Electrical contacts to a ring transducer

Various embodiments include apparatus and methods of providing a piezoelectric element having a surface front surface to operate as an active surface of a transducer on which a number of separate electrodes are disposed such that the electrodes on the front surface provide an effectively flat surface to the transducer. Additional apparatus, systems, and methods are disclosed.

RELATED APPLICATIONS

This application is a U.S. National Stage Filing under 35 U.S.C. 371 from International Application No. PCT/US2011/031972, filed on 11 Apr. 2011, and published as WO 2012/141683 A1 on 18 Oct. 2012, which application and publication are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates generally to apparatus for making measurements related to oil and gas exploration.

BACKGROUND

In drilling wells for oil and gas exploration, understanding the structure and properties of the associated geological formation provides information to aid such exploration. Measurements in a borehole are typically performed to attain this understanding. However, the pressure and temperatures accompanying measurement tools in the borehole of a well can affect operation of these tools in the borehole. The usefulness of such measurements may be related to the precision or quality of the information derived from such measurements.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings that show, by way of illustration and not limitation, various embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice these and other embodiments. Other embodiments may be utilized, and structural, logical, and electrical changes may be made to these embodiments. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The following detailed description is, therefore, not to be taken in a limiting sense.

FIGS. 1 and 2show a top view and a side view, respectively, of a piezoelectric element100to be processed to attach as a sensing unit in an acoustic transducer. Piezoelectric element100has a front surface2and a back surface1, where front surface2is to be disposed in the acoustic transducer as the active side of piezoelectric element100and back surface1can be used to attach to a housing of the acoustic transducer. Front surface2can also be referred to as the face of piezoelectric element100. Piezoelectric element100can be realized as a piezoelectric ceramic. Piezoelectric element100can be processed to provide an electrical connection to ring electrodes formed on the active surface of piezoelectric element100without extending above the surface of the piezoelectric element.FIGS. 3-11show stages of and/or features in processing piezoelectric element100to provide electrical connections to ring electrodes formed on front surface2of piezoelectric element100effectively without extending above front surface2of piezoelectric surface100.FIG. 3shows piezoelectric element100after recesses10are cut in front surface2at two locations8. Recesses10can be made as, but are not limited to, 0.005 inch deep recesses with sloped edges or as shallow concave grooves. As shown, the two locations can be formed on a line through the center of piezoelectric element100, where each location8extends from the periphery of piezoelectric element100towards the center of piezoelectric element100. An electrode surface can be applied to front surface2and to surface1, if not already in place.

FIG. 4shows piezoelectric element100with slots24cut in the front surface of piezoelectric element100. Slots20can also be cut in back surface1, not shown, offset by 90 degrees from slots in front surface2, shown in a dotted format indicating that slots20are made in the surface opposite front surface2. As with slots24, slots20do not extend from one surface to the other surface. Slots24are made to hold electrode assemblies used to connect electrodes on front surface2externally from side edges of piezoelectric element100after processing surface connections to piezoelectric element100. Slots24can be used to reduce unwanted modes of vibration of piezoelectric element100in operation as part of an acoustic transducer. Slots20can also reduce unwanted mode of vibration. The number of slots20can be more or less than two and can be arranged at different locations on back surface1, other than offset 90 degrees from slots24. Slots20can be made before, after, or at the same time as forming slots24and can be formed using a diamond-coated disk. Other cutting tools and/or material removal methods can be used.FIGS. 1-4show piezoelectric element100before electrode material is applied to front surface2in an example embodiment of a processing procedure to make electrical connections for piezoelectric element100.

