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.

Abstract: Systems and methods for evaluating a cement installation are provided. In one example, 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. External signals (e.g., signals other than the casing arrival signals) may be attenuated by firing an attenuation firing signal.

Abstract: A method for extending reach of a coiled tubing string in a deviated wellbore includes determining a frequency of vibration of the tubing string based on a function of the bending resonance of the tubing string and vibrating the tubing string at the determined frequency while the tubing string is inside the wellbore. A non-transitory computer-readable storage medium to execute the foregoing method and a system for extending reach of a coiled tubing string in a deviated wellbore are also described.

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: The subject disclosure relates to energy harvesting. More particularly, the subject disclosure relates to harvesting energy from the relative motion between a rotary stabilizer and the drill string. In further embodiments, the subject disclosure relates to harvesting energy from vibrations in the drill string.

Abstract: The subject disclosure relates to sonic logging while drilling. A transmitter and at least one receiver are mounted on a drill collar for performing sonic investigations of the formation traversing a borehole.

Abstract: A mechanism for selectively activating a plurality of downhole pathways is disclosed. 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 from the closed position to the open position.

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: 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 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: 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: 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: The present application relates to energy harvesting. More particularly, the present application relates to harvesting energy from non-stationary, multi-frequency mechanical vibrations using a tunable electrical circuit.

Abstract: Electrical energy is produced at a remote site by converting kinetic energy from fluid flow to electrical energy using a downhole harvesting apparatus. The downhole harvesting apparatus includes a vibrating sleeve member that vibrates in response to fluid flow through a tubular housing structure. The vibration of the sleeve is used to generate electrical power. The harvesting apparatus may include features to help maintain constant fluid flow in the tubular structure. The harvesting apparatus can be tuned to different vibration and flow regimes in order to enhance energy conversion efficiency.

Abstract: Apparatus and method comprising a plurality of particles which are magnetically attracted to one another in response to exposure to a magnetic field, and which maintain attraction to one another after removal of the magnetic field, the attraction being disabled when the particles are demagnetized, whereby the particles operate to alter the rheological properties of a fluid in which the particles are mixed when the attraction is enabled or disabled is disclosed.

Abstract: A method of estimating extended reach for a downhole line traversing a deviated section of a well. The method may include storing line and well architectural and physical data and then performing a static analysis of substantially axial-exclusive estimated friction between the line and well wall during conveyance (which may be thought of as the contact force due to interference therebetween). A one dimensional dynamic analysis may then be performed. Thus, based on these factors, speed of the conveyance, vibration parameters of an incorporated vibration tool, etc., an efficient simulation of the conveyance may be run.

Abstract: Apparatus and a method for delivering a rod in a cylinder including propagating a rod in a cylinder along the interior of the cylinder, and introducing a motion in an orientation orthogonal to a length of the rod, wherein the motion comprises multiple motion sources along the length of the rod, and wherein the multiple motion sources comprise a control system that controls at least one of the motion sources. An apparatus and method for delivering a rod in a cylinder including a cylinder comprising a deviated portion, a rod comprising a length within the cylinder, multiple motion sources positioned along the length of the rod, and a control system in communication with at least one of the motion sources, wherein the control system controls the location of frictional contact between the rod and cylinder over time.

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: The invention provides drill bits and methods of drilling curved boreholes. One aspect of the invention provides a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths. Another aspect of the invention provides a method for drilling a curved borehole. The method includes: providing a drill string including a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths; rotating the drill string; and selectively actuating the one or more blades to a plurality of cut depths; thereby drilling a curved borehole.

Abstract: An apparatus and method to enhance the efficiency of an energy harvesting device is disclosed. A modulator module creates fluctuations in the flow at a predetermined frequency or group of frequencies and these fluctuations increase mechanical vibrations which are then harvested by an energy harvesting module.