Patent Description:
A mechanically locking hydraulic jar device is configured to impart an impact force on other components secured directly or indirectly to the hydraulic jar device, such as a drill bit that has been immobilized or stuck within a wellbore. The hydraulic jar device includes a mechanical lock that prevents the hydraulic jar device from being unintentionally activated. The hydraulic jar includes an outer sleeve and an inner sleeve partially disposed within an inner bore of the outer sleeve. In a default position, the mechanical lock engages the outer sleeve and the inner sleeve to prevent axial movement of the inner sleeve relative to the outer sleeve. The mechanical lock maintains the hydraulic jar in the default position until a user intentionally activates the hydraulic jar to disable the mechanical lock, thereby allowing axial movement between the inner sleeve and the outer sleeve. For example, the inner sleeve may axially slide relative to the outer sleeve to place the hydraulic jar in an activated position. The hydraulic jar may also include an upward block and a downward block configured to limit the upward and downward axial movement, respectively, of the inner sleeve relative to the outer sleeve when the mechanical lock has been disabled. The hydraulic jar may be activated by applying an upward force on the outer sleeve or a downward force on the inner sleeve. Alternatively, the hydraulic jar may include a ball seat on the inner sleeve, and the hydraulic jar may be activated by engaging the ball seat with a ball that is pumped through the hydraulic jar. The ball can be made of dissolvable material, such as magnesium, a dissolvable rubber, or a dissolvable polymer. The ball fluidly seals an inner bore of the inner sleeve such that continued pumping of fluid applies a downward force on the inner sleeve.

With reference to <FIG>, mechanically locking hydraulic jar <NUM> may include outer sleeve <NUM> and inner sleeve <NUM> partially disposed within inner bore <NUM> of outer sleeve <NUM>. In the embodiment illustrated, a lower end of inner sleeve <NUM> extends beyond a lower end of outer sleeve <NUM>. Inner sleeve <NUM> includes an inner bore <NUM>.

Referring again to <FIG>, inner sleeve <NUM> includes upper inner sleeve segment <NUM> and lower inner sleeve segment <NUM>. Upper inner sleeve segment <NUM> is completely disposed within inner bore <NUM> of outer sleeve <NUM>, while lower inner sleeve segment <NUM> is partially disposed within inner bore <NUM> of outer sleeve <NUM>. Upper inner sleeve segment <NUM> extends from upper end <NUM> of inner sleeve <NUM> to lower end <NUM> of upper inner sleeve segment <NUM>. The outer surface of upper inner sleeve segment <NUM> includes recess <NUM> forming cavity <NUM> between outer sleeve <NUM> and inner sleeve <NUM>. Cavity <NUM> may extend from upper cavity shoulder <NUM> to lower cavity shoulder <NUM> of the outer surface of upper inner sleeve segment <NUM>. Lower inner sleeve segment <NUM> extends from upper end <NUM> secured to lower end <NUM> of upper inner sleeve segment <NUM> to lower end <NUM> of inner sleeve <NUM>. The outer surface of lower inner sleeve segment <NUM> includes expanded diameter section <NUM> disposed below the lower end of outer sleeve <NUM>. Expanded diameter section <NUM> forms upward facing shoulder <NUM>. Upper and lower inner sleeve segments <NUM>, <NUM> may be secured together by threaded connection.

With reference still to <FIG>, outer sleeve <NUM> includes inward protrusion <NUM> extending radially inward from the surface of inner bore <NUM> of outer sleeve <NUM>. Inward protrusion <NUM> is formed by a reduced diameter section of the inner surface of inner bore <NUM> of outer sleeve <NUM>. Inward protrusion <NUM> is axially aligned with cavity <NUM>. In other words, inward protrusion <NUM> extends into cavity <NUM>. Throttling rings <NUM> and <NUM> are disposed in cavity <NUM>, with throttling ring <NUM> above inward protrusion <NUM> and throttling ring <NUM> below inward protrusion <NUM>. Upper cavity <NUM> is formed between upper cavity shoulder <NUM> and throttling ring <NUM>, and lower cavity <NUM> is formed between throttling ring <NUM> and lower cavity shoulder <NUM>. In the default position as shown in <FIG>, upper cavity <NUM> is larger than lower cavity <NUM>. A hydraulic fluid may be disposed within cavity <NUM>. Throttling ring <NUM> is configured to restrict the flow of hydraulic fluid from upper cavity <NUM> to lower cavity <NUM> when hydraulic jar <NUM> is under tension. When the hydraulic fluid flows past throttling ring <NUM> and into lower cavity <NUM>, hydraulic jar <NUM> generates a downward impact. Throttling ring <NUM> is configured to restrict the flow of hydraulic fluid from lower cavity <NUM> to upper cavity <NUM> when hydraulic jar <NUM> is under compression in an activated position (described in more detail below). When hydraulic fluid flows past throttling ring <NUM> and into upper cavity <NUM>, hydraulic jar <NUM> generates an upward impact.

