Abstract: Systems and methods relating to determination of oil saturation, kerogen content, and/or water saturation within kerogen-containing subsurface formations such as unconventional formations (e.g., tight formations such as shales) are provided herein. These methods advantageously rely on a simplified measurement process, reducing the direct measurements of a subsurface formation relied upon in determining oil saturation, kerogen content, and/or water saturation. In particular, methods according to some embodiments include determining or otherwise obtaining values of TOC; bulk density; porosity; and densities of kerogen, oil, and water corresponding to a subsurface formation of interest or a zone thereof. Methods of various embodiments further include, based at least in part upon the obtained values, determining one or more of kerogen content, oil saturation So, and water saturation Sw of the subsurface formation of interest, and/or a corresponding zone thereof.

Abstract: Systems and methods relating to determination of oil saturation, kerogen content, and/or water saturation within kerogen-containing subsurface formations such as unconventional formations (e.g., tight formations such as shales) are provided herein. These methods advantageously rely on a simplified measurement process, reducing the direct measurements of a subsurface formation relied upon in determining oil saturation, kerogen content, and/or water saturation. In particular, methods according to some embodiments include determining or otherwise obtaining values of TOC; bulk density; porosity; and densities of kerogen, oil, and water corresponding to a subsurface formation of interest or a zone thereof. Methods of various embodiments further include, based at least in part upon the obtained values, determining one or more of kerogen content, oil saturation So, and water saturation Sw of the subsurface formation of interest, and/or a corresponding zone thereof.

Abstract: A method to interpret and quantify mineral compositions and concentrations, the method including: determining, with a computer, mineral composition models from a non-linear inversion of core or log elemental and mineral concentration data; and determining, with a computer, mineral concentrations for subsurface region from a linear inversion of core or geochemical log data from the subsurface region or analogous region and the mineral composition models.

Abstract: A method to interpret and quantify mineral compositions and concentrations, the method including: determining, with a computer, mineral composition models from a non-linear inversion of core or log elemental and mineral concentration data; and determining, with a computer, mineral concentrations for subsurface region from a linear inversion of core or geochemical log data from the subsurface region or analogous region and the mineral composition models.

Abstract: Method for evaluating cement integrity in a cased well environment using a logging tool that has a neutron source and one or more neutron or gamma ray detectors. Neutron porosity logs are obtained from the well before (42) and after (41) casing. This log data along with well dimensions and material composition parameters are the input quantities to a multi-parameter database (43) that is constructed by computer modeling or laboratory experiments to relate volume fraction for fluid filled channels in the cement sheath to the input quantities. The channel volume fraction (45) corresponding to the input quantities is identified or interpolated (44) from the multi-parameter database.

Abstract: Well logging method and logging tool for measuring cement density and thickness at different azimuth angles for a cemented, cased well. The method uses a gamma source, a short-spaced detector, a long-spaced detector, and preferably a backscatter detector, where the detector-to-source spacings are designed for calculating (93) thickness and density of the cement annulus (94) from the detector count rates (91).

Abstract: Well logging method and logging tool for measuring cement density and thickness at different azimuth angles for a cemented, cased well. The method uses a gamma source, a short-spaced detector, a long-spaced detector, and preferably a backscatter detector, where the detector-to-source spacings are designed for calculating (93) thickness and density of the cement annulus (94) from the detector count rates (91).

Abstract: Method for evaluating cement quality in a cased well. A density log of the well is obtained using, for example, a GammaRay sources and detectors (51). The detector count rates are inverted to provide initial estimates of cement density and thickness (53). Acoustic waveform data are obtained from the well using an acoustic logging tool (52). The acoustic data are inverted (54-56), using the initial estimates of cement density and thickness obtained from the density logs, and an updated density log is inferred. Cement images are obtained from the updated density log, and cement bond quality can be estimated (57).

