Electromagnetic jarring tool

An electromagnetic jarring tool and related systems and methods provide for the use of an electromagnetic system to generate jarring forces within a wellbore. The electromagnetic jarring tool includes a chamber having a first end and a second end, a magnetic hammer disposed within the chamber, and an electromagnet operable to generate an electromagnetic field across at least a portion of the chamber. The magnetic hammer is operable to move toward the second end of the chamber in response to the electromagnetic field to deliver an impact. One or more electromagnets may be included to enhance operation of the tool, and the tool may be actuated by a surface controller that selectively delivers electrical power or a control signal to the tool to specify a mode of operation of the electromagnetic jarring tool.

FIELD OF THE INVENTION

The present disclosure relates generally to jarring tools for use in moving downhole tools within a wellbore.

DESCRIPTION OF RELATED ART

Wells are drilled at various depths to access and produce oil, gas, minerals, and other naturally-occurring deposits from subterranean geological formations. The drilling of a well is typically accomplished with a drill bit that is rotated within the well to advance the well by removing topsoil, sand, clay, limestone, calcites, dolomites, or other materials to form a wellbore. The drill bit is typically attached to a drill string that may be rotated to drive the drill bit and within which drilling fluid, referred to as “drilling mud” or “mud”, may be delivered downhole. The drilling mud is used to cool and lubricate the drill bit and downhole equipment and is also used to transport any rock fragments or other cuttings to the surface of the well.

After the wellbore is formed, tools may be deployed by, for example, wireline, slickline, or other conveyances. Wireline-delivered tools are suspended from a wireline that is electrically connected to control systems at the surface of the well, usually for the purposes gathering and conveying data about the formation, wellbore, or fluid in the wellbore. Slickline tools are similarly deployed into a wellbore but may not have an electrical connection to surface equipment. The tools may be deployed by first removing the drill string and then lowering the wireline and tools to an area of interest within the formation. The tools associated with wireline and slickline deployment may be used to measure pressure, temperature, and other properties of formation and wellbore fluids, and may require electric power to operate.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In addition to the types of downhole tools mentioned above, other downhole operations may also necessitate the use of downhole electrically powered systems and devices. Yet in some situations, it may be difficult, costly, or impractical to supply a dedicated power line or battery to such systems and devices. As a result, downhole tools may include mechanisms for generating power downhole. Such power generation mechanisms may include turbines that harvest kinetic energy from the fluid circulating through the wellbore, circuits that derive energy from steady-state tool vibrations, or similar systems derived from energy sources that operate at a steady state.

When tools used in drilling operations or in subsequent wireline and slickline operations become stuck, it may be necessary to deliver an impact to the stuck tool to free the tool and allow it to be repositioned or removed from a wellbore. Drilling, testing, and production equipment, for example, may become stuck in the wellbore and freed upon the application of sufficient impact delivered along the axis of the tool string. Such an impact may be referred to herein as an axial impact.

To deliver such an axial impact, a jar may be deployed within the tool string. For example, a “drilling jar” may be included in a drill string or a production string to free drilling or production equipment that becomes stuck in the wellbore. In operation, such a jar may be placed or installed in the tool string near the location of the stuck equipment and actuated to deliver an axial impact or series of axial impacts to dislodge the stuck equipment. Once the equipment is dislodged, drilling operations or production operations may continue.

Other types of jars may be inserted into a wellbore to retrieve a tool that has become lodged in a wellbore. Such jars may be referred to as “fishing jars”, and may include an attachment that couples the jar to the tool so that the jar may be actuated to deliver an impact to the tool to dislodge the tool from the wellbore. Similar jars may be included in slickline and wireline tool strings adjacent tool modules to free stuck tooling or to dislodge the tool string if it becomes stuck.

