Abstract: Methods, tools, and systems for determining the lithium concentration of a formation traversed by a wellbore using pulsed neutron logging are described. Since determining lithium directly using pulsed neutron logging is problematic, this disclosure provides ways of determining lithium concentration indirectly using models that relate lithium concentration with concentrations of other elements that are predicted to be associated with lithium.

Abstract: Methods and tools for determining one or more parameters of an earth formation using time-of-flight (TOF) measurements of fast neutrons through the formation are disclosed. The disclosed tools feature a neutron source capable of emitting a population of fast neutrons having a distribution of neutron energies and one or more neutron detectors. The TOF of the fast neutrons travelling from the neutron source to the detector(s) and traversing a portion of the formation is measured and binned as a function of TOF (which is a function of neutron energy). By determining which neutron energies are attenuated by the intervening formation, the composition of the intervening formation is determined.

Abstract: Example embodiments are described for a method and system for logging data processing in determining permeability anisotropy effects. A permeability anisotropy model is used to derive a relationship between formation permeability anisotropy and resistivity anisotropy in both TI and BA formations. Implementations can provide the permeability anisotropy plus the true reservoir (or sand) permeability by using an integrated interpretation of the MCI resistivity anisotropy measurements with conventional permeability logs from other sensors (e.g., NMR or sonic). Biaxial and triaxial permeability components of the permeability anisotropy tensor can be determined for application to synthetic and field log interpretations.

Abstract: Methods and tools for determining one or more parameters of an earth formation using time-of-flight (TOF) measurements of fast neutrons through the formation are disclosed. The disclosed tools feature a neutron source capable of emitting a population of fast neutrons having a distribution of neutron energies and one or more neutron detectors. The TOF of the fast neutrons travelling from the neutron source to the detector(s) and traversing a portion of the formation is measured and binned as a function of TOF (which is a function of neutron energy). By determining which neutron energies are attenuated by the intervening formation, the composition of the intervening formation is determined.

Abstract: Example embodiments are described for a method and system for logging data processing in determining permeability anisotropy effects. A permeability anisotropy model is used to derive a relationship between formation permeability anisotropy and resistivity anisotropy in both TI and BA formations. Implementations can provide the permeability anisotropy plus the true reservoir (or sand) permeability by using an integrated interpretation of the MCI resistivity anisotropy measurements with conventional permeability logs from other sensors (e.g., NMR or sonic). Biaxial and triaxial permeability components of the permeability anisotropy tensor can be determined for application to synthetic and field log interpretations.

Abstract: 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.

Abstract: Disclosed herein are embodiments of systems, methods, and computer program products for determining fracture and stress characterization using layer thickness variation over an azimuthally anisotropic medium, which may include one or more of the following functions: acquiring seismic data by recording reflected seismic waves in at least two directions; sorting of the seismic data so that offset is zero at a center and increases radially from a single common-point (CMP) gather for a plurality of data points; generating a multi-dimensional volume by juxtaposing a set of common-offset sections by one of their common-depth point (CDP) and CMP locations; selecting reflectors for each layer in the one of the multi-dimensional volume; computing layer parameters including effective anisotropy and interval anisotropy for each layer in the multi-dimensional volume based on a geometry of the reflectors selected for each layer in the multi-dimensional volume; and applying the layer parameters to an earth model.

Abstract: In some embodiments, a method and apparatus, as well as an article, may operate to estimate a property of an earth formation by generating at least one shale model to represent an earth formation comprised of a non-zero percentage of shale. The shale model includes two curves to represent a relationship between a porosity parameter and a pulsed neutron measurement at two different corresponding percentages of gas saturation, respectively. A matrix model representing an earth formation with 0% shale is combined with one or more shale models to create a formation model. Measured pulsed neutron data is compared with the formation model to estimate a property of the earth formation. Additional apparatus, systems, and methods are disclosed.

Abstract: Systems and methods for simultaneously correcting the effects of deviation and dispersion on sonic log measurements of deviated wells in laminated formations and validating the corrected sonic log measurements using rock physics cross-plots.

Abstract: A system for determining a wettability associated with a subterranean formation can include a dielectric logging tool, a resistivity logging tool, a pulsed neutron tool, and a computing device. The dielectric logging tool can transmit a first data set associated with the subterranean formation. The resistivity logging tool can transmit a second data set associated with the subterranean formation. The pulsed neutron tool can transmit a third data set associated with the subterranean formation. The computing device can be in communication with the dielectric logging tool, the resistivity logging tool, and the pulsed neutron tool. The computing device can receive the first data set, the second data set, and the third data set and determine the wettability associated with the subterranean formation based on the first data set, the second data set, and the third data set.

