Patent Description:
It is known in the oil and gas industry to attach a whipstock to a milling tool by a shearable member for deployment into a wellbore. Once the whipstock is in a desired location in the wellbore, an axial load is applied to shear the shearable member and thus separate the milling tool from the whipstock. The shearable attachment between the whipstock and milling tool can be unintentionally sheared if an unexpected obstruction is encountered in the wellbore or during extended reach operations in horizontal wellbores where friction forces are high. During an anchor test, the shearable member is prone to shearing, thereby resulting in the need to remove the whipstock and then initiate a separate retrieval operation to remove the anchor from the wellbore if the anchor fails the test. The shearable members are prone to inadvertent shearing if a torsional load is transferred between the milling tool and the whipstock, such as an operation to orientate a whipstock in a certain direction in the wellbore.

There is a need for a releasable connection between a whipstock and downhole tool that will release on command while not inadvertently shearing by the application of a torsional or axial load. <CIT> discloses a latch assembly connectable to a riser. A rotating control device can be positioned with the riser, sealing the rotating control device with the latch assembly and removably latching the rotating control device to the latch assembly and to the riser. <CIT> discloses a fluid pressure cylinder which comprises a piston moveable in a housing and an electrically-operated switch that can block and unblock a fluid supply port. This arrangement can be used to actuate a further device.

The invention is defined by independent claims <NUM>, <NUM>, <NUM> and <NUM>.

Further aspects of the invention are defined by the dependent claims.

In an embodiment, a latch release mechanism includes a housing having a fluid inlet, an actuator piston, a latch member, and a switch. The actuator piston is at least partially disposed in the housing and movable from a first positon to a second position in response to fluid communication from the fluid inlet. The latch member is coupled to the actuator piston and movable from a first positon to a second position by the actuator piston. The switch has a first configuration, a second configuration, and an intermediate configuration, wherein fluid communication is blocked when the switch is in the first configuration and the intermediate configuration, and wherein the fluid communication is unblocked when the switch is in the second configuration. The actuator piston is movable to the second position when the switch is in the second configuration.

In one embodiment, an assembly for use downhole includes an actuator and a switch assembly. The switch assembly has an inlet in selective fluid communication with the actuator, and a switch having a first configuration, an intermediate configuration, and a second configuration. The switch blocks fluid communication between the inlet and the actuator when in the first configuration and the intermediate configuration, and wherein the switch allows fluid communication between the inlet and the actuator when in the second configuration.

In one embodiment, a bottom hole assembly (BHA) has a whipstock, a downhole tool having a lock mechanism, and a latch release mechanism attached to the whipstock and configured to releasably attach the whipstock to the downhole tool. The latch release mechanism has an actuator piston, a switch, and a latch member. The actuator piston is movable from a first position to a second position in response to fluid communication. The switch having a first configuration, a second configuration, and an intermediate configuration, wherein fluid communication is blocked when the switch is in the first configuration and the intermediate configuration, and wherein the fluid communication is unblocked when the switch is in the second configuration. The latch member is coupled to the piston and configured to engage the lock mechanism in a first positon and to disengage from the lock mechanism in a second position, wherein the latch member is movable from the first position to the second position by the actuator piston when the switch is in the second configuration.

In one embodiment of a method of releasing a whipstock from a downhole tool includes running a BHA having the whipstock releasably attached to the downhole tool into a wellbore. The whipstock has a latch release mechanism and the downhole tool has a lock mechanism, and a latch member of the latch release mechanism is engaged with a locking member of the lock mechanism. The method further includes converting a switch of the latch release mechanism from a first configuration to a second configuration to unblock a fluid communication between a fluid communication line and an actuator piston attached to the latch member. The method further includes releasing the whipstock from the downhole tool by moving the actuator piston coupled to the latch member to disengage the latch member from the locking member in response to the fluid communication in the fluid communication line.

In one embodiment, a BHA includes a whipstock having a latch release mechanism and a milling tool having a plurality of blades and a lock mechanism. The BHA further includes a collar coupled to the whipstock and disposed about a portion of the milling tool, wherein the blades of the milling tool abut the collar. The milling tool is releasably coupled to the whipstock by the interaction of the latch release mechanism and the lock mechanism.

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particularized description of the disclosure, briefly summarized above, may be had in reference to embodiments, some of which are illustrated in the appended drawings. It is noted, however, that the appended drawings illustrate only the typical embodiments of this disclosure and are therefore not to be considered limiting in scope, for the disclosure may admit to other equally effective embodiments.

<FIG> illustrates a BHA <NUM> placed in a wellbore <NUM> within a subsurface formation <NUM>, according to embodiments disclosed herein. The BHA <NUM> has a whipstock <NUM> releasably attached to a downhole tool <NUM>, such as a milling tool. For example, the whipstock <NUM> may be attached to the downhole tool <NUM> by the interaction of a lock mechanism <NUM> of the downhole tool <NUM> with a latch release mechanism <NUM> of the whipstock <NUM>, as will be discussed in greater detail below.

The whipstock <NUM> has a concave face <NUM>, a body <NUM>, and a latch release mechanism <NUM> coupled to the body <NUM>. The whipstock <NUM> is attached to an anchoring mechanism <NUM>, which secures the whipstock <NUM> in the wellbore <NUM>. For example, the anchoring mechanism may include a packer, an inflatable anchor, a slip type anchor, or combinations thereof. In some embodiments, the body <NUM> is connected to an anchoring mechanism <NUM> for securing the whipstock <NUM> in the wellbore <NUM>. In some embodiments, the anchoring mechanism <NUM> is integrated with the whipstock <NUM>. For the purposes of this illustration, the whipstock <NUM> is not shown anchored to the wellbore <NUM> by the anchoring mechanism <NUM>.

The concave face <NUM> is generally a curved surface. In some embodiments, the concave face <NUM> is a surface that is primarily flat. The concave face <NUM> may be most narrow at an upper end. The concave face <NUM> may be approximately cylindrical at a lower end. The body <NUM> may be generally cylindrical and extends from the lower end of the concave face <NUM>. In some embodiments, the whipstock <NUM> has a fluid communication line <NUM> that is disposed on, or along at least a portion of the length of the concave face <NUM>. In some embodiments, the fluid communication line <NUM> extends along at least a portion of the length of the body <NUM>. In some embodiments, the fluid communication line <NUM> extends along both at least a portion of the length of the concave face <NUM> and at least a portion of the length of the body <NUM>. In some embodiments, the fluid communication line <NUM> is disposed within the body <NUM> of the whipstock <NUM> and extends along at least a portion of the length of the body <NUM> and/or the concave face <NUM>. In other embodiments, the fluid communication line <NUM> is only partially disposed within the body <NUM> of the whipstock and extends along at least a portion of the length of the body <NUM> and/or the concave face <NUM>. The fluid communication line <NUM> may be fluidly connected to both the anchoring mechanism <NUM> and the latch release mechanism <NUM>.

For operational purposes, it may be desirable to secure the whipstock <NUM> in wellbore <NUM> so that it is positioned at a particular depth. As illustrated in <FIG>, wellbore <NUM> is shown as being vertical (i.e., generally parallel to gravitational force) in subsurface formation <NUM>, but in many circumstances at least a portion of wellbore <NUM> will not be vertical. Nonetheless, as used herein, "depth" refers to a length along the wellbore <NUM> measured from the surface. The direction that is locally generally parallel to the wellbore may be referred to as the "axial" direction. Terms such as "up", "down", "top", "bottom", "upper," "lower," etc., should be similarly construed.

For operational purposes, it may be desirable to secure the whipstock <NUM> so that concave face <NUM> is oriented at a particular orientation relative to the wellbore <NUM>. The concave face <NUM> has an angle <NUM> relative to wellbore <NUM>. For example, the angle <NUM> between the center of curvature of the upper end of concave face <NUM> and the wellbore <NUM> may help to determine the bit path direction/trajectory during subsequent drilling operations. The angle <NUM> may be expressed, for example, as a compass measurement or with reference to a clock face.

<FIG> illustrates a collar <NUM> attached to one end of the whipstock <NUM>. The collar <NUM> may be a partial ring attached to the whipstock <NUM>, such as by welding or a bolt attachment. In another example, the collar <NUM> is a full ring attached to the whipstock <NUM>. The whipstock <NUM> may be manufactured such that the collar <NUM> is an integral feature. The collar may have a concave region <NUM>. A face of the milling tool <NUM> may abut the collar <NUM>. In another embodiment, the collar <NUM> abuts the lower portions of the blades <NUM> of the milling tool <NUM>. The lower portions of the blades <NUM> abutting the collar <NUM>, as shown in <FIG>, may be cutting faces of the blades <NUM>. The collar <NUM> helps accommodate axial load placed on the whipstock <NUM> by the milling tool <NUM>.

<FIG> illustrates an alternative embodiment of the collar <NUM> having a plurality of apertures <NUM> in the collar <NUM> for retaining torque keys <NUM>. As shown in <FIG>, collar <NUM> is disposed about a portion of the milling tool <NUM>. As shown in <FIG>, the torque keys <NUM> are at least partially disposed in a corresponding recess <NUM> formed in the milling tool <NUM>. In another example, the torque keys <NUM> are at least partially disposed between adjacent blades <NUM>. The torque keys <NUM> allow the transfer of torque between the milling tool <NUM> and the whipstock <NUM>. In another embodiment, instead of torque keys <NUM>, a plurality of castellations in the collar <NUM> are engaged with a corresponding blade <NUM> of the milling tool to allow torque transfer between the milling tool <NUM> and the whipstock <NUM>.