Outer sleeve <NUM> may also include first outer sleeve segment <NUM>, anchor outer sleeve segment <NUM> disposed below first outer sleeve segment <NUM>, second outer sleeve segment <NUM> disposed below anchor outer sleeve segment <NUM>, and lower outer sleeve segment <NUM> disposed below second outer sleeve segment <NUM>. Inward protrusion <NUM> may be disposed on anchor outer sleeve segment <NUM>. Throttling ring <NUM> may be secured between lower end <NUM> of first outer sleeve segment <NUM> and inward protrusion <NUM>. Throttling ring <NUM> may be secured between inward protrusion <NUM> and upper end <NUM> of second outer sleeve segment <NUM>. Inner bore <NUM> of lower outer sleeve segment <NUM> has a diameter that is smaller than the diameter of the inner bores of first and second outer sleeve segments <NUM>, <NUM>. Hydraulic jar <NUM> may further include top sub <NUM> connected above first outer sleeve segment <NUM>. Top sub <NUM> is configured to attach hydraulic jar <NUM> below a tubular member or a coiled tubing string. Segments <NUM>, <NUM>, <NUM>, <NUM> and top sub <NUM> may be secured together by threaded connection. The lower end of inner sleeve <NUM> is configured to attach one or more components below hydraulic jar <NUM>, such as a measurement while drilling sub, a drilling motor, and/or a drill bit.

Referring now to <FIG> and <FIG>, hydraulic jar <NUM> includes a mechanical lock that prevents the hydraulic jar device from being unintentionally activated. In the embodiment illustrated in <FIG>, the mechanical lock includes shear pins <NUM>, <NUM>. The mechanical lock may include any number of shear pins, such as <NUM>-<NUM> shear pins. Lower outer sleeve segment <NUM> includes one or more radial bores <NUM>. The outer surface of lower inner sleeve segment <NUM> includes one or more recesses <NUM>. In the default position shown in <FIG>, each recess <NUM> is aligned with one of the radial bores <NUM> and each of shear pins <NUM>, <NUM> are partially disposed within a radial bore <NUM> in outer sleeve <NUM> and partially disposed within a recess <NUM> in inner sleeve <NUM>. In this way, shear pins <NUM>, <NUM> engage inner and outer sleeves <NUM>, <NUM> in the default position to prevent axial movement between outer and inner sleeves <NUM>, <NUM>.

Hydraulic jar <NUM> may be activated by applying a downward force on inner sleeve <NUM> or by applying a downward or an upward force on top sub <NUM> and outer sleeve <NUM>. When the downward or upward force exceeds a threshold, the mechanical lock is disabled to allow relative axial movement between inner sleeve <NUM> and outer sleeve <NUM>. The movement of inner sleeve <NUM> relative to outer sleeve <NUM> generates an impact force, which is transmitted to the components attached to hydraulic jar <NUM>.

With reference to <FIG>, activation of hydraulic jar <NUM> may cause shear pins <NUM>, <NUM> to be severed into segments 66A, 68A held in radial bores <NUM> of lower outer sleeve segment <NUM> and segments 66B, 68B held in recesses <NUM> of lower inner sleeve segment <NUM>, respectively. The severing of shear pins <NUM>, <NUM> allows inner sleeve <NUM> to move axially relative to outer sleeve <NUM>.

