to engage. After applying the high magnitude differential pressure across the actuation driver 942, the pressure is decreased, causing the actuation driver 942 to return to its home position. The actuation driver 942 is rotated by 60 degrees on the return stroke due to the ramp of the cam profile.

To deactivate the caliper, a high magnitude differential pressure is reapplied across the actuation driver 942. However, the castellations are now aligned with flexible members 982 of the actuation member 944. This causes the flexible members 982 to contact an inner ramp on the actuation driver 942 castellations. As the actuation driver 942 moves axially, the flexible members 982 are elastically bent inward toward the center axis of the collar 910. This causes the locking features 980 to disengage, releasing the actuation member 944. After applying the high magnitude differential pressure across the actuation driver 942, the pressure is decreased, causing the actuation driver 942 to return to its home position. The actuation driver is rotated by 60 degrees on the return stroke due to the ramp of the cam profile.

FIG. 10 is an illustration of an example method for measuring a wellbore diameter using a wellbore caliper tool. At stage 1010, the caliper tool is installed on a drill string. For example, the drill string can include various modules coupled to each other. The caliper tool can be strategically installed based on the other modules and where the desired measurements will be taken. In one example, the caliper tool can be installed below a pump module so that the pump module can pump drilling fluid into the caliper tool necessary for activation. After installation, the caliper tool can be inserted into the wellbore as part of the wireline assembly.

At stage 1020, pressure in the bore is increased by increasing flow of drilling fluid through the drill string. For example, a pump module in the drill string can include a pump that pumps drilling fluid into the wellbore. The pressure level can be controlled at the surface. The pump can pump drilling fluid at a pressure that causes the caliper tool to activate according to predetermined specifications.

At stage 1030, when a threshold pressure for activation has been reached, the constraining members of the caliper tool fail, causing the actuation member to separate from the actuation driver. The actuation member and actuation driver can be castellated, and initially be locked together through interlocking castellations. The constraining members can keep the actuation member and actuation driver from separating. When the constraining member fails, and due to the pressure, the actuation member and actuation driver can axially separate until the castellations no longer interlock. In some examples, the actuation driver, or a subcomponent thereof, can move away from the actuation member while the actuation member remains in its position.

At stage 1040, the pressure can be reduced, causing the actuation member to move toward the actuation driver, thereby releasing a sliding block coupled to a measurement band. In one example, the actuation member can be coupled to a coil spring that exerts a force on the actuation member toward the actuation driver. The pressure is reduced to a level where the force of the coil spring can overcome the force of the fluid pressure. This causes the actuation member to move toward the actuation driver, releasing the sliding block. In one example, the actuation driver can include a cam profile that causes the actuation driver to rotate when the pressure drops.

At stage 1050, the position of the sliding blocks are recorded. For example, measurement bands can apply a force on sliding blocks in the caliper tool. When the sliding blocks are released, they are free to move axially along the caliper tool. This allows the measurement bands to extend away from the caliper tool toward the inner surface of the wellbore. When the measurement bands contact the inner surface of the wellbore, they stop extending away from the caliper tool, and consequently the corresponding sliding blocks come to rest as well. The positions of the sliding blocks in this resting position are then recorded.

In an example, the sliding block positions are recorded using magnetic sensors. For example, the caliper tool can include magnetic sensors that can measure electromagnetic fields. The sliding blocks can include magnets that create such an electromagnetic field. When the sliding blocks come to rest, the magnetic sensors measure the electromagnetic field created by the magnets in the blocks. The measurements can then be used to interpret the positions of the sliding blocks.

At stage 1060, the width of the wellbore is calculated. For example, the positions of the sliding blocks directly corresponds with how far the measurement bands extend from the caliper tool. The caliper tool can have multiple sets of measurement bands and sliding blocks. The caliper tool can be calibrated to calculate the width of the wellbore based on the sliding block positions. In one example, the magnetic sensors can send the recorded measurements to a computing device at the surface that interprets the measurements and calculates the wellbore width.

FIG. 11 is an example illustration of a downhole deployable offset module 1100 that can be used in conjunction with the embodiments discussed previously herein. The offset module 1100 includes a piston 1102 that separates a high-pressure region 1106 from a low-pressure region 1108. In an example, the high-pressure region 1106 can correspond to the bore in a wireline drilling assembly, and the low-pressure region 1108 can correspond to an annulus. Unintentional movement of the piston 1102 is controlled using constraining members 1112 designed to fail at a certain differential pressure. Window 1120 shows a close-up view of a constraining member 1112. The piston 1102 advances axially after the constraining members 1112 fail, and in the presence of a differential pressure.

