Abstract: Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole string comprising a disintegration device and a damping system at least one of in and on the downhole string, the damping system configured to damp torsional oscillations of the downhole string. The methods include installing a damping system at least one of on and in the downhole system with the downhole system including a downhole string having a disintegration device and the damping system is configured to damp torsional oscillation of the downhole string.

Abstract: Communication methods and systems for communicating from a surface location to a downhole component in a borehole in an earth formation are described. The methods and systems include modulating, by a first device at the surface location, a fluid flow through a mud motor according to a predetermined pattern, the mud motor disposed in the borehole, the modulated fluid flow generating a mechanical movement variation pattern of at least a part of the mud motor, detecting, by a second device in the downhole component, the mechanical movement variation pattern, and demodulating the mechanical movement variation pattern to receive a signal that is related to the predetermined pattern.

Abstract: Systems and methods for mitigating vibration in downhole strings are described. The methods include obtaining first and second load measurements of first and second loads during a drilling operation and creating first and second load measurement data, with first and second load sensors separated by a sensor distance. First and/or second representative values of the first and second loads are determined form the first and second load measurement data and the sensor distance. The determined representative value(s) are compared against respective load limit(s) and a vibration mitigation operation is performed in response to the determined representative value(s) equaling or exceeding the respective load limit.

Abstract: An example system for optimal storage of load data for lifetime prediction for a piece of equipment used in a well operation includes a sensor collecting load data of the piece of equipment and a processing device for executing computer readable instructions. The computer readable instructions include: determining a lifetime model for the piece of equipment; calculating a bucket size using one of the lifetime model and a distribution of load data; discretizing a load data spectrum into one or more buckets using the calculated bucket size; assigning the collected load data to the one or more buckets of the load data spectrum; storing the collected load data assigned to the one or more buckets to a memory; and determining a lifetime estimation of the piece of equipment based on the load data assigned to the one or more buckets of the load data spectrum and stored to the memory.

Abstract: Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a damping system configured on the downhole system. The damping system includes a first element and a second element in frictional contact with the first element. The second element moves relative to the first element with a velocity that is a sum of a periodic velocity fluctuation having an amplitude and a mean velocity, wherein the mean velocity is lower than the amplitude of the periodic velocity fluctuation.

Abstract: A device for transferring torque to a drill bit in a borehole having a borehole axis includes a support element configured to rotate in the borehole about the borehole axis, a torque transferring element configured to transfer torque from the support element to the drill bit and further configured to isolate torsional oscillations that are created at the drill bit from the support element, a blocking element configured to block rotation of the torque transferring element relative to the support element about the borehole axis in at least one direction, and a bearing element between the support element and the drill bit.

Abstract: A method of operating a Moineau system to substantially eliminate vibrations, the method includes rotating a first rotational member, and rotating a second rotational member. Each of the first rotational member and the second rotational member includes a plurality of lobes. A first rotational speed of one of the first rotational member and the second rotational member is selected based on 1) a second rotational speed of the other of the first rotational member and the second rotational member and 2) the number of lobes of one of the first rotational member and the second rotational member to maintain eccentric force of one of the first and second rotational members below a predetermined threshold.

Abstract: Examples of techniques for optimal storage of load data for lifetime prediction for a piece of equipment used in a well operation are disclosed. In one example implementation according to aspects of the present disclosure, a method may include: using a lifetime model for the piece of equipment used in the well operation; discretizing, by a processing device, a load data spectrum into one or more buckets, the one or more buckets having a bucket size, wherein the bucket size of at least one bucket is based on one of the lifetime model and a distribution of load data; collecting load data of the piece of equipment; assigning, by the processing device, the collected load data to the one or more buckets of the load data spectrum; and storing, by the processing device, the collected load data assigned to the one or more buckets to a memory.

Abstract: A method for selecting drilling parameters for drilling a borehole penetrating the earth with a drill string. The method includes: measuring vibration-related amplitudes of the drill string during operation using one or more vibrations sensor to provide amplitude measurements; determining with a downhole processor one or more modal properties comprising one or more eigenfrequencies of the drill string using the amplitude measurements, the determination being made by including any excitation force in a white noise term of a model of the drillstring; and selecting drilling parameters that apply an excitation force at a frequency that avoids a selected range of frequencies that bound the one or more eigenfrequencies using the processor.

Abstract: A method for adjusting a drilling parameter of a drill string includes: determining one or more modes of the drill string; sensing a first oscillation amplitude at a first position in the drill string and/or an oscillation parameter of the drill string at the first position or a second position to provide measured first oscillation amplitude data and/or measured oscillation parameter data; identifying a mode of the drill string using one or more determined modes and a stability criterion and at least one of the measured first oscillation amplitude data and the measured oscillation parameter data; calculating an oscillation amplitude at a position of interest in the drill string using the identified mode and at least one of the measured first oscillation amplitude data, the measured oscillation parameter data and the stability criterion; and adjusting the drilling parameter in response to the calculated oscillation amplitude at the position of interest.

Abstract: An embodiment of a method of detecting and correcting for spiraling in a downhole carrier includes: deploying the carrier in a borehole in an earth formation as part of a subterranean operation; acquiring time based data from at least one sensor disposed at the carrier; acquiring time and depth data, the time and depth data correlating time values with depths of the carrier; generating a depth based profile based on the time based data and the time and depth data; generating a frequency profile by transforming the depth based profile into the frequency domain; detecting a spiraling event based on an amplitude of the frequency profile; and taking corrective action based on detecting the spiraling event.

