Patent Description:
Measurement of parameters such as location, environment, weight on bit, torque, wear, and bearing condition in real time provides for more efficient drilling operations. MWD techniques help achieve faster penetration rates, better trip planning, reduced equipment failures, fewer delays for directional surveys, and the elimination of a need to interrupt drilling for abnormal pressure detection.

Antennae, whether used for the transmission and reception of interrogating fields during logging operations or for the electromagnetic communication of data, can be delicate devices that cannot be too heavily shielded or they will not be able to perform their functions. Furthermore, antennae cannot be exposed to wellbore conditions, particularly during drilling operations, without substantial risk of harm or malfunction. Consequently, traditional antenna constructions for downhole use utilize solid wellbore tubulars, such as drill collar tubulars and drill pipe tubulars, to form a housing that protects the antenna from damage due to the corrosive fluids, high pressures, and high temperatures frequently encountered in wellbores particularly during drilling operations. Traditional techniques require that a portion of the tubular be "necked-down" during milling and/or machining operations by radially reducing the tubular at a particular location to provide a rather deep and wide groove. Typically, a layer of cushioning and electrically-insulating material is provided in the groove, and the antenna windings are wound about the tubular at the position of the groove to protect the antenna from physical damage and to allow communication of electromagnetic fields between the antenna windings and the borehole and surrounding formation. A slotted sleeve is typically provided and secured in position over the antenna windings provided within the necked-down portion of the tubular member.

<CIT> discloses flex (or printed) circuit axial coils for a downhole logging tool with a sleeve (<NUM>) slid over the entire antenna to, in part, provide protection to the tool circuitry. However, it is not disclosed how to secure the electronic structures to the bobbin to prevent damage caused by dynamic conditions such as vibration, fluids or pressure.

<CIT> discloses an overmoded waveguide elbow and fabrication process.

<CIT> discloses a smooth composite structure.

<CIT> discloses replacement antennas for a wellbore apparatus.

According to a first aspect of the present invention, there is disclosed an apparatus according to Claim <NUM>.

According to a second aspect of the present invention, there is disclosed a method according to Claim <NUM>.

The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure.

The present disclosure relates generally to antenna design and, more particularly, to antenna sensors and transmitters for use in a drilling operations environment.

An antenna section in a downhole logging tool can include components that are vulnerable to malfunction if not adequately protected from the downhole drilling environment. Protective structures of the present disclosure can secure electronic components in the antenna assembly and encapsulate the assembly in such a manner as to prevent any damage from downhole pressure, temperature, fluid, vibrations, and other dynamic conditions.

According to at least one embodiment, a logging tool can provide a single or multiple antenna sections of same or varying dimensions. According to embodiments, an antenna section provides components of an antenna assembly that are held in place with adhesives, encapsulants, and protective layers. Layers of adhesives are utilized to install successive layers of components. An outer impervious layer of material, including a non-metallic compound, elastomers or polymers, encapsulates the components to provide protection from downhole pressure, fluid invasion, thermal effects, impact and other adverse dynamic conditions.

According to at least one embodiment, the antenna assembly can include components of an electronics assembly, windings for an antenna, layers of electrical and magnetic shielding, antenna carriers, and other components that are surrounded with impervious layers of nonconductive material. The layers are provided in a manner that limits or prevents air gaps there between. The layers are also formed to protect the antenna sections without hindering the propagation of electromagnetic signals. Accordingly, the antenna assembly can facilitate increased the range of data transmission. At the same time, the encapsulation can dampen any vibration and protect the components from harsh drilling environments.

Exemplary antenna assemblies of the subject technology can be used in a wellbore and provide protection to the antenna itself from the harsh wellbore environment without significantly interfering with the operational capabilities (e.g., sensing) of the antenna assemblies. Exemplary antenna assemblies of the subject technology provide housing and support for an antenna with a contoured portion on an outer peripheral surface of a bobbin.

Exemplary antenna assemblies can provide a measurement-while-drilling apparatus for use in drilling operations to interrogate a borehole and surrounding formation, which includes transmitting and receiving antennae that are spaced apart along a tubular member and utilized to generate and receive an interrogating electromagnetic signal. At least one antenna assembly includes an antenna disposed in an antenna pathway along a tool string and a mechanism for preferentially communicating electromagnetic energy between at least a portion of the antenna and the borehole and surrounding formation.

