Abstract: A mechanism for selectively activating a plurality of downhole pathways. The method includes a casing segment which includes a plurality of casing ribs, a valve which includes a sleeve coupled for movement between an open and normally closed position, a rocker member mounted to the sleeve, a dart for pumping in hole including a dart profile matched to the rocker member profile such that the dart profile couples to the rocker member profile when in close proximity and, in turn, the sleeve moves using hydraulic force from the closed position to the open position.

Abstract: Harvesting energy from non-stationary, multi-frequency mechanical vibrations using a tunable electrical circuit. In an embodiment, an apparatus for converting vibrational energy to electrical energy includes a vibrational energy harvester having a transducer for generating time-varying electrical signals in response to environmental vibration; at least one power storage device; a switching network operably coupled between the transducer of the vibrational energy harvester and the at least one power storage device, wherein the switching network includes a plurality of switching elements each defining a switchable current path that is controlled by a control signal supplied to the respective switching element; and electronics configured to generate the control signals for supply to the switching elements of the switching network, the electronics including first circuitry, second circuitry, third circuitry, and fourth circuitry.

Abstract: Backward whirling reduction is provided. In one possible implementation a system for reducing backward whirling includes a drill, a bottom hole assembly associated with the drill, and at least one backward whirling disruptor associated with the bottom hole assembly. In another possible implementation, information from a computer simulation associated with a behavior of the bottom hole assembly during a simulated drilling operation is accessed. Then a first section of the bottom hole assembly exhibiting backward whirling during the simulated drilling operation is identified and the bottom hole assembly is modified to include one or more backward whirling disruptors to at least reduce the backward whirling during the simulated drilling operation.

Abstract: A system for use in treating a wellbore may include a tubular string deployed in the wellbore; and at least one valve assembly connected to the tubular string, each valve assembly for establishing communication between the tubular string and a formation zone, the at least one valve assembly comprises a sleeve having at least one fluid port therein that expands in an axial direction when the valve assembly opens to form a flowpath between an interior of the tubular string and the formation zone.

Abstract: A technique employs the use of oscillations downhole to facilitate a desired functionality of a downhole tool. According to this technique, a tool is initially conveyed downhole and operated to perform a function that relates to a downhole application. The operational efficiency of the tool is improved by creating oscillating forces which vibrate the tool to achieve a desired result, e.g. freeing the tool from a stuck position.

Abstract: A technique that is usable with a well includes communicating an untethered object in a passageway downhole in the well and using a cross-sectional dimension of the object and an axial dimension of the object to select a seat assembly of a plurality of seat assemblies to catch the object to form an obstruction in the well.

Abstract: A technique employs the use of oscillations downhole to facilitate a desired functionality of a downhole tool. According to this technique, a tool is initially conveyed downhole and operated to perform a function that relates to a downhole application. The operational efficiency of the tool is improved by creating oscillating forces which vibrate the tool to achieve a desired result, e.g. freeing the tool from a stuck position.

Abstract: Embodiments may include methods that include emplacing a degradable material into a wellbore, wherein the degradable material includes a thermoplastic elastomer; contacting the degradable material with an aqueous fluid downhole; and allowing the degradable material to at least partially degrade. In another aspect, methods may include emplacing into a wellbore a tool containing a sealing element thereon, wherein the sealing element contains a degradable material; engaging the sealing element with a downhole surface to establish a seal; contacting the sealing element with an aqueous fluid; and allowing the sealing element to at least partially degrade, thereby disrupting the established seal.

Abstract: An acoustic logging tool is provided with a first acoustic source that generates an acoustic signal primarily directed into the formation, the acoustic signal including a noise signal carried axially along the tool, a second acoustic source adapted to generate a noise canceling signal along the tool that actively and significantly cancels the noise signal, and a plurality of acoustic sensors axially spaced from each other along the tool and spaced from the first acoustic source and the second acoustic source. The acoustic sensors receive and record indications of pressure signals resulting from the acoustic signal and the noise canceling signal. The pressure signal indications may be processed in order to generate information regarding the formation.

Abstract: Active stabilization is provided. In one possible implementation a drilling tool associated with a drill bit includes one or more rotation alteration devices configured to alter a rotational radius of a drill string. The drilling tool also includes at least one active stabilizer rotatively attached to the drilling tool, as well as a variable brake configured to control a rotation of the at least one active stabilizer relative to the drilling tool. In another possible implementation, a drilling tool includes an active stabilizer rotatably coupled to the drilling tool, as well as an actuation system configured to control a torque placed on the active stabilizer through contact with a wall of a borehole.