Referring now to <FIG>, the downward and upward axial movement of inner sleeve <NUM> (in the orientation shown) relative to outer sleeve <NUM> is limited by a downward block and an upward block, respectively, when the mechanical lock is disabled. The upward block may be formed by lower end <NUM> of top sub <NUM>, which is disposed within inner bore <NUM> of outer sleeve <NUM>. Lower end <NUM> of top sub <NUM> is configured to engage upper end <NUM> of inner sleeve <NUM> to limit the upward movement of inner sleeve <NUM>. In the default position shown in <FIG>, upper end <NUM> of inner sleeve <NUM> abuts lower end <NUM> of top sub <NUM>. The downward block may be formed by upper end <NUM> of lower outer sleeve segment <NUM>, which is configured to engage lower end <NUM> of upper inner sleeve segment <NUM> to limit the downward movement of inner sleeve <NUM> relative to outer sleeve <NUM>. In other embodiments, hydraulic jar <NUM> may have other configurations including an upward block and a downward block formed of any other components of an inner sleeve and an outer sleeve that are arranged to limit the upward and downward axial movement of inner sleeve <NUM> relative to outer sleeve <NUM>.

With reference to <FIG>, inner sleeve <NUM> may slide axially relative to outer sleeve <NUM> until reaching an activated position (shown in <FIG>). In this embodiment, lower end <NUM> of upper inner sleeve segment <NUM> engages upper end <NUM> of lower outer sleeve segment <NUM> (i.e., the downward block) in the activated position. When pulling with the drill string on top sub <NUM>, inner sleeve <NUM> slides downward (in the illustrated orientation), upper cavity shoulder <NUM> applies a downward force on a hydraulic fluid held in upper cavity <NUM>. This causes a portion of the hydraulic fluid to flow through a small space between the outer surface of upper inner sleeve segment <NUM> and throttling ring <NUM>. In this way, the hydraulic fluid is transferred from upper cavity <NUM> to lower cavity <NUM> as inner sleeve <NUM> slides axially downward relative to outer sleeve <NUM>. In the activated position shown in <FIG>, lower cavity <NUM> is larger than upper cavity <NUM>. An impact force is created when the small space between the outer surface of upper inner sleeve segment <NUM> and throttling ring <NUM> opens up and the hydraulic fluid can flow freely from upper cavity <NUM> to lower cavity <NUM> and lower end <NUM> of upper inner sleeve segment <NUM> strikes upper end <NUM> of lower outer sleeve segment <NUM> to stop the downward axial movement of inner sleeve <NUM>. This impact force is transmitted to components connected above and below hydraulic jar <NUM>. A user may activate hydraulic jar <NUM> in order to create an impact force or impact load to loosen a portion of a tubular string or bottom hole assembly that is stuck or immobilized in an area of a wellbore.

<FIG> illustrates mechanically locking hydraulic jar <NUM>. Except as otherwise described, hydraulic jar <NUM> includes the same components, features, and functions as hydraulic jar <NUM>. Hydraulic jar <NUM> may include outer sleeve <NUM> and inner sleeve <NUM> partially disposed within inner bore <NUM> of outer sleeve <NUM>. Inner sleeve <NUM> includes inner bore <NUM>. Except as otherwise noted, inner sleeve <NUM> includes the same components, features, and functions as inner sleeve <NUM>.

Referring still to <FIG>, inner sleeve <NUM> includes upper inner sleeve segment <NUM> and lower inner sleeve segment <NUM>. Upper inner sleeve segment <NUM> is completely disposed within inner bore <NUM> of outer sleeve <NUM>, while lower inner sleeve segment <NUM> is partially disposed within inner bore <NUM> of outer sleeve <NUM>. Upper inner sleeve segment <NUM> extends from upper end <NUM> of inner sleeve <NUM> to lower end <NUM> of upper inner sleeve segment <NUM>. Upper end <NUM> may include ball seat surface <NUM> configured to receive a ball pumped through the inner bore of hydraulic jar <NUM>. In the same arrangement as in upper inner sleeve segment <NUM>, upper inner sleeve segment <NUM> may include recess <NUM> forming cavity <NUM> between outer sleeve <NUM> and inner sleeve <NUM>. Cavity <NUM> may extend from upper cavity shoulder <NUM> to lower cavity shoulder <NUM> of the outer surface of upper inner sleeve segment <NUM>. Upper and lower inner sleeve segments <NUM>, <NUM> may be secured together by threaded connection.

