Abstract: Systems and method presented herein enable the estimation of porosity using neutron-induced gamma ray spectroscopy. For example, the systems and methods presented herein include receiving, via a control and data acquisition system, data relating to energy spectra of gamma rays captured by one or more gamma ray detectors of a neutron-induced gamma ray spectroscopy logging tool. The method also includes deriving, via the control and data acquisition system, one or more spectral yields relating to one or more elemental components from the data relating to the energy spectra of the gamma rays. The method further includes estimating, via the control and data acquisition system, a measurement of porosity based on the one or more spectral yields relating to the one or more elemental components.

Abstract: Systems and method presented herein enable the estimation of porosity using neutron-induced gamma ray spectroscopy. For example, the systems and methods presented herein include receiving, via a control and data acquisition system, data relating to energy spectra of gamma rays captured by one or more gamma ray detectors of a neutron-induced gamma ray spectroscopy logging tool. The method also includes deriving, via the control and data acquisition system, one or more spectral yields relating to one or more elemental components from the data relating to the energy spectra of the gamma rays. The method further includes estimating, via the control and data acquisition system, a measurement of porosity based on the one or more spectral yields relating to the one or more elemental components.

Abstract: A method for estimating at least one geological constituent may include obtaining a measured energy spectrum for the at least one geological constituent for a first borehole configuration, generating a calculated energy spectrum for the at least one geological constituent for the first borehole configuration, and generating a calculated energy spectrum for the at least one geological constituent for a second borehole configuration different than the first borehole configuration. The method may further include determining a relationship between the calculated energy spectra for the first and second borehole configurations, and generating an estimated energy spectrum for the at least one geological constituent for the second borehole configuration based upon the measured energy spectrum and the relationship between the calculated energy spectra for the first and second borehole configurations.

Abstract: A borehole tool calibration method may include obtaining a measured energy spectrum for at least one geological constituent based upon a first borehole tool, generating a calculated energy spectrum for the at least one geological constituent for the first borehole tool, and generating a calculated energy spectrum for the at least one geological constituent for a second borehole tool different than the first borehole tool. The method may further include determining a relationship between the calculated energy spectra for the first and second borehole tools, and determining a calibration parameter for the second borehole tool based upon the measured energy spectrum and the relationship between the calculated energy spectra for the first and second borehole tools.

Abstract: Composition-matched downhole tools and methods for using such tools are provided. One such method includes emitting neutrons using a neutron source in the downhole tool to generate formation gamma rays in a surrounding formation. At the same time, however, some of the neutrons may interact with different parts of the downhole tool to form tool gamma rays. The gamma ray spectra of at least some of the formation gamma rays and the tool gamma rays may be detected using a gamma ray detector. The tool gamma rays from the different parts of the tool may have a substantially similar spectral shape. As such, a processor may be used to analyze the spectra of the tool gamma rays using a single tool background standard, thereby simplifying the analysis and improving the precision of the results.

Abstract: A method for estimating at least one geological constituent may include obtaining a measured energy spectrum for the at least one geological constituent for a first borehole configuration, generating a calculated energy spectrum for the at least one geological constituent for the first borehole configuration, and generating a calculated energy spectrum for the at least one geological constituent for a second borehole configuration different than the first borehole configuration. The method may further include determining a relationship between the calculated energy spectra for the first and second borehole configurations, and generating an estimated energy spectrum for the at least one geological constituent for the second borehole configuration based upon the measured energy spectrum and the relationship between the calculated energy spectra for the first and second borehole configurations.

Abstract: A borehole tool calibration method may include obtaining a measured energy spectrum for at least one geological constituent based upon a first borehole tool, generating a calculated energy spectrum for the at least one geological constituent for the first borehole tool, and generating a calculated energy spectrum for the at least one geological constituent for a second borehole tool different than the first borehole tool. The method may further include determining a relationship between the calculated energy spectra for the first and second borehole tools, and determining a calibration parameter for the second borehole tool based upon the measured energy spectrum and the relationship between the calculated energy spectra for the first and second borehole tools.

Abstract: Composition-matched downhole tools and methods for using such tools are provided. One such method includes emitting neutrons using a neutron source in the downhole tool to generate formation gamma rays in a surrounding formation. At the same time, however, some of the neutrons may interact with different parts of the downhole tool to form tool gamma rays. The gamma ray spectra of at least some of the formation