Abstract: A method for reducing vibrations in a drill tubular coupled to a drill bit configured to drill a borehole in a formation includes: constructing a model of a system having the drill tubular, the model having a mass distribution, a stiffness, and/or a damping of the drill tubular; and calculating a plurality of modes using the model. The method also includes increasing an effective damping of the drill tubular for the plurality of modes by modifying at least one of the mass distribution, the stiffness, and the damping of the drill tubular using a predefined damping criterion, wherein the predefined damping criterion includes a ratio, the ratio having a deflection at the drill bit of at least one mode in the plurality and an eigenfrequency of the at least one mode in the plurality, wherein the deflection at the drill bit is raised to a power other than one.

Abstract: An embodiment of a method of detecting and correcting for spiraling in a downhole carrier includes: deploying the carrier in a borehole in an earth formation as part of a subterranean operation; acquiring time based data from at least one sensor disposed at the carrier; acquiring time and depth data, the time and depth data correlating time values with depths of the carrier; generating a depth based profile based on the time based data and the time and depth data; generating a frequency profile by transforming the depth based profile into the frequency domain; detecting a spiraling event based on an amplitude of the frequency profile; and taking corrective action based on detecting the spiraling event.

Abstract: A method for reducing drill tubular vibrations includes: constructing a mathematical model the drill tubular having mass distribution, material stiffness and material damping; constructing an equation of motion of the drill tubular in one of a time domain and frequency domain; transforming the equation of motion into a modal domain equation of motion to provide a mode shape of the drill tubular at an eigenfrequency, the mode shape providing an amplitude at a position along the drill tubular; comparing the amplitude at the position along the drill tubular to a threshold amplitude value; modifying at least one of the mass distribution, material stiffness and material damping if the amplitude exceeds the threshold value; and iterating the above step until at least one of the amplitude of the latest mode shape at the position is less than or equal to the threshold amplitude value and a predetermined constraint limits the modifying.

Abstract: Examples of techniques for optimal storage of load data for lifetime prediction for a piece of equipment used in a well operation are disclosed. In one example implementation according to aspects of the present disclosure, a method may include: using a lifetime model for the piece of equipment used in the well operation; discretizing, by a processing device, a load data spectrum into one or more buckets, the one or more buckets having a bucket size, wherein the bucket size of at least one bucket is based on one of the lifetime model and a distribution of load data; collecting load data of the piece of equipment; assigning, by the processing device, the collected load data to the one or more buckets of the load data spectrum; and storing, by the processing device, the collected load data assigned to the one or more buckets to a memory.

Abstract: A method of operating a Moineau system to substantially eliminate vibrations, the method includes rotating a first rotational member, and rotating a second rotational member. Each of the first rotational member and the second rotational member includes a plurality of lobes. A first rotational speed of one of the first rotational member and the second rotational member is selected based on 1) a second rotational speed of the other of the first rotational member and the second rotational member and 2) the number of lobes of one of the first rotational member and the second rotational member to maintain eccentric force of one of the first and second rotational members below a predetermined threshold.

Abstract: A method for selecting drilling parameters for drilling a borehole penetrating the earth with a drill string. The method includes: measuring vibration-related amplitudes of the drill string during operation using one or more vibrations sensor to provide amplitude measurements; determining with a downhole processor one or more modal properties comprising one or more eigenfrequencies of the drill string using the amplitude measurements, the determination being made by including any excitation force in a white noise term of a model of the drillstring; and selecting drilling parameters that apply an excitation force at a frequency that avoids a selected range of frequencies that bound the one or more eigenfrequencies using the processor.

Abstract: A method for defining a permissible borehole curvature includes determining curvature characteristics of at least one of a borehole and a downhole assembly in the borehole and calculating an envelope of permissible borehole curvatures from a predetermined location in the borehole based on the curvature characteristics, a direction of the borehole at the predetermined location in the borehole, and a turning angle of the borehole relative to the direction of the borehole at the predetermined location.

Abstract: A method for selecting drilling parameters for drilling a borehole penetrating the earth with a drill string includes: varying a frequency of an excitation force applied to the drill string using an excitation device controlled by a drill string controller and measuring vibration-related amplitudes of the drill string due to the applied excitation force using a vibration sensor to provide amplitude measurements. The method further includes determining one or more modal properties comprising one or more eigenfrequencies of the drill string using the amplitude measurements and selecting drilling parameters that apply an excitation force at a frequency that avoids a selected range of frequencies that bound the one or more eigenfrequencies.

Abstract: A method for estimating drilling parameters for drilling a borehole in the earth includes: drilling the borehole with a drill string having a mud motor and a drill bit; constructing a mathematical model of a system including the drill string, the mud motor, and a borehole geometry; calculating a mud motor lateral excitation force imposed on the drill string by the mud motor for one or more combinations of drill string rotational speed and mud motor rotational speed; calculating lateral motion of the drill string and a force imposed on the drill string at positions along the drill string for the one or more of combinations using the model and the excitation force; selecting a range of combinations of drill string rotational speed and mud motor rotational speed that result in the force imposed upon the drill string being less than a threshold value; and displaying the range of combinations.