Inward protrusion <NUM> of outer sleeve <NUM> is axially aligned with cavity <NUM>. Throttling rings <NUM> and <NUM> are disposed in cavity <NUM>, with throttling ring <NUM> above inward protrusion <NUM> and throttling ring <NUM> below inward protrusion <NUM>. Upper cavity <NUM> is formed between upper cavity shoulder <NUM> and throttling ring <NUM>, and lower cavity <NUM> is formed between throttling ring <NUM> and lower cavity shoulder <NUM>. A hydraulic fluid may be disposed within cavity <NUM>.

Hydraulic jar <NUM> may also include top sub <NUM> connected above outer sleeve <NUM>. Top sub <NUM> is configured to attach hydraulic jar <NUM> below a tubular string or a coiled tubing string. Hydraulic jar <NUM> further includes a mechanical lock as described above in connection with hydraulic jar <NUM>. In the illustrated embodiment, the mechanical lock includes shear pins <NUM>, <NUM> each partially disposed in one of the radial bores <NUM> in lower outer sleeve segment <NUM> and partially disposed in one of the recesses <NUM> in lower inner sleeve segment <NUM> in the default position illustrated in <FIG>. Alternatively, the mechanical lock of hydraulic jar <NUM> may include a snap ring, a mechanical nose, or a ball and wedge combination as described above.

With reference to <FIG>, hydraulic jar <NUM> may be activated by pumping ball <NUM> in a fluid through the tubular string or coiled tubing string above hydraulic jar <NUM>. When ball <NUM> reaches hydraulic jar <NUM>, ball <NUM> engages ball seat <NUM> on upper end <NUM> of inner sleeve <NUM>. Ball <NUM> fluidly seals inner bore <NUM> of inner sleeve <NUM>. A downward force is applied to upper end <NUM> of inner sleeve <NUM> with the continued pumping of fluid above ball <NUM>. When the downward force exceeds a threshold, the mechanical lock is disabled to allow relative axial movement between inner sleeve <NUM> and outer sleeve <NUM>, which causes hydraulic jar <NUM> to impart an impact load on the components attached to hydraulic jar <NUM>. In the embodiment illustrated, the downward force on inner sleeve <NUM> severs shear pins <NUM> and <NUM> to disable the mechanical lock and to allow the axial movement of inner sleeve <NUM> relative to outer sleeve <NUM>.

Inner sleeve <NUM> may move axially downward relative to outer sleeve <NUM> until reaching the activated position shown in <FIG>. The downward movement of inner sleeve <NUM> is limited by the interaction of lower end <NUM> of upper inner sleeve segment <NUM> with upper end <NUM> of lower outer sleeve segment <NUM> (the downward block). As inner sleeve <NUM> slides downward (in the illustrated orientation), upper cavity shoulder <NUM> applies a downward force on a hydraulic fluid held in upper cavity <NUM>. This causes a portion of the hydraulic fluid to flow through a small space between the outer surface of inner sleeve <NUM> and throttling ring <NUM>. In this way, the hydraulic fluid is transferred from upper cavity <NUM> to lower cavity <NUM> as inner sleeve <NUM> slides axially downward relative to outer sleeve <NUM>. An impact force is created when the small space between the outer surface of inner sleeve <NUM> and first throttling ring <NUM> opens up and the hydraulic fluid flows from upper cavity <NUM> to lower cavity <NUM> and lower end <NUM> of upper inner sleeve segment <NUM> strikes upper end <NUM> of lower outer sleeve segment <NUM> to stop the downward axial movement of inner sleeve <NUM>. This impact force is transmitted to components connected above and below hydraulic jar <NUM>. A user may activate hydraulic jar <NUM> in order to create an impact force or impact load to loosen a portion of a tubular string or bottom hole assembly that is stuck or immobilized in an area of a wellbore.