Referring to <FIG>, illustrated is an exemplary drilling system <NUM> that may employ one or more principles of the present disclosure. Boreholes may be created by drilling into the earth <NUM> using the drilling system <NUM>. The drilling system <NUM> may be configured to drive a bottom hole assembly (BHA) <NUM> positioned or otherwise arranged at the bottom of a drill string <NUM> extended into the earth <NUM> from a derrick <NUM> arranged at the surface <NUM>. The derrick <NUM> includes a traveling block <NUM> used to lower and raise the drill string <NUM>.

The BHA <NUM> may include a drill bit <NUM> operatively coupled to a tool string <NUM> which may be moved axially within a drilled wellbore <NUM> as attached to the drill string <NUM>. During operation, the drill bit <NUM> penetrates the earth <NUM> and thereby creates the wellbore <NUM>. The BHA <NUM> provides directional control of the drill bit <NUM> as it advances into the earth <NUM>. The tool string <NUM> can be semi-permanently mounted with various measurement tools (not shown) such as, but not limited to, measurement-while-drilling (MWD) and logging-while-drilling (LWD) tools, that may be configured to take downhole measurements of drilling conditions. In other embodiments, the measurement tools may be self-contained within the tool string <NUM>, as shown in <FIG>.

Fluid or "mud" from a mud tank <NUM> may be pumped downhole using a mud pump <NUM> powered by an adjacent power source, such as a prime mover or motor <NUM>. The mud may be pumped from the mud tank <NUM>, through a standpipe <NUM>, which feeds the mud into the drill string <NUM> and conveys the same to the drill bit <NUM>. The mud exits one or more nozzles arranged in the drill bit <NUM> and in the process cools the drill bit <NUM>. After exiting the drill bit <NUM>, the mud circulates back to the surface <NUM> via the annulus defined between the wellbore <NUM> and the drill string <NUM>, and in the process, returns drill cuttings and debris to the surface. The cuttings and mud mixture are passed through a flow line <NUM> and are processed such that a cleaned mud is returned down hole through the standpipe <NUM> once again.

According to at least one embodiment, one or more antenna sections <NUM> (<FIG>) can form a part of the BHA <NUM> and, more particularly, an LWD tool. The antenna sections <NUM> can include an electronics assembly <NUM> (<FIG>) for transmitting and receiving electromagnetic signals relating to operation of the BHA <NUM>. According to at least one embodiment, the antenna section <NUM> may include transceivers for communications via electromagnetic signals. The system <NUM> can include a remote antenna <NUM> coupled to a remote ground station <NUM>. The remote antenna <NUM> and/or the remote ground station <NUM> may or may not be positioned near or on the drilling rig floor. The remote ground station <NUM> may communicate with the antenna section <NUM> wirelessly via a signal <NUM> using the remote antenna <NUM>. A more detailed description of communications is set forth below.

Although the drilling system <NUM> is shown and described with respect to a rotary drill system in <FIG>, those skilled in the art will readily appreciate that many types of drilling systems can be employed in carrying out embodiments of the disclosure. For instance, drills and drill rigs used in embodiments of the disclosure may be used onshore (as depicted in <FIG>) or offshore (not shown). Offshore oilrigs that may be used in accordance with embodiments of the disclosure include, for example, floaters, fixed platforms, gravity-based structures, drill ships, semi-submersible platforms, jack-up drilling rigs, tension-leg platforms, and the like. It will be appreciated that embodiments of the disclosure can be applied to rigs ranging anywhere from small in size and portable, to bulky and permanent.

Further, although described herein with respect to oil drilling, various embodiments of the disclosure may be used in many other applications. For example, disclosed methods can be used in drilling for mineral exploration, environmental investigation, natural gas extraction, underground installation, mining operations, water wells, geothermal wells, and the like. Further, embodiments of the disclosure may be used in weight-on-packers assemblies, in running liner hangers, in running completion strings, etc., without departing from the scope of the disclosure.

According to embodiments, and as shown in <FIG>, the drill string <NUM> (<FIG>) can include an antenna section <NUM> or a plurality of antenna sections <NUM> positioned or otherwise included in the tool string <NUM>. Each antenna section <NUM> can provide a collar <NUM> for receiving an antenna assembly <NUM> (<FIG>). The antenna assembly <NUM> can be operated to communicate information to a base station at a location remote from the tool string <NUM>, as described herein.