<FIG> illustrates the whipstock <NUM> releasably attached to the milling tool <NUM> of the BHA <NUM>. In one embodiment, the milling tool <NUM> has a lock mechanism <NUM> disposed in the milling tool <NUM>. As illustrated, a locking member <NUM> is disposed within a bore <NUM> of the milling tool <NUM>. The bore <NUM> may be located proximate to mill face <NUM>. <FIG> illustrates a cross-section view of the milling tool <NUM> showing the lock mechanism <NUM>. The bore <NUM>, as shown in <FIG>, is generally perpendicular to the longitudinal axis of the milling tool <NUM>, but in other embodiments, the bore <NUM> may be aligned at an angle relative to mill face <NUM>. The bore <NUM> and locking member <NUM> are configured to allow the locking member <NUM> to move in the bore <NUM> between an extended positon, as shown in <FIG>, and a retracted position, as shown in <FIG>. In the extended position, a lower end <NUM> of the locking member <NUM> extends outside of the milling tool <NUM> and at least partially into an aperture <NUM> of the whipstock <NUM>. In the retracted position, the end <NUM> of the locking member <NUM> does not extend outside of the milling tool <NUM>. The locking member <NUM> is biased toward the retracted position by a biasing mechanism <NUM>, such as a spring. In some embodiments, the bias mechanism <NUM> may be a magnet or a shape memory alloy. In some embodiments, the bias mechanism <NUM> may generate a biasing force by using mechanical, electromagnetic, chemical, hydraulic, or pneumatic components. In some embodiments, the biasing mechanism <NUM> may be located closer to a lower end <NUM> of the locking member <NUM>.

In some embodiments, the milling tool <NUM> and whipstock <NUM> are torsionally coupled by the torque keys <NUM> and the aperture <NUM> is sized such that a gap is formed between the locking member <NUM> and the walls of the aperture <NUM> of the whipstock <NUM> when torsional loading is applied to the BHA <NUM> from the surface. For example, by providing a gap between the portion of the protruding locking member <NUM> and the whipstock <NUM>, no torque applied to the milling tool <NUM> will be transferred to the locking member <NUM>. Torque is transferred from the milling tool <NUM> to the whipstock <NUM> via the torque keys <NUM>. Thus, the lock mechanism <NUM> is isolated from torsional loads applied to the whipstock <NUM> by the milling tool <NUM>.

In some embodiments, the locking member <NUM> is not isolated from axial and torsional loads applied to the whipstock <NUM> by the milling tool. For example, the locking mechanism may contact the aperture <NUM> when axial or torsional loading is applied. For example, axial load may be applied to the locking member <NUM> if the BHA <NUM> is lifted or lowered within the well. The locking member <NUM> is configured to not inadvertently shear from the applied torsional and axial loads.

In some embodiments, the lock mechanism <NUM> includes a plurality of locking members <NUM>, whereby each locking member protrudes into a corresponding aperture of a plurality of apertures <NUM> in the whipstock <NUM>. In some embodiments, the locking member <NUM> may be shaped as a bolt, pin, a plate, fork, or otherwise shaped to meet manufacturing and/or operational specifications while providing a locking member function and a retraction action. The locking member <NUM>, as shown in <FIG> is a pin. In some embodiments, the locking member <NUM> may have a circular, triangular, square, hexagonal, or other cross-sectional shape to meet manufacturing and/or operational specifications. In some embodiments, the locking member <NUM> may include a rigid, sturdy material, such as metal, alloy, composite, fiber, etc., to meet manufacturing and/or operational specifications. For example, the locking member <NUM> is configured to not inadvertently shear from applied torsional or axial loads during normal operation of the BHA <NUM>.

In some embodiments, the milling tool <NUM> may have an installation aperture <NUM> coupled to bore <NUM>. Prior to positioning BHA <NUM> in wellbore <NUM>, installation aperture <NUM> may be utilized to install the locking member <NUM> and/or spring <NUM> in the bore <NUM> so that the locking member <NUM> is biased toward a retracted position. The concave region <NUM> of the collar <NUM> allows access to the installation aperture <NUM>. The locking member <NUM> may move in the bore <NUM> between the retracted position and the extended position. As an example, the locking member <NUM> will not inadvertently fail thereby causing pre-mature release of the whipstock <NUM> from the milling tool <NUM> if an obstruction is encountered during run-in of the BHA <NUM> or during a test of the anchoring mechanism <NUM>. In some embodiments, the lock mechanism <NUM> includes a plurality of locking members, wherein at least one of the plurality of locking members is a locking member <NUM> that moves without failure during planned operational conditions.

A latch portion <NUM> is disposed at one end of the locking member <NUM>. When in the extended position, the latch portion <NUM> protrudes beyond the outer diameter of the milling tool <NUM>. The latch portion <NUM> is configured to engage with the latch member <NUM> of the latch release mechanism <NUM> to attach the whipstock <NUM> to the milling tool <NUM>. In one embodiment, the latch portion <NUM> includes a recess for engaging the latch member <NUM>. In one embodiment, the latch portion <NUM> includes one recess on each side of the locking member <NUM> for engaging the latch member <NUM>.

<FIG> illustrates another view of the BHA <NUM> with the latch member <NUM> of the latch release mechanism <NUM> engaged with the latch portion <NUM> of the lock mechanism <NUM> to retain the locking member <NUM> in the extended position. The latch release mechanism <NUM> includes the latch member <NUM> and a latch actuator <NUM> for moving the latch member <NUM>. The latch actuator <NUM> is disposed in an aperture <NUM> of the whipstock <NUM> and may be affixed to the whipstock <NUM>, such as by a screws or bolts inserted through mounting bores <NUM> formed in the housing <NUM> of the latch actuator <NUM>.

The latch member <NUM> has a latch <NUM> attached at one end. The latch <NUM> of the latch member <NUM> is configured to engage with the latch portion <NUM> of the locking member <NUM>. In one embodiment, the latch <NUM> includes a two-pronged fork configuration, as shown, that are inserted into the corresponding recess of the latch portion <NUM>. In one embodiment, the latch <NUM> includes a two-pronged fork configuration that is inserted into two corresponding recesses of the latch portion <NUM>. In an alternative embodiment, the latch portion <NUM> may comprise a bore through the locking member <NUM> and the latch <NUM> may comprise a portion of the latch member <NUM> sized to be inserted into bore forming the latch portion <NUM>. As shown, the latch member <NUM> is a rod having an adjustable length with a latch <NUM> attached at one end. In another embodiment, the latch member <NUM> may be a rod having a fixed length with a latch <NUM> attached at one end. In another embodiment, the latch member <NUM> may be a cable having a latch <NUM> attached at one end.

<FIG> illustrates a partial cross-sectional view of the latch actuator <NUM> of the latch release mechanism <NUM>. The latch actuator <NUM> includes a housing <NUM>, an inlet <NUM> coupled to the fluid communication line <NUM>, a first switch <NUM>, a second switch <NUM>, and a third piston assembly <NUM> having an actuator piston <NUM>. In one embodiment, the first switch <NUM> is a first piston assembly <NUM>, and the second switch <NUM> is a second piston assembly <NUM>. The first piston assembly <NUM> is at least partially disposed in a first piston assembly bore <NUM> of the housing <NUM>. The second piston assembly <NUM> is at least partially disposed in the second piston assembly bore <NUM> of the housing <NUM>. The third piston assembly <NUM> is at least partially disposed in the third piston assembly bore <NUM> of the housing. A fluid communication line <NUM> allows fluid communication between the first piston assembly bore <NUM> and the second piston assembly bore <NUM>. Fluid communication line <NUM> allows for fluid communication between the second piston assembly bore <NUM> and the third piston assembly bore <NUM>. A portion of the latch member <NUM> may be disposed within the housing <NUM> or within a channel formed in the housing.

The first piston assembly <NUM> has a housing connection member <NUM>, first piston <NUM>, and at least one shearable member <NUM>. The housing connection member <NUM> has a bore therethrough to accommodate a portion of the first piston <NUM>. As illustrated in <FIG>, the shearable member <NUM> releasably attaches the first piston <NUM> to the housing connection member <NUM> to retain the first piston <NUM> in the first position. The housing connection member <NUM> may be threadedly attached to the housing <NUM>, but it may be attached by other suitable means. One or more sealing members <NUM> are disposed about the circumference of the first piston <NUM> and form a seal with the bore <NUM>. When the piston first <NUM> is in the first position, the first piston <NUM> blocks fluid flow and pressure from being transmitted from the inlet <NUM> to the fluid communication lines <NUM> and <NUM>. The first piston <NUM> is allowed to move to the second position (shown in <FIG>) after pressure applied to the first piston <NUM> from the inlet <NUM> is sufficient to shear the shearable member <NUM>. When the first piston <NUM> is in the second position, it may protrude from the housing connection member <NUM>. When the first piston <NUM> is in the second position, fluid communication between the inlet <NUM> and the bore <NUM> is established via communication line <NUM>.

