Patent Description:
A whipstock is sometimes used in well drilling operations to form a lateral or branch wellbore from a main or parent wellbore. If the main or parent wellbore is lined with casing, a window may be formed through the casing by use of the whipstock with a mill specifically designed for this purpose.

Typically, the whipstock is releasably attached to the mill during conveyance of this equipment into the well. When the whipstock is at a desired position, an anchor is set and the mill is released from the whipstock.

A shearable bolt is typically used to releasably secure the whipstock to the mill. However, the bolt may be inadvertently or prematurely sheared, for example, if an obstruction is encountered during the conveyance of the equipment into the well, substantial changes in wellbore direction are encountered, etc..

Therefore, it will be readily appreciated that improvements are continually needed in the art of designing, constructing and operating mechanisms for releasing mills from whipstocks in wells. Such improvements may be useful in a variety of different drilling operations, such as, forming casing exit windows, drilling lateral or branch wellbores, sidetracking, etc..

<CIT> discloses signal operated tools for milling, drilling, and/or fishing operations. In one embodiment, a bottomhole assembly includes a lead mill, a whipstock and an anchor. Once the whipstock is oriented, an RFID tag is dropped/pumped through coiled tubing to a setting tool. The setting tool receives an instruction signal from the tag and sets the anchor.

<CIT> discloses methods for drilling a lateral borehole from a primary wellbore. A window is milled in a wellbore casing using a casing bit. The casing bit passes through the window and into the surrounding formation. A protective sheath coupled to the casing bit also extends through the window. An anchor is used to secure the protective sheath and/or casing bit in place. A drill bit drills through the casing bit and into the formation to extend the lateral borehole. The drill bit is included in a single trip assembly with the casing bit and protective sheath.

<CIT> discloses systems, assemblies, and methods which relate to drilling a lateral borehole from a primary wellbore. The primary wellbore has a casing therein and a window is milled in the casing using a casing bit.

<CIT> discloses an RFID tag arrangement for actuating a downhole tool including a non-metallic housing enclosing a passive RFID tag, power source, pulsed oscillator circuit, and energizer coil.

<CIT> discloses a whipstock assembly for use in deviating a wellbore of a well.

Representatively illustrated in <FIG> is a system <NUM> and associated method which can embody principles of this disclosure. However, it should be clearly understood that the system <NUM> and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible. The scope of the invention is nevertheless defined by independent assembly claim <NUM> and independent method claim <NUM>. The dependent claims represent alternatives.

In the <FIG> example, a bottom hole assembly <NUM> is being conveyed into a wellbore <NUM> that is lined with casing <NUM> and cement <NUM>. It is desired, in this example, to drill another wellbore (such as, a branch or lateral wellbore) intersecting the wellbore <NUM>.

The bottom hole assembly <NUM> includes an anchor <NUM>, a whipstock <NUM> and a mill <NUM>. Additional or different components (such as, a casing annular section locator, an orienting device, etc.) may be used in other examples. The scope of this disclosure is not limited to the use of any particular components or combination of components in a bottom hole assembly.

The anchor <NUM> is used to secure the whipstock <NUM> at a desired position in the wellbore <NUM> for forming an exit window through the casing <NUM>. The anchor <NUM> may be set in the wellbore <NUM> using a variety of different techniques, such as, by applying hydraulic pressure to a setting mechanism of the anchor, by mechanical manipulation of the anchor (for example, raising, rotating, lowering, etc.), or by inflating an elastomeric element of the anchor.

In some examples, the anchor <NUM> may include slips for gripping an inner surface of the casing <NUM>, or keys that engage one or more corresponding profiles formed in the casing. The anchor <NUM> could be a packer, or an anchoring device without an annular seal element for sealing against the casing <NUM>. The scope of this disclosure is not limited to use of any particular type of anchor in a bottom hole assembly, or to any particular technique for securing the anchor in a wellbore.