According to at least one embodiment, as shown in <FIG>, each collar <NUM> can be formed as a radially inset region on an outer surface of the tool string <NUM>. The collar <NUM> can extend radially inward relative to radially outer surfaces of axially adjacent regions <NUM> of the tool string <NUM>. As shown, the section defined by each collar <NUM> can have an outer diameter that is less than an outer diameter of other portions of the tool string <NUM>. Within the tool string <NUM>, a channel <NUM> (<FIG>) can extend axially along or parallel with a central axis of the tool string <NUM>.

<FIG> shows a sectional view of an exemplary antenna section <NUM> of a tool string. In the illustrated embodiment, an outer sleeve <NUM> is provided to house the various components of the antenna section <NUM>. For example, the outer sleeve <NUM> provides a circumferential encapsulation by extending about a central axis of the tool string <NUM>. An inner diameter of the outer sleeve <NUM> is greater than an outer diameter of the collar <NUM>, thereby defining an annular space between the collar <NUM> and the outer sleeve <NUM>. Other components of the antenna section <NUM> are positioned within the annular space. According to at least one embodiment, the outer sleeve <NUM> can be formed of a nonconductive material. For example, the outer sleeve <NUM> can be formed of a nonmetallic material, such as fiberglass. By further example, the outer sleeve <NUM> is formed of a polymer or polymeric material, such as polyether ether ketone (PEEK). Alternatively or in combination, the outer sleeve <NUM> can include conductive and/or metallic materials, such as nickel-based alloys, chromium-based alloys, copper-based alloys, INCONEL®, MONEL®, fiberglass, and/or combinations thereof. Different materials or combinations of materials can be provided in multiple layers.

According to at least one embodiment, and as shown in <FIG>, a first (e.g., downhole) end of the outer sleeve <NUM> may have a size and shape to engage a receiving portion <NUM> of the collar <NUM>. For example, the collar <NUM> can provide a shoulder <NUM> to limit travel of the first end of the outer sleeve <NUM> in a downhole direction (i.e., to the right in <FIG>). The first end of the outer sleeve <NUM> can connect to the collar <NUM> with a locking mechanism (not shown). For example, the locking mechanism can connect and secure to the collar <NUM> by a mechanical attachment (e.g., snap rings, latches, bolts, screws, other threaded fasteners, etc.).

According to at least one embodiment, a second (e.g., uphole) end of the outer sleeve <NUM> can engage to another portion of the collar <NUM> by another locking mechanism (not shown). For example, the second end of the outer sleeve <NUM> can connect and secured to the collar <NUM> by the same or a different mechanical attachment (e.g., with a lock ring).

The antenna section <NUM> includes a bobbin <NUM> for engaging the collar <NUM> of the tool string <NUM> and for radially supporting an electronics assembly <NUM> thereon. According to at least one embodiment, the bobbin <NUM> can be formed of a thermoplastic material. The bobbin <NUM> can be formed, for example, by <NUM>-D printing, injection molding, or other processes.

The electronics assembly <NUM> can include a coil winding <NUM> of an antenna <NUM>. As shown in <FIG>, the coil winding <NUM> can extend wrapped about the collar <NUM> and extend along at least a portion of an axial length thereof. The coil winding <NUM> can form any number of turns or windings about the collar <NUM>. The coil winding <NUM> can be concentric or eccentric relative to a central axis of the collar <NUM>.

<FIG> shows an exploded perspective view of an exemplary collar <NUM> of a tool string with components of an antenna section <NUM> at a stage of assembly. As illustrated, at least a portion of the coil winding <NUM> may be provided about at least a portion of a bobbin <NUM>. For example, the bobbin <NUM> can extend axially along the collar <NUM> and provide an antenna region <NUM> to receive the coil windings <NUM>. The antenna region <NUM> is a region of the bobbin <NUM> about which the coil windings <NUM> of the antenna <NUM> can be wrapped. The antenna region <NUM> of the bobbin <NUM> can be formed as a radially inset region on an outer surface of the bobbin <NUM>. The antenna region <NUM> can extend radially inward relative to radially outer surfaces of axially adjacent regions of the bobbin <NUM>. The antenna region <NUM> can include ridges, slots, channels or other structures to receive the coil windings <NUM>. While coil windings <NUM> are shown to form the antenna of the electronics assembly <NUM>, other shapes and pathways can be used to form an antenna upon the bobbin <NUM>. Shapes and geometries for alternative antennae are known and can be applied to the electronics assembly <NUM> of the present disclosure.

