Extracting a core sample from within a wellbore is optimized based on information extracted from acoustic signals that are generated downhole. The acoustic signals provide an indication of the formation being cored, which is used to obtain or adjust designated coring operating parameters for accomplishing an efficient and effective coring procedure. Coring operating parameters that are adjusted include weight on bit and bit rotational speed. Optimizing coring operating parameters reduces wear on the bit and produces samples with less fractures. Generating acoustic signals is done by the operation of coring itself, or contacting the formation with a coring bit. Contacting includes impacting the coring bit radially against the wellbore's sidewall, or moving the bit laterally after coring operations have initiated.

Material on a remote side of a partition separating first and second domains is evaluated by disposing at least one ultrasonic transmitter and a plurality of spaced ultrasonic receivers along a first side of the partition in the first domain. The transmitter is activated to form ultrasonic waveforms that comprise propagated quasi leaky-Lamb waves constituting extensional waves having symmetrical zero-order modes within the partition. The received ultrasonic waveforms are processed to determine the envelope of the waves propagating through the partition from a first receiver to a second receiver that is located more remote from the transmitter than the first receiver and whose separation from the first receiver is known. The integral envelope attenuation per distance of the wave propagating through the second domain over a predefined interval establishes that the second domain contains a solid when higher than a predetermined threshold.

A method and system for estimating a full elastic tensor. The method may comprise taking a measurement for compressional wave sonic data and cross-dipole shear data with a sonic logging tool at a first location as cross-dipole data, processing the compressional wave sonic data to produce a compressional wave slowness (P), and processing the cross-dipole shear data to produce a fast horizontal polarized shear wave slowness (SH) and a slow quazi-vertical shear wave slowness (qSV) as a function of depth. The method may further comprise setting an initial guess for at least five constants of the full elastic tensor for Vertical Transversely Isotropy (VTI) symmetry, determining a modeled slowness surfaces from the full elastic tensor, and comparing the modeled slowness surfaces with measured values of the P, the SH, and the qSV. The method may be performed by a system comprising a sonic logging tool and an information handling system.

A subsoil region is represented using a grid having columns of cells arranged in an array of horizontal positions. The cells of a column are delineated by geological layering of the subsoil region. The method, used for estimating elastic parameters in the subsoil region, comprises obtaining seismic traces and performing seismic inversion for the columns of cells. The seismic inversion for a column comprises selecting a set of elastic parameter values that minimizes a cost function regardless of statistical distribution of the elastic parameter values. The set of elastic parameter values is selected among a plurality of candidate sets of elastic parameter values each having values of elastic parameters for the cells of the column.

Material on a remote side of a partition separating first and second domains is evaluated by disposing at least one ultrasonic transmitter and a plurality of spaced ultrasonic receivers along a first side of the partition in the first domain. The transmitter is activated to form ultrasonic waveforms that comprise propagated quasi leaky-Lamb waves constituting extensional waves having symmetrical zero-order modes within the partition. The received ultrasonic waveforms are processed to determine the envelope of the waves propagating through the partition from a first receiver to a second receiver that is located more remote from the transmitter than the first receiver and whose separation from the first receiver is known. The integral envelope attenuation per distance of the wave propagating through the second domain over a predefined interval establishes that the second domain contains a solid when higher than a predetermined threshold.

A method for evaluating brittleness of a deep shale reservoir and a computer readable storage medium. The method includes determining a Rickman brittleness index of the deep shale reservoir and determining an effective pressure of the deep shale reservoir according to a pore pressure and an overlying formation pressure of the deep shale reservoir. The Rickman brittleness index is adjusted to obtain the brittleness index of the deep shale reservoir according to an exponential relationship of the brittleness index with the effective pressure of the deep shale reservoir. Inherent properties, such as rock brittle mineral content and the like, are better indicated by the Rickamn brittleness index, and then the brittleness index of the deep shale reservoir is obtained by utilizing the exponential relationship of the brittleness index with the effective pressure of the deep shale reservoir, to realize reasonable evaluation for the brittleness of the deep shale reservoir.

An interconnect structure includes an interconnect structure includes an etching stop layer; a dielectric layer and an insert layer on the etching stop layer, and a conductive feature in the dielectric layer, the insert layer and the etching stop layer. A material of the insert layer is different from the dielectric layer and the etching stop layer.

Methods and systems are provided that identify relatively large anisotropic horizontal stresses in a formation based on (i) azimuthal variations in the compressional and shear slownesses or velocities of the formation measured from ultrasonic data acquired by at least one acoustic logging tool as well as (ii) cross-dipole dispersions of the formation measured from sonic data acquired by the at least one acoustic logging tool. In addition, the azimuthal variations in the compressional and shear slownesses or velocities of the formation and dipole flexural dispersions of the formation can be jointly inverted to obtain the elastic properties of the rock of the formation in terms of linear and nonlinear constants and the magnitude of maximum horizontal stress of the formation. A workflow for estimating the magnitude of the maximum horizontal stress can employ estimates of certain formation properties, such as overburden stress, magnitude of minimum horizontal stress, and pore pressure.

An information processing system having a processor and a memory device coupled to the processor, wherein the memory device includes a set of instruction that, when executed by the processor, cause the processor to receive a multi-dimensional grid of acoustic or elastic impedances determined from seismic survey data associated with a subterranean formation, receive elastic property data that describes elastic property characteristics used to sort pseudo-components, and wherein the respective pseudo-components are formed of a combination of two or more lithologies. The instructions, when executed by the processor, further cause the processor to define select design variables using the impedance arrays, perform optimization operations for optimizing select design variables by applying the elastic property data as a part of a constitutive relation, and output a distribution of the pseudo-components to characterize volumetric concentrations of spatially grouped lithologies in a control volume of the subterranean formation.

Methods and systems for identifying a pay zone in a subterranean formation can include: logging a well extending into the subterranean formation including measuring bulk density, compressional wave travel time and shear wave travel time at different depths in the subterranean formation; calculating elastic attributes including acoustic impedance and compressional velocity-shear velocity ratio at different depths in the subterranean formation; and displaying and analyzing the calculated elastic attributes to identify the low resistivity pay zones.