FIG. 5shows piezoelectric element100after an electrode material has been applied to front surface2, having slots10at locations8, and cuts12have been made in the electrode material to form separated electrodes9. Cuts12can be made as shallow cuts to separate rings9in the electrode material only. There are a number of mechanisms by which the electrode material can be formed on front surface2. For example, a conductive paste can be applied to front surface2using a screen process in which the paste is heated until the carrier solvent is removed leaving a coating of silver on front surface2. For example, silver can be deposited over the complete front surface2of a ceramic piezoelectric100. Other conductive materials may be used and other procedures can be used to form electrode material on front surface2of piezoelectric element100. Electrode rings9can then be generated by cutting out regions12in the conductive electrode material in a circle fashion, for example removing silver electrode material off of a piezoelectric ceramic, such that there are breaks in the conductive electrode material forming separate electrodes isolated between the circular cuts12. Other shapes may be used to form multiple electrodes on piezoelectric element100.

FIG. 6shows an embodiment of example electrode assemblies5and7that can be disposed in slots24ofFIGS. 3-5. Each of electrode assemblies,5and7, includes electrical connectors6to couple to an electrode9on front surface2. Electrode assemblies,5and7, may comprise a tape4, such as but not limited to a Kapton tape, and ribbon conductors6. Ribbon conductors6can be configured with tape4in arrangement in electrode assemblies,5and7, such that an electrical connection can be made to each of the electrode rings9. To allow contact to each electrode ring, ribbon conductors6can be arranged on tape4in electrode assembly5near one end of tape4compared with ribbon conductors6arranged on tape4in electrode assembly7near the other end of tape4. Ribbon conductors6can be cut having a thickness of approximately 1 mil thick and a width of approximately 20 mils, for example, from sheet material. Ribbon conductors having different dimensions can be used depending on the size of piezoelectric element100and the application of piezoelectric element100in a transducer. Each conductor6can be configured as two layers thick. In an embodiment having four electrode rings and a pair of ribbon conductors6with two layers in each of two slots24, the two electrode assemblies5and7can provide a total of eight conductors.

FIG. 7shows an embodiment of piezoelectric element100processed with electrode assemblies5and7attached into slots24. As can be seen inFIGS. 6 and 7, the different orientations of ribbon conductors on electrode assemblies5and7provide for independent isolated connections individually to each of electrode ring9. Pairs of ribbon conductors6are used in each electrode assembly5and7so that once installed, the conductors can be folded outwards to connect to the electrode ring on piezoelectric element100on each side of slot24using a conductive epoxy or soldering methods. As the conductors exit slot24on the edge of piezoelectric element100, the conductors can be folded in opposite directions to allow a stranded wire to be attached to the conductors to provide an external electrical connection to piezoelectric element100.FIG. 8shows an example embodiment of assembly7ofFIG. 7, where connections13of one ribbon conductor and connections14of the second of the pair of ribbon conductors are in a folded orientation when fitted into a slot24of piezoelectric element100. As such shown, external connections to piezoelectric element100can be made at the edges of piezoelectric element100.

FIG. 9shows a side view of piezoelectric element100having back surface1and front surface2with electrode assembly7affixed in slot24in front surface2of piezoelectric element100with the conductors of electrode assembly7in a folded out configuration. As shown, the folded out conductive ribbons lie flat on the electrode material of electrode rings9. With all connections of piezoelectric element100to electrodes9made in the same manner, all such connections lie flat in the recesses10on their respective electrodes9essentially without extending above the surface of the piezoelectric unit formed by the electrodes9and piezoelectric element100. With small ribbon dimensions in the folded out configuration, electrodes9can be maintained as flat electrodes.

FIG. 10shows a cross section along line A-A of piezoelectric element100ofFIG. 7. Piezoelectric element100includes electrode assemblies5and7formed in slots10of piezoelectric element100. As shown, conductors6extend into piezoelectric element100from the edge of piezoelectric element100at different distances, which allows each conductor6to be folded the ring electrode that is at the distance from the periphery of piezoelectric element100to which the conductor is disposed to its fold out position.

FIG. 11shows piezoelectric element100ofFIG. 7with electrical wires11connected to piezoelectric element100to make electrical connections external to piezoelectric element100without extending above the surface of the piezoelectric element to make the connections. The wires and connections to the ceramic electrode, structured as one electrode or multiple electrodes such as electrode rings, are fully within the surface bounds of the face of the piezoelectric element. Piezoelectric element100includes four connections to front face2, while having front face2of piezoelectric element100flat with no protrusions.