The bore <NUM> has a first piston bore portion <NUM> and a second piston bore portion <NUM>. The second piston bore portion <NUM> has a smaller diameter than the diameter of the first piston bore portion <NUM>. The first piston bore portion <NUM> has a first diameter portion 505a and a second diameter portion 505b, wherein the second diameter portion 505b has a greater diameter than the first diameter portion 505a. The second piston assembly <NUM> has a housing connection member <NUM>, a second piston <NUM>, and at least one shearable member <NUM>. The housing connection member <NUM> is threadedly attached to the housing <NUM>, but it may be attached by other suitable means. The housing connection member <NUM> has a bore accommodating a portion of the second piston <NUM>. The shearable member <NUM> releasably attaches the second piston <NUM> to the housing connection member <NUM> to retain the second piston <NUM> in the first position, as shown in <FIG>. The second piston <NUM> has a first piston head <NUM> having a greater piston surface area than a piston surface area of the second piston head <NUM>. The piston heads <NUM>, <NUM> are spaced apart from each other. One or more sealing members <NUM> may be disposed about the outer circumference of the first piston head <NUM> to seal against the first diameter portion 505a of bore <NUM>. One or more sealing members <NUM> may be disposed about the outer circumference of the second piston head <NUM> to seal against the second piston bore portion <NUM>. The one or more sealing members <NUM>, <NUM> may be only one sealing member, such as an O-ring. An optional biasing member <NUM>, such as a spring, is disposed between the first piston head <NUM> and the second housing connection member <NUM>. The first piston head <NUM> is disposed in the first piston bore portion <NUM> and the second piston head <NUM> is disposed in the second piston bore portion <NUM>. As shown in <FIG>, the second piston head <NUM> is disposed in the bore <NUM> at a location between the fluid communication line <NUM> and the fluid communication line <NUM>. In this first position, the second piston <NUM> blocks fluid flow and pressure from being transmitted from the fluid communication line <NUM> to the fluid communication <NUM>. Sufficient pressure may be applied to the second piston <NUM> from the inlet <NUM> to shear the shearable member <NUM> retaining the second piston <NUM> in the first position. After shearing, the second piston <NUM> is allowed to move to the second position (shown in <FIG>) to unblock fluid and pressure communication between the fluid communication line <NUM> and the fluid communication line <NUM>. In the second position, the second piston head <NUM> is no longer between the fluid communication lines <NUM>, <NUM>. Prior to moving to the second position, the second piston <NUM> moves to an intermediate position (shown in <FIG>) after the shearable member <NUM> shears. The second piston <NUM> moves to the intermediate position, and not to the second position, because of the larger piston surface area of the first piston head <NUM> with respect to the piston surface area of the second piston head <NUM>. In the intermediate position, the second piston <NUM> may protrude from the housing connection member <NUM> while the second piston head <NUM> is still disposed between the fluid communication lines <NUM>, <NUM> to prevent fluid communication between lines <NUM> and <NUM>. After flow and/or pressure applied to the latch release mechanism <NUM> through the inlet <NUM> drops below a certain level, the biasing member <NUM> expands to move the second piston <NUM> to the second position to allow fluid communication between the fluid communication line <NUM> and fluid communication line <NUM>. When the second piston <NUM> is in the second position, the first piston head <NUM> is disposed in the second diameter portion 505b of the bore <NUM>. When the first piston head <NUM> is disposed in the second diameter portion 505b, the one or more sealing members <NUM> disposed about the outer circumference of first piston head <NUM> no longer seal against the first diameter portion 505a of the first piston bore portion <NUM> of the bore <NUM>. The second piston <NUM> will not be return to the intermediate position by fluid pressure in the bore <NUM> after moving to the second position because the first piston head <NUM> is not in sealing engagement with the second diameter portion 505b of the bore <NUM>.

After shearing the shearable members and prior to moving to the second position, fluid pressure fluctuation in the bore <NUM> may result in the displacement of the second piston <NUM> by acting on the first piston head <NUM>. The intermediate position of the second piston <NUM> is any positon that the second piston <NUM> is in after the shearable members <NUM> fail and prior to moving to the second position. When in the intermediate position, the one or more sealing members <NUM> about the outer circumference of the first piston head <NUM> are maintained in sealing engagement with the first diameter portion 505a of the first bore portion <NUM> of bore <NUM>.

Referring to <FIG>, the third piston assembly <NUM> is at least partially disposed in the bore <NUM>. The bore <NUM> is in communication with the fluid line <NUM>. When the first piston <NUM> and the second piston <NUM> are in their respective second positions, then fluid flow and/or pressure is able to be communicated to the bore <NUM>. The third piston assembly <NUM> has an actuator piston <NUM>. The actuator piston <NUM>, as illustrated in <FIG>, is a tandem piston <NUM>. However, it is contemplated the actuator piston <NUM> could be one piston or more than two pistons coupled together. The bore <NUM> is configured to receive the one or more actuator pistons <NUM> of the third piston assembly <NUM>. The tandem piston <NUM> have a back member <NUM> and a recess <NUM> (see <FIG>) between the two individual pistons 534a,b of the tandem piston <NUM> to accommodate the housing <NUM> between the two individual pistons 534a,b. The back member <NUM> may be attached to each of the individual pistons 534a,b by screws, as shown, or by some other suitable connection member. The back member <NUM> may be formed integral with the actuator piston <NUM>. Sealing members <NUM> disposed about the individual pistons <NUM> a,b to seal against the housing <NUM>. The sealing members <NUM> may be an O-ring disposed about each individual piston 534a,b. The latch member <NUM> is attached to the third piston assembly <NUM>, such as being directly attached to the back member <NUM> or to actuator piston <NUM>. When the actuator piston <NUM> moves from the first position (see <FIG>) to the second position (see <FIG>), then the latch member <NUM> is able to move relative to the housing <NUM>, whipstock <NUM>, and latch portion <NUM> of the locking member <NUM>. As a result of the actuator piston <NUM> moving from the first position to the second position, the latch <NUM> disengages from the latch portion <NUM> (see <FIG>) to allow the locking member <NUM> of the lock mechanism <NUM> to move to the retracted position (see <FIG>), thus releasing the whipstock <NUM> from the milling tool <NUM>.

In an alternative embodiment, the fluid communication line <NUM> has a junction with the first piston bore portion <NUM> of the second piston bore <NUM> instead of a junction with the second piston bore portion <NUM> of the bore <NUM>. The second piston head <NUM> of the second piston <NUM> is disposed between the respective junctions of the fluid communication lines <NUM>, <NUM> with the respective portions <NUM>, <NUM> of the bore <NUM> in the first and intermediate position. When the second piston <NUM> is in the second position, then fluid communication between the fluid communication lines <NUM>, <NUM> is established. The shearable members <NUM>, <NUM>, may be shear screws or any another suitable type of frangible member, such as shear rings. The shear strength of the shearable member <NUM> may be selected to be greater than the shear strength of shearable member <NUM>. In one embodiment, this difference in shear strength may be selected such that the pressure in fluid communication line <NUM> required to shear shearable member <NUM> is greater than the pressure in the fluid communication line <NUM> required to shear shearable member <NUM>. Thus, an operator can delay freeing the second piston <NUM> from the first position for a desired period of time after freeing first piston <NUM> from the first position. In another embodiment, the shear strength of shearable member <NUM> can be less than or equal to the shear strength of shearable member <NUM> such that the shearable member <NUM> shears after fluid communication from the inlet <NUM> to the bore <NUM> is no longer blocked by the first piston <NUM>.

In one embodiment, the first switch <NUM> has a first configuration corresponding to the first position of the first piston <NUM> and a second configuration corresponding to the second position of the first piston <NUM>. The second switch <NUM> has a first configuration corresponding to the first position of the second piston <NUM>, an intermediate configuration corresponding to the intermediate position of second piston <NUM>, and a second configuration corresponding to the second position of the second piston <NUM>. Fluid communication from the inlet <NUM> to the bore <NUM> is blocked by the first switch <NUM> and the second switch <NUM> when both switches <NUM>, <NUM> are in their respective first configuration. When the second switch <NUM> is in the intermediate configuration and the first switch <NUM> is in the second configuration, fluid communication between the inlet <NUM> and the bore <NUM> remains blocked. Fluid communication from the inlet <NUM> to the bore <NUM> is unblocked when the first and second switches <NUM>, <NUM> are in their respective second configurations. Once the second switch <NUM> is in the second configuration, fluid communication between the inlet <NUM> and the bore <NUM> is established and the actuator piston <NUM> of the latch actuator <NUM> may be moved in response to fluid communication.

In one embodiment, the latch actuator <NUM> has the second switch <NUM> but the first switch <NUM> is omitted. In this embodiment, the bore <NUM> and first piston assembly <NUM> is omitted and the fluid communication line <NUM> extends from the inlet <NUM> to the bore <NUM>. Fluid communication from the inlet <NUM> to the bore <NUM> is blocked by the second switch <NUM> when the second switch <NUM> is in the first and intermediate configurations. Fluid communication from the inlet <NUM> to the bore <NUM> is unblocked when the second switch <NUM> is in the second configuration. Once the second switch <NUM> is in the second configuration, the actuator piston <NUM> may be moved in response to fluid communication.

In one embodiment, the first switch <NUM> of the latch actuator <NUM> is a rupture disc. The rupture disc is disposed in the fluid communication line <NUM>. In this embodiment, the rupture disc is used instead of the first piston assembly <NUM>. The rupture disc is configured to fails at a predetermined pressure. After the rupture disc fails, fluid communication is established between the inlet <NUM> and the bore <NUM>. The first switch <NUM> is in the first configuration prior to the rupture of the rupture disc and in the second configuration after the rupture of the rupture disc. Thus, the rupture disc is ruptured prior to the actuation of the second switch <NUM>. Fluid communication from the inlet <NUM> to the bore <NUM> is blocked by the second switch <NUM> when the second switch <NUM> is in the first configuration and the intermediate configuration. Fluid communication is unblocked when the second switch <NUM> is in the second configuration. Once the second switch is in the second configuration, the actuator piston <NUM> may be moved in response to fluid communication.

The housing <NUM> may be manufactured by milling a block of material, such as a metal or dense plastic, to form the first piston assembly bore <NUM>, the second piston assembly bore <NUM>, and the third piston assembly bore <NUM>. Threads can be formed in the first piston assembly bore <NUM> and second piston assembly bore <NUM> that corresponds to a threaded portion of their respective housing connection members <NUM>, <NUM>. The fluid communication lines <NUM>, <NUM> may be formed by drilling into the block of material, including drilling into the respective bores <NUM>, <NUM> to create a desired junction with the fluid communication lines with the bores. After the fluid connection lines <NUM>, <NUM> are formed, then the holes formed through a side of the housing <NUM> are plugged with plugs <NUM> attached to the housing <NUM>. A bore or channel is formed to accommodate the latch member <NUM>. However, it is also contemplated that the housing <NUM> may be <NUM>-D printed, thereby omitting the need for plugs <NUM>. It is also contemplated that the housing <NUM> may be integral with the body <NUM> of the whipstock <NUM>.

An exemplary operation sequence of the latch release mechanism <NUM> will now be described in more detail. The BHA <NUM> is deployed in the wellbore <NUM> to a desired location and the BHA <NUM> is turned, using a Measurement-While-Drilling (MWD) or Logging-While-Drilling (LWD) unit coupled to or integral with the BHA <NUM>, such that the angle <NUM> of the concave face <NUM> relative to the wellbore <NUM> is oriented in the direction that the side track will be drilled. Once the proper orientation is reached, fluid pressure or flow is communicated through the fluid communication line <NUM> to the anchoring mechanism <NUM> to anchor the whipstock <NUM> to the wellbore. The fluid communication line <NUM> is also in communication with the latch actuator <NUM> of the latch release mechanism <NUM>; however, fluid communication from the inlet <NUM> (shown in <FIG>) to the bore <NUM> is blocked by first piston assembly <NUM> and the second piston assembly <NUM>. The shearing of the shearable member <NUM> and <NUM> may transpire during or after the anchor of the anchor mechanism <NUM> is set depending on the shear strength of the shearable members <NUM>, <NUM>. After the shearable members <NUM>, <NUM> fail, fluid communication between the fluid communication line <NUM> and the third piston assembly <NUM> remains blocked by the second piston head <NUM> of the second piston <NUM> because the fluid communicated into the latch release mechanism <NUM> via the fluid communication line <NUM> will cause the second piston <NUM> to move to the intermediate position instead of the second position due to the greater piston surface area of the first piston head <NUM> relative to piston surface area of the second piston head <NUM>.