Abstract: Systems and methods for simultaneously correcting the effects of deviation and dispersion on sonic log measurements of deviated wells in laminated formations and validating the corrected sonic log measurements using rock physics cross-plots.

Abstract: Disclosed herein are embodiments of systems, methods, and computer program products for determining fracture and stress characterization using layer thickness variation over an azimuthally anisotropic medium, which may include one or more of the following functions: acquiring seismic data by recording reflected seismic waves in at least two directions; sorting of the seismic data so that offset is zero at a center and increases radially from a single common-point (CMP) gather for a plurality of data points; generating a multi-dimensional volume by juxtaposing a set of common-offset sections by one of their common-depth point (CDP) and CMP locations; selecting reflectors for each layer in the one of the multi-dimensional volume; computing layer parameters including effective anisotropy and interval anisotropy for each layer in the multi-dimensional volume based on a geometry of the reflectors selected for each layer in the multi-dimensional volume; and applying the layer parameters to an earth model.

Abstract: An embodiment of a method of estimating characteristics of an earth formation includes: disposing an acoustic tool in a borehole in an earth formation, the acoustic tool including an acoustic multipole transmitter and at least one multipole acoustic receiver; transmitting acoustic signals into the borehole, the acoustic signals generating at least one acoustic body wave that radiates away from the borehole into a far-field formation region; measuring reflected signals including body waves reflected from reflective boundaries in the far-field formation region; identifying a reflective boundary in the formation and reflection attributes associated with the reflective boundary; and estimating at least one of a thickness, distance and a lateral extent of a hydrocarbon formation feature based on the reflected signals and the reflection attributes.

Abstract: 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.

Abstract: Systems and methods for identifying formation layer boundaries on well log measurements using a second derivative of the last iteratively smoothed well log measurements and a fluctuation index to determine the extent of smoothing.

Abstract: In some embodiments, a method and apparatus, as well as an article, may operate to estimate a property of an earth formation by generating at least one shale model to represent an earth formation comprised of a non-zero percentage of shale. The shale model includes two curves to represent a relationship between a porosity parameter and a pulsed neutron measurement at two different corresponding percentages of gas saturation, respectively. A matrix model representing an earth formation with 0% shale is combined with one or more shale models to create a formation model. Measured pulsed neutron data is compared with the formation model to estimate a property of the earth formation. Additional apparatus, systems, and methods are disclosed.

Abstract: Systems and methods for identifying formation layer boundaries on well log measurements using a second derivative of the last iteratively smoothed well log measurements and a fluctuation index to determine the extent of smoothing.

Abstract: A method of estimating fractures in an earth formation includes: disposing an acoustic tool in a cased borehole in an earth formation, the acoustic tool including a multipole acoustic transmitter and an acoustic receiver; transmitting an acoustic signal into the borehole; measuring deep shear wave (DSW) signals generated from shear body waves reflected in the formation in a far-field region of the formation around the borehole; and estimating at least a location and an orientation of a fracture in the formation based on the DSW signals.

Abstract: An embodiment of a method of estimating characteristics of an earth formation includes: disposing an acoustic tool in a borehole in an earth formation, the acoustic tool including an acoustic multipole transmitter and at least one multipole acoustic receiver; transmitting acoustic signals into the borehole, the acoustic signals generating at least one acoustic body wave that radiates away from the borehole into a far-field formation region; measuring reflected signals including body waves reflected from reflective boundaries in the far-field formation region; identifying a reflective boundary in the formation and reflection attributes associated with the reflective boundary; and estimating at least one of a thickness, distance and a lateral extent of a hydrocarbon formation feature based on the reflected signals and the reflection attributes.

Abstract: A method of estimating fractures in an earth formation includes: disposing an acoustic tool in a cased borehole in an earth formation, the acoustic tool including a multipole acoustic transmitter and an acoustic receiver; transmitting an acoustic signal into the borehole; measuring deep shear wave (DSW) signals generated from shear body waves reflected in the formation in a far-field region of the formation around the borehole; and estimating at least a location and an orientation of a fracture in the formation based on the DSW signals.