In the example embodiment ofFIG. 11, piezoelectric element100has two slots24cut in front face2at two locations8and four electrode rings9disposed on front surface2separated by cuts12in the electrode. The four electrical surfaces of the electrode rings can be driven with appropriate signals to focus an acoustic signal. In like manner, a received signal can be focused from the same distance. Piezoelectric element100can also include slots20in the back surface offset by 90 degrees from slots24, where slots20, which may be configured as four in number, can help to reduce unwanted modes of vibration during operation of piezoelectric element100in an acoustic transducer. Slots24may also aid in reducing unwanted modes of vibration. Slots24include electrode assemblies,5and7, which can consist of Kapton tape and ribbon conductors6, which folded out provide a total of 8 conductors. As conductors6exit slots24on the edge of piezoelectric element100, conductors6fold out in opposite directions to allow stranded wire11to be attached at the edge of piezoelectric element100. This lead attachment allows front face2of piezoelectric element100to be lapped to a fine finish to optimize its acoustic performance when assembled into a final transducer configuration. Piezoelectric element100can be realized as a piezoelectric ceramic.

The various procedures to process piezoelectric element100, such that wires and connections to electrodes disposed on the face of piezoelectric element100are fully within the surface bounds of the face of piezoelectric element100, can be conducted in various orders of processing. For example, after slots are cut in the face of piezoelectric element100, the electrode assemblies can be attached into the slots of piezoelectric element100followed by deposition of electrode material and processing of the electrode material to form the number of isolated, separate electrodes selected for a given application. Before depositing the electrical material, ribbon conductors can be folded on the front surface of piezoelectric element100on each side of the slots cut in the front face and connected using conductive epoxy or soldering methods. Piezoelectric element100can be further processed to provide to a fine finish to the front face with the folded conductors appropriately sized such that the front surface of piezoelectric element100is provided essentially flat. With electrode material disposed on the front surface of piezoelectric element100that includes folded out conductors, the electrode material can be processed such that the surface of the electrodes are flat to a specified design, such as but not limited to, based on the operating frequency of the transducer of which piezoelectric element100is a component. In addition, the number of slots, electrode rings, shapes of electrodes, and shape of the piezoelectric element can be modified according to the application of the piezoelectric element in an acoustic transducer. For example, the front electrode may include a number of rings different than four rings and may use a configuration different from concentric annular rings, such as square electrode surfaces disposed on the face of the piezoelectric element separated from one another by cuts or appropriate insulating material. Other shapes for the electrodes may be used.

In various embodiments, processing of a piezoelectric element to be used in a transducer can include a number of techniques to attach leads to the piezoelectric element. The piezoelectric element can be configured as a sensing portion of an annular focused transducer. The transducer can be arranged in a housing with electrical connections on the face of the piezoelectric element such that a flat surface for acoustically coupling the piezoelectric element to the housing is maintained. In order to make electrical connections on the face of the piezoelectric element and maintain a flat surface for acoustically coupling the piezoelectric element to the housing, an electrode or electrodes on the face can be configured to provide connections to the edge of the piezoelectric element. A piezoelectric element identical to or similar to the piezoelectric element ofFIG. 11can provide connections to the edge of the piezoelectric element essentially without extending above the surface of the piezoelectric element. The piezoelectric element can be a piezoelectric ceramic and the housing can be structured to operate at pressures and temperatures associated with drilling in a borehole. For example, the housing can be a housing of polyether ether ketone. Polyether ether ketone, commonly referred to as PEEK, is an organic polymer thermoplastic. Other materials appropriate for the pressures and temperatures associated with drilling operations in a borehole can be used. Other procedures and designs can be used to provide electrical connections to an electrode structure, such as a pattern of rings, for a piezoelectric element to allow attaching electrical connections to the edge of the piezoelectric element for transferal of electrical signals to and from the edge of the piezoelectric element. These attachment points can be arranged such that they do not extend above a nominal surface of the piezoelectric element.