In an alternate embodiment, the mechanically locking hydraulic jar is designed to allow the inner sleeve to slide axially upward relative to the outer sleeve when the mechanical lock is disabled. This arrangement may be accomplished by rearranging the parts in hydraulic jar <NUM> or hydraulic jar <NUM>. In another alternate embodiment, the mechanically locking hydraulic jar is designed to allow the inner sleeve to slide both axially upward and axially downward relative to the outer sleeve when the mechanical lock is disabled.

Referring now to <FIG>, mechanically locking hydraulic jar <NUM> may be secured below tubular string <NUM>. Measurement while drilling sub <NUM>, drilling motor <NUM>, and drill bit <NUM> may be secured below hydraulic jar <NUM>. Tubular string <NUM>, hydraulic jar <NUM>, and the components secured below may be lowered into wellbore <NUM> extending below surface <NUM> through subterranean formation <NUM>. If drill bit <NUM> or any other component or portion of tubular string <NUM> becomes immobilized or "stuck" in wellbore <NUM>, a user may activate hydraulic jar <NUM> as described above to generate an impact force that is transmitted throughout tubular string <NUM>. The mechanical lock of hydraulic jar <NUM> prevents unintentional activation of hydraulic jar <NUM> by any tool incorporated into tubular string <NUM>, such as those that create a pressure pulse or vibration. As described above, hydraulic jar <NUM> may be activated by applying a downward force on inner sleeve <NUM> through tubular string <NUM> or by applying an upward force on outer sleeve <NUM> through tubular string <NUM>. Hydraulic jar <NUM> may be secured to tubular string <NUM> as shown in <FIG> in the same manner described for hydraulic jar <NUM>, and may be used for the same purposes as hydraulic jar <NUM>. As described above, hydraulic jar <NUM> may be activated by pumping a fluid with ball <NUM> through tubular string <NUM> until ball <NUM> engages ball seat <NUM> of inner sleeve <NUM>.

With reference to <FIG>, mechanically locking hydraulic jar <NUM> may be secured below coiled tubing string <NUM>, with measurement while drilling sub <NUM>, drilling motor <NUM>, and drill bit <NUM> secured below hydraulic jar <NUM>. Coiled tubing string <NUM>, hydraulic jar <NUM>, and the components secured below may be lowered into wellbore <NUM> extending below surface <NUM> through subterranean formation <NUM>. If drill bit <NUM> or any other component becomes immobilized or "stuck" in wellbore <NUM>, a user may activate hydraulic jar <NUM> as described above to generate an impact force that is transmitted throughout coiled tubing <NUM>. The mechanical lock of hydraulic jar <NUM> prevents unintentional activation of hydraulic jar <NUM> by any tool incorporated into the bottom hole assembly that creates a pressure pulse or vibration. As described above, hydraulic jar <NUM> may be activated by applying an upward force on outer sleeve <NUM> through coiled tubing string <NUM>. Hydraulic jar <NUM> may be secured to coiled tubing string <NUM> as shown in <FIG> in the same manner described for hydraulic jar <NUM>, and may be used for the same purposes as hydraulic jar <NUM>. As described above, hydraulic jar <NUM> may be activated by pumping a fluid with ball <NUM> through coiled tubing string <NUM> until ball <NUM> engages ball seat <NUM> of inner sleeve <NUM>.

The mechanical lock may include any components configured to engage the outer and inner sleeves in the default position, and configured to be sheared, retracted, or otherwise disabled to allow axial movement of the inner sleeve relative to the outer sleeve to place the hydraulic jar in the activated position. For example, the mechanical lock may include one or more shear members (e.g., set screws, shear pins, shear pin balls, dowels), spring-loaded dogs, or protrusions. In other examples, the mechanical lock may include a snap ring, a collet arrangement, or a ball and wedge combination.