The whipstock <NUM> is used to laterally deflect the mill <NUM>. For this purpose, the whipstock <NUM> includes an inclined surface <NUM> formed thereon. When the mill <NUM> is displaced downhole relative to the whipstock <NUM> after the anchor <NUM> is set, the inclined surface <NUM> will deflect the mill laterally, thereby causing the mill to cut an opening or window through the casing <NUM>.

In the example depicted in <FIG>, the mill <NUM> is of the type known to those skilled in the art as a lead or pilot mill specially configured to initiate the cutting of the window through the casing <NUM>. A drill string <NUM> connected above the mill <NUM> can include other types of mills and other cutting devices, such as, watermelon mills, finishing mills, etc. The scope of this disclosure is not limited to use of any particular type or combination of mills or other cutting devices in a drill string.

The mill <NUM> in this example is also specially configured for releasable attachment to the whipstock <NUM>, as described more fully below. It is desirable for the anchor <NUM>, the whipstock <NUM> and the mill <NUM> to be conveyed into the wellbore <NUM> in a single trip into the well, for convenience, efficiency and reduced expense. Thus, after the whipstock <NUM> has been appropriately positioned in the wellbore <NUM> and the anchor <NUM> has been set, the mill <NUM> is released from the whipstock and is displaced downhole while rotating, in order to begin cutting through the casing <NUM>.

Referring additionally now to <FIG>, a more detailed cross-sectional view of an example of the releasable attachment between the mill <NUM> and the whipstock <NUM> is representatively illustrated. In this example, a collar or annular section <NUM> near an upper end <NUM> of the whipstock <NUM> encircles the mill <NUM> and is releasably secured to an outer diameter <NUM> of the mill positioned longitudinally between cutting structures <NUM>, <NUM> on the mill.

As depicted in <FIG>, a retractable pin <NUM> is laterally slidingly received in the mill <NUM>. The pin <NUM> is biased rightward (as viewed in <FIG>) by a spring <NUM> or another biasing device. The pin <NUM> has a grooved head <NUM> that is received in an opening <NUM> formed through the annular section <NUM> of the whipstock <NUM>.

A latch member <NUM> of a hydraulic release mechanism <NUM> initially retains the head <NUM> in the opening <NUM>, thereby preventing the pin <NUM> from fully retracting into the mill <NUM>. The latch member <NUM> is configured to engage the grooved head <NUM> and thereby prevent retraction of the pin <NUM> when the latch member is in an upper position as depicted in <FIG>.

However, when the hydraulic release mechanism <NUM> is actuated to displace the latch member <NUM> downward and out of engagement with the grooved head <NUM>, the spring <NUM> will then be able to displace the pin <NUM> to the right (as viewed in <FIG>). This will withdraw the head <NUM> from the opening <NUM>, and will thereby permit the mill <NUM> to be displaced downhole relative to the whipstock <NUM>.

Suitable hydraulic release mechanisms are described in <CIT> and <CIT>. A hydraulic release mechanism described in the <CIT> and <CIT> is actuated by flowing fluid <NUM> through an internal flow passage <NUM> extending through the drill string <NUM>. When a flow rate of the fluid <NUM> is increased to a predetermined level, hydraulic pressure is applied to one or more pistons of the hydraulic release mechanism <NUM>, thereby causing the latch member <NUM> to be displaced downward and out of engagement with the head <NUM>.

In the <FIG> & <FIG> system <NUM>, however, hydraulic pressure is not applied to the pistons of the hydraulic release mechanism <NUM> in response to a predetermined flow rate of the fluid <NUM> being achieved. Instead, increased pressure is applied to the pistons of the hydraulic release mechanism <NUM> in response to a radio frequency identification (RFID) tag <NUM> being displaced with the fluid <NUM> through (or at least into) the bottom hole assembly <NUM>. In some examples described below, the RFID tag <NUM> may be displaced through the flow passage <NUM>, and then through the mill <NUM> and into the wellbore <NUM>.