FIGS. 12 and 13show a top view and a side view, respectively, of a piezoelectric element200to be processed for attachment as a sensing unit in an acoustic transducer with electrical attachments at the side of piezoelectric element200such that attachment points do not extend above nominal surfaces of the front and back of piezoelectric element200. Piezoelectric element200has a front surface22and a back surface21, where front surface22is to be disposed in the acoustic transducer as the active side of piezoelectric element200and back surface21can be used to attach to a housing of the acoustic transducer. Piezoelectric element200can be realized as a piezoelectric ceramic.

Piezoelectric element200can be processed to provide an electrical connection to ring electrodes formed on the active surface of piezoelectric element200. Piezoelectric element200can be processed to make electrical connections on the face of piezoelectric element200and maintain a flat surface for acoustically coupling piezoelectric element200to a PEEK housing, with electrodes configured to provide connections to the edge of piezoelectric element200. In addition, the contact points for the wires connected to the electrodes can be recessed into piezoelectric element200at the point of contact. The bond between a wire and its corresponding electrode can be finished to be at or below the nominal surface of the electrode on piezoelectric element200.

FIG. 14shows a side view of piezoelectric element200having recessed area29formed at an edge of piezoelectric element200. Recessed area29can be cut from piezoelectric element200using a diamond-coated disk or other cutting tool and/or material removal methods. Recessed area29can be formed before forming an electrode on front surface22of piezoelectric element200.

FIG. 15shows front surface22of piezoelectric element200after electrode material is formed on piezoelectric element200and after cuts in the electrode material have been made to form separate individual electrodes31,32,33, and34, which can be arranged substantially concentric around the center of piezoelectric element200on front surface22. The electrode material and cuts that form multiple electrodes can be made on front surface22of piezoelectric element200in a manner similar to the manner in which electrode material and cuts that formed multiple electrodes are processed on piezoelectric element100ofFIGS. 5, 7, and 11. Separate individual electrodes31,32,33, and34provide rings, which allow focusing acoustic energy in operation as a transducer. Each pair of electrodes can be isolated by cuts41,42, and43through the electrode material. Each electrode31,32,33, and34can be arranged to be continuous to the edge of piezoelectric element200at36,37,38, and35, respectively. Each electrode31,32,33, and34on piezoelectric element200can be formed to be continuous into recessed area29. Recessed area29can be recessed by 0.005 inches to 0.01 inches. Recessed area29can be structured to other dimensions depending on the size of piezoelectric element200and/or the application to which piezoelectric element200is designed.

Recessed area29provides a region in which each electrode31,32,33, and34can be bonded to a corresponding wire56,57,58, and55to provide electrical contacts to the edge of piezoelectric element200. Each corresponding wire56,57,58, and55can be realized as a thin flat wire, which can be bonded to its perspective electrode. The bonding can be made using a conductive epoxy in recessed area29. A wire having dimensions of 0.020 inches wide and 0.002 inches thick can be used. These dimensions can be used to allow the bond to be thin and below the nominal surface of piezoelectric element200. A stranded wire can be attached to the flat wires56,57,58, and55for the external connections to the transducer. The wires56,57,58, and55and recessed area29can have different dimensions depending on the size of piezoelectric element200and/or the transducer application of piezoelectric element200.

The number of electrode rings, shapes of electrodes, and shape of the piezoelectric element ofFIG. 15can be modified according to the application of the piezoelectric element in an acoustic transducer. For example, the front electrode may include a number of rings different than four rings and may use a configuration different from substantially concentric annular rings, such as square electrode surfaces disposed on the face of the piezoelectric element separated from one another by cuts or appropriate insulating material. Other shapes for the electrodes may be used.