A typical jar may include a movable hammer and mandrel assembly that is enclosed but movable within a stationary housing. The housing may include a surface that is configured to absorb impact from the hammer, which may be referred to as an anvil. The jar may be actuated to cause the hammer to accelerate into the anvil, resulting an in impact and resultant force that is imparted to the housing body and adjacent tooling elements.

Typical jars include hydraulic jars, mechanical jars, mechanical-hydraulic jars, and bumper jars. Hydraulic jars and mechanical jars are typically configured to deliver an upward or downward force relative to the tool string, while bumper jars are typically configured to deliver a downward force. A typical bumper jar may be actuated by lifting and dropping a pipe, which in turn causes the hammer of the jar to strike the anvil to deliver an impact that results in a downward force. Conversely, mechanical, hydraulic, and mechanical-hydraulic jars typically include actuation mechanisms that activate in response to the application of a control signal, which may be a pressure pulse or an application of tensile strain to a cable or tool string from which the jar is deployed. The cable or tool string may be referred to herein as a conveyance. In operation of a mechanical, hydraulic, or mechanical-hydraulic jar to deliver an upward force, a tensile load is applied to the conveyance. The tensile load results in the storage of potential energy in the jar until the load exceeds a threshold magnitude, which results in actuation of the jar. Such jars may also be used to provide an upward impact by reversing the orientation of the jar and applying a compressive load to the conveyance.

The jars discussed above typically perform well in normal operating environments, but may not be well suited to deliver multiple impacts in heavy fluid, high pressure, or in deviated wells. Such wells may include segments of wellbore that vary from vertical to horizontal or near-horizontal. The present disclosure relates to an electromagnetic jarring tool that performs well in such environments and includes a triggering mechanism that is not materially affected by gravitational forces.

The electromagnetic jarring tool may include a chamber having a first end and a second end and a magnetic hammer disposed within the chamber. The chamber may be a vacuum chamber, an atmospheric chamber, or prefilled with a gas that does not interfere with the movement of the magnetic hammer. The electromagnetic jarring tool may also include an electromagnet, which may be a conductive coil that is operable to receive a current and generate an electromagnetic field across at least a portion of the chamber. Further, it is noted that while a conductive coil is described as an illustrative apparatus for generating an electromagnetic force to cause movement of the magnetic hammer, other types of electromagnets may be used. For example, a discrete electromagnet may be assembled at either end of the chamber described below to attract or repulse the electromagnetic hammer to generate jarring forces when the magnetic hammer strikes anvils within the hammer.

The magnetic hammer is operable to move toward the second end of the chamber in response to the electromagnetic field to deliver an impact. As such, the chamber and magnetic hammer may be formed to have complementary dimensions so that the magnetic hammer and chamber resemble a piston and cylinder, respectively, to allow for movement of the magnetic hammer from one end of the chamber to the other. In addition, the magnetic hammer and chamber may be formed with complementary alignment features to ensure that the magnetic hammer moves through the chamber along the axis of the chamber. Such alignment features may include, for example, one or more projections and complementary grooves that slidably engage one another to allow constrained movement of the magnetic hammer within the chamber. The grooves and protrusions may be formed on the interior surface of the chamber and exterior surface of the magnetic hammer, respectively. In another embodiment, the grooves and protrusions may be formed on the exterior surface of the magnetic hammer and interior surface of the chamber, respectively. In an embodiment, a low-friction interface may be provided between the magnetic hammer and the cylinder. Such a low-friction interface may be a lubricant, a low-friction layer applied to one or both of the magnetic hammer and chamber, a low-friction coating applied to one or both of the magnetic hammer and chamber, or any combination of the foregoing.