Referring additionally now to <FIG>, a side view of the mill <NUM> and the whipstock <NUM> is representatively illustrated. In this view, the hydraulic release mechanism <NUM> has been actuated in response to the RFID tag <NUM> being displaced with the fluid <NUM> through the flow passage <NUM>.

Pistons <NUM> of the hydraulic release mechanism <NUM> have displaced downward due to increased hydraulic pressure applied to the pistons. The pistons <NUM> are connected to the latch member <NUM> via a rod, cable or other linkage <NUM>. Thus, the latch member <NUM> is displaced downward out of engagement with the head <NUM> of the pin <NUM> in response to the increased hydraulic pressure applied to the pistons <NUM> of the hydraulic release mechanism <NUM>.

Referring additionally now to <FIG>, a recessed area <NUM> in a lower portion of the whipstock <NUM> is representatively illustrated. In this view it may be seen that an RFID controller <NUM> and a valve <NUM> are positioned in the recessed area <NUM>. An actuator <NUM> for the valve <NUM> is electrically connected to the RFID controller <NUM>.

Tubing <NUM> extends longitudinally through the recessed area <NUM>. The tubing <NUM> provides fluid communication between the flow passage <NUM> (see <FIG>) and the anchor <NUM>. In this example, the flow of the fluid <NUM> through a restriction in the flow passage <NUM> causes an increase in pressure in the flow passage, and this increased pressure is communicated via the tubing <NUM> to the anchor <NUM>, in order to set the anchor.

After the anchor <NUM> is set, thereby securing the bottom hole assembly <NUM> in the wellbore <NUM>, the RFID tag <NUM> is released into the drill string <NUM> with the flow of the fluid <NUM>. The RFID tag <NUM> is conveyed into and through the bottom hole assembly <NUM> with the fluid <NUM> flow.

An antenna connected to the RFID controller <NUM> receives a predetermined radio frequency signal from the RFID tag <NUM>. In response, the controller <NUM> causes the actuator <NUM> to operate the valve <NUM>, which is initially closed. When the valve <NUM> is opened, fluid pressure in the tubing <NUM> is communicated via a flow path <NUM> to the pistons <NUM> of the release mechanism <NUM>, thereby allowing the pin <NUM> to retract as described above and releasing the mill <NUM> from the whipstock <NUM>.

In other examples, the release mechanism <NUM> may not operate hydraulically. For example, the release mechanism <NUM> could operate electrically. The RFID controller <NUM> could be connected to an electrical solenoid that displaces the latch member <NUM> in response to the RFID tag <NUM> being displaced into the bottom hole assembly <NUM>. Thus, the scope of this disclosure is not limited to hydraulic actuation of the release mechanism <NUM>, or to any other specific details of the bottom hole assembly <NUM> as described herein or depicted in the drawings.

Referring additionally now to <FIG>, another view of the releasable attachment between the whipstock <NUM> and the mill <NUM> is representatively illustrated. In this view, one manner in which an antenna <NUM> may be incorporated into the whipstock <NUM> is depicted.

In the <FIG> example, the antenna <NUM> is positioned in the annular section <NUM> at the upper end <NUM> of the whipstock <NUM>. In this position, the antenna <NUM> is capable of interrogating and receiving the radio frequency signal from the RFID tag <NUM> as it is displaced with the fluid <NUM> through the mill <NUM>.

The antenna <NUM> is electrically connected to the RFID controller <NUM>. The antenna <NUM> enables the RFID controller <NUM> to detect when the RFID tag <NUM> has been displaced into (and through in this example) the bottom hole assembly <NUM>. When the RFID controller <NUM> detects the predetermined radio frequency signal, the controller causes the valve <NUM> to be actuated as described above, thereby releasing the mill <NUM> from the whipstock <NUM>.

Referring additionally now to <FIG>, a schematic of an example of the RFID actuated system <NUM> is representatively illustrated. In this schematic, the manner in which the controller <NUM> can control operation of the valve <NUM> can be seen.

