Abstract: Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.

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 computer-readable medium performs a method for performing a drilling operation in a formation. A plurality of predictive models are determined. Each predictive model of the plurality of predictive models is determined for an interval in the downhole formation, wherein each predictive model of the plurality of predictive models relates one or more drilling parameters of the drilling operation to a plurality of objectives for the drilling operation. A plurality of target objectives is defined. A plurality of outcomes is determined for each of the predictive models of the plurality of predictive models and the plurality of target objectives. An optimization is performed to select an outcome from the plurality of outcomes. The drilling operation is performed using the selected outcome to achieve the plurality of target objectives.

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: 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: Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.

Abstract: A method of predicting behavior of a drilling assembly includes: generating a mathematical representation of a geometry of each of a plurality of components of a drilling assembly, the plurality of components including a plurality of cutters and one or more additional components configured to at least one of: support the plurality of cutters and operably connect the plurality of cutters to the drill string, the one or more additional components including a drill bit crown; simulating one or more operating conditions incident on the drilling assembly representation, and simulating an interaction between the plurality of components and an earth formation; and predicting physical responses of the drilling assembly representation to the one or more conditions.

Abstract: Unwanted oscillations of a drill string while a borehole is being drilled are limited by adjusting a drilling parameter. Measurements related to oscillations of the drill string can be extrapolated by calculation to a position of interest along the drill string using a mode identified from one or more determined modes and a stability criterion that models the drill string. The stability criterion includes a specific modal damping for each of the one or more determined modes. The position of interest may correspond to a location of a tool or component that may be damaged by the unwanted oscillations. If the tool or component can be damaged by the oscillations as calculated, then the drilling parameter is adjusted to limit those oscillations.

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: 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 of predicting behavior of a drilling assembly includes: generating a mathematical representation of a geometry of each of a plurality of components of a drilling assembly, the plurality of components including a plurality of cutters and one or more additional components configured to at least one of: support the plurality of cutters and operably connect the plurality of cutters to the drill string, the one or more additional components including a drill bit crown; simulating one or more operating conditions incident on the drilling assembly representation, and simulating an interaction between the plurality of components and an earth formation; and predicting physical responses of the drilling assembly representation to the one or more conditions.

Abstract: A method of predicting behavior of a drilling assembly includes: generating a mathematical representation of a geometry of each of a plurality of components of a drilling assembly, the plurality of components including a plurality of cutters and one or more additional components configured to at least one of: support the plurality of cutters and operably connect the plurality of cutters to the drill string, the one or more additional components including a drill bit crown; simulating one or more operating conditions incident on the drilling assembly representation, and simulating an interaction between the plurality of components and an earth formation; and predicting physical responses of the drilling assembly representation to the one or more conditions.

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.