FIG. 16shows features of an embodiment of a method to couple electrical contacts to a front surface of a piezoelectric element such that the front surface remains effectively flat. At1610, a piezoelectric element is provided. The piezoelectric element has a front surface and a back surface opposite the front surface, where the front surface is arranged to operate as an active surface of an acoustic transducer. At1620, recesses are formed in the front surface of the piezoelectric element. Electrode material can be applied to the front surface after forming the recesses. The process can include making cuts in the electrode material forming separate rings in the electrode material. Alternatively, electrode material can be applied to the front surface before forming the recesses. The process can also include making cuts in the electrode material forming separate rings in the electrode material.

At1630, an electrode assembly is attached into each recess. The electrode assembly can be attached into each grove after forming the separate electrode rings or before forming the electrodes. When the electrode assembly is attached before forming electrodes, attaching each electrode assembly can include, after installing each electrode assembly in its respective recess, folding conductors of each electrode assembly outwards on each side of the respective recess to connect to the piezoelectric element on the front surface. Connecting the conductors to the piezoelectric element on each side of the respective recess can include using conductive epoxy or solder. When the electrode assembly is attached after forming the separate electrode rings, attaching each electrode assembly can include, after installing each electrode assembly in its respective recess, folding conductors of each electrode assembly outwards on each side of the respective recess to connect to respective electrode rings on the front surface of the piezoelectric element. Connecting the conductors to each respective electrode ring on each side of the respective recess can include using conductive epoxy or solder.

The process can include attaching wires to the conductors of each electrode assembly folded outwards on each side of the respective recess at an outside edge of the piezoelectric element between the front surface and the back surface. Attaching the wires at the outside edge can be conducted whether the conductors are folded on the front surface of the piezoelectric element or folded on electrodes on the front surface of the piezoelectric element.

In various embodiments, a process to attach electrical contacts to a front surface of a piezoelectric element such that the front surface remains effectively flat can also include forming a number of slots in the piezoelectric element from the back surface towards the front surface such that the slots do not reach the front surface. Further, the process can include lapping the front surface to a specified finish to optimize acoustic performance of the piezoelectric element in the acoustic transducer. After processing a mechanism to connect electrical contacts to the piezoelectric element, the process can include attaching the piezoelectric element to a housing, where the housing is compatible with operation at temperatures and pressures associated with drilling in a borehole. In various embodiments, the piezoelectric element can include a piezoelectric ceramic.

FIG. 17shows features of an embodiment of a method to couple electrical contacts to a front surface of a piezoelectric element such that the front surface remains effectively flat. At1710, a piezoelectric element is provided. The piezoelectric element has a front surface and a back surface opposite the front surface, where the front surface is arranged to operate as an active surface of an acoustic transducer. At1720, a recess region is formed in the front surface of the piezoelectric element at an edge of the piezoelectric element.

At1730, an electrode is formed on the front surface of the piezoelectric element such that the electrode extends into the recess. The process can include forming the electrode on the front surface by forming electrode material on the front surface and making a number of cuts in the electrode material forming a number of separate electrodes electrically isolated from each other by the cuts such that each separate electrode is continuous into the recess region.

At1740, a contact wire is formed in the recess region, where the contact wire is coupled to the electrode such that the coupling is below the front surface within the recess. The contact wire provides a mechanism to couple the electrode to a wire external to the piezoelectric element. The process can also include forming an individual contact wire to each respective electrode of a set of electrodes in the recess region below the front surface within the recess to couple each electrode to a respective wire external to the piezoelectric element. The process can include bonding each individual contact wire to its respective electrode using conductive epoxy.

After forming electrical contacts to the piezoelectric element, the piezoelectric element can be attached to a housing, where the housing is compatible with operation at temperatures and pressures associated with drilling in a borehole. In various embodiments, the piezoelectric element includes a piezoelectric ceramic.