The coil windings <NUM> of the antenna 253can be oriented to transmit signals to or receive signals from a particular location with respect to the tool string <NUM>. For example, each turn of the coil windings <NUM> can be substantially formed in a plane that is or is not orthogonal to the central axis of the tool string <NUM>. According to at least one embodiment, sets of coil windings <NUM> from each of a plurality of antenna sections <NUM> can have orientations that are distinct from each other to provide broad coverage for transmitting and receiving signals.

According to at least one embodiment, the electronics assembly <NUM> of the antenna section <NUM> can include a printed circuit board ("PCB") <NUM> and/or other electronic components, mounted within the annular space defined by the outer sleeve <NUM>. The PCB <NUM> can be provided on an outer or inner surface of the bobbin <NUM>, or otherwise embedded therein. The PCB <NUM> can connect to the coil windings <NUM> of an antenna via an internal connection line <NUM>. The internal connection line <NUM> can be provided on an outer or inner surface of the bobbin <NUM>, or otherwise embedded therein. The PCB <NUM> can further connect to other systems outside of the antenna section <NUM> via an external connection line <NUM>.

According to at least one embodiment, a shield <NUM> may be provided at least partially within at least a portion of the coil windings <NUM> (e.g., positioned radially inward from the coil windings <NUM>). The shield <NUM> can be concentric with or otherwise radially within the coil windings <NUM>. For example, the shield <NUM> can extend axially along the collar <NUM> and radially within a portion of the coil windings <NUM>. A first end of the shield <NUM> can extend axially beyond a first end of the coil winding <NUM>, and a second end of the shield <NUM> can extend axially beyond a second end of the coil winding <NUM>. The shield <NUM> can be formed of a ferromagnetic material, such as iron or an iron-based alloy, to limit or prevent Eddy currents within the collar <NUM> that would be generated by the coil windings <NUM> and potentially alter the direction in which a field or signal is propagated by the coil windings <NUM>. The shield <NUM> may also be formed of any soft magnetic material, such as manganese zinc (MnZn).

According to at least one embodiment, a protective layer <NUM> (<FIG>) can be formed about the bobbin <NUM> and the electronics assembly <NUM>. The protective layer <NUM> can provide securement of the bobbin <NUM> and the electronics assembly <NUM> while permitting propagation of signals from the antenna. According to at least one embodiment, the material of the protective layer <NUM> can be any material that is capable of withstanding conditions during a wellbore operation. For example, the material can withstand pressure (e.g., <NUM> ksi or greater), temperature, and exposure to environmental component (e.g., drilling fluids, contaminants, oil and gas). A thickness of the protective layer <NUM> can be between about <NUM>" and <NUM>" (<NUM> and <NUM>). For example, a thickness of the protective layer <NUM> can be about <NUM>" (<NUM>). The protective layer <NUM> can be formed of a nonconductive and/or nonmetallic material. For example, the protective layer <NUM> can be formed of a rubber material or other a polymers and/or polymeric materials. By further example, the protective layer <NUM> can be formed of a fluoropolymer elastomer (e.g., VITON®).

With reference to <FIG>, components of the antenna section <NUM> can be assembled in a manner that secures each to the collar <NUM> and preserves effective transmission and reception of electromagnetic signals. As shown in <FIG>, the collar <NUM> can provide a surface on which other components of the antenna section <NUM> can be placed.

According to at least one embodiment, a bond coating <NUM> is provided on at least a portion of an outer surface of the collar <NUM>. The bond coating <NUM> can be provided, for example, on portions of the collar <NUM> that are exposed to the protective layer <NUM>. By further example, the bond coating <NUM> can be provided on an entire outer surface of the collar <NUM>. The bond coating <NUM> can be formed of a material that promotes adhesion of the protective layer <NUM> to the collar <NUM>. For example, adhesion between the bond coating <NUM> and the protective layer <NUM> can be superior to adhesion between the protective layer <NUM> and the collar <NUM>. The bond coating <NUM> can be formed of a nonconductive material. The bond coating <NUM> can include aluminum oxide, ceramics, or other nonconductive materials.