A plurality of members 1110, referred to as blades 1110, are located near the perimeter of the offset module 1100 and are coupled to the piston 1102. Angled features 1114 in the collar, or in additional members, convert the axial advancement of the piston 1102 to radial deployment of the blades 1110. A ratchet ring 1116 wraps round the outer diameter of the piston 1102. The ratchet ring 1116 has an axial cut that allows the ratchet ring 1116 to expand in diameter. Thread features are cut into its inner diameter. The piston 1102 has complementary thread features cut into its diameter. The thread features of both the ratchet ring 1116 and piston 1102 have flank angles that are biased in one direction, f, but it is difficult to expand the ratchet ring 1116 over the piston 1102 in the opposite direction. The offset module 1100 can include a chamfer that also resists expansion of the ratchet ring 1116. Window 1122 shows a close-up view of the interface of the ratchet ring 1116 and the piston 1102.

The ratchet ring 1116 is linked to the piston 1102 such that the advancement of the piston 1102 easily expands the ratchet ring over 1116 the piston 1102. Conversely, any force moving the piston 1102 in the opposite direction is reacted by the ratchet ring 1116. This configuration allows the piston 1102 to move axially and deploy the blades 1110. However, force from the wellbore acting on the blades 1110 is not able to move the piston 1102 due to the ratchet ring 1116.

FIG. 12 is an illustration of an example method for deploying a downhole deployable offset module. At stage 1210, the offset module 1100 is installed on a drill string. For example, the drill string can include various modules coupled to each other. The offset module 1100 can be strategically installed to protect certain components of the drill string. As an example, an offset module 1100 can be installed on either end of a caliper tool, such as the caliper tools described previously herein. The blades 1110 can extend radially further than the measurement bands while the caliper tool is deactivated, thereby protecting the exposed measurement bands from contacting the surrounding rock formation. After installation, the offset module 1100 can be inserted into the wellbore as part of the wireline assembly.

At stage 1220, pressure in the bore is increased by flowing additional fluid through the drill string. The fluid can be any kind of fluid that can be pumped into a wellbore, such as water or drilling mud.

At stage 1230, when a threshold for activation has been reached, the constraining members 1112 fail, allowing the piston 1002 to advance. For example, the constraining members 1112 can prevent the piston 1102 from advancing. The constraining members 1112 can be designed to fail at a certain differential pressure. When that differential pressure is reached, the constraining members 1112 fail, causing the piston 1102 to release and advance in the direction of the force created by the pumped fluid.

At stage 1240, the piston 1102 deploys the blades 1110 outward radially as the piston 1002 advances. In an example, the outer surface of the piston 1102 is threaded with the inner surface of the ratchet ring 1116. As a result, the piston 1102 rotates axially as it advances. This can also control the speed of the piston's 1102 advance, and subsequently the speed at which the blades 1110 deploy. The piston 1102 can advance until the blades 1110 contact the surrounding rock formation. This centers the surrounding components of the wireline assembly in the wellbore and prevents those components from contacting the surrounding rock formation.

At stage 1250, the ratchet ring 1116 expands over each thread of the piston 1002 as the piston 1002 advances. After the blades 1110 are deployed, no further energization is required to keep the blades 1110 deployed because the ratchet ring 1116 resists any opposing motion from the piston 1102. The blades 1110 remain deployed until the offset module 1110 is reset at the surface.

It is possible for the blades 1110 to become caught at transitions in the wellbore. If this occurs, the ratchet ring 1116 is designed to function as a mechanical fuse that will fail if enough load is applied to the blades 1110. This failure protects the other components within the offset module 1100 and prevents the entire drill string from becoming caught.

Feedback from the offset module 1100 can be received as changes in pressure occur at the surface. If the deployed blades 1110 provide a significant restriction to annulus flow, then the deployment of the blades 1110 can be confirmed by a decrease in annulus pressure. Alternatively, the tattle-tale device 7770 can be implemented into the bore. This tattle-tale device 7770 can create a restriction in drill string flow when the piston 1102 advances. Advancement of the piston 1102, and by extension, the deployment of the blades 1110, can be confirmed by an increase in drill string bore pressure at the surface.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is understood that the control functionality can be carried out be a processor-enabled device, which can be separate from or part of the slot cutter, depending on the example. Also, the terms slot cutter and cutting device are used interchangeably. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. A wellbore caliper tool, comprising:

a collar;

measurement bands coupled to the collar, the measurement bands configured to extend radially away from the collar when activated;

sliding blocks, each of the sliding blocks being coupled to one of the measurement bands, the sliding blocks being configured to freely move axially within the collar when activated; and

an actuation mechanism,

wherein, when the wellbore caliper tool is deactivated, the actuating mechanism exerts a force on the sliding blocks that holds the measuring bands in a position that is flush or nearly flush to an outer surface of the collar.