FIG. 18shows an embodiment of an example apparatus1800having a piezoelectric element1805disposed in a housing1807. Piezoelectric element1805has a first surface1802and a second surface1801opposite first surface1802. First surface1802of piezoelectric element1805can be arranged as a front surface to couple in the transducer as a sensing element and second surface1801can be arranged as a back surface1801that couples to a backing material1804. Backing material1804can be bonded to back surface1801and backing material1804can be bonded to housing1807to provide stability for piezoelectric element1805.

Piezoelectric element1805can be realized similar or identical to a piezoelectric element associated with one or more ofFIGS. 1-17. Piezoelectric element1805can be arranged with a set of separate electrodes such that each electrode is connected at the edge of piezoelectric element1805to wires1811providing electrical paths for signals to and from piezoelectric element1805. In some embodiments, piezoelectric element1805is maintained effectively flat with electrode assemblies in slots in piezoelectric element1805with conductors folded outward from the slots to contact electrodes on front surface1802of piezoelectric element1805. In other embodiments, piezoelectric element1805is maintained flat with each electrode ring in a set of electrode rings extended into a recess in piezoelectric element1805in front surface1802at an edge of piezoelectric element1805. In various embodiments, piezoelectric element1805can include slots in back surface1801to aid in reducing unwanted vibrational modes.

Apparatus1800can be constructed such that a single electrode can be used on back surface1801and conductive electrode rings can be disposed on front surface1802. Housing1807provides a protective housing for operation of piezoelectric element1805arranged as a sensor. Backing material1804, bonded to piezoelectric element1805, can be bonded to housing1807with epoxy1818. Backing material1804can be bonded to housing1807without bonding piezoelectric element1805to housing1807. Electrical conductors1811can be provided through openings1809in housing1807. Piezoelectric element1805can be realized as a piezoelectric ceramic. Piezoelectric element1805can also be arranged as a focused transducer in housing1807, where housing1807can be constructed to be compatible with operation at temperatures and pressures associated with drilling in a borehole.

FIG. 19depicts a block diagram of features of an example embodiment of a system1900having a measurement tool1956including a transducer module1957for measurements downhole in a well. Transducer module1957can be structured with a configuration such that the sensor of transducer module1957is a piezoelectric element having electrical contacts at a side edge of the piezoelectric element such that the front sensing surface of the piezoelectric element is essentially flat without contacts protruding from the face of the piezoelectric element. The piezoelectric element with its front surface electrode structure can be realized in accordance with any of the teachings described herein. The piezoelectric element can be structured to operate in a thickness mode. Transducer module1957can be realized as a focused ultrasonic transducer module. Transducer module1957can be structured similar to or identical to a configuration associated with any ofFIGS. 1-18.

System1900can include a controller1951, a memory1952, an electronic apparatus1954, and a communications unit1955. Controller1951, memory1952, and communications unit1955can be arranged to operate as a processing unit to control management of measurement tool1956and to perform operations on data signals collected by measurement tool1956. A data processing unit can be distributed among the components of system1900including electronic apparatus1954. Alternatively, system1900can include a processing unit1958to mange measurement tool1956.

Communications unit1955can include downhole communications for communication to the surface at a well from measurement tool1956. Such downhole communications can include a telemetry system. Communications unit1955may use combinations of wired communication technologies and wireless technologies at frequencies that do not interfere with on-going measurements.

System1900can also include a bus1953, where bus1953provides electrical conductivity among the components of system1900. Bus1953can include an address bus, a data bus, and a control bus, each independently configured. Bus1953can be realized using a number of different communication mediums that allows for the distribution of components of system1900. Use of bus1953can be regulated by controller1951.

In various embodiments, peripheral devices1959can include displays, additional storage memory, and/or other control devices that may operate in conjunction with controller1951and/or memory1952. In an embodiment, controller1951can be realized as a processor or a group of processors that may operate independently depending on an assigned function. Peripheral devices1959can be arranged with a display, as a distributed component on the surface, that can be used with instructions stored in memory1952to implement a user interface to manage the operation of measurement tool1956and/or components distributed within system1900. Such a user interface can be operated in conjunction with communications unit1955and bus1953.