In the embodiment shown in <FIG>, the mechanical lock of the hydraulic jar includes shear pin balls <NUM>, <NUM>. The mechanical lock may include any number of shear pin balls, such as <NUM>-<NUM> shear pin balls. Lower outer sleeve segment <NUM> includes one or more radial bores <NUM>. The outer surface of lower inner sleeve segment <NUM> includes one or more recesses <NUM>. In the default position shown in <FIG>, each recess <NUM> is aligned with one of the radial bores <NUM> and each of the shear pin balls <NUM>, <NUM> is partially disposed within a radial bore <NUM> and a recess <NUM> in lower inner sleeve segment <NUM>. Shear pin balls <NUM>, <NUM> may be retained within radial bores <NUM> with plugs or set screws <NUM>, <NUM>. In this way, shear pin balls <NUM>, <NUM> engage the inner sleeve and the outer sleeve in the default position to prevent relative axial movement between the inner and outer sleeves. With reference to <FIG>, activation of the hydraulic jar may cause shear pin balls <NUM>, <NUM> to be severed into segments 140A, 142A held in radial bores <NUM> of lower outer sleeve segment <NUM> and segments 140B, 142B held, at least initially, in recesses <NUM> of lower inner sleeve segment <NUM>, respectively. The severing of shear pin balls <NUM>, <NUM> disables the mechanical lock to allow the inner sleeve of the hydraulic jar to move axially relative to the outer sleeve.

In the embodiment shown in <FIG>, the mechanical lock of the hydraulic jar includes dowel <NUM>. The mechanical lock may include any number of dowels, such as <NUM>-<NUM> dowels. Lower outer sleeve segment <NUM> includes one or more bores <NUM>. The outer surface of lower inner sleeve segment <NUM> includes one or more recesses <NUM>. In the default position shown in <FIG>, recess <NUM> is aligned with bore <NUM> and dowel <NUM> is partially disposed within bore <NUM> and recess <NUM> in lower inner sleeve segment <NUM>. In this way, dowel <NUM> engages the inner sleeve and the outer sleeve in the default position to prevent relative axial movement between the inner and outer sleeves. With reference to <FIG>, activation of the hydraulic jar may cause dowel <NUM> to be severed into segments 158A held in bore <NUM> of lower outer sleeve segment <NUM> and segment 158B held, at least initially, in recess <NUM> of lower inner sleeve segment <NUM>, respectively. The severing of dowel <NUM> disables the mechanical lock to allow the inner sleeve to move axially relative to the outer sleeve.

In the embodiment shown in <FIG>, the mechanical lock of the hydraulic jar includes snap ring <NUM>. Lower outer sleeve segment <NUM> includes recess <NUM>. Recess <NUM> may be formed by a shoulder on the inner surface of lower outer sleeve segment <NUM>. The outer surface of lower inner sleeve segment <NUM> includes recess <NUM>. In the default position shown in <FIG>, recess <NUM> is aligned with recess <NUM> and snap ring <NUM> is partially disposed within recess <NUM> and recess <NUM> in lower inner sleeve segment <NUM>. In this way, snap ring <NUM> engages the inner sleeve and the outer sleeve in the default position to prevent relative axial movement between the inner and outer sleeves. With reference to <FIG>, activation of the hydraulic jar may cause snap ring <NUM> to be severed or broken into segments 170A held in recess <NUM> of lower outer sleeve segment <NUM> and segment 170B held, at least initially, in recess <NUM> of lower inner sleeve segment <NUM>, respectively. The severing of snap ring <NUM> disables the mechanical lock to allow the inner sleeve to move axially relative to the outer sleeve.

In the embodiment shown in <FIG>, the mechanical lock of the hydraulic jar includes protrusion <NUM> extending radially inward from an inner surface of lower outer sleeve segment <NUM>. The hydraulic jar may include a single protrusion or numerous protrusions around the circumference of the inner surface of lower outer sleeve segment <NUM>. The outer surface of lower inner sleeve segment <NUM> includes recess <NUM>. In the default position shown in <FIG>, protrusion <NUM> is at least partially disposed within recess <NUM> in lower inner sleeve segment <NUM>. In this way, protrusion <NUM> of the outer sleeve engages the inner sleeve in the default position to prevent relative axial movement between the inner and outer sleeves. With reference to <FIG>, activation of the hydraulic jar may cause protrusion <NUM> to be severed from lower outer sleeve segment <NUM>. The severing of protrusion <NUM> disables the mechanical lock to allow the inner sleeve to move axially relative to the outer sleeve.