In this example, the actuator <NUM> comprises an electrical solenoid connected between a switch <NUM> and a battery <NUM>. Operation of the switch <NUM> is controlled by the RFID controller <NUM>. The switch <NUM> and the battery <NUM> may be positioned in the whipstock <NUM> (for example, in the recessed area <NUM>, see <FIG>) or in another component of the system <NUM>. In some examples, at least the switch <NUM> may be an integral component of the RFID controller <NUM>. Thus, the scope of this disclosure is not limited to any particular elements, combination of elements or arrangement of elements as depicted in <FIG> or described herein.

In the <FIG> example, the antenna <NUM> receives the predetermined radio frequency signal <NUM> from the RFID tag <NUM>. In response, the controller <NUM> closes the switch <NUM>. Electrical power is thereby applied from the battery <NUM> to the actuator <NUM>.

When the actuator <NUM> is supplied with the electrical power from the battery <NUM>, the valve <NUM> is operated to its open configuration, thereby opening the flow path <NUM>. Increased hydraulic pressure (due to the flow of the fluid <NUM>) is then communicated from the flow passage <NUM> to the pistons <NUM> of the release mechanism <NUM> via the tubing <NUM> and the flow path <NUM>.

Referring additionally now to <FIG>, another example of the system <NUM> is representatively illustrated. In this example, the controller <NUM>, valve <NUM>, actuator <NUM>, switch <NUM> and battery <NUM> are not contained in the whipstock <NUM>. Instead, these elements and others are incorporated into an RFID sub <NUM> that is connected in the drill string <NUM> above the mill <NUM>.

The <FIG> system <NUM> operates in a manner fundamentally similar to that described above for the <FIG> example. Fluid pressure in the flow passage <NUM> due to flow of the fluid <NUM> is used to set the anchor <NUM> (see <FIG>) and then, when it is desired to release the mill <NUM> from the whipstock <NUM>, an RFID tag <NUM> is deployed into the flow passage. However, in the <FIG> example, the mill <NUM> is released in response to the RFID tag <NUM> being displaced into the RFID sub <NUM>.

Referring additionally now to <FIG> & <FIG>, an example of the RFID sub <NUM> is representatively illustrated in respective extended and retracted configurations. Note that, in the <FIG> extended configuration, a tubular mandrel <NUM> extends outwardly from an outer housing <NUM> of the RFID sub <NUM>. In the <FIG> retracted configuration, the mandrel <NUM> is displaced upward into the outer housing <NUM>.

The actuator <NUM> displaces the mandrel <NUM> between its extended and retracted positions in response to predetermined radio frequency signals received by the antenna <NUM> from RFID tags <NUM> displaced through the flow passage <NUM>. In one example, the actuator <NUM> may only displace the mandrel <NUM> from the extended to the retracted position in response to an RFID tag <NUM> being displaced into the flow passage <NUM> in the RFID sub <NUM>. In another example, the mandrel <NUM> may also be displaced from the retracted position to the extended position in response to another RFID tag <NUM> being displaced into the flow passage <NUM> in the RFID sub <NUM>.

In the <FIG> & <FIG> example, the RFID sub <NUM> is initially in the extended configuration and is deployed into the well with the remainder of the bottom hole assembly <NUM>. When the whipstock <NUM> is appropriately positioned in the wellbore <NUM>, the anchor <NUM> is set by flowing the fluid <NUM> through the flow passage <NUM> at or above a predetermined flow rate to thereby cause an increase in fluid pressure in the flow passage. This increased fluid pressure is communicated to the anchor <NUM> via the tubing <NUM> as described above.

After the anchor <NUM> is set and it is desired to release the mill <NUM> from the whipstock <NUM>, an RFID tag <NUM> is released into the drill string <NUM>, and the RFID tag is displaced with the fluid <NUM> flow into the flow passage <NUM>. The predetermined radio frequency signal <NUM> transmitted by the RFID tag <NUM> is received by the antenna <NUM> and, in response, the controller <NUM> operates the actuator <NUM>. The mandrel <NUM> is displaced from the <FIG> extended position to the <FIG> retracted position by the actuator <NUM>.