Referring now to the Figures,FIGS. 1A-1Cshow an illustrative embodiment of a downhole system100that includes an electromagnetic jarring tool170. The downhole system100is used in a well102having a wellbore104that extends from a surface108of the well to or through a subterranean geological formation112. The well102is illustrated onshore inFIG. 1Awith the system100being deployed in a land-based well. Alternatively, the system100may be deployed as part of a wireline assembly115(seeFIG. 1B), either onshore or off-shore. The wireline assembly115includes a winch117to lift and lower a downhole portion of the wireline assembly115into the well. In still another embodiment, the system100may be deployed in a subsea well119(seeFIG. 1C) accessed by a fixed or floating platform121.FIGS. 1A-1Ceach illustrate these possible uses of the system100, and while the following description of the system100and associated energy harvesting subsystems focuses primarily on the use of the system100in the drill string120ofFIG. 1A, the system100may be used instead in the well configurations illustrated inFIGS. 1B and 1C, as well as in other well configurations where it is desired to harvest energy downhole. Similar components inFIGS. 1A-1Care identified with similar reference numerals.

In the embodiment illustrated inFIG. 1A, the well102is formed by a drilling process in which a drill bit116is turned by a drill string120that extends the drill bit116from the surface108to the bottom of the well102. The drill string120may be made up of one or more connected tubes or pipes of varying or similar cross-section. The drill string may refer to the collection of pipes or tubes as a single component, or alternatively to the individual pipes or tubes that comprise the string. The term drill string is not meant to be limiting in nature and may refer to any component or components that are capable of transferring energy from the surface of the well to the drill bit. In several embodiments, the drill string120may include a central passage disposed longitudinally in the drill string and capable of allowing fluid communication between the surface of the well and downhole locations.

At or near the surface108of the well, the drill string120may include or be coupled to a kelly128. The kelly128may have a square, hexagonal or octagonal cross-section. The kelly128is connected at one end to the remainder of the drill string and at an opposite end to a rotary swivel132. The kelly passes through a rotary table136that is capable of rotating the kelly and thus the remainder of the drill string120and drill bit116. The rotary swivel132allows the kelly128to rotate without rotational motion being imparted to the rotary swivel132. A hook138, cable142, traveling block (not shown), and hoist (not shown) are provided to lift or lower the drill bit116, drill string120, kelly128and rotary swivel132. The kelly128and swivel132may be raised or lowered as needed to add additional sections of tubing to the drill string120as the drill bit116advances, or to remove sections of tubing from the drill string120if removal of the drill string120and drill bit116from the well102is desired.

A reservoir144is positioned at the surface108and holds drilling mud148for delivery to the well102during drilling operations. A supply line152is fluidly coupled between the reservoir144and the inner passage of the drill string120. A pump156drives fluid through the supply line152and downhole to lubricate the drill bit116during drilling and to carry cuttings from the drilling process back to the surface108. After traveling downhole, the drilling mud148returns to the surface108by way of an annulus160formed between the drill string120and the wellbore104. At the surface108, the drilling mud148is returned to the reservoir144through a return line164. The drilling mud148may be filtered or otherwise processed prior to recirculation through the well102.

The electromagnetic jarring tool170may be positioned downhole adjacent a downhole tool172or work piece to prevent the tool172or work piece from becoming lodged in the wellbore104or to dislodge the tool172in the event the tool172becomes stuck. Electromagnetic jarring tool170may include threaded connections or similar connections at each end to allow for insertion into a tool string or coupling to a discrete tool.

The tool172may be any number of downhole tools. For example, the tool172may be a measurement device that measures temperature, pressure, acceleration, or forces that are experienced by the tool172. While the electromagnetic jarring tool170and tool172are illustrated as a part of the drill string120inFIG. 1A, in other embodiments, the electromagnetic jarring tool170may be lowered into the well by wireline103(seeFIG. 1B), slickline, or any other suitable conveyance, either through the central passage of the drill string120, or if the drill string120is not present, directly through the wellbore104. As described in more detail below, the electromagnetic jarring tool170and tool172may include a communications subsystem, including a transceiver for communicating using mud pulse telemetry or another suitable method of wired or wireless communication with a surface controller. The transceiver may transmit data gathered by the tool172or receive instructions from a well operator via the surface controller to operate the tool172or electromagnetic jarring tool170.