Abstract: According to the invention, a method for designing a rotary drill bit for drilling a cavity in a medium is disclosed. The method may include determining a characteristic of a drillstring with which the rotary drill bit is coupled. The method may also include determining an initial number of groups of cutters for the rotary drill bit, where each group of cutters includes a plurality of cutters substantially aligned along a different radius of the drilling face. The method may moreover include determining a characteristic of the medium relative to a characteristic of the cutters. The method may additionally include determining a characteristic of a rotational motion source used to rotate the rotary drill bit. The method may further include determining the angles of pitch between each of the groups of cutters to minimize an amount of sticking or slipping of the bit in the medium during a drilling operation.

Abstract: Systems and methods for evaluating cement in the annulus of a wellbore are provided. In one embodiment, the cement may be evaluated using a casing arrival measurement sensor that measures casing arrival signals resulting from firing a signal from a cement bond logging acoustic source. Signals other than casing arrival signals may be attenuated using grooves between the transmitter and receiver in the drill collar.

Abstract: Apparatus and methods are disclosed for directionally drilling an earth formation where magnet arrays are utilized to provide net lateral force between a first member coupled to a drill bit and another member that either extends through or around the first member.

Abstract: A multi-step autofrettage process for pre-treating a multi-cylinder reciprocating pump fluid end that has a central cylinder and at least two side cylinders is provided that includes autofrettaging the central cylinder; and autofrettaging the at least two side cylinders, wherein the autofrettaging of the central cylinder is performed independently of the autofettaging of the at least two side cylinders.

Abstract: A downhole tool, having a central axis defined, may selectively include a sensor section including one or more arms connected to the tool body with an open/close mechanism. The open/close mechanism is configured to move in a radial direction with respect to the axis of the tool body. The tool also includes at least one sensor attached to the arm, and the tool may include at least one transmitter section on the tool. The transmitter is configured to transmit acoustic energy to a formation.

Abstract: A first wireline tool embodiment includes a segmented tool body having a joint deployed between each adjacent pair of tool body sections. The joint may be configured to extend axially (causing a relative axial displacement of the adjacent tool body sections) when the wireline tool is subject to an axial load. The joint may include, for example, a compliant joint or a protractible joint. The joint may be further configured to cause a relative rotation between the adjacent tool body sections when the wireline tool is subject to axial load. A second wireline tool embodiment includes a plurality of standoff rings deployed about an outer surface of a rigid tool body. The standoff rings engage helical grooves in the outer surface of the tool body such that axial displacement of the tool body causes the standoff rings to rotate.

Abstract: Techniques are described for axial vibration control of wireline tools and cables during logging operations. In undesirable cases the axial vibrations may lead to or exasperate the stick-slip problems of the logging tool. Control systems and strategies to minimize vibrations are described. Techniques are also described for identifying and inhibiting the sticking of the cable. A described system includes a surface actuator and a sensor. The actuator generates an axial wave on the wireline cable which travels down the cable. If there is sticking of the cable, a reflection can also occur at the location of sticking. This shift in the transmission of the wave on the wireline cable is used to identify the onset and/or presence of sticking.

Abstract: Techniques for axial vibration control of wireline tools and cables during logging operations. In undesirable cases the axial vibrations may lead to or exasperate the stick-slip problems of the logging tool. Control systems and strategies to minimize vibrations and techniques for identifying and inhibiting the sticking of the cable. A system includes a surface actuator and a sensor. The actuator generates an axial wave on the wireline cable which travels down the cable. If there is sticking of the cable, a reflection can also occur at the location of sticking. This shift in the transmission of the wave on the wireline cable is used to identify the onset and/or presence of sticking.

Abstract: Methods and apparatus to identify layer boundaries in subterranean formations are described. An example method of identifying a layer boundary of a subterranean formation includes transmitting an acoustic signal from a transmitter into a borehole of the subterranean formation and receiving the acoustic signal at a receiver coupled to the downhole tool and spaced from the transmitter. Additionally, the example method includes logging an energy value associated with the acoustic signal received by the receiver as the downhole tool is moved in the borehole and identifying a change in the logged energy value associated with an impedance change in the subterranean formation to identify the layer boundary.

Abstract: Methods and apparatus facilitating radial profiling of shear slowness are disclosed. According to some aspects of the invention, acoustic tool bias is accounted for in the calculation of radial profiles. According so some aspects, acoustic tool bias is accounted for by replacing acoustic tool structure with a resonance-impedance model. The resonance-impedance modeling according to principles of the present invention is applicable to vertical, deviated, and horizontal boreholes.