Abstract: Aspects provide for methods that successfully evaluates multiple compressional and shear arrival events received by a sonic logging tool to evaluate the presence of structures, such as shoulder beds, in downhole environments. In particular, the methods described herein enable automated determination of properties of laminated reservoir formations by, for example, enabling the automated determination of arrival times and slownesses of multiple compressional and shear arrival events received by a sonic logging tool.

Abstract: Methods and systems are provided that perform sonic measurements in a high-angle wellbore or horizontal wellbore or vertical wellbore penetrating highly dipped formation layers where the formation layers can have a high degree of dip relative to the wellbore. Sonic data can be generated from the sonic measurements and processed using multiple arrival event processing to determine formation porosity, elastic rock properties and geometric information for a tool layer and nearby shoulder bed. Such information can be integrated into a 2D or 3D layered model of the formation. The elastic rock properties of the tool layer and shoulder bed derived from the multiple arrival event processing can provide more representative elastic property values, which can account for heterogeneity along the wellbore.

Abstract: Embodiments provide for a method that utilizes the azimuthally spaced receivers of a sonic logging tool. Signals from monopole and dipole sources are reflected from the geologic interfaces and recorded by arrays of receivers of the same tool. For the incident P-waves from the monopole source, phase arrival times for the azimuthal receivers are compensated for stacking using properties of wave propagation in the borehole, and for the incident SH-waves from the dipole source, signs of waveforms for the receivers are changed for specified azimuths.

Abstract: A method, apparatus, and program product estimate anisotropic properties of an anisotropic formation based at least in part on determinations of a deviation of a wellbore associated with the anisotropic formation and an availability of non-sonic measurement data associated with the anisotropic formation. The determinations are used in the selection of at least one computer-implemented model that in turn may be applied to determine one or more unknown elastic constants for an elastic stiffness matrix.

Abstract: A method includes receiving information that includes elastic property information and that includes sonic data acquired via a tool disposed at a plurality of depths in a bore in a subterranean environment that includes at least one anisotropic formation; processing the information to generate processed information where the processed information includes variance information associated with the elastic property information and where the processed information includes velocity information and orientation information associated with the sonic data; performing an inversion based at least in part on the processed information; and outputting values for elastic parameters based at least in part on the inversion.

Abstract: A method, apparatus, and program product model stress characteristics of a subsurface formation based at least in part on acoustic data and image data associated with the subsurface formation. The acoustic data is analyzed to determine acoustic based stress values, and the image data is analyzed to determine image based stress values. The acoustic based stress values and the image based stress values are integrated to generate an integrated stress profile that includes one or more modeled stress characteristics of the subsurface volume.

Abstract: A method for estimating formation slowness is provided. The method comprises forward modeling to compute formation slownesses based on a first method for orthorhombic media using stress magnitudes and third-order elastic constants as inputs, and forward modeling to determine formation slownesses analytically based on a second method using stress magnitudes, stress azimuth and third-order elastic constants as inputs. The first method may be based on Tsvankin method and the second method may be based on Christoffel method. The forward modeling may further use well configuration and reference moduli as inputs, and the results from the forward modeling may include formation slownesses, and at least one of vertical slownesses, anisotropic parameters, anellipticity indicators and fast shear azimuth. The method may further comprise assessing quality of the forward modeling based on results output from the forward modeling.

Abstract: Systems and methods for differential energy analysis of dipole acoustic signals to facilitate identification of geological or borehole characteristics are provided. An acoustic downhole tool may be placed into a borehole in a geological formation. A dipole acoustic signal may be emitted using one or more acoustic transmitters of the downhole tool, and the dipole acoustic signal may be measured using one or more acoustic receivers of the downhole tool. Using a processor, a dipole differential energy of the dipole acoustic signal (as measured by two of the one or more acoustic receivers or as emitted by two of the one or more acoustic transmitters, or both) may be computed. The processor may provide an indication of the dipole differential energy to facilitate identification of characteristics of the geological formation or the borehole, or both.

Abstract: A method for estimating formation slowness is provided. The method comprises forward modeling to compute formation slownesses based on a first method for orthorhombic media using stress magnitudes and third-order elastic constants as inputs, and forward modeling to determine formation slownesses analytically based on a second method using stress magnitudes, stress azimuth and third-order elastic constants as inputs. The first method may be based on Tsvankin method and the second method may be based on Christoffel method. The forward modeling may further use well configuration and reference moduli as inputs, and the results from the forward modeling may include formation slownesses, and at least one of vertical slownesses, anisotropic parameters, anellipticity indicators and fast shear azimuth. The method may further comprise assessing quality of the forward modeling based on results output from the forward modeling.

Abstract: A method, apparatus, and program product model stress characteristics of a subsurface formation based at least in part on acoustic data and image data associated with the subsurface formation. The acoustic data is analyzed to determine acoustic based stress values, and the image data is analyzed to determine image based stress values. The acoustic based stress values and the image based stress values are integrated to generate an integrated stress profile that includes one or more modeled stress characteristics of the subsurface volume.

Abstract: Systems and methods for differential energy analysis of dipole acoustic signals to facilitate identification of geological or borehole characteristics are provided. An acoustic downhole tool may be placed into a borehole in a geological formation. A dipole acoustic signal may be emitted using one or more acoustic transmitters of the downhole tool, and the dipole acoustic signal may be measured using one or more acoustic receivers of the downhole tool. Using a processor, a dipole differential energy of the dipole acoustic signal (as measured by two of the one or more acoustic receivers or as emitted by two of the one or more acoustic transmitters, or both) may be computed. The processor may provide an indication of the dipole differential energy to facilitate identification of characteristics of the geological formation or the borehole, or both.

Abstract: A method, apparatus, and program product estimate anisotropic properties of an anisotropic formation based at least in part on determinations of a deviation of a wellbore associated with the anisotropic formation and an availability of non-sonic measurement data associated with the anisotropic formation. The determinations are used in the selection of at least one computer-implemented model that in turn may be applied to determine one or more unknown elastic constants for an elastic stiffness matrix.

Abstract: Fracture- and stress-induced sonic anisotropy is distinguished using a combination of image and sonic logs. Borehole image and sonic logs are acquired via known techniques. Analysis of sonic data from monopole P- and S-waves, monopole Stoneley and cross-dipole shear sonic data in an anisotropic formation are used to estimate at least one compressional and two shear moduli, and the dipole fast shear direction. Fracture analysis of image logs enables determination of fracture types and geometrical properties. Geological and geomechanical analysis from image logs provide a priori discrimination of natural fractures and stress-induced fractures. A forward quantitative model of natural fracture- and stress-induced sonic anisotropy based on the knowledge of fracture properties interpreted from image logs allows the computation of the fast-shear azimuth and the difference in slowness between the fast- and slow-shear. The misfit between predicted and observed sonic measurements (i.e.

Abstract: Fracture- and stress-induced sonic anisotropy is distinguished using a combination of image and sonic logs. Borehole image and sonic logs are acquired via known techniques. Analysis of sonic data from monopole P- and S-waves, monopole Stoneley and cross-dipole shear sonic data in an anisotropic formation are used to estimate at least one compressional and two shear moduli, and the dipole fast shear direction. Fracture analysis of image logs enables determination of fracture types and geometrical properties. Geological and geomechanical analysis from image logs provide a priori discrimination of natural fractures and stress-induced fractures. A forward quantitative model of natural fracture- and stress-induced sonic anisotropy based on the knowledge of fracture properties interpreted from image logs allows the computation of the fast-shear azimuth and the difference in slowness between the fast- and slow-shear. The misfit between predicted and observed sonic measurements (i.e.