The electromagnetic jarring tool170is an electromagnetically-actuated apparatus that delivers an impact load to another object within a drill string120, completion string, or other tool string deployed in the wellbore104. The electromagnetic jarring tool170may be used to free a stuck object or to set the tool172. Generally, the electromagnetic jarring tool170includes a movable element, which may be a magnetic hammer that is activated to generate an impact on a stationary member. The stationary member may be an anvil or impact surface at either end of a chamber or housing that encloses the movable element. The electromagnetic jarring tool170may be actuated by activating an electromagnetic field that results in the application of an electromagnetic force against the magnetic hammer to generate an impact when the magnetic hammer collides with the stationary member. The electromagnetic jarring tool170can be actuated multiple times as needed and generate an impact in either direction along the tool string, regardless of the orientation of the wellbore.

FIGS. 2A-2Cshow an illustrative embodiment of an electromagnetic jarring tool170as it transitions from a pre-actuated stateFIG. 2A, to a first actuated state inFIG. 2B, and a second actuated state inFIG. 2C. to generate jarring forces toward either end of the electromagnetic jarring tool170. The electromagnetic jarring tool170may be deployed in the wellbore by a conveyance, which may be a drill string, wireline, slickline, or other conveyance. The electromagnetic jarring tool170includes a housing202, which may be a generally cylindrical housing included within a tool string. Within the housing, the electromagnetic jarring tool170includes a chamber204having a first end216and a second end218. Each of the first end216and second end218may include an anvil220to absorb and transfer impacts that generate jarring forces to the tool string120and an adjacent tool172.

The aforementioned impacts are generated by collisions between the anvils220and a magnetic hammer206. The magnetic hammer206may be formed from a permanent magnet, an electromagnetic, a magnetized material, a ferromagnetic material, or any combination of the foregoing that renders the magnetic hammer206susceptible to an electromagnetic force.

In an embodiment, the magnetic hammer206is enclosed within the chamber204, and operable to slide between the first end216and the second end218. To minimize resistance or fluid effects on the movement of the magnetic hammer206, the chamber204may be an atmospheric chamber, a vacuum chamber, or another chamber prefilled with a low-density fluid that does not significantly resist movement of the magnetic hammer206. In an embodiment, the configuration of the chamber204allows the magnetic hammer206to move freely in either direction within the chamber204without contact with well fluids.

To actuate the magnetic hammer204, the electromagnetic jarring tool170includes at least a first conductive coil208that is wrapped around at least a portion of the chamber204. In an embodiment, the first conductive coil208is wrapped around the chamber204from approximately the first end216to the second end218. The first conductive coil208is operable to receive a current that flows through the first conductive coil208and around the chamber204to generate a magnetic field212within the chamber204to impart an electromagnetic force on the magnetic hammer206. The direction of current flow through the first conductive coil208and resultant magnetic field212generates an upward or downward electromagnetic force on the magnetic hammer206, depending on the polarity of the magnetic hammer206. For example, where the magnetic field212has a positive polarity facing downward, and a top surface of the magnetic hammer206is positively polarized, the electromagnetic force propels the magnetic hammer206downward to impact the second end218of the chamber204. Conversely, where the magnetic field212has a negative polarity facing downward, and the top surface of the magnetic hammer206is positively polarized, the electromagnetic force propels the magnetic hammer206upward to impact the first end216of the chamber204, as shown inFIG. 2B.

In an embodiment, the electromagnetic jarring tool170also includes a second conductive coil210, which may be configured to operate in unison with the first conductive coil208, or to generate a second magnetic field214that opposes the first magnetic field212. In such an embodiment, current may be alternatingly provided to the first conductive coil208and second conductive coil210to effectuate magnetic fields212,214that selectively motivate the magnetic hammer206toward the first end216or second end218of the chamber204.