According to at least one embodiment, an adhesive may be applied to at least a portion of the collar <NUM> (and/or the bond coating <NUM>). The adhesive forms an inner adhesive layer <NUM> (<FIG>) between the collar <NUM> and the bobbin <NUM> and/or shield <NUM>. The adhesive can be, for example, an epoxy, such as RTV. The adhesive can be provided as a gel or liquid on an outer surface of the collar <NUM>. For example, as the bobbin <NUM> and/or the shield <NUM> are placed over a region of the collar <NUM> that includes the inner adhesive layer <NUM>, air gaps (e.g. bubbles) can be displaced from between the collar <NUM> and the bobbin <NUM> and/or shield <NUM>.

According to at least one embodiment, and as shown in <FIG>, the shield <NUM> can be provided as first and second shield portions 230a and 230b. Each of the first and second shield portions 230a,b are provided on opposite sides of the collar <NUM>. The first and second shield portions 230a,b can be provided over a portion of the collar <NUM> to which the adhesive of the inner adhesive layer <NUM> has been applied. The adhesive of the inner adhesive layer <NUM> can be applied in greater abundance than is required to fill the space <NUM> between the shield <NUM> and the collar <NUM>. As the first and second shield portions 230a,b are applied over the inner adhesive layer <NUM>, at least a portion of the adhesive is displaced such that air gaps are limited or prevented between the collar <NUM> and the shield <NUM>.

According to at least one embodiment, and as shown in <FIG>, the bobbin <NUM> can be provided as first and second bobbin portions 240a and 240b. Each of the first and second bobbin portions 240a,b are provided on opposite sides of the collar <NUM>. The first and second bobbin portions 240a,b may be secured to each other with one or more locking mechanisms. For example, first locking mechanisms 244a of the first bobbin portion 240a can be aligned and configured to engage with second locking mechanisms 244b of the second bobbin portion 240b. The first and second locking mechanisms 244a,b can include fasteners, pins, latches, threaded engagements, or other structures capable of holding the first and second bobbin portions 240a,b to each other.

According to at least one embodiment, the first and second bobbin portions 240a,b can be provided over a portion of the collar <NUM> to which the adhesive of the inner adhesive layer <NUM> has been applied. An additional adhesive layer can be provided between the shield <NUM> and the bobbin <NUM>. As with the shield <NUM>, the adhesive of the inner adhesive layer <NUM> can be applied in greater abundance than is required to fill the space <NUM> radially between the bobbin <NUM> and the collar <NUM>. As the first and second bobbin portions 240a,b are applied over the inner adhesive layer <NUM>, at least a portion of the adhesive is displaced such that air gaps are limited or prevented between the collar <NUM> and the bobbin <NUM>.

<FIG> shows a perspective view of the collar <NUM> of the antenna section <NUM> in a partially assembled configuration. As illustrated, with the first and second bobbin portions 240a,b in place, the coil windings <NUM> can be provided to the antenna region <NUM> (<FIG>) of the bobbin <NUM>. Any other components of the electronics assembly <NUM> can be provided and/or connected after the first and second bobbin portions 240a,b are in place.

According to at least one embodiment, an adhesive forms an outer adhesive layer <NUM> (<FIG>) between (i) the bobbin <NUM> and electronics assembly <NUM> and (ii) the protective layer <NUM>. The adhesive can be, for example, an epoxy, such as RTV. The adhesive can be mixed and vacuumed to remove any air bubbles, and is then applied through vacuum/pressure process to an area of interest to fill/displace any air pockets between bobbin <NUM> and coil windings <NUM>. Subsequently, the adhesive is cured in an oven to set fully. After curing, the adhesive provides a smooth layer for bonding with the protective layer <NUM>. The outer adhesive layer <NUM> can be formed of the same or a different adhesive as the adhesive of the inner adhesive layer <NUM>. The adhesive can be provided as a gel or liquid on an outer surface of the bobbin <NUM> and/or electronics assembly <NUM>. For example, after the bobbin <NUM> and/or electronics assembly <NUM> are placed about the collar <NUM>, the adhesive of the outer adhesive layer <NUM> is provided over an outer surface of the bobbin <NUM> and electronics assembly <NUM>. The outer adhesive layer <NUM> is formed in a manner that prevents air gaps (e.g. bubbles) from between the bobbin <NUM> and the protective layer <NUM>. Optionally, the outer adhesive layer <NUM> is also formed in a manner that prevents air gaps (e.g. bubbles) from between the electronics assembly <NUM> and the protective layer <NUM>. For example, the adhesive of the outer adhesive layer <NUM> can be applied in greater abundance than is required to fill the space <NUM> radially between (i) the bobbin <NUM> and/or electronics assembly <NUM> and (ii) the protective layer <NUM>. As the protective layer <NUM> is applied over the outer adhesive layer <NUM>, at least a portion of the adhesive is displaced such that air gaps are prevented between the bobbin <NUM> and the protective layer <NUM>. Optionally, air gaps are also prevented between the electronics assembly <NUM> and the protective layer <NUM>. An additional adhesive layer <NUM> can be applied to the coil windings <NUM> of the antenna prior to application of the outer adhesive layer <NUM>. The adhesive of the additional adhesive layer <NUM> can be the same as or different from the adhesive of the outer adhesive layer <NUM>.