FIG. 20depicts an embodiment of a system2000at a drilling site, where system2000includes a measurement tool2056including a transducer module for measurements downhole in a well. The transducer module can be structured with a configuration such that the sensor of the transducer module is a piezoelectric element having electrical contacts at a side edge of the piezoelectric element such that the front sensing surface of the piezoelectric element is essentially flat without contacts protruding from the face of the piezoelectric element. The piezoelectric element with its front surface electrode structure can be realized in accordance with any of the teachings described herein. The piezoelectric element can be structured to operate in a thickness mode. The transducer module can be realized as a focused ultrasonic transducer module. The transducer module can be structured similar to or identical to a configuration associated with any ofFIGS. 1-19, in accordance with the teachings of various embodiments taught herein.

System2000can include a drilling rig2002located at a surface2004of a well2006and a string of drill pipes, that is, drill string2008, connected together so as to form a drilling string that is lowered through a rotary table2007into a wellbore or borehole2012. The drilling rig2002can provide support for drill string2008. The drill string2008can operate to penetrate rotary table2007for drilling a borehole2012through subsurface formations2014. The drill string2008can include drill pipe2018and a bottom hole assembly2020located at the lower portion of the drill pipe2018.

The bottom hole assembly2020can include drill collar2015, measurement tool2056attached to drill collar2015, and a drill bit2026. The drill bit2026can operate to create a borehole2012by penetrating the surface2004and subsurface formations2014. Measurement tool2056can be structured for an implementation in the borehole of a well as a measurements-while-drilling (MWD) system such as a logging-while-drilling (LWD) system. The housing containing measurement tool2056can include electronics to manage measurement tool2056and collect responses from measurement tool2056. Such electronics can include a processing unit to analyze signals sensed by measurement tool2056and provide measurement results to the surface over a standard communication mechanism for operating a well. Alternatively, the electronics can include a communications interface to provide signals sensed by measurement tool2056to the surface over a standard communication mechanism for operating a well, where these sensed signals can be analyzed at a processing unit at the surface.

In various embodiments, measurement tool2056may be included in a tool body2070coupled to a logging cable2074such as, for example, for wireline applications. Tool body2070containing measurement tool2056can include electronics to manage measurement tool2056and collect responses from measurement tool2056. Such electronics can include a processing unit to analysis signals sensed by measurement tool2056and provide measurement results to the surface over a standard communication mechanism for operating a well. Alternatively, the electronics can include a communications interface to provide signals sensed by measurement tool2056to the surface over a standard communication mechanism for operating a well, where these collected sensed signals are analyzed at a processing unit at the surface. Logging cable2074may be realized as a wireline (multiple power and communication lines), a mono-cable (a single conductor), and/or a slick-line (no conductors for power or communications), or other appropriate structure for use in bore hole2012.

During drilling operations, the drill string20020can be rotated by the rotary table2007. In addition to, or alternatively, the bottom hole assembly2020can also be rotated by a motor (e.g., a mud motor) that is located downhole. The drill collars2015can be used to add weight to the drill bit2026. The drill collars2015also can stiffen the bottom hole assembly2020to allow the bottom hole assembly2020to transfer the added weight to the drill bit2026, and in turn, assist the drill bit2026in penetrating the surface2004and subsurface formations2014.

During drilling operations, a mud pump2032can pump drilling fluid (sometimes known by those of skill in the art as “drilling mud”) from a mud pit2034through a hose2036into the drill pipe2018and down to the drill bit2026. The drilling fluid can flow out from the drill bit2026and be returned to the surface2004through an annular area2040between the drill pipe2018and the sides of the borehole2012. The drilling fluid may then be returned to the mud pit2034, where such fluid is filtered. In some embodiments, the drilling fluid can be used to cool the drill bit2026, as well as to provide lubrication for the drill bit2026during drilling operations. Additionally, the drilling fluid may be used to remove subsurface formation2014cuttings created by operating the drill bit2026.