In operation, the electromagnetic jarring tool170may be actuated without any mechanical manipulation of the wireline from the surface, and the electromagnetic jarring tool170may be actuated within a tool string while tension remains applied to the tool string to provide additional force to free a stuck object. The actuation of the magnetic hammer206is controllable by the application of electric current from the surface, or from the application of electric current from a local power source in response to a control signal received from the surface. The current may be selectively applied to one or more conductive coils to cause the magnetic hammer to move in either direction. In addition, the current may be varied in magnitude to controllably select the magnitude of the impact, or impacts, delivered by the electromagnetic jarring tool170. In general, higher current may be understood to result in severe impacts and greater impact forces applied to adjacent tools or the tool string that includes the electromagnetic jarring tool170. In addition, the electromagnetic jarring tool170may vary in the length of travel and mass of the magnetic hammer206to allow for the achievement of relatively heavy jarring. Similarly, the current may be supplied at a low rate for relatively light or delicate jarring.

In an embodiment, the electromagnetic jarring tool170may be configured such that the magnetic hammer206is self-centering. Self-centering may be achieved by including an additional, relatively low-power conductive coil or electromagnet that causes the magnetic hammer to return to a pre-actuated position, which may be at the center of the chamber204or at an end of the chamber that is opposite the anvil that is intended to be impacted in the case of unidirectional jarring. In another embodiment, multiple conductive coils may be used to apply equivalent electromagnetic forces to each side of the magnetic hammer206until the magnetic hammer206comes to rest at the center of the chamber204. In addition, the electromagnetic jarring tool170may be reinitialized by alternatively applying small amounts of current to generate an electromagnetic force to urge the magnetic hammer206away from the end of the chamber204at which impact is desired, or by continuously supplying current to a low-powered electromagnet that causes the magnetic hammer206to return to its pre-actuated position.

FIG. 3shows an alternative embodiment of an electromagnetic jarring tool300that is similar in many respects to the electromagnetic jarring tool170described above with regard toFIGS. 2A-2C. The electromagnetic jarring tool300includes a housing302, which may be a generally cylindrical housing included within a tool string. In an embodiment, the housing302may be formed to have the shape of an annulus so that it can be deployed as a segment of a drill string that allows fluids to flow through a conduit formed by the housing302. In another embodiment, the housing302may have any other shape or profile, such a cylindrical profile or a rectangular profile and be sized to have a cross section that is smaller than the cross section of a drill string so that the electromagnetic jarring tool may be deployed within a drill string.

Within the housing302, the electromagnetic jarring tool300includes a chamber304having a first end316and a second end318. Each of the first end316and second end318may include an anvil320to absorb impacts that impart jarring forces to the tool string and adjacent tools or other objects when the magnetic hammer306collides with the anvils320. Again, the magnetic hammer306may be formed from a permanent magnet, an electromagnet, a magnetized material, a ferromagnetic material, or any combination of the foregoing that renders the magnetic hammer306susceptible to an electromagnetic force. The magnetic hammer306is enclosed within the chamber304, and operable to slide between the first end316and the second end318. The chamber304may be an atmospheric chamber, a vacuum chamber, or another chamber prefilled with a low-density fluid that does not significantly resist movement of the magnetic hammer306.

To actuate the magnetic hammer306, the electromagnetic jarring tool300includes a first electromagnet310installed adjacent the first end316of the chamber304and a second electromagnet311installed adjacent the second end318of the chamber304. In another embodiment, a single electromagnet may be used in place of the first electromagnet310and second electromagnet311. The first electromagnet310and second electromagnet311are operable to apply an electromagnetic force, as indicated by the arrow312to move the magnetic hammer306from one end of the chamber304to the other.

