In accordance with embodiments of the present disclosure, a simplified geomechanical model that considers the anisotropic (e.g., directional) properties of a formation and the presence of natural fractures in the formation is provided. A system and method may be designed according to the present disclosure to create a simplified geomechanical model of a horizontally laminated formation that includes pre-existing natural fractures. The simplified geomechanical model can be used to calculate the fracture closure pressure of the formation and to design a fracturing operation for injecting fracture fluid into the formation, thus improving the efficiency of a subterranean operation. The disclosed model may provide a more realistic model for fractured shales than an isotropic or vertically transverse isotropic (VTI) model. In addition, the disclosed model may be simpler to implement than a full orthorhombic model.

The present disclosure is directed to numerically estimating the shear modulus of Kerogen by using a combination of mineralogy from digital image analysis and sonic log analysis, when measured data on only one elastic constant (Bulk, Young's or P-wave modulus) is available. In some instances, elastic properties predicted from the digital images are compared with sonic, shear, and density logs, to estimate the shear modulus of kerogen. As a one-to-one correspondence is not expected between the core sub-samples and the rock unit sampled by the well logs, cross-property relations can be used to identify the suitability of the effective medium models and to iteratively determine the shear modulus of kerogen.

A method and system for producing a Quasi-Static Stoneley Slowness log. The method for producing a Quasi-Static Stoneley Slowness log may comprise recording a pressure wave at a receiver; determining a slowness-frequency range with an information handling system from the pressure wave, processing a frequency-domain semblance, extracting a Stoneley Dispersion, minimizing a misfit between theoretical and the Stoneley Dispersion, and identifying Quasi-Static Stoneley slowness from the Stoneley Dispersion. The well measurement system for producing an Quasi-Static Stoneley Slowness log and shear slowness anisotropy may comprise a downhole tool, a vehicle, and an information handling system. Wherein the information handling system may be operable to record a pressure wave at a receiver, determine a slowness-frequency range with an information handling system from the pressure wave, process a frequency-domain semblance, extract a Stoneley Dispersion; minimize a misfit between theoretical and the Stoneley Dispersion; and identify Quasi-Static Stoneley slowness from the Stoneley Dispersion.

A method of fluid substitution, wherein an initial data set is provided, wherein a substituted data set is provided, wherein a rock physics model is provided, wherein the initial data set includes initial data of a geophysical parameter and initial fluid data, and wherein the substituted data set includes substituted fluid data. The method includes using the model and the initial data set to calculate first calculated data of the geophysical parameter, using the model and the substituted data set to calculate second calculated data of the geophysical parameter, calculating the difference between the first calculated data of the geophysical parameter and the second calculated data of the geophysical parameter, and applying the difference to the initial data of the geophysical parameter to produce substituted data of the geophysical parameter.

A method for generating one or more subsurface stress models. The method may include receiving seismic data. A plurality of first geomechanical property models may be generated based at least partially on the seismic data. A second geomechanical property model may be generated based at least partially on the seismic data. The second geomechanical property model may have a lower resolution than the first geomechanical property models. A stress model, a strain model, or a combination thereof may be generated based on the second geomechanical property model. One or more subsurface stress models may be generated based on the stress model, the strain model, or the combination thereof and the first geomechanical property models.

An acoustic signal is transmitted from a downhole tool positioned within a wellbore. Amplitudes and travel times of the acoustic signal received at different azimuthal locations of the downhole tool are measured. Correction factors, each corresponding to a different one of the measured amplitudes, are determined based on the travel times measured at each of the different azimuthal locations. Corrected amplitudes are each determined based on the corresponding measured amplitude and the corresponding correction factor.

The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for determining a mudweight of drilling fluids in a hydrocarbon reservoir. One computer-implemented method includes: receiving pore pressure data of a rock formation in the hydrocarbon reservoir; determining permeability data of fractures of the hydrocarbon reservoir; determining Hoek-Brown failure criterion data; and determining a safe mudweight window based on the pore pressure data of the rock formation, the permeability data of the fractures, and the Hoek-Brown failure criterion data.

Methods for inversion of seismic data to infer subsurface physical property parameters, comprising constructing an inhomogeneous anisotropy model and/or inhomogeneous V.sub.S/V.sub.P or V.sub.P/V.sub.S model; and inverting the seismic data in a sequential or simultaneous approach to obtain at least one subsurface physical property parameter using an elastic inversion algorithm and the inhomogeneous anisotropy model and/or inhomogeneous V.sub.S/V.sub.P or V.sub.P/V.sub.S model. Constructing an inhomogeneous anisotropy model may comprise deriving geobodies from at least one of seismic facies analysis, regional geologic information, or seismically derived earth models; and adjusting at least one of , , , or parameters of the elastic stiffness tensor matrix in a homogeneous anisotropy model in areas corresponding to the geobodies. Constructing an inhomogeneous V.sub.S/V.sub.P or V.sub.P/V.sub.S model may comprise deriving geobodies and adjusting values in a homogeneous V.sub.S/V.sub.P or V.sub.P/V.sub.S model in areas corresponding to the geobodies.

This disclosure describes a novel method for predicting continuous wellbore mechanical properties such as static elastic stiffness and failure strength, where the properties solutions are deterministic and based on mechanical theory. It has at least three immediate applications: (a) continuous plots of mechanical properties vs. depth, (b) conceptual testing of the effect of changing constituent volume fractions, (c) ternary plots.

A seismic exploration method used lateral well data to validate lateral elastic properties values. The validated lateral elastic properties values are obtained by generating a constrained 3D rock facies model using the lateral and vertical well data and the seismic inversion results, cross-correlating synthetic lateral elastic properties values for locations along the lateral well, based on the lateral and vertical well data with the seismic inversion results to obtain calibrated synthetic lateral elastic properties values, and adjusting the calibrated synthetic lateral elastic properties values according to the constrained 3D rock facies model.