Abstract: An array electromagnetic tool is run in a borehole, and resulting signals are processed to provide at least one of real and imaginary conductivity components, ?R* and ?I*. The at least one of real and imaginary conductivity components is compared to a corresponding representative conductivity component of a plurality of different clay groups and a determination of clay type in the formation is made therefrom.

Abstract: Methods and systems are described for using pulsed neutron ?-ray spectroscopy to measure formation water salinity from within a borehole. Through generating a cross-plot of database values of ratios of spectroscopically determined yields of hydrogen (H) and chlorine (Cl) from two detectors, deriving apparent salinities therefrom, formation and borehole water salinities can be determined.

Abstract: In-phase and quadrature components have different relationships with some important petrophyscial parameters, such as water saturation and mineral cation exchange capacity (CEC). In clay-containing subterranean rock formation such as shaly sand formations, these parameters can be estimated using different components of array induction tool data combined with other knowledge about the clay-containing formation. Some parameters, such as mobility and fraction of counterions are valid in cases where the pore water solution is an electrolyte of NaCl.

Abstract: The present disclosure describes various embodiments related to methods for determining salinity of water in a borehole of a formation and the water in the formation. Various methods may use inelastic and capture gamma-ray spectra obtained from a pulsed neutron logging tool. Various embodiments may use a ratio of chlorine from a capture spectrum to oxygen from an inelastic spectrum for a near and a far detector to calculate apparent salinity ratios for water in a borehole and a formation. From the apparent salinity ratios, a borehole salinity and a formation salinity may be calculated using a tool characterization database and without using formation water saturation for the calculation. Other embodiments may be disclosed or claimed.

Abstract: Provided in some embodiments are systems and methods for determining characteristics of a hydrocarbon reservoir. Embodiments include conducting a nuclear magnetic resonance (NMR) logging operation of a targeted reservoir section of a wellbore extending into a hydrocarbon reservoir to generate a NMR log of the targeted reservoir section, conducting a resistivity logging of the targeted reservoir section to generate an uninvaded water saturation (Sw) log of the targeted reservoir section, determining for each of a plurality of depths in the section, a T2 cutoff point based on values of the NMR and Sw logs, identifying a subset of the T2 cutoff points that exhibit a hyperbolic trend, determining a theoretical cutoff curve corresponding to the subset of the T2 cutoff points, determining a free water level (FWL) of the reservoir based on the theoretical cutoff curve, and determining a rock type of the reservoir based on the theoretical cutoff curve.

Abstract: In-phase and quadrature components have different relationships with some important petrophyscial parameters, such as water saturation and mineral cation exchange capacity (CEC). In clay-containing subterranean rock formation such as shaly sand formations, these parameters can be estimated using different components of array induction tool data combined with other knowledge about the clay-containing formation. Some parameters, such as mobility and fraction of counterions are valid in cases where the pore water solution is an electrolyte of NaCl.

Abstract: The present disclosure describes various embodiments related to methods for determining salinity of water in a borehole of a formation and the water in the formation. Various methods may use inelastic and capture gamma-ray spectra obtained from a pulsed neutron logging tool. Various embodiments may use a ratio of chlorine from a capture spectrum to oxygen from an inelastic spectrum for a near and a far detector to calculate apparent salinity ratios for water in a borehole and a formation. From the apparent salinity ratios, a borehole salinity and a formation salinity may be calculated using a tool characterization database and without using formation water saturation for the calculation. Other embodiments may be disclosed or claimed.

Abstract: Provided are embodiments of systems, computer medium and computer-implemented methods for logging using a customizable logging tool. In some embodiments, the logging tool is capable of being disposed in a borehole formed in a geologic formation. The logging tool includes a source for emitting signals into the geologic formation surrounding the borehole and a plurality of detectors for detecting signals generated as a result of emission of signals by the source into the geologic formation surrounding the borehole. The plurality of detectors are independently repositionable such that a source-to-detector spacing for the detectors is independently variable, to provide optimum signal depending on the characteristics of the target reservoir, the borehole, and the tool source and detectors.