<FIG> shows a perspective view of the collar <NUM> of the antenna section <NUM> with a protective layer <NUM> positioned thereon. The protective layer <NUM> may be formed by providing a plurality of strips over portions of the collar <NUM>, the bobbin <NUM>, and/or the electronics assembly <NUM>. In particular, the protective layer <NUM> is formed over the outer adhesive layer <NUM> (<FIG>) that is applied to the collar <NUM>, the bobbin <NUM>, and/or the electronics assembly <NUM>. Alternatively or in combination, the material of the protective layer <NUM> can bond to the bond coating <NUM> that has been applied to the collar <NUM>. The strips forming the protective layer <NUM> can be applied as extending circumferentially about or axially over the collar <NUM>, the bobbin <NUM>, and/or the electronics assembly <NUM>. The strips forming the protective layer <NUM> can be applied in segments or as a continual winding. With the strips in place, the protective layer <NUM> can achieve a persistent condition by applying heat and/or pressure to the strips, for example as in an autoclave process.

<FIG> shows a perspective view of an exemplary collar of a tool string with an outer sleeve at a stage of assembly. As shown in <FIG>, the outer sleeve <NUM> is depicted as being positioned about the protective layer <NUM>. The outer sleeve <NUM> can engage the receiving portion <NUM> (<FIG>) of the collar <NUM> and be locked thereon, as discussed herein.

According to at least one embodiment, at least a portion of the shield <NUM> is provided within a shield region <NUM> (<FIG>) of the bobbin <NUM>. For example, the shield region <NUM> of the bobbin <NUM> can be formed as a radially inset region on an inner surface of the bobbin <NUM>. The shield region <NUM> can extend radially outward relative to radially inner surfaces of axially adjacent regions of the bobbin <NUM>.

According to at least one embodiment, a plurality of antenna sections <NUM> may cooperate together to interrogate a borehole and surrounding formation. Each antenna section <NUM> is operable in at least one of (<NUM>) a reception mode of operation and (<NUM>) a transmission mode of operation. In the reception mode of operation, the antenna region <NUM> detects electromagnetic energy in the wellbore and surrounding formation and generates a current corresponding thereto. In the transmission mode of operation, the antenna region <NUM> emits electromagnetic energy in the wellbore and surrounding formation in response to an energizing current.

According to at least one embodiment, information obtained by one or more antenna assemblies <NUM> (<FIG>) can be recorded as operation logs for later reference by a system or user. Information obtained by one or more antenna assemblies <NUM> can be applied by an onboard system to manage geo-steering of the drill string <NUM> (<FIG>). According to at least one embodiment, information obtained by one or more antenna assemblies <NUM> can be communicated to a remote system for logging or managing geo-steering of the drill string <NUM>. According to at least one embodiment, an antenna section <NUM> can allow signals to pass into and out of the well during drilling operations. Communications can demonstrate performance based upon monitoring during drilling operations. Electromagnetic communication can be provided for one- or two-way communication with downhole tools. Electronic components and support structures can facilitate two-way communication with downhole tools.

For example, an electric signal <NUM> (<FIG>) from the antenna section <NUM> can be sent to the remote ground station <NUM> (<FIG>) that can include a telemetry tool. Examples of downhole tools used with the telemetry tool can include measurement while drilling (MWD) tools, pressure while drilling (PWD) tools, formation logging tools, and production monitoring tools. For example, downhole tools can include one or more sensors that provide signals corresponding to sensed conditions. The downhole tools (e.g., the antenna section <NUM>) can include circuitry required to process such signals and transmit associated data to the surface. Based on the data received at the surface, an operator can adjust operating parameters associated with the downhole tools. For example, an operator can adjust a pressure applied by changing a fluid pressure supplied to the downhole tools.