Referring additionally now to <FIG>, a cross-sectional view of an example of the mill <NUM> and the upper end <NUM> of the whipstock <NUM> is representatively illustrated. In this view, a manner in which the displacement of the mandrel <NUM> may be used to release the mill <NUM> from the whipstock <NUM> can be seen.

In the <FIG> example, a sleeve <NUM> is sealingly and reciprocally received in a bore <NUM> formed in the mill <NUM>. The sleeve <NUM> may be formed on a lower end of the mandrel <NUM> (see <FIG> & <FIG>), or the sleeve may be a separate component connected to the lower end of the mandrel.

In this example, a flow restriction or nozzle <NUM> is positioned in a lower end of the sleeve <NUM> in order to produce an increased fluid pressure in the flow passage <NUM> due to the flow of the fluid <NUM>. The increased fluid pressure is communicated to the tubing <NUM> via openings <NUM> formed through a wall of the sleeve <NUM>. As described above, the tubing <NUM> communicates the fluid pressure in the flow passage <NUM> to the anchor <NUM>. A similar nozzle <NUM> may be used in the <FIG> example to increase fluid pressure in the flow passage <NUM> caused by the flow of the fluid <NUM>.

As depicted in <FIG>, the fluid pressure in the flow passage <NUM> is isolated from the flow paths <NUM>, <NUM> by the valve <NUM>. In this example, the valve <NUM> comprises an upper section of the sleeve <NUM> on which seals <NUM> are carried. In the position of the sleeve <NUM> shown in <FIG>, the seals <NUM> straddle openings <NUM>, <NUM> formed through a wall of the mill <NUM>.

When the sleeve <NUM> is displaced somewhat upward, however, the opening <NUM> and the flow path <NUM> in communication therewith will be exposed to the fluid pressure in the flow passage <NUM>. When the sleeve <NUM> is displaced further upward, the opening <NUM> and the flow path <NUM> in communication therewith will be exposed to the fluid pressure in the flow passage <NUM>.

The position of the sleeve <NUM> depicted in <FIG> corresponds to the extended position of the mandrel <NUM> depicted in <FIG>. When the mandrel <NUM> is displaced upward, the sleeve <NUM> is also displaced upward, thereby placing the flow path <NUM> in communication with the flow passage <NUM> and communicating the fluid pressure in the flow passage to the anchor <NUM> to set the anchor.

When the mandrel <NUM> is displaced further upward to the retracted position of <FIG>, the sleeve <NUM> is again displaced upward, thereby placing the flow path <NUM> in communication with the flow passage <NUM> and communicating the fluid pressure in the flow passage to the pistons <NUM> of the release mechanism <NUM>. This releases the mill <NUM> from the whipstock <NUM> as described above.

Thus, the anchor <NUM> can be set in response to an RFID tag <NUM> being displaced into the RFID sub <NUM>, and then the mill <NUM> can be released from the whipstock <NUM> in response to another RFID tag <NUM> being displaced into the RFID sub <NUM>. The predetermined radio frequency signal <NUM> transmitted by the RFID tag <NUM> is received by the antenna <NUM>, and in response the controller <NUM> causes the actuator <NUM> to displace the mandrel <NUM> upward. This upward displacement of the mandrel <NUM> and the sleeve <NUM> formed thereon or connected thereto opens the valve <NUM>, thereby applying increased fluid pressure first to the anchor <NUM> and then to the pistons <NUM> of the release mechanism <NUM> and releasing the mill <NUM> from the whipstock <NUM>.