2. The wellbore caliper tool of claim 1, wherein, when the wellbore caliper tool is activated, the actuating mechanism releases the sliding blocks, which causes the measurement bands to extend radially away from the outer surface of the collar and the sliding blocks to move axially based on a distance that the corresponding measurement bands extend.

3. The wellbore caliper tool of claim 2, wherein the sliding blocks include magnets, and the wellbore caliper tool includes electromagnetic sensors that measure positions of the magnets to determine the positions of the sliding blocks.

4. The wellbore caliper tool of claim 1, wherein the actuation mechanism comprises:

an actuation driver;

an actuation member; and

a constraining member.

5. The wellbore caliper tool of claim 4, wherein

the constraining member holds a dynamic member of the actuation driver in a first position when the wellbore caliper tool is deactivated, and

the dynamic member holds the actuation member in a second position when the wellbore caliper tool is deactivated.

6. The wellbore caliper tool of claim 5, wherein the wellbore caliper tool is activated by:

pumping fluid through the wellbore caliper tool at a pressure that causes the constraining member to fail and release the dynamic member, and

reducing the pressure of the pumped fluid so that a coil spring exerting a force on the actuation member causes the actuation member to move axially away from the sliding blocks.

7. The wellbore caliper tool of claim 5, wherein the dynamic member includes a cam profile that causes the dynamic member to rotate during activation and deactivation of the wellbore caliper tool.

8. A method for measure the width of a wellbore, comprising:

installing a wellbore caliper tool on drilling string, the wellbore caliper tool comprising: a collar, a measurement bands coupled to the collar, the measurement bands configured to extend radially away from the collar when activated, a sliding blocks, each of the sliding blocks being coupled to one of the plurality of measurement bands, the sliding blocks being configured to freely move axially within the collar when activated, and an actuation mechanism,

inserting the wellbore caliper tool into the wellbore;

pumping drilling fluid into the wellbore caliper tool at a first pressure above a first threshold pressure;

reducing the pumped drilling fluid to a second pressure below a second threshold pressure;

receiving measurements corresponding to positions of the sliding blocks; and

calculating the wellbore width based on the measurements.

9. The method of claim 8, wherein the actuation mechanism comprises:

a dynamic member;

an actuation member; and

a constraining member, wherein, when the wellbore caliper tool is deactivated, the constraining member holds dynamic member in place, and the dynamic member holds the sliding blocks in place.

10. The method of claim 9, wherein

pumping drilling fluid into the wellbore caliper tool at the first pressure causes a constraining member of the actuation mechanism to fail,

the constraining member failing causes the dynamic member to axially separate from the actuating member,

reducing the pumped drilling fluid to the second pressure causes the actuating member to move axially toward the dynamic member, and

the actuating member moving axially toward the dynamic member released the sliding blocks, which in turn causes the measurement bands to extend radially from the collar to an inner surface of the wellbore.

11. The method of claim 10, wherein a coil spring exerts a force on the actuating member that causes the actuating member to move axially toward the dynamic member when the drilling fluid is reduced to the second pressure.

12. The method of claim 10, wherein the wellbore width is calculated based on a known relationship between positions of each of the sliding blocks and a corresponding distance that the measurement bands extend from the collar.

13. The method of claim 8, wherein the measurements corresponding to positions of the sliding blocks are received from electromagnetic sensors and include measurements of an electromagnetic field created by magnets in the sliding blocks.

14. The wellbore caliper tool of claim 12, wherein the wellbore width is calculated using the measurements of the electromagnetic field created by the magnets in the sliding blocks.

15. An offset module that can be deployed in a wireline drilling assembly, comprising:

a piston that separates a high pressure region from a low pressure region;

a constraining member that controls unintended movement of the piston, the constraining member being designed to fail at a predetermined differential pressure;

blades coupled to the piston;

angled members coupled to each of the blades such that the angled members convert advancement of the piston to radial deployment of the blades; and

a ratchet ring wrapped around an outer surface of the piston that allows the piston to move axially in a single direction.

16. The offset module of claim 15, wherein the high pressure region corresponds to a bore in the wireline drilling assembly.

17. The offset module of claim 15, wherein the low pressure region corresponds to an annulus in the wireline drilling assembly.

18. The offset module of claim 15, wherein

the ratchet ring includes first thread features on an inner diameter of the ratchet ring,

the piston includes second thread features on an outer diameter of the piston, the second thread features being complementary to the first thread features, and

the first thread features and second thread features having flank angles that are biased in a single direction such that an axial force applied to the ratchet ring allows the ratchet ring to expand over the piston in the single direction.

19. The offset module of claim 15, wherein the piston advances axially in response to fluid being pumped into the offset module above a threshold differential pressure that causes the constraining member to fail.

20. The offset module of claim 15, wherein the ratchet ring fails when a load above a threshold load is applied to the blades.