After the anchor mechanism <NUM> is set, and the shearable members <NUM>, <NUM> have been sheared to release their respective pistons <NUM>, <NUM>, the operator initiates a test to determine if the BHA <NUM> is properly anchored to the wellbore. The test may involve increasing the axial load on the BHA <NUM> from the surface to determine if the BHA <NUM> moves beyond an allowable tolerance.

If the BHA <NUM> moves beyond an allowable tolerance, the operator will determine that the anchor mechanism <NUM> did not properly anchor the BHA <NUM> to the wellbore <NUM>. If the anchor mechanism <NUM> did not satisfactorily anchor the BHA to the wellbore <NUM>, then the BHA <NUM> may be retrieved from the wellbore. A retrieval tool is not necessary to retrieve the whipstock <NUM> or anchoring mechanism <NUM> from the wellbore <NUM> because the releasable attachment of the whipstock <NUM> to the milling tool <NUM> will not release during the anchor test. Thus, only one trip is needed to remove the BHA <NUM> from the wellbore <NUM> if the anchoring mechanism <NUM> does not properly anchor the BHA <NUM>. This saves time and costs associated with a retrieval operation as compared to conventional multi-trip retrieval operations.

If the anchoring test determines that the BHA <NUM> is properly anchored to the wellbore <NUM>, then the operator may proceed with releasing the whipstock <NUM> from the milling tool <NUM>. The second piston <NUM> needs to move to the second position before the whipstock <NUM> can be released from the milling tool <NUM>. For example, the pressure in the fluid communication line <NUM> is lowered to below the biasing force of the biasing member <NUM> of the second piston assembly <NUM>. The biasing member <NUM> is allowed to expand, thereby causing the second piston <NUM> to move to the second position. In the second position, the second piston <NUM> no longer blocks fluid communication between the bore <NUM> and the bore <NUM>. Thus, fluid communication is established between the fluid communication line <NUM> and the bore <NUM>.

When the operator is ready to release the whipstock <NUM> from the milling tool <NUM>, the pressure and or fluid flow is applied through fluid communication line <NUM> to move the actuator piston <NUM> from the first position to the second position. If the operator had stopped fluid flow in the line fluid communication <NUM>, then pumping is reestablished to actuate the actuator piston <NUM> of the third piston assembly <NUM>.

The movement of the actuator piston <NUM> moves the latch <NUM> of the latch member <NUM> away from the latch portion <NUM> of the locking member <NUM>. Once the latch <NUM> fully disengages with the latch portion <NUM> as shown in <FIG>, then the locking member <NUM> is moved from the extended position (<FIG>) to the retracted position (<FIG>), thereby releasing to whipstock <NUM> from the milling tool <NUM>.

After the whipstock <NUM> is released, the milling tool <NUM> may begin a milling operation to create a side track of wellbore <NUM>. The collar <NUM> will be completely or partially milled away at the beginning of the operation. The milling tool <NUM> is moved along the whipstock <NUM> to form at least a portion of the side track. In some embodiments, a portion of the whipstock <NUM> and the latch release mechanism <NUM> will be milled away by the milling tool <NUM>. In some embodiments, the latch actuator <NUM> will be milled completely away. Thereafter, what remains of the whipstock <NUM> may be retrieved from the wellbore <NUM> by a retrieval tool.

The fluid communication line <NUM> may be connected to a control line (not shown) that extends to the surface. Alternatively, as shown in <FIG>, the fluid communication line is in fluid communication with a bore <NUM> of the milling tool <NUM>. The bore <NUM> may have a nozzle <NUM> disposed therein and be in communication with fluid flow paths <NUM>. Thus, the bore <NUM> is in fluid communication with the wellbore <NUM> via the fluid flow paths <NUM>. The nozzle <NUM> presents a restriction to fluid flow in the bore <NUM>. To generate flow through the nozzle <NUM>, a pressure difference is required, which manifests in a higher pressure in the bore <NUM> upstream from the nozzle <NUM> than immediately downstream of the nozzle <NUM>. This higher pressure is communicated through the fluid communication line <NUM> to both the anchoring mechanism <NUM> and the latch release mechanism <NUM>. As shown in <FIG>, the fluid communication line <NUM> can be disposed outside of the whipstock <NUM>; however, it is contemplated that the fluid communication line <NUM> may be at least partially disposed within the body <NUM> of the whipstock <NUM> as shown in <FIG>. It is contemplated that the fluid communication line <NUM> would be in communication with a bore <NUM> of the milling tool <NUM> that does not have a nozzle <NUM>. It is also contemplated that the inlet <NUM> could not be connected to the fluid communication line <NUM>, and instead would be sensitive to pressure increase and decreases in the wellbore <NUM> to actuate the piston assemblies <NUM>, <NUM>, <NUM> of the latch release mechanism <NUM>.

<FIG> illustrates a cross section of whipstock <NUM> with the latch actuator <NUM> of the latch release mechanism <NUM> disposed in the aperture <NUM>. <FIG> is an expanded view of the region circled in <FIG>. A portion of the fluid communication line <NUM> is shown. The latch member <NUM> may also be secured to the housing <NUM> by at least one shearable member <NUM>. The shearable members <NUM> are configured to retain the latch member <NUM> in engagement with the latch portion <NUM> of the locking member <NUM> during run in of the BHA <NUM> in the event an obstruction in the wellbore contacts a portion of the latch member <NUM>. The shearable members <NUM> are sheared, thus releasing the latch member <NUM> from the housing <NUM>, by the application of sufficient pressure to the actuator piston <NUM> after fluid communication is established between the inlet <NUM> and the third piston assembly <NUM>. The latch member <NUM> and the actuator piston <NUM> is allowed to move once the shearable members <NUM> are sheared. Thus, the shearable members <NUM> retain the latch member <NUM> in a deployment position and retain the actuator piston <NUM> in the first position prior to being sheared.

A gap <NUM> exists between the back member <NUM> of the third piston assembly <NUM> and a wall of the aperture <NUM> in the body <NUM> of the whipstock <NUM>. The gap <NUM> is sized to allow for the extension of the actuator piston <NUM> from the first position to the second position. In an alternative embodiment, the gap <NUM> may be sized such that, just after the actuator piston <NUM> reaches the second position and thus allows the latch member <NUM> to disengage with the latch portion <NUM> of the locking member <NUM>, the back member <NUM> contacts the wall of the aperture <NUM> to prevent further extension of the actuator piston <NUM> as shown in <FIG>. Thus, the extension of the actuator piston <NUM> is physically restrained by the wall of the aperture <NUM> and not by the engagement of a portion of the actuator piston <NUM> with the housing <NUM>. However, it is contemplated that a portion of the actuator piston <NUM> may limit the extension of the actuator piston <NUM>.

A gap <NUM>, as shown in <FIG>, exists between the wall of the aperture <NUM> and the first piston assembly <NUM> and the second piston assembly <NUM>. The gap <NUM> is configured to accommodate the extension of pistons <NUM> or <NUM>. The gap <NUM> may be omitted if the pistons <NUM> or <NUM> do not extend beyond their respective housing connection members <NUM>, <NUM>.

The actuator piston <NUM> and latch member <NUM> of the latch release mechanism <NUM>, shown in <FIG>, will move in the downhole direction when the actuator piston <NUM> moves from the first position to the second position. However, it is contemplated that the latch release mechanism <NUM> can be inverted such that the extension of the actuator piston <NUM> and latch member <NUM> will move in the uphole direction when the actuator piston <NUM> moves from the first position to the second position. The latch <NUM> of the latch member <NUM> would be configured to disengage from the latch portion <NUM> of the locking member <NUM> when moved uphole by the actuator piston <NUM>.

As shown in <FIG>, the aperture <NUM> is formed fully through the body <NUM> of the whipstock <NUM>. As shown in <FIG>, the concave face <NUM> is partially defined by the aperture <NUM>. However, it is contemplated that the aperture <NUM> is only formed partially through the body <NUM> such that a concave face <NUM> will not be defined, in part, by the aperture <NUM>.

The latch member <NUM> may be adjustable in length. An embodiment of the adjustable latch member is illustrated in <FIG>. The latch member <NUM> may be formed from a first latch member <NUM> coupled to a second latch member <NUM> via a connection member <NUM>. The latch <NUM> of the latch member <NUM> may be attached to the second latch member <NUM> and the first latch member <NUM> may be attached to the third piston assembly <NUM>. The connection member <NUM> may be adjusted to change the length of the latch member <NUM>. For example, the connection member <NUM> is threadedly connected to at least one of the first and second latch members <NUM>, <NUM>. Rotation of the connection member <NUM> may axially move the connection member <NUM> relative to at least one of the first and second latch members <NUM>, <NUM>. During assembly, the latch member <NUM> may be extended from a retracted position to an extended position so the latch <NUM> engages the latch portion <NUM> of the locking member <NUM>. The abutment of abutment member <NUM> of the second latch member <NUM> with an inner surface of the connection member <NUM> facilitates the translation of the second latch member <NUM> when the first latch member <NUM> is translated by the third piston assembly <NUM>.

As shown in <FIG>, the latch member <NUM> is attached to the back member <NUM> and partially disposed within the wall of the body <NUM> of the whipstock <NUM>. The latch member <NUM> may be disposed within a bore formed within the whipstock <NUM> or a channel <NUM> formed on the surface of the whipstock <NUM> as shown in <FIG>. A latch channel <NUM> may be formed in the whipstock <NUM> to accommodate the movement of the latch <NUM>. The latch member <NUM> may also be disposed outside of the whipstock <NUM>.