The first RFID tag <NUM> used to cause setting of the anchor <NUM> may transmit the same radio frequency signal <NUM> as the second RFID tag used to cause release of the mill <NUM> from the whipstock <NUM>. In other examples, the first and second RFID tags <NUM> may transmit different radio frequency signals <NUM>. Thus, the "set" RFID tag <NUM> (used to set the anchor <NUM>) transmits a "set" radio frequency signal <NUM>, the subsequent "release" RFID tag <NUM> (used to release the mill <NUM> from the whipstock <NUM>) transmits a "release" radio frequency signal <NUM>, and the set and release radio frequency signals may be the same or different.

It may now be fully appreciated that the above disclosure provides significant advancements to the art of designing, constructing and operating mechanisms for releasing mills from whipstocks in wells. In examples described above, the mill <NUM> can be released from the whipstock <NUM> by deploying an RFID tag <NUM> into a flow passage <NUM> in conjunction with flow of a fluid <NUM> through the flow passage.

In one example, a bottom hole assembly <NUM> for use in a subterranean well can comprise a whipstock <NUM>, a mill <NUM> releasably secured to the whipstock <NUM>, an antenna <NUM> and a release mechanism <NUM>. The release mechanism <NUM> is configured to release the mill <NUM> from the whipstock <NUM> in response to a predetermined release radio frequency signal <NUM> received by the antenna <NUM>.

The antenna <NUM> may be incorporated into the whipstock <NUM>. The antenna <NUM> may be disposed in an annular section <NUM> of the whipstock <NUM> which encircles a portion of the mill <NUM>.

The bottom hole assembly <NUM> may include a valve <NUM> and a controller <NUM>. The controller <NUM> may operate the valve <NUM> in response to the predetermined release radio frequency signal <NUM> received by the antenna <NUM>. The valve <NUM> may selectively open a flow path <NUM> between a piston <NUM> of the release mechanism <NUM> and a flow passage <NUM> in the mill <NUM>.

The whipstock <NUM> may include an opening <NUM>, a retractable pin <NUM> may extend from the mill <NUM> into the opening <NUM>, and the mill <NUM> may be releasable from the whipstock <NUM> in response to retraction of the pin <NUM> from the opening <NUM>.

The antenna <NUM> may be configured to receive the predetermined release radio frequency signal <NUM> in response to displacement of a release radio frequency identification tag <NUM> into the bottom hole assembly <NUM>.

The bottom hole assembly <NUM> may include an anchor <NUM>. The anchor <NUM> may be set in response to a predetermined set radio frequency signal <NUM> received by the antenna <NUM>.

In another example, a method for use with a subterranean well can include positioning a bottom hole assembly <NUM> in the well, the bottom hole assembly <NUM> including a mill <NUM> and a whipstock <NUM> releasably secured to the mill <NUM>, and then releasing the mill <NUM> from the whipstock <NUM> by displacing a release radio frequency identification tag <NUM> into the bottom hole assembly <NUM>.

The displacing step may include displacing the release radio frequency identification tag <NUM> through the mill <NUM>.

The displacing step may include displacing the release radio frequency identification tag <NUM> through an annular section <NUM> of the whipstock <NUM>. The annular section <NUM> may encircle a portion of the mill <NUM>.

The displacing step may include displacing the release radio frequency identification tag <NUM> through a sub <NUM>, with the mill <NUM> being connected between the sub <NUM> and the whipstock <NUM>.

The releasing step may include an actuator <NUM> of the sub <NUM> actuating a valve <NUM> in the mill <NUM>, thereby opening the valve <NUM> and permitting fluid communication between a flow passage <NUM> in the mill <NUM> and a flow path <NUM> to a piston <NUM> of a hydraulic release mechanism <NUM> of the whipstock <NUM>.

The releasing step may include an antenna <NUM> of the whipstock <NUM> receiving a predetermined release radio frequency signal <NUM> from the release radio frequency identification tag <NUM>.

The releasing step may include a controller <NUM> actuating a valve <NUM> and thereby opening a flow path <NUM> between a flow passage <NUM> in the mill <NUM> and a piston <NUM> of a hydraulic release mechanism <NUM>.