The magnitude and direction of the electromagnetic force may be controlled by a controller324that is coupled to a power source322to supply power to the electromagnets. In turn, the controller324is communicatively coupled to a surface controller via a control line308. The surface controller may generate a control signal to the controller324to specify a mode of operation of the electromagnetic jarring tool300, as described in more detail below. In another embodiment, the controller324and power source322may be omitted and the surface controller may be directly coupled to the electromagnets to supply power from a remote power source to operate the electromagnets. Like the electromagnetic jarring tool170described above with regard toFIGS. 2A-2C, the first electromagnet310and second electromagnet311may generate an upward or downward electromagnetic force on the magnetic hammer306, depending on the polarity of the magnetic hammer306. Depending on the specified mode of operation, the first electromagnet310and second electromagnet311may be operated to controllably cause the magnetic hammer to collide with the anvils320to generate the desired jarring forces. To cause the magnetic hammer306to self-center or return to a pre-actuated position within the chamber304, a third electromagnet or a permanent magnet326that generates a relatively weak magnetic field (relative to the electromagnets) may be included near the center of the chamber or at a location that corresponds with the pre-actuated position of the magnetic hammer306to facilitate repeated activation of the electromagnetic jarring tool300.

In accordance with the foregoing disclosure, an electromagnetic jarring tool is disclosed that includes a chamber having a first end and a second end and a magnetic hammer disposed within the chamber. The electromagnetic jarring tool also includes at least one conductive coil operable to receive a current and generate an electromagnetic field across at least a portion of the chamber. In an embodiment, the magnetic hammer is operable to move toward the second end of the chamber in response to the electromagnetic field to deliver an impact when the magnetic hammer strikes an anvil at the second end of the chamber. The electromagnetic jarring tool may also include a second conductive coil operable to receive a current and generate a second electromagnetic field across at least a portion of the chamber. In such an embodiment, an electromagnetic force generated by the second electromagnetic field may opposes an electromagnetic force of the first electromagnetic field, and the magnetic hammer may be operable to move toward the first end of the chamber in response to the second electromagnetic field to deliver an impact. Such a configuration results in an electromagnetic jarring tool that is operable to deliver an impact in either direction along a tool string.

In another embodiment, the a jarring tool may be constructed approximately as described above, but including a chamber that provides a range of travel for a magnetic hammer that is perpendicular to axis of the tool string. Such a configuration may provide for horizontal jarring forces that typical jar configurations are unable to provide.

Further, in accordance with any of the embodiments described above, the electromagnetic jarring tool may be configured to be self-centering by including a default state for the magnetic fields generated by the first conductive coil or the first conductive coil and second conductive coil to motivate the magnetic hammer toward the center of the chamber.

The electromagnetic jarring tools may be included in a jarring system that also includes a power source and a controller electrically coupled to the power source and the conductive coil (or coils) of the electromagnetic jarring tool. The controller may be a surface controller that is part of a control system that actuates the jarring tool, and may be coupled to the power source to provide current to the conductive coils from the power source. In another embodiment, the surface controller may be coupled to an onboard controller via a control line. The onboard controller may be included in the electromagnetic jarring tool with a local power source that is included within the tool or tool string such that the surface controller may cause the onboard controller to actuate the jarring tool by controlling the flow of current to the conductive coils from the local power source.

An operator at the surface controller may specify a mode of operation that specifies the frequency of jarring impacts, the direction of jarring impacts, and the magnitude of jarring impacts. Based on the specified mode of operation, the surface controller may cause current to flow to the conductive coils that causes the magnetic hammer to move within the chamber to generate the specified impacts. In another embodiment, the surface controller may generate and transmit a control signal to an onboard controller that controls the flow of current to the conductive coils and cause the magnetic hammer to generate impacts that are consistent with the specified mode of operation.

As described above, the application of current to the conductive coils generates a magnetic field to motivate the magnetic hammer the first end of a chamber of the tool and the second end of the chamber to provide jarring forces of the desired magnitude in either direction along the axis of travel of the magnetic hammer. In an embodiment, the jarring forces may be applied in each direction along the axis of a generally cylindrical tool string. Such a tool string may be deployed by any suitable conveyance, which may be a slick line, a wireline, a drill string, or any other suitable tool string.