<FIG> illustrate an alternative embodiment a latch release mechanism <NUM> releasably connecting a whipstock <NUM> to a downhole tool <NUM>, such as a milling tool. The latch release mechanism <NUM>, whipstock <NUM>, anchor <NUM>, and downhole tool <NUM> may be part of a BHA. The latch release mechanism <NUM> includes a connection mechanism <NUM>. As shown in <FIG>, the connection mechanism <NUM> includes a tubular sub <NUM> disposed between a whipstock <NUM> and an anchor <NUM>. The tubular sub <NUM> has a first bore portion <NUM>, a second bore portion, <NUM>, and a third bore portion <NUM> that links the first and second bore portions <NUM>, <NUM>. As shown in <FIG>, the whipstock <NUM> is threadedly attached to the second bore portion <NUM>, and the anchor <NUM> has a mandrel <NUM> at least partially disposed within the first bore portion <NUM>. A biasing member <NUM> may be disposed about the mandrel <NUM> and between adjacent faces of the tubular sub <NUM> and the anchor <NUM>.

As shown in <FIG>, the connection mechanism <NUM> has a switch <NUM>. The switch <NUM> is a valve assembly <NUM> having a first valve member <NUM> and a second valve member <NUM> may be at least partially disposed in the third bore <NUM>. The first valve member <NUM> may be threadedly attached to the tubular sub <NUM> or attached by other conventional mechanism. In this embodiment, the first valve member <NUM> is a tubular sleeve having a bore <NUM>, and the second valve member <NUM> is a cylindrical rod. The second valve member <NUM> is disposed within the bore <NUM> of the first valve member <NUM> and movable from a first position (<FIG>) to a second position (<FIG>).

The tubular sub <NUM> may have an inlet port <NUM> and an outlet port <NUM>. The inlet port is in fluid communication with an inlet port <NUM> of the first valve member <NUM>. The outlet port <NUM> is in fluid communication with an outlet port <NUM> of the first valve member <NUM>. Sealing members <NUM> prevent unintended fluid communication between the inlet port <NUM> and outlet port <NUM> about the outer circumference of the first valve member <NUM>.

The second valve member <NUM> has rod body <NUM>, a first sealing region <NUM> defined between sealing member 758a and sealing member 758b, and a second sealing region <NUM> defined between sealing member 758b and sealing member 758c. The sealing members 758a,b,c are disposed about the outer diameter of the rod body <NUM> to seal against the first valve member <NUM>. The rod body <NUM> of the second valve member <NUM> has a spacer portion <NUM> disposed between the sealing members 758b, 758c. The spacer portion <NUM> has an outer diameter that is smaller than the outer diameter of the rod body <NUM> where seals 758a,b,c are disposed. An annular chamber <NUM> is formed between the outer surface of the spacer portion <NUM> and the first valve member <NUM>, the annular chamber <NUM> being further disposed between the sealing members 758b, 758c. A biasing member <NUM>, such as a spring, is disposed between a first end <NUM> of the second valve member <NUM> and a shoulder of the first valve member <NUM>. A second end of the second valve member <NUM> has an outer diameter that is larger than the bore <NUM> of the first valve member <NUM>. In one embodiment, the first end <NUM> is a cap that is attached to the rod body <NUM> after it is inserted into the first valve member <NUM> and the biasing member <NUM> is disposed around the rod body <NUM>.

When the second valve member <NUM> is in the first position, a portion of the second valve member <NUM> protrudes into the first bore portion <NUM> of the tubular sub <NUM>. Fluid communication between the inlet port <NUM> and the outlet port <NUM>, and fluid communication between inlet port <NUM> and outlet port <NUM>, are blocked by the second valve member <NUM> when in the first position. As shown in <FIG>, the second valve member <NUM> is positioned such that the outlet port <NUM> is between two sealing members 758a,b defining the first sealing region <NUM>.

When the second valve member is moved to the second position, as shown in <FIG>, fluid communication is established between the inlet port <NUM> and the outlet port <NUM> because the first sealing region <NUM> no longer blocks the outlet port <NUM> of the first valve member <NUM>. In this embodiment, the second valve member <NUM> has moved left relative to the first valve member <NUM>. In particular, the sealing member 758b has moved to the left of the outlet port <NUM> while the sealing member 758c remained to the right of the inlet port <NUM>. In this respect, the inlet port <NUM> is allowed to communicate with the outlet port <NUM> via the annular chamber <NUM> between the sealing members 758b,c.

The second valve member <NUM> is shifted from the first position to the second position by the movement of the mandrel <NUM> in the first bore <NUM>. The contact of the mandrel <NUM> with the second valve member <NUM> is not by itself sufficient to move the second valve member <NUM> from the first position to the second position. A force is applied by the mandrel <NUM> that exceeds the biasing force of the biasing member <NUM> to move the second valve member <NUM>. In this respect, the biasing member <NUM> prevents unintended movement of the second valve member <NUM>.

In one embodiment, one or more optional shearable members (not shown) may attach the anchor <NUM> to the tubular sub <NUM>. The shearable members may be sheared upon the application of an axial force from the surface after the anchor <NUM> has been activated to engage the wellbore <NUM>. The shearable members will fail in response to an axial force that exceeds the shear strength of the shearable members. Once the shearable members fail, the mandrel <NUM> is free to axially movable relative to the tubular sub <NUM>. The biasing member <NUM> prevents premature engagement of the mandrel <NUM> with the second valve member <NUM> after the mandrel <NUM> is released.

If an anchor test determines that the anchor <NUM> failed to properly set against the wellbore <NUM>, then the whipstock <NUM>, anchor <NUM>, and tubular sub <NUM> can be removed from the wellbore <NUM>. If the anchor test determines that the anchor <NUM> failed to properly set against the wellbore <NUM>, and the anchor <NUM> has become stuck, then an axial load can be applied to shear the shearable members to allow the retrieval of the whipstock <NUM> and the tubular sub <NUM>. Thereafter, a retrieval operation may commence to retrieve the stuck anchor <NUM>.

If the anchor test is passed, and after the shearable members are sheared, then the operator can increase axial force such that the mandrel <NUM> moves the second valve member <NUM> from the first to the second position.

In an alternative embodiment, the optional shearable members (not shown) are partially disposed in slots <NUM> formed in first bore portion <NUM> of the tubular sub. Thus, the mandrel <NUM> may move within the tubular sub <NUM> without shearing the shearable members. The biasing member <NUM> prevents premature engagement of the mandrel <NUM> with the second valve member <NUM>. If an anchor test determined that the anchor <NUM> failed to properly set against the wellbore <NUM>, then the whipstock <NUM>, tubular sub <NUM>, and anchor <NUM> may be withdrawn uphole because the shearable members will engage the end of the slot <NUM> without being sheared. If the test anchor test is passed, then the operator can increase axial loading to cause the mandrel <NUM> to displace the second valve member <NUM> from the first position to the second positon. The shearable members do not have to be sheared to allow the displacement of the second valve member <NUM>.

The inlet port <NUM> may be fluidly connected with a fluid communication fluid communication line <NUM> that is in communication with the anchor <NUM> and the inlet port <NUM>. Thus, the inlet port <NUM> may experience a pressure and/or fluid flow to set the anchor <NUM>. The second valve member <NUM> in the first position blocks fluid communication between the inlet port <NUM> and the outlet port <NUM> while the anchor is being set. Then, the operator will test the anchor <NUM> by increasing axial load on the anchor <NUM>. While the anchor test is performed, fluid flow may be prevented to enter the inlet port <NUM>, such as by ceasing all pumping operations. The anchor test may result in the mandrel <NUM> advancing into contact with the second valve member <NUM> and the movement of second valve member from the first position to the second position. If the test is not passed, then the whipstock <NUM>, tubular sub <NUM>, and anchor <NUM> may be retrieved from the wellbore <NUM>. If the test is not passed, then the operator may commence an additional test. If the anchor test did not cause the displacement of the second valve member <NUM>, then axial load can be increased, if necessary, until the second valve member <NUM> is moved to the second position. If the test is passed, then reestablishing fluid flow and an increase in pressure through the inlet port <NUM>, such as by resuming pumping operations, will then cause fluid flow and/or pressure to be communicated from the inlet port <NUM> to the outlet port <NUM>. In some instances, reestablishment of the fluid flow may still occur if the operator decides to not retrieve the BHA based on other criteria. The outlet port <NUM> directs fluid to a latch actuator <NUM> of the alternative latch release mechanism <NUM>.

The latch release mechanism <NUM> has a latch actuator <NUM>, a latch member <NUM>, and the connection mechanism <NUM>. The latch member <NUM> may have a latch <NUM> attached at one end. <FIG> shows the whipstock <NUM> attached to the downhole tool <NUM>, such as a milling tool. As shown in <FIG>, the latch <NUM> is in engagement with the latch portion <NUM> of the lock mechanism <NUM> of the downhole tool <NUM>. <FIG> shows the latch member <NUM> disengaged from the latch portion <NUM> after the latch member <NUM> is moved by the latch actuator <NUM>. The whipstock <NUM> is released from the downhole tool once the latch member <NUM> disengages from the latch portion <NUM> of the lock mechanism <NUM>.

As shown in <FIG>, the latch actuator <NUM> is disposed in an aperture <NUM> of the whipstock <NUM>, which is similar to aperture <NUM>. The latch actuator <NUM> may be attached to the whipstock <NUM> such as by a bolts or screws inserted through mounting bores <NUM> formed in the housing <NUM> of the latch actuator <NUM>.

An embodiment of the latch actuator <NUM> is illustrated in <FIG>. The latch actuator <NUM> has a housing <NUM>, and a piston assembly <NUM> having at least one actuator piston <NUM> disposed in a piston assembly bore <NUM> of the housing <NUM>. An inlet <NUM> of the housing <NUM> is in fluid communication with the bore <NUM> via a fluid communication line <NUM>. The housing <NUM> may be integral with the downhole tool, such as whipstock <NUM>.

