摘要:
In some embodiments, an apparatus and a system, as well as a method and an article, may operate to rotate a rotatable driving member having at least one driving lobe, and to periodically contact at least one cam on a unitary driven member with the at least one driving lobe during rotation of the rotatable driving member, to set the driven member in motion. This motion can be used to launch an acoustic wave along an axis substantially orthogonal to the axis of rotation of the driving member, where the driving member disposed completely within the driven member. The signature of the acoustic wave can be at least partially determined by the profile of the cam and the rotation rate of the driving member. Additional apparatus, systems, and methods are disclosed.
摘要:
Acoustic logging systems and methods are provided with multi-mode inversion for at least vertical shear slowness and shear anisotropy. At least some method embodiments acquire waveforms for multiple acoustic wave modes as a function of tool position in a borehole, derive position-dependent mode dispersion curves from the waveforms, match the derived dispersion curves with parameterized dispersion curves to determine a vertical shear slowness and a shear anisotropy as a function of position, and displaying a borehole log that represents at least one of the vertical shear slowness and the shear anisotropy as a function of position. The objective function employed for the inversion is evaluated across multiple wave propagation modes and mud slownesses and may employ an adaptive, frequency-dependent weighting based on distance between the derived dispersion curves and the parameterized dispersion curves.
摘要:
Various systems and methods for implementing and using a variable stiffness downhole tool housing include cylindrical segments positioned along a common axis, with a pair of segments each coupled to a bulkhead and positioned at either axial end of the tool housing. The housing also includes a flexible cylindrical sleeve, positioned along the common axis between two of the plurality of cylindrical segments, that includes a first and second region with an outer diameter no larger than a common segment inner diameter and a third region located between the first and second regions and with an outer diameter no larger than a common segment outer diameter (the first and second regions each at least partially inserted into an end of one segment). A stiffness controller controls the stiffness of the tool housing by controlling at least part of an axial force exerted between the two segments.
摘要:
In some embodiments, apparatus and systems, as well as methods, may operate to record a plurality of acoustic waveforms corresponding to acoustic waves received at azimuthally orthogonal dipole receiver arrays surrounded by a geological formation, the waves being generated by azimuthally orthogonal transmitter arrays. Further activity may include analytically estimating a global minimum of a predefined objective function with respect to an azimuth angle at a point in an auxiliary parameter space associated with a set of auxiliary parameters, minimizing the objective function at the analytically estimated angle with respect to the auxiliary parameters, removing existing ambiguities associated with the fast and slow principal flexural wave axes, and determining at least one property of the geological formation based on the global minimum. Additional apparatus, systems, and methods are disclosed.
摘要:
Various embodiments include apparatus and methods to process acoustic signals according to joint time-frequency processing. The joint time-frequency processing can combine features of both time-based processing and frequency-based processing. This processing may be based on delay calculation from amplitude phases generated from the acoustic signals. The joint time-frequency processing may be applied to a variety of applications to evaluate properties associated with a borehole or surrounding formations. Additional apparatus, systems, and methods are disclosed.
摘要:
Acoustic logging systems and methods are provided with multi-mode inversion for at least vertical shear slowness and shear anisotropy. At least some method embodiments acquire waveforms for multiple acoustic wave modes as a function of tool position in a borehole, derive position-dependent mode dispersion curves from the waveforms, match the derived dispersion curves with parameterized dispersion curves to determine a vertical shear slowness and a shear anisotropy as a function of position, and displaying a borehole log that represents at least one of the vertical shear slowness and the shear anisotropy as a function of position. The objective function employed for the inversion is evaluated across multiple wave propagation modes and mud slownesses and may employ an adaptive, frequency-dependent weighting based on distance between the derived dispersion curves and the parameterized dispersion curves.
摘要:
In some embodiments, apparatus and systems, as well as methods, may operate to shift signal data associated with a set of receivers, in time or phase with respect to signal data associated with a receiver reference point, to transform the signal data into shifted data, wherein the signal data corresponds to energy waves propagated through a geological formation before being received by the set of receivers; to multiply the shifted data by a complex conjugate of the signal data associated with the receiver reference point to provide differential phase values; to sum and average the differential phase values to provide differential phase semblance values; and to publish the differential phase semblance values, or information derived from the differential phase semblance values to one of a storage medium, a hardcopy printout, or a display. Additional apparatus, systems, and methods are disclosed.
摘要:
In various embodiments, apparatus and methods are provided to perform acoustic imaging. An acoustic wave can be acquired at a detector, where the acoustic wave propagates from a target to the detector. The target may be acoustically illuminated to provide the acoustic wave. A signal from the detector in response to acquiring the acoustic wave can be processed in a model such that the processing implements a synthetic acoustic lens to generate an image of the target. Additional apparatus, systems, and methods are disclosed.