According to another illustrative embodiment, a method for operating an electromagnetic jarring tool includes applying a current to conductive coils of the electromagnetic jarring tool to activate an electromagnetic field and apply an electromagnetic force to a magnetic hammer included within the tool. The electromagnetic force causes the magnetic hammer to deliver one or more impacts to the first end of the chamber, one or more impacts to the second end of the chamber, or one or more impacts to both ends of the chamber. In an embodiment, the method includes delivering a control signal from a surface controller to a power source to cause current to flow through conductive coils in the electromagnetic jarring tool. The method may also include reversing the direction of current flow through the conductive coils to reverse the direction of the electromagnetic field and electromagnetic force such that the reversed electromagnetic force causes the magnetic hammer to move in the opposite direction.

The method may also include applying a current to a second conductive coil to activate a second electromagnetic field and a second electromagnetic force that oppose the electromagnetic field and electromagnetic force. In accordance with such an embodiment, the controller may be operable to apply a current to the second conductive coil, such that the the second electromagnetic force will cause the magnetic hammer to deliver a second one or more impacts to the second end of the chamber. Such a method may also include simultaneously applying current to the first conductive coil and second conductive coil to center the magnetic hammer in the chamber.

In an embodiment, the method includes delivering a control signal from an onboard controller to a power source to cause the power source to apply current to the conductive coil or second conductive coil. The method may include using the surface controller to transmit a control signal to the onboard controller via a control line or using a wireless communication protocol, such as mud-pulse telemetry or a similar communications protocol.

The method may also include delivering an impact to the first end of the chamber by applying an impact to a tool string.

The illustrative systems, methods, and devices described herein may also be described by the following examples:

Example 1. An electromagnetic jarring tool comprising:a chamber having a first end and a second end;a magnetic hammer disposed within the chamber; andan electromagnet operable to generate an electromagnetic field across at least a portion of the chamber;wherein the magnetic hammer is operable to move toward the second end of the chamber in response to the electromagnetic field to deliver an impact.

Example 2. The electromagnetic jarring tool of Example 1, wherein the electromagnet comprises a conductive coil surrounding at least a portion of the chamber.

Example 3. The electromagnetic jarring tool of Example 1, further comprising:a second electromagnet operable to receive a current and generate a second electromagnetic field across at least a portion of the chamber;wherein an electromagnetic force of the second electromagnetic field opposes an electromagnetic force of the first electromagnetic field; andwherein the magnetic hammer is operable to move toward the first end of the chamber in response to the second electromagnetic field to deliver an impact.

Example 4. The electromagnetic jarring tool of Example 3, wherein the second electromagnet comprises a second conductive coil surrounding at least a portion of the chamber.

Example 5. The electromagnetic jarring tool of Example 1, further comprising:a second electromagnet operable to receive a current and generate a second electromagnetic field across at least a portion of the chamber;wherein an electromagnetic force of the second electromagnetic field opposes an electromagnetic force of the first electromagnetic field; andwherein the magnetic hammer is operable to move toward the center of the chamber in response to simultaneous activation of the electromagnetic field and the second electromagnetic field.

Example 6. The electromagnetic jarring tool of Example 5, wherein the second electromagnet comprises a second conductive coil surrounding at least a portion of the chamber.

Example 7. The electromagnetic jarring tool of Example 1, wherein the magnetic hammer comprises a permanent magnet.

Example 8. The electromagnetic jarring tool of Example 1, wherein the magnetic hammer comprises a permanent magnet and a ferromagnetic material.

Example 9. The electromagnetic jarring tool of Example 1, wherein the magnetic hammer includes a projection and wherein the chamber comprises a groove that complements the projection.