In some embodiments, as shown in <FIG>, the whipstock <NUM> may have a collar <NUM> and an aperture <NUM>, similar to aperture <NUM>, to facilitate axial and torsional load applied to the whipstock <NUM> and downhole tool <NUM> while isolating the lock mechanism <NUM> from torsional and/or axial loading.

The latch member <NUM>, having a latch <NUM>, of the latch release mechanism <NUM> is connected to the piston assembly <NUM>. The latch member <NUM> and latch <NUM> are similar to the latch member <NUM> having latch <NUM>. The latch member <NUM> may be partially disposed in a wall of the whipstock <NUM>, a channel formed on an outer surface of the whipstock <NUM>, or disposed outside of the walls of the whipstock <NUM>. The latch <NUM> engages the latch portion <NUM> of the locking member <NUM>. Shearable members <NUM>, similar to shearable members <NUM>, initially retain the latch member <NUM> in a fixed position relative to the housing <NUM>. The shearable members <NUM> are sheared, thus releasing the latch member <NUM> from the housing <NUM>, by the application of sufficient pressure to the actuator piston <NUM> after the second valve member <NUM> has been moved to the second position. Thus, the shearable members <NUM> retain the latch member <NUM> in a deployment position and retain the actuator piston <NUM> in the first position prior to being sheared. Once the latch <NUM> has moved out of engagement with the latch portion <NUM> of the lock mechanism <NUM>, then the locking member <NUM> may retract allowing the release of the whipstock <NUM> from the downhole tool <NUM>. The latch member <NUM> may be partially disposed in housing <NUM>. The latch member <NUM> is attached to the actuator piston <NUM> or a back member <NUM>.

Fluid communication directed to the latch actuator <NUM> of the latch release mechanism <NUM> enters the housing via inlet <NUM>. The inlet <NUM> is in fluid communication with piston assembly bore <NUM> via a fluid communication line <NUM>. The piston assembly <NUM> may be similar to the third piston assembly <NUM>. As shown in <FIG>, the actuator piston <NUM> may be a tandem piston, similar to tandem piston <NUM>, and has a back member <NUM>. However, it is contemplated that actuator piston <NUM> may be one piston or more than two pistons. The actuator piston <NUM> may have one or more sealing members <NUM> disposed about each individual piston of the actuator piston <NUM> to seal against the piston assembly bore <NUM>. In some embodiments, the one or more sealing members <NUM> is an O-ring disposed about each individual piston.

Fluid flow and or pressure communicated from the outlet port <NUM> to the piston assembly bore <NUM> will displace the actuator piston <NUM> from a first position to a second position. When the actuator piston <NUM> moves to the second position, then the latch member <NUM> moves with respect to the latch portion <NUM>, thereby allowing the locking member <NUM> to retract. The aperture <NUM> may be sized sufficiently to accommodate the movement of the actuator piston <NUM> from the first position to the second position in a similar manner to aperture <NUM>.

As shown in <FIG>, a gap <NUM> exists between the back member <NUM> of the piston assembly <NUM> and a wall of the aperture <NUM> in the body <NUM> of the whipstock <NUM>. The whipstock has a concave face <NUM>. The gap <NUM> is sized to allow for the extension of the actuator piston <NUM> from the first position to the second position. In an alternative embodiment, the gap <NUM> may be sized such that, just after the actuator piston <NUM> reaches the second position and thus allows the latch member <NUM> to disengage with the latch portion <NUM> of the locking member <NUM>, the back member <NUM> contacts the wall of the aperture <NUM> to prevent further extension of the actuator piston <NUM> as shown in <FIG>. Thus, the extension of the actuator piston <NUM> is physically restrained by the wall of the aperture <NUM> and not by the engagement of a portion of the actuator piston <NUM> with the housing <NUM>. However, it is contemplated that a portion of the actuator piston <NUM> may limit the extension of the actuator piston <NUM>. It is contemplated that the latch release mechanism <NUM> maybe be orientated such that the movement of the actuator piston <NUM> and latch member <NUM> occur in either the uphole or downhole direction with respect to the housing <NUM>.

The switch <NUM> is in the first configuration when the second valve member <NUM> is in the first position. The switch <NUM> is in the second configuration when the second valve member <NUM> is in the second position. Thus, the switch <NUM> blocks fluid communication from the fluid communication line <NUM> to the inlet <NUM>, and thus the bore <NUM>, when in the first configuration and unblocks fluid communication from the fluid communication line <NUM> to the inlet <NUM>, and thus the bore <NUM>, when in the second configuration. Once the switch <NUM> is in the second configuration, the actuator piston <NUM> may be moved in response to fluid communication.

An exemplary method of using the alternative latch mechanism <NUM> will be discussed below. The anchor <NUM> and whipstock <NUM> connected to the downhole tool <NUM> by the engagement of the latch member <NUM> with the lock mechanism <NUM> is deployed downhole. Once in the desired location and position within the wellbore <NUM>, the anchor <NUM> is set by communicating fluid flow and or pressure from the fluid communication line <NUM> to the anchor <NUM>. Fluid communication between the latch actuator <NUM> and the fluid communication line <NUM> is blocked during the setting of the anchor <NUM> by the position of the second valve member <NUM>. A test of the anchor <NUM> commences by the application of axial load to the anchor <NUM> and the cessation of pumping operations. The axial load applied during the test causes the mandrel <NUM> to move into contact with the second valve member <NUM> resulting in the second valve member <NUM> moving from the first to the second position. No fluid flow or pressure is communicated through the valve assembly <NUM> to the latch actuator <NUM> because no fluid flow or pressure is being supplied downhole from the surface.

If the operator determines that the anchor <NUM> passes the test, fluid flow and or pressure are supplied downhole. For example, fluid flow from the surface and through the nozzle <NUM> creates a high pressure zone in the milling tool bore <NUM> which allows facilitates fluid communication through the fluid communication line <NUM> to the valve assembly <NUM> and the latch actuator <NUM>. Because the second valve member <NUM> has moved from the first to the second position, fluid communication between the inlet port <NUM> and the outlet port <NUM> is established. Fluid communication is thus allowed between the fluid communication line <NUM> and the latch release mechanism <NUM>. The operator then increases pressure until the shearable members <NUM> shear allowing the latch member <NUM> and the actuator piston <NUM> to move. The actuator piston <NUM> is then displaced from the first position to the second position, causing the latch <NUM> of the latch member <NUM> to disengage with the latch portion <NUM> of the lock mechanism <NUM> to allow the locking member <NUM> to retract and thus release the milling tool <NUM> from the whipstock <NUM>. Then, the detached milling tool <NUM> may begin a milling operation to create a side track in the wellbore <NUM>. The whipstock <NUM>, tubular sub <NUM>, and anchor <NUM> can be removed from the wellbore by a retrieval tool.

In some embodiments, the latch release mechanism <NUM>, <NUM> is configured to attach a first downhole tool to a second downhole tool before being actuated to release the first downhole tool from the second downhole tool. In one embodiment, the first downhole tool is a milling tool <NUM>. In another embodiment, the first downhole tool is a running tool. In another embodiment, the second downhole tool is a packer. In another embodiment, the second downhole tool is an anchor.

In one embodiment, the first valve member <NUM> and sealing members <NUM> are omitted. A biasing member <NUM>, such as a spring, is disposed between a first end <NUM> of the second valve member <NUM> and a shoulder of the tubular sub <NUM>. Thus, the second valve member <NUM> is at least partially disposed in the third bore portion <NUM>. The annular chamber <NUM> is formed between the outer surface of the spacer portion <NUM> and the inner surface of the tubular sub <NUM>, the annular chamber <NUM> being further disposed between the sealing members 758b, 758c. The first sealing region <NUM> of the second valve member <NUM> blocks fluid communication between the inlet port <NUM> and the outlet port <NUM> when the second valve member is in the first position and fluid communication is unblocked when the second valve member <NUM> is in the second position.

<FIG> shows a downhole tool actuator assembly <NUM> having a switch assembly <NUM> and an actuator <NUM>. As shown in <FIG>, the switch assembly <NUM> may be incorporated into or disposed on a first downhole tool <NUM>, and the actuator <NUM> may be incorporated into or disposed on a second downhole tool <NUM>. The actuator <NUM> can activate or operate a downhole tool, such as the second downhole tool <NUM>. The switch assembly has a housing <NUM> and a switch <NUM>. The switch has a piston <NUM> initially retained in a first position (<FIG>) by at least one shearable member <NUM>. The shearable member <NUM> may be partially attached to the housing <NUM> or to a housing connection member <NUM>. The piston <NUM> is disposed in a bore <NUM> of the housing <NUM>. The bore <NUM> is similar to bore <NUM>, in that it has a first bore portion <NUM> and a second bore portion <NUM>. The first bore portion <NUM> has a first diameter portion 1005a and a second diameter portion 1005b, wherein the second diameter portion has a greater diameter than the first diameter portion 1005a. Fluid communication line <NUM> is in communication with inlet <NUM> and the bore <NUM>. Fluid communication line <NUM> is in communication with the bore <NUM> and outlet <NUM>. One end of the fluid communication lines <NUM>, <NUM> may be sealed by plugs <NUM> to facilitate manufacturing of the switch assembly <NUM>. A fluid communication line <NUM> is in communication with the outlet <NUM> and the actuator <NUM>. The fluid communication line <NUM> has a length to span the distance between the outlet <NUM> and the actuator <NUM>. Thus, the inlet <NUM> is in fluid communication with the piston assembly <NUM>. The actuator <NUM> has a housing <NUM> and an actuator piston <NUM> at least partially disclosed in the housing <NUM>. The actuator piston <NUM> is movable from a first position to a second position in response to fluid communication from the inlet <NUM>. The actuator <NUM> activates or actuates the first downhole tool <NUM> when in the actuator piston <NUM> is in the second position.

