Abstract: A technique facilitates determination of a quantitative bond between a pipe and adjacent materials, e.g. between a wellbore casing and adjacent cement. The quantitative bond is established via acoustic measurements related to signal attenuation. Additionally, the acoustic measurements may be conducted with a sonic tool during a wellbore operation, e.g. during a drilling operation. The methodology enables use of signal attenuation in a manner which facilitates determination of bond index coverage up to a high percentage, e.g. 100 percent.

Abstract: A method of quantitative cement evaluation is provided. The method includes deploying a logging-while-drilling downhole sonic tool into a wellbore inside a casing, measuring acoustic signals propagating through the casing with the logging-while-drilling downhole sonic tool, and performing quantitative cement evaluation with respect to cement bonding around the casing by using waveform data of the acoustic signals measured with the logging-while-drilling downhole sonic tool.

Abstract: A technique facilitates determination of a quantitative bond between a pipe and adjacent materials, e.g. between a wellbore casing and adjacent cement. The quantitative bond is established via acoustic measurements related to signal attenuation. Additionally, the acoustic measurements may be conducted with a sonic tool during a wellbore operation, e.g. during a drilling operation. The methodology enables use of signal attenuation in a manner which facilitates determination of bond index coverage up to a high percentage, e.g. 100 percent.

Abstract: A method of quantitative cement evaluation is provided. The method includes deploying a logging-while-drilling downhole sonic tool into a wellbore inside a casing, measuring acoustic signals propagating through the casing with the logging-while-drilling downhole sonic tool, and performing quantitative cement evaluation with respect to cement bonding around the casing by using waveform data of the acoustic signals measured with the logging-while-drilling downhole sonic tool.

Abstract: A disclosed example method includes providing, in a borehole, a transmitter (Tx) and receivers (Rxs) spaced linearly from Tx at known distances, measuring linear propagation times (LPts) for a signal to propagate from Tx to each of Rxs, determining an inline velocity (VINL) based on LPts, measuring reflection times (Rts) for a signal to propagate from Tx to each of the Rxs via a boundary, for each of Rts, providing a time-distance anisotropic velocity (TDAV) relationship depending on an effective signal velocity (ESV) in an anisotropic formation adjacent the boundary as a function of reflection angle for the reflection time signal to the boundary, VINL and orthogonal velocity, performing semblance processing to combine the TDAV relationships with VINL for a best-fit calculation of the ESVs for the different reflection angles of the reflection time signals, and calculating a distance for the corresponding receiver to the boundary on the calculation.

Abstract: A disclosed example method includes providing, in a borehole, a transmitter (Tx) and receivers (Rxs) spaced linearly from Tx at known distances, measuring linear propagation times (LPts) for a signal to propagate from Tx to each of Rxs, determining an inline velocity (VINL) based on LPts, measuring reflection times (Rts) for a signal to propagate from Tx to each of the Rxs via a boundary, for each of Rts, providing a time-distance anisotropic velocity (TDAV) relationship depending on an effective signal velocity (ESV) in an anisotropic formation adjacent the boundary as a function of reflection angle for the reflection time signal to the boundary, VINL and orthogonal velocity, performing semblance processing to combine the TDAV relationships with VINL for a best-fit calculation of the ESVs for the different reflection angles of the reflection time signals, and calculating a distance for the corresponding receiver to the boundary on the calculation.

Abstract: Methods and systems for analyzing subterranean formations in-situ stress are disclosed. A method for extracting geological horizon on-demand from a 3D seismic data set, comprises receiving sonic log data; computing the anisotropic shear moduli C44, C55 and C66; determining in-situ stress type and selecting an in-situ stress expression corresponding to the in-situ stress type; computing stress regime factor Q of the formation interval; and computing and outputting the maximum stress ?H by using the stress regime factor Q, Vertical stress ?v and Minimum horizontal stress ?h.

Abstract: Methods and apparatus to calculate a distance from a borehole to a boundary of an anisotropic subterranean rock layer are disclosed. A disclosed example method includes transmitting a first signal from a first transmitter at a first location in a borehole traversing a subterranean formation, receiving the first signal at a first receiver after a first time period at a second location in the borehole, receiving the first signal at a second receiver after a second time period at a third location in the borehole, and calculating a first distance from the first transmitter to a first portion of a boundary of a subterranean rock layer adjacent to the borehole by compensating for an anisotropy of the subterranean rock layer based on the first time period and the second time period.

Abstract: Methods and systems for analyzing subterranean formations in-situ stress are disclosed. A method for extracting geological horizon on-demand from a 3D seismic data set, comprises receiving sonic log data; computing the anisotropic shear moduli C44, C55 and C66; determining in-situ stress type and selecting an in-situ stress expression corresponding to the in-situ stress type; computing stress regime factor Q of the formation interval; and computing and outputting the maximum stress ?H by using the stress regime factor Q, Vertical stress ?v and Minimum horizontal stress ?h.

Abstract: A method for in-situ calibrating acoustic receivers while the tool is in an open or cased borehole or during a logging run in a borehole. The method and system facilitate calibrating the acoustic receivers while they are mounted to a downhole acoustic tool. Calibrating the acoustic receivers in situ provides more accurate results than previously available. The method and system provide separate compensation factors for the acoustic receivers at different frequencies and for different transmission sources. The separate compensation factors facilitate more accurate signal acquisition over a wider range of conditions.

Abstract: An acoustic logging tool sleeve with a preferably discontinuous, alternating structure that is acoustically opaque in some zones, and acoustically transparent in others. The sleeve may be modular, with several stages connected together. The multiple stages provide a sleeve that may be useful with a variety of borehole logging tools to reduce or eliminate the transmission of noise to the receiving elements.

Abstract: A method and system for calibrating acoustic receivers. The method and system facilitate calibrating the acoustic receivers while they are mounted to a downhole acoustic tool. Calibrating the acoustic receivers in situ provides more accurate results than previously available. The method and system provide separate compensation factors for the acoustic receivers at different frequencies and for different transmission sources. The separate compensation factors facilitate more accurate signal acquisition over a wider range of conditions.

Abstract: An acoustic logging tool sleeve with a preferably discontinuous, alternating structure that is acoustically opaque in some zones, and acoustically transparent in others. The sleeve may be modular, with several stages connected together. The multiple stages provide a sleeve that may be useful with a variety of borehole logging tools to reduce or eliminate the transmission of noise to the receiving elements.

Abstract: Methods for determining the best value for at least one slowness-related parameter that has been determined in a number of ways is disclosed. Sonic logging data input in the methods are processed to determine multiple values of at least one slowness-related parameter using slowness/time coherence (STC) processing methods. The error of each determined parameter is determined and the determined errors used in selecting a representative parameter value from the multiple determined slowness-related parameter values.