Abstract: Method for evaluating cement integrity in a cased well environment using a logging tool that has a neutron source and one or more neutron or gamma ray detectors. Neutron porosity logs are obtained from the well before (42) and after (41) casing. This log data along with well dimensions and material composition parameters are the input quantities to a multi-parameter database (43) that is constructed by computer modeling or laboratory experiments to relate volume fraction for fluid filled channels in the cement sheath to the input quantities. The channel volume fraction (45) corresponding to the input quantities is identified or interpolated (44) from the multi-parameter database.

Abstract: Systems and methods which provide accurate formation information regardless of formation and borehole geometry, including those associated with high angle and horizontal wells, are shown. In providing processing of logging or image data, such as may be provided by a density tool or other tool, according to embodiments, formation attributes or features (e.g., density and dip angle) are estimated using raw data provided by a the tool. The foregoing estimations may thereafter be iteratively refined using effective volume of interest (EVOI) information. According to embodiments, depth boundaries of formation information provided by the tool are shifted as a function of azimuth for correct spatial positioning of formation features using EVOI information. Processing of formation attribute or feature data provided by embodiments may be used with respect to various tool configurations, including configurations with and without borehole standoff.

Abstract: A C/O ratio is determined using measurements of inelastically scattered gamma rays with a pulsed neutron source. Combined with look-up tables, the C/O measurement is used as an indicator of formation fluid influx into wellbore such as gas kick.

Abstract: Systems and methods which provide accurate formation information regardless of formation and borehole geometry, including those associated with high angle and horizontal wells, are shown. In providing processing of logging or image data, such as may be provided by a density tool or other tool, according to embodiments, formation attributes or features (e.g., density and dip angle) are estimated using raw data provided by a the tool. The foregoing estimations may thereafter be iteratively refined using effective volume of interest (EVOI) information. According to embodiments, depth boundaries of formation information provided by the tool are shifted as a function of azimuth for correct spatial positioning of formation features using EVOI information. Processing of formation attribute or feature data provided by embodiments may be used with respect to various tool configurations, including configurations with and without borehole standoff.

Abstract: Resolution of thin beds made by a natural gamma ray logging tool is improved using a relation between the width of the response and the bed thickness. The peak gamma ray of the bed is determined using another relation between the measured gamma ray response and the bed thickness.

Abstract: Caliper measurements made during rotation of a bottomhole assembly are processed to estimate the location of the BHA, and size and shape of the borehole. A piecewise elliptical fitting procedure may be used. These estimates may be used to correct measurements made by a standoff-sensitive formation evaluation sensor such as a neutron porosity tool.

Abstract: Elemental analysis of an earth formation (including Aluminum) is obtained using measurements from a gamma ray logging tool. The inelastic spectrum of Aluminum is determined from measurements made in a water tank. From the elemental analysis, an estimate of the mineralogy of the formation is made treating the problem as one of Linear Programming (maximizing an objective function subject to equality and/or inequality constraints.

Abstract: A pulsed neutron tool with three or more detectors is used for making measurements inside casing. The measurements may be used to determine gas saturation at a constant gas pressure, pressure at constant gas saturation, or to determine both gas saturation and gas pressure.

Abstract: A pulsed neutron tool with three or more detectors is used for making measurements inside casing. The measurements may be used to determine gas saturation at a constant gas pressure, pressure at constant gas saturation, or to determine both gas saturation and gas pressure.

Abstract: A pulsed neutron tool with three or more detectors is used for making measurements inside casing. The measurements may be used to determine gas saturation at a constant gas pressure, pressure at constant gas saturation, or to determine both gas saturation and gas pressure.

Abstract: Caliper measurements made during rotation of a bottomhole assembly are processed to estimate the location of the BHA, and size and shape of the borehole. A piecewise elliptical fitting procedure may be used. These estimates may be used to correct measurements made by a standoff-sensitive formation evaluation sensor such as a neutron porosity tool. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A neutron source for a downhole logging tool includes 241Am and 9Be. Stainless steel shielding is used to control the generation of neutrons by the source. The device may be used for both continuous as well as pulsed neutron logging and may also be used for gamma ray logging.