The piston <NUM> has a first piston head <NUM> having a greater piston surface area than a piston surface area of a second piston head <NUM>. The first piston head <NUM> has one or more sealing members <NUM> disposed about the outer circumference of the first piston head <NUM> configured to seal against the first diameter portion 1005a of the first bore portion <NUM> of the bore <NUM> when the piston <NUM> is in the first position (<FIG>) and the intermediate position (<FIG>). The second piston head <NUM> has one or more sealing members <NUM> disposed about the second piston head <NUM> and configured to seal against the second bore portion <NUM> of the bore <NUM>. The one or more sealing members <NUM>, <NUM> may be only one sealing member, such as an O-ring. The first piston head <NUM> is disposed in the first portion <NUM> of the bore <NUM>. The second piston head <NUM> is disposed in the second bore portion <NUM>. When the piston <NUM> is in the first position (<FIG>) and intermediate position (<FIG>), the second piston head <NUM> is disposed between the junctions of the fluid communication lines <NUM>, <NUM> with the bore <NUM> and blocks fluid communication between the fluid communication lines <NUM>, <NUM>. Since fluid communication is blocked between the fluid communication lines <NUM>, <NUM>, fluid communication is also blocked between the inlet <NUM> and the outlet <NUM>. The piston <NUM> is allowed to move from the first position when fluid pressure applied to the piston <NUM> is sufficient to shear the shearable members <NUM>. The piston <NUM> moves to the intermediate position as shown in <FIG>, and not the second position as shown in <FIG>, because of the differential in piston head areas of the piston heads <NUM>, <NUM>. The piston surface area of the first piston head <NUM> is greater than the piston surface area of the second piston head <NUM>. Once pressure decreases below the biasing force of biasing member <NUM>, the biasing member <NUM> extends moving the piston <NUM> to the second position as shown in <FIG>. Once in the second position, the piston head <NUM> no longer blocks fluid communication between the fluid communication lines <NUM>, <NUM>. Thus, fluid flow is no longer blocked between the inlet <NUM> and the outlet <NUM>.

Furthermore, once in the second position, the first piston head <NUM> is disposed in the second diameter portion 1005b of the first bore portion <NUM> of bore <NUM> and the one or more sealing members <NUM> disposed about the outer circumference of the first piston head <NUM> no longer seals against the bore <NUM>. The piston <NUM> will not return to the first or intermediate positon by fluid pressure in the bore <NUM> after moving to the second position because the first piston head <NUM> is not in sealing engagement with the second diameter portion 1005b of the first bore portion <NUM> of the bore <NUM>.

The switch <NUM> is in the first configuration, as shown in <FIG>, when the piston <NUM> is in the first position. Fluid communication between a fluid communication line <NUM> and a fluid communication line <NUM> is blocked when the switch <NUM> is in the first configuration. The switch <NUM> is in an intermediate configuration, as shown in <FIG>, when the piston <NUM> is in the intermediate position after the shearable members <NUM> fail. Fluid communication between the fluid communication lines <NUM>, <NUM> is blocked when the switch <NUM> is in the intermediate configuration. The switch <NUM> is in the second configuration, as shown in <FIG>, when the piston <NUM> is in the second position. Fluid communication between the fluid communication line <NUM> and the fluid communication line <NUM> is unblocked when the piston <NUM> is in the second position. Thus, fluid communication between the inlet <NUM> and the actuator <NUM>, via the fluid communication line <NUM> extending from the outlet <NUM> to the actuator <NUM>, is established when the switch <NUM> is in the second configuration. Once the switch <NUM> is in the second configuration, the actuator piston <NUM> may be moved from the first position (see <FIG>) to the second position (see <FIG>) in response to fluid communication in the fluid communication line <NUM>. The actuator <NUM> activates or actuates the second downhole tool <NUM> when the actuator piston <NUM> is in the second position.

The inlet <NUM> is in communication with a first branch 1230a of the fluid communication line <NUM>. The fluid communication line <NUM> is also in communication with a first downhole tool actuator <NUM> of the first downhole tool <NUM> via a second branch 1230b of the fluid communication line <NUM>. The first downhole tool actuator <NUM> is configured to actuate or activate the first downhole tool <NUM> in response to fluid communication in the second branch 1230b of the fluid communication line <NUM>. Thus, the switch <NUM> is responsive to the fluid pressures in the fluid communication line <NUM> via the inlet <NUM>. The switch <NUM> of the switch assembly <NUM> prevents the actuation or activation of the second downhole tool <NUM> while the first downhole tool <NUM> is being activated or actuated by the first downhole tool actuator <NUM>.

For example, the first downhole tool <NUM> is activated or actuated by the first downhole tool actuator <NUM> in response to a pressure in the fluid communication line <NUM> that is higher than the pressure necessary to actuate or activate the second downhole tool <NUM> with the actuator <NUM>. The shearable members <NUM> are configured to shear in response to the pressure needed to operate the first downhole tool actuator <NUM> to cause the actuation or activation of the first downhole tool <NUM>. The shearable members <NUM> may be configured to shear at a pressure greater than necessary to operate the first downhole tool actuator <NUM> to cause the actuation or activation of the first downhole tool <NUM>. Once the shearable members <NUM> fail, the piston <NUM> moves from the first position (<FIG>) to the intermediate position (<FIG>). The piston <NUM> does not move to the second position because of the differential in piston head surface areas between the first piston head <NUM> and the second piston head <NUM>. After the first downhole tool <NUM> is actuated or activated by the first downhole tool actuator <NUM>, then pressure in the fluid communication line <NUM>, and thus the bore <NUM>, can be decreased below the biasing force of the biasing member <NUM>. As a result, the piston <NUM> moves to the second position (<FIG>) to establish fluid communication between the first branch 1230a of the fluid communication line <NUM> and the actuator <NUM>. When the piston <NUM> is in the second position, fluid communication between the fluid communication line <NUM> and the actuator <NUM> is established. Thus, the actuator piston <NUM> can then be moved in response to fluid communication in the fluid communication line <NUM> to activate or actuate the second downhole tool <NUM>.

In some embodiments, as shown in <FIG>, the switch assembly <NUM> is incorporated into or disposed on a first downhole tool <NUM> and the actuator <NUM> is also incorporated into or disposed on the first downhole tool <NUM>. In this embodiment, the actuator <NUM> is configured to activate or actuate the first downhole tool <NUM> instead of the first downhole tool actuator <NUM>. The first downhole tool <NUM> is coupled to the second downhole tool <NUM>. A second downhole tool actuator <NUM> of the second downhole <NUM> tool is configured to activate or actuate the second downhole tool <NUM> in response to a pressure in the second branch 1230b of the fluid communication line <NUM>. The fluid communication line <NUM> is also in communication with the inlet <NUM> of the switch assembly <NUM> via the first branch 1230a of the fluid communication line <NUM>. The switch <NUM> of the switch assembly <NUM> prevents fluid communication between the fluid communication line <NUM> and the actuator <NUM> while the second downhole tool <NUM> is activated or actuated via the second downhole tool actuator <NUM>.

For example, the shearable members <NUM> are configured to shear in response to the pressure in the fluid communication line <NUM> needed to operate the second downhole tool actuator <NUM> to cause the actuation or activation of the second downhole tool <NUM>. The shearable members <NUM> may be configured to shear at a pressure greater than necessary to operate the second downhole tool actuator <NUM> to cause the actuation or actuation of the second downhole tool <NUM>. Once the shearable members <NUM> fail, the piston <NUM> moves from the first position (<FIG>) to the intermediate position (<FIG>). The piston <NUM> does not move to the second position because of the differential in piston head surface areas between the first piston head <NUM> and the second piston head <NUM>. After the second downhole tool <NUM> is actuated or activated by the second downhole tool actuator <NUM>, then pressure in the fluid communication line <NUM>, and thus pressure in the bore <NUM>, can be decreased below the biasing force of the biasing member <NUM>. As a result, the piston <NUM> moves to the second position (<FIG>) to establish fluid communication between the fluid communication line <NUM> and the actuator <NUM>. The actuator piston <NUM> can then be moved in response fluid communication in the fluid communication line <NUM> to activate or actuate the first downhole tool <NUM>.

In some embodiments, the switch assembly <NUM> is not incorporated into or disposed on a first downhole tool, and is instead located on another downhole tool, such as a tubular sub, and is in fluid communication with the first downhole tool and the actuator <NUM>.

In some embodiments, the switch assembly <NUM> has a second switch (not shown) similar to the first piston assembly <NUM> having the first piston <NUM>. The second switch blocks fluid communication between the inlet <NUM> and the switch <NUM> when the second switch is in a first position. The second switch is movable from the first position to the second position in response to pressure communicated through the inlet <NUM>. Once the second switch is in the second position, fluid communication between the inlet <NUM> and the outlet <NUM> is still blocked by the switch <NUM> until the piston <NUM> moves to the second position. Instead of the first piston assembly <NUM>, the second switch maybe a rupture disc may be disposed in the fluid communication line <NUM> to initially block fluid communication between the inlet <NUM> and the switch <NUM> prior to the rupturing of the disc in response to an increase in pressure sufficient to rupture the disc.

In one or more embodiments, a latch release mechanism incudes a housing having a fluid inlet and an actuator piston at least partially disposed in the housing and movable from a first positon to a second position in response to fluid communication from the fluid inlet. The latch release mechanism further includes a latch member coupled to the actuator piston and movable from a first positon to a second position by the actuator piston. The latch release mechanism further includes a switch having a first configuration, a second configuration, and an intermediate configuration, wherein fluid communication is blocked when the switch is in the first configuration and the intermediate configuration, and wherein the fluid communication is unblocked when the switch is in the second configuration. The actuator piston is movable to the second position when the switch is in the second configuration.

In one or more embodiments, the switch comprises a piston assembly at least partially disposed in the housing, the piston assembly having a piston with a first piston head and a second piston head, wherein the first piston head has a greater piston surface area than a piston surface area of the second piston head.

In one or more embodiments, the piston has a first position corresponding to the first configuration of the switch, a second positon corresponding to the second configuration of the switch, and an intermediate position corresponding to an intermediate configuration of the switch.

In one or more embodiments, the latch member is adjustable in length.

In one or more embodiments, the switch is a second switch and the latch release mechanism further includes a first switch having a first configuration and a second configuration. Fluid communication is blocked when the first switch and second switch are both in their respective first configurations and wherein the fluid communication is unblocked when the first switch and the second switch are in their respective second configurations.