Abstract: Provided in some embodiments are systems and methods for determining characteristics of a hydrocarbon reservoir. Embodiments include conducting a nuclear magnetic resonance (NMR) logging operation of a targeted reservoir section of a wellbore extending into a hydrocarbon reservoir to generate a NMR log of the targeted reservoir section, conducting a resistivity logging of the targeted reservoir section to generate an uninvaded water saturation (Sw) log of the targeted reservoir section, determining for each of a plurality of depths in the section, a T2 cutoff point based on values of the NMR and Sw logs, identifying a subset of the T2 cutoff points that exhibit a hyperbolic trend, determining a theoretical cutoff curve corresponding to the subset of the T2 cutoff points, determining a free water level (FWL) of the reservoir based on the theoretical cutoff curve, and determining a rock type of the reservoir based on the theoretical cutoff curve.

Abstract: Well trajectory adjustment is provided. In one possible implementation, an initial 3D model of a portion of a formation in which a well is being drilled is accessed. Subsurface data associated with the formation is then used to tune the initial 3D model to create a revised 3D model. In another possible implementation, subsurface data associated with a formation in which a well is being drilled is used to tune an initial 3D model of the formation to create a revised 3D model. An initial planned trajectory of the well can also be adjusted to reach a sweet spot in the revised 3D model.

Abstract: Methods are described for wettability characterization based on NMR measurements, which are sensitive to the surface wetting conditions of oil and water at the pore scale. The described methods make use of surface relaxation effects on the NMR relaxation (T2). Workflows are described to obtain wettability profiles of a porous media such as a rock either in the native state or prepared to a certain state in the laboratory. An underlying forward model is also described for the mixed wet and fractionally saturated pore spectrum. Outputs of the described inversion include continuous saturation and wettability profiles as a function of the pore sizes in the porous media, as well as an averaged value for saturation and wettability over the entire pore spectrum.

Abstract: Provided are embodiments of systems, computer medium and computer-implemented methods for logging using a customizable logging tool. In some embodiments, the logging tool is capable of being disposed in a borehole formed in a geologic formation. The logging tool includes a source for emitting signals into the geologic formation surrounding the borehole and a plurality of detectors for detecting signals generated as a result of emission of signals by the source into the geologic formation surrounding the borehole. The plurality of detectors are independently repositionable such that a source-to-detector spacing for the detectors is independently variable, to provide optimum signal depending on the characteristics of the target reservoir, the borehole, and the tool source and detectors.

Abstract: A method of measuring a parameter characteristic of a rock formation is provided, the method including the steps of obtaining crosswell electromagnetic signals between two wells and using an inversion of said signals to investigate or delineate the presence of a resistivity anomaly, such as brine in a low resistivity background, wherein the resistivity anomaly is assumed to be distributed as one or more bodies characterized by a limited number of geometrical parameters and the inversion is used to determine said geometrical parameters. The method can also be applied to determine the trajectory of an in-fill well to be drilled.

Abstract: Methods are described for wettability characterization based on NMR measurements, which are sensitive to the surface wetting conditions of oil and water at the pore scale. The described methods make use of surface relaxation effects on the NMR relaxation (T2). Workflows are described to obtain wettability profiles of a porous media such as a rock either in the native state or prepared to a certain state in the laboratory. An underlying forward model is also described for the mixed wet and fractionally saturated pore spectrum. Outputs of the described inversion include continuous saturation and wettability profiles as a function of the pore sizes in the porous media, as well as an averaged value for saturation and wettability over the entire pore spectrum.

Abstract: A method of measuring a parameter characteristic of a rock formation is provided, the method including the steps of obtaining crosswell electromagnetic signals between two wells and using an inversion of said signals to investigate or delineate the presence of a resistivity anomaly, such as brine in a low resistivity background, wherein the resistivity anomaly is assumed to be distributed as one or more bodies characterized by a limited number of geometrical parameters and the inversion is used to determine said geometrical parameters. The method can also be applied to determine the trajectory of an in-fill well to be drilled.