The releasing step may include retracting a pin <NUM> into the mill <NUM> from an opening <NUM> in the whipstock <NUM>.

The method may include setting an anchor <NUM> in response to displacing a set radio frequency identification tag <NUM> into the bottom hole assembly <NUM>.

In another example, a well system <NUM> can include a bottom hole assembly <NUM> comprising an anchor <NUM>, a whipstock <NUM> and a mill <NUM>; and a release radio frequency identification tag <NUM> displaceable with fluid <NUM> flow into the bottom hole assembly <NUM>. The anchor <NUM> is settable by fluid pressure applied to a flow passage <NUM> in the mill <NUM>. A hydraulic release mechanism <NUM> releasably secures the mill <NUM> to the whipstock <NUM>. A valve <NUM> is configured to permit fluid communication between the flow passage <NUM> and a piston <NUM> of the hydraulic release mechanism <NUM> in response to a predetermined release radio frequency signal <NUM> transmitted by the release radio frequency identification tag <NUM>.

The antenna <NUM> may be incorporated into the whipstock <NUM>. The antenna <NUM> may be disposed in an annular section <NUM> of the whipstock <NUM>. The annular section <NUM> may encircle a portion of the mill <NUM>.

The well system <NUM> may include a controller <NUM> configured to operate the valve <NUM> in response to the predetermined release radio frequency signal <NUM> transmitted by the radio frequency identification tag <NUM>. The controller <NUM> may be positioned in the whipstock <NUM> (as in the <FIG> example). The mill <NUM> may be connected between the whipstock <NUM> and the controller <NUM> (as in the <FIG> example).

The valve <NUM> may be configured to permit fluid communication between the flow passage <NUM> and an anchor <NUM> in response to a predetermined set radio frequency signal <NUM> transmitted by a set radio frequency identification tag <NUM>.

Although various examples have been described above, with each example having certain features, it should be understood that it is not necessary for a particular feature of one example to be used exclusively with that example. Instead, any of the features described above and/or depicted in the drawings can be combined with any of the examples, in addition to or in substitution for any of the other features of those examples. One example's features are not mutually exclusive to another example's features. Instead, the scope of this disclosure encompasses any combination of any of the features.

Although each example described above includes a certain combination of features, it should be understood that it is not necessary for all features of an example to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used.

It should be understood that the various embodiments described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of this disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments.

In the above description of the representative examples, directional terms (such as "above," "below," "upper," "lower," "upward," "downward," etc.) are used for convenience in referring to the accompanying drawings. However, it should be clearly understood that the scope of this disclosure is not limited to any particular directions described herein.

The terms "including," "includes," "comprising," "comprises," and similar terms are used in a non-limiting sense in this specification. For example, if a system, method, apparatus, device, etc., is described as "including" a certain feature or element, the system, method, apparatus, device, etc., can include that feature or element, and can also include other features or elements. Similarly, the term "comprises" is considered to mean "comprises, but is not limited to.

Claim 1:
A bottom hole assembly (<NUM>) for use in a subterranean well, the bottom hole assembly (<NUM>) comprising:
a whipstock (<NUM>);
a mill (<NUM>) releasably secured to the whipstock (<NUM>);
an antenna (<NUM>);
a release mechanism (<NUM>), in which the release mechanism (<NUM>) is configured to release the mill (<NUM>) from the whipstock (<NUM>) in response to a predetermined release radio frequency signal (<NUM>) received by the antenna (<NUM>); and
a valve (<NUM>) and a controller (<NUM>), in which the controller (<NUM>) is configured to operate the valve (<NUM>) in response to the predetermined release radio frequency signal (<NUM>) received by the antenna (<NUM>), and in which the valve (<NUM>) is configured to selectively open a flow path (<NUM>) between a piston (<NUM>) of the release mechanism (<NUM>) and a flow passage (<NUM>) in the mill (<NUM>).