In one or more embodiments, the first switch is a first piston assembly having a first piston, and the second switch is a second piston assembly having a second piston. The second piston has a first piston head and a second piston head, wherein the first piston head has a greater piston surface area than a piston surface area of the second piston head.

In one or more embodiments, an assembly for use downhole includes an actuator and a switch assembly. The switch assembly has a housing having an inlet in selective fluid communication with the actuator, and a switch having a first configuration, an intermediate configuration, and a second configuration. The switch blocks fluid communication between the inlet and the actuator when in the first configuration and the intermediate configuration. The switch allows fluid communication between the inlet and the actuator when in the second configuration.

In one or more embodiments, the switch is a piston assembly with a piston having a first piston head and a second piston head, wherein the first piston head has a greater piston surface area than a piston surface area of the second piston head.

In one or more embodiments, the piston has a first position corresponding to the first configuration of the switch, a second position corresponding to the second configuration of the switch, and an intermediate position corresponding to the intermediate configuration of the switch.

In one or more embodiments, the switch is a first switch, and the switch assembly further includes a second switch having a first configuration and a second configuration, wherein the second switch moves from the first configuration to the second configuration prior to the switch converting to the second configuration.

In one or more embodiments, the first switch of the switch assembly is a first piston assembly and the second switch of the switch assembly is a second piston assembly.

In one or more embodiments, the actuator of the assembly for use downhole is incorporated into a first downhole tool and the switch assembly of the assembly for use downhole is incorporated into a second downhole tool.

In one or more embodiments, a bottom hole assembly includes a whipstock, a downhole tool having a lock mechanism, and a latch release mechanism attached to the whipstock and configured to releasably attach the whipstock to the downhole tool.

In one or more embodiments, the latch release mechanism of the bottom hole assembly includes an actuator piston movable from a first position to a second position in response to fluid communication. The latch release mechanism further includes a switch having a first configuration, a second configuration, and an intermediate configuration, wherein fluid communication is blocked when the switch is in the first configuration and the intermediate configuration, and wherein the fluid communication is unblocked when the switch is in the second configuration. The latch release mechanism further includes a latch member coupled to the piston and configured to engage the lock mechanism in a first positon and to disengage from the lock mechanism in a second position, wherein the latch member is movable from the first position to the second position by the actuator piston when the switch is in the second configuration.

In one or more embodiments, the switch of the latch release mechanism comprises a piston assembly having a piston with a first piston head and a second piston head, wherein the first piston head has a greater piston surface area than a piston surface area of the second piston head.

In one or more embodiments, the switch is a second switch and the latch release mechanism further includes a first switch having a first configuration and a second configuration, wherein the fluid communication is blocked when the first switch and second switch are both in their respective first configurations and wherein the fluid communication is unblocked when the first switch and the second switch are in their respective second configurations.

In one or more embodiments, the first switch is a first piston assembly having a first piston, and the second switch is a second piston assembly having a second piston with a first piston head and a second piston head, wherein the first piston head has a greater piston surface area than a piston surface area of the second piston head.

In one or more embodiments, a method of releasing a whipstock from a downhole tool includes running a bottom hole assembly having the whipstock releasably attached to the downhole tool into a wellbore, wherein the whipstock has a latch release mechanism and the downhole tool has a lock mechanism, and wherein a latch member of the latch release mechanism is engaged with a locking member of the lock mechanism. The method further includes converting a switch of the latch release mechanism from a first configuration to a second configuration to unblock a fluid communication between a fluid communication line and an actuator piston attached to the latch member. The method further includes releasing the whipstock from the downhole tool by moving the actuator piston coupled to the latch member to disengage the latch member from the locking member in response to the fluid communication in the fluid communication line.

In one or more embodiments, the method includes setting an anchor of the BHA by increasing pressure in the fluid communication line prior to converting the switch.

In one or more embodiments the method includes testing the anchor prior to moving the piston coupled to the latch member.

In one or more embodiments, the switch converts to an intermediate configuration prior to converting to the second configuration, wherein the fluid communication between the fluid communication line and the piston coupled to the latch member is blocked in the intermediate configuration.

In one or more embodiments, a collar is attached to the whipstock and disposed about a portion of the downhole tool, and wherein torque is transferred from the downhole tool to the whipstock via the collar.

In one or more embodiments, the bottom hole assembly includes a whipstock having a latch release mechanism, a milling tool having a plurality of blades and a lock mechanism, and a collar coupled to the whipstock and disposed about a portion of the milling tool, wherein the blades of the milling tool abut the collar. The milling tool is releasably coupled to the whipstock by the interaction of the latch release mechanism and the lock mechanism.

In one or more embodiments, the collar has a plurality of apertures and the milling tool has a plurality of recesses. The bottom hole assembly further includes and a plurality of torque keys, wherein each torque key is at least partially disposed in a corresponding aperture and recess, and wherein the torque keys are configured to allow the transfer of torque from the milling tool to the whipstock.

In one or more embodiments, the latch release mechanism includes an actuator piston movable from a first position to a second position in response to fluid communication. The latch release mechanism further includes a switch having a first configuration, a second configuration, and an intermediate configuration, wherein fluid communication is blocked when the switch is in the first configuration and the intermediate configuration, and wherein the fluid communication is unblocked when the switch is in the second configuration. The latch release mechanism further includes a latch member coupled to the piston and configured to engage the lock mechanism in a first positon and to disengage from the lock mechanism in a second position, wherein the latch member is movable from the first position to the second position by the actuator piston when the switch is in the second configuration.

In one or more embodiments, the switch of the latch release mechanism is a piston and the piston has a first position corresponding to the first configuration of the switch, a second positon corresponding to the second configuration of the switch, and an intermediate position corresponding to an intermediate configuration of the switch.

In one or more embodiments, the switch is a second switch. The latch release mechanism further includes a first switch having a first configuration and a second configuration, wherein the fluid communication is blocked when the first switch and second switch are both in their respective first configurations and wherein the fluid communication is unblocked when the first switch and the second switch are in their respective second configurations.

In one or more embodiments, the latch release mechanism has a first and second switch. The first switch is a first piston assembly having a first piston, and the second switch is a second piston assembly having a second piston with a first piston head and a second piston head, wherein the first piston head has a greater piston surface area than a piston surface area of the second piston head.

In one or more embodiments, a bottom hole assembly has a milling tool having a lock mechanism, a whipstock, and anchor. The bottom hole assembly has a latch release mechanism having a tubular connection mechanism disposed between the whipstock and anchor and a latch actuator. The tubular connection mechanism has a tubular sub having a bore therethrough a valve assembly. The valve assembly has a first valve member having an inlet port and an outlet port, and a second valve member movable from a first position to a second position, the second valve member having a first sealing region and a second sealing region, wherein when the second valve member is in the first position, the first sealing region prevents fluid communication between the inlet port and the outlet port, and wherein when the second valve member is in the second position, the second sealing region allows fluid communication between the inlet port and the outlet port. The latch actuator is coupled to the whipstock and in selective fluid communication with the inlet port. The latch actuator has an actuator piston movable from a first position to a second position in response to fluid communication when the second valve member is in the second position, and a latch member coupled to the piston and movable by the actuator piston from a first position where the latch member is engaged with the lock mechanism to a second position where the latch member is disengage from the lock mechanism.

In one or more embodiments, the bottom hole assembly also has a collar attached to the whipstock, wherein the downhole tool is engaged with the collar when the latch member is in a first position.

In one or more embodiments, the collar has a plurality of apertures and the milling tool has a plurality of recesses. A plurality of torque keys is at least partially disposed in a corresponding aperture and recess.

In one or more embodiments, the collar has a plurality of apertures and the downhole tool has a plurality of recesses. A plurality of torque keys is at least partially disposed in a corresponding aperture and recess.

In one or more embodiments, a biasing member is disposed between a first end of the second valve member and the first valve member, wherein the biasing member is configured to bias the second valve member in the first position.

In one or more embodiments, the latch release mechanism includes a tubular connection mechanism having a tubular sub having a bore therethrough and a valve assembly. The valve assembly has a first valve member having an inlet port and an outlet port. The valve assembly also has a second valve member movable from a first position to a second position and having a first sealing region and a second sealing region. When the second valve member is in the first position, the first sealing region prevents fluid communication between the inlet port and the outlet port. When the second valve member is in the second position, the second sealing region allows fluid communication between the inlet port and the outlet port.

In one or more embodiments, the latch release mechanism includes a latch actuator in selective fluid communication with the inlet port, having a housing, an actuator piston at least partially disposed in the housing and movable in response to fluid communication from the inlet port, and a latch member coupled to the piston and movable from a first position to a second position by the actuator piston.

In one or more embodiments, the latch release mechanism includes a biasing member disposed between a first end of the second valve member and the first valve member, and the biasing member is configured to bias the second valve member in the first position.

In one or more embodiments, the latch actuator is attached to a whipstock and the connection mechanism is disposed between an anchor and the whipstock.

In one or more embodiments, a collar is attached to the whipstock and abuts a milling tool.

In one or more embodiments, a plurality of torque keys are partially disposed in recesses in the milling tool and corresponding apertures in the collar.

Claim 1:
A latch release mechanism (<NUM>), comprising:
a housing (<NUM>) having a fluid inlet (<NUM>);
an actuator piston (<NUM>) at least partially disposed in the housing (<NUM>) and movable from a first positon to a second position in response to fluid communication from the fluid inlet (<NUM>);
a latch member (<NUM>) coupled to the actuator piston (<NUM>) and movable from a first positon to a second position by the actuator piston (<NUM>); and
a switch (<NUM>) having a first configuration, a second configuration, and an intermediate configuration, wherein fluid communication is blocked when the switch (<NUM>) is in the first configuration and the intermediate configuration, and wherein the fluid communication is unblocked when the switch is in the second configuration, wherein the switch (<NUM>) comprises a piston assembly (<NUM>) at least partially disposed in the housing (<NUM>), the piston assembly (<NUM>) having a piston (<NUM>) with a first piston head (<NUM>) and a second piston head (<NUM>), wherein the first piston head (<NUM>) has a greater piston surface area than a piston surface area of the second piston head (<NUM>);
wherein the actuator piston (<NUM>) is movable to the second position when the switch (<NUM>) is in the second configuration.