In a signal sending operation, communications module of the electronics assembly <NUM> (<FIG>), acting as a sending antenna, sends electromagnetic signals to other equipment in the wellbore and/or at the surface. Operation and data transmission by the communications module can be controlled, for example, by the PCB <NUM> (<FIG>) of the electronics assembly <NUM>. In a receiving operation, the communications module of the electronics assembly <NUM>, acting as a receiving antenna, receive electrical signals from other equipment in the wellbore and/or at the surface. Reception by the receiving antenna and processing of receive signals can be operated, for example, by the PCB <NUM> of the electronics assembly <NUM>.

One or more of a variety of communication means can be employed for wireless communication. For example, communication between the antenna section <NUM> and the remote ground station <NUM> (<FIG>) may be formatted according to CDMA (Code Division Multiple Access) <NUM> and WCDMA (Wideband CDMA) standards, a TDMA (Time Division Multiple Access) standard and a FDMA (Frequency Division Multiple Access) standard. The communication may also be formatted according to an Institute of Electrical and Electronics Engineers (IEEE) <NUM>, <NUM>, or <NUM> standard. The communication between the antenna section <NUM> and the remote ground station <NUM> may be based on a number of different spread spectrum techniques. The spread spectrum techniques may include frequency hopping spread spectrum (FHSS), direct sequence spread spectrum (DSSS), orthogonal frequency domain multiplexing (OFDM), or multiple-in multiple-out (MIMO) specifications (i.e., multiple antenna), for example.

Each of embodiments A, B, and C may have one or more of the following additional elements in any combination: Element <NUM>: the antenna assembly or tool string can further include a ferromagnetic shield on an inner surface of the bobbin and radially within the antenna. Element <NUM>: the ferromagnetic shield can be disposed within an inset shield region on an inner surface of the bobbin. Element <NUM>: the antenna assembly or tool string can further include an inner adhesive layer radially between the bobbin and the collar. Element <NUM>: the antenna assembly or tool string can further include an outer sleeve slidably disposed about the protective layer. Element <NUM>: the antenna can be formed by coil windings about the bobbin. Element <NUM>: the antenna assembly or tool string can further include electronic circuitry at the bobbin and connected to the antenna. Element <NUM>: the antenna can be disposed within an inset antenna region on an outer surface of the bobbin. Element <NUM>: the antenna assembly or tool string can further include a bond coating between an outer surface of the collar and an inner surface of the protective layer.

Element <NUM>: placing the bobbin about the collar includes placing first and second bobbin parts on opposite sides of the collar and securing the first bobbin part to the second bobbin part. Element <NUM>: applying the protective layer includes placing strips of material against the outer adhesive layer while the outer adhesive layer is in a liquid or gel state.

Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of "comprising," "containing," or "including" various components or steps, the compositions and methods can also "consist essentially of" or "consist of" the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, "from about a to about b," or, equivalently, "from approximately a to b," or, equivalently, "from approximately a-b") disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles "a" or "an," as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification, the definitions that are consistent with this specification should be adopted.

As used herein, the phrase "at least one of" preceding a series of items, with the terms "and" or "or" to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase "at least one of" allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items.

Claim 1:
An antenna assembly (<NUM>), comprising:
a bobbin (<NUM>) positionable about a collar (<NUM>) of a tool string (<NUM>);
an antenna (<NUM>) positioned on an outer surface of the bobbin (<NUM>);
an outer adhesive layer (<NUM>) covering the antenna (<NUM>) and at least a portion of the bobbin (<NUM>), wherein the outer adhesive layer is in direct contact with the bobbin;
a protective layer (<NUM>) about the outer adhesive layer (<NUM>), wherein the outer adhesive layer (<NUM>) fills a space (<NUM>), lacking air gaps, defined radially between the bobbin (<NUM>) and the protective layer (<NUM>) and the outer adhesive layer provides a smooth layer to which the protective layer is bonded; and
an outer sleeve (<NUM>) extending about a central axis of the tool string and providing circumferential encapsulation of the tool string, the bobbin, the antenna, the outer adhesive layer and the protective layer, the outer sleeve having an inner diameter greater than an outer diameter of the collar to define an annular space between the collar and the outer sleeve,
further comprising a ferromagnetic shield (<NUM>) positioned on an inner surface of the bobbin and disposed radially within the antenna (<NUM>).