Example 10. The electromagnetic jarring tool of Example 1, further comprising a low-friction interface between an outer surface of the magnetic hammer and an inner surface of the chamber.

Example 11. An electromagnetic jarring system comprising:an electromagnetic jarring tool having a chamber, a magnetic hammer disposed within the chamber and operable to move between a first end and a second end of the chamber, and an electromagnet operable to generate an electromagnetic field across at least a portion of the chamber;a power source; anda controller electrically coupled to the power source and the electromagnet.

Example 12. The electromagnetic jarring system of Example 11, wherein the electromagnet comprises a conductive coil that surrounds at least a portion of the chamber.

Example 13. The electromagnetic jarring system of Example 11, wherein the controller is a surface controller.

Example 14. The electromagnetic jarring system of Example 11, wherein the controller is operable to apply a current to the electromagnet to motivate the hammer between the first end of the chamber and the second end of the chamber.

Example 15. The electromagnetic jarring system of Example 11, further comprising a second electromagnet coupled to the controller, wherein the controller is operable to apply a current to the second electromagnet to motivate the hammer between the first end of the chamber and the second end of the chamber.

Example 16. The electromagnetic jarring system of Example 15, wherein the second electromagnet comprises a second conductive coil that surrounds at least a second portion of the chamber.

Example 17. The electromagnetic jarring system of Example 11, further comprising a third electromagnet positioned at or near a pre-actuated position of the magnetic hammer.

Example 18. The electromagnetic jarring system of Example 11, wherein the controller is an onboard controller and the power source is an onboard power source, and wherein the controller is coupled to a control line.

Example 19. The electromagnetic jarring system of Example 18, wherein the electromagnetic jarring tool is coupled to a conveyance selected from the group consisting of: a slick line, a wireline, and a drill string.

Example 20. The electromagnetic jarring system of Example 19, wherein the onboard controller is operable to receive a control signal from the conveyance, the control signal specifying a mode of operation.

Example 21. A method for operating an electromagnetic jarring tool having a chamber, a magnetic hammer disposed within the chamber and operable to move between a first end and a second end of the chamber, and an electromagnet operable to generate an electromagnetic field across at least a portion of the chamber, the method comprising:using the electromagnet to apply an electromagnetic force to the magnetic hammer, the electromagnetic force causing the magnetic hammer to deliver an impact to the first end of the chamber.

Example 22. The method of Example 21, wherein using the electromagnet to apply the electromagnetic force comprises delivering a control signal from a surface controller to a power source.

Example 23. The method of Example 22, further comprising reversing the direction of current provided to the electromagnet to reverse the direction of the electromagnetic field and electromagnetic force, the reversed electromagnetic force causing the magnetic hammer to deliver a second impact to the second end of the chamber.

Example 24. The method of Example 21, further comprising using a second electromagnet to generate a second electromagnetic force that opposes the electromagnetic force to cause the magnetic hammer to deliver a second impact to the second end of the chamber.

Example 25. The method of Example 24, further comprising simultaneously applying the current and second current to center the magnetic hammer in the chamber.

Example 26. The method of Example 21, wherein using the electromagnet to apply an electromagnetic force comprises providing a current to a conductive coil that surrounds at least a portion of the chamber to form the electromagnet.

Example 27. The method of Example 26, wherein using the electromagnet to apply an electromagnetic force comprises delivering a control signal from an onboard controller to a power source.

Example 28. The method of Example 21, wherein applying the current to the conductive coil comprises transmitting a control signal from a surface controller to the onboard controller via a control line.

Example 29. The method of Example 21, wherein causing the magnetic hammer to deliver the impact to the first end of the chamber comprises applying an impact to a tool string.

It should be apparent from the foregoing that an invention having significant advantages has been provided. While the invention is shown in only a few of its forms, it is not limited to only these embodiments but is susceptible to various changes and modifications without departing from the spirit thereof.