In the embodiment shown in <FIG>, the mechanical lock of the hydraulic jar includes dogs <NUM>, <NUM> biased by springs <NUM>, <NUM>, respectively, in a radially inward direction. The mechanical lock may include any number of dogs biased by springs, such as <NUM>-<NUM> dogs. Lower outer sleeve segment <NUM> includes one or more radial bores <NUM>. The outer surface of lower inner sleeve segment <NUM> includes recess <NUM>. Springs <NUM>, <NUM> are each disposed within one of the radial bores <NUM> in lower outer sleeve segment <NUM>. In the default position shown in <FIG>, recess <NUM> is aligned with bores <NUM> and each dog <NUM>, <NUM> is partially disposed within one of the radial bores <NUM> and partially disposed within recess <NUM> in lower inner sleeve segment <NUM>. In this way, dogs <NUM>, <NUM> engage the inner sleeve and the outer sleeve in the default position to prevent relative axial movement between the inner and outer sleeves. With reference to <FIG>, activation of the hydraulic jar may overcome the spring force of springs <NUM>, <NUM> to push dogs <NUM>, <NUM> outward into radial bores <NUM>. Recess <NUM> in lower inner sleeve segment <NUM> may include an upper tapered surface and a lower tapered surface, which may be configured to allow for retraction of dogs <NUM>, <NUM> without severing these components. The retraction of dogs <NUM>, <NUM> disables the mechanical lock to allow the inner sleeve to move axially relative to the outer sleeve.

In the embodiment shown in <FIG>, the mechanical lock of the hydraulic jar includes collet assembly <NUM> on lower outer sleeve segment <NUM>. As shown in <FIG>, collet assembly <NUM> may include two or more segments <NUM>. A lower end of each segment <NUM> includes inward protrusion <NUM>. The outer surface of lower inner sleeve segment <NUM> includes recess <NUM>. In the default position shown in <FIG>, protrusions <NUM> are at least partially disposed within recess <NUM> in lower inner sleeve segment <NUM>. In this way, protrusions <NUM> of the outer sleeve engage the inner sleeve in the default position to prevent relative axial movement between the inner and outer sleeves. With reference to <FIG>, activation of the hydraulic jar may force protrusions <NUM> radially outward (i.e., expanded radially), thereby disabling the mechanical lock and allowing the inner sleeve of the hydraulic jar to move axially relative to the outer sleeve.

Claim 1:
A hydraulic jar device (<NUM>) comprising:
an outer sleeve (<NUM>) including an inner bore (<NUM>);
an inner sleeve (<NUM>) partially disposed within the inner bore (<NUM>) of the outer sleeve (<NUM>), wherein the inner sleeve (<NUM>) includes an inner bore (<NUM>);
a mechanical lock (<NUM>, <NUM>) engaging the outer sleeve (<NUM>) and the inner sleeve (<NUM>) in a default position to prevent axial movement of the inner sleeve (<NUM>) relative to the outer sleeve (<NUM>), wherein disabling the mechanical lock (<NUM>, <NUM>) allows axial movement between the inner sleeve (<NUM>) and the outer sleeve (<NUM>) to generate an impact force when the inner sleeve (<NUM>) reaches an activated position;
an upward block (<NUM>) configured to limit the upward axial movement of the inner sleeve (<NUM>) relative to the outer sleeve (<NUM>) when the mechanical lock (<NUM>, <NUM>) is disabled;
a downward block (<NUM>) configured to limit the downward axial movement of the inner sleeve (<NUM>) relative to the outer sleeve (<NUM>) when the mechanical lock (<NUM>, <NUM>) is disabled;
the hydraulic jar device (<NUM>) characterized in that the hydraulic jar device further comprises a top sub (<NUM>) connected above an upper end of the outer sleeve (<NUM>), wherein the top sub (<NUM>) is configured to be attached below a tubular string (<NUM>) or a coiled tubing string (<NUM>), wherein the upward block (<NUM>) is formed by a lower end of the top sub (<NUM>) disposed within the inner bore (<NUM>) of the outer sleeve (<NUM>) and configured to engage an upper end (<NUM>) of the inner sleeve (<NUM>), and wherein the upward axial movement of the inner sleeve (<NUM>) relative to the outer sleeve (<NUM>) is limited by the upper end (<NUM>) of the inner sleeve (<NUM>) contacting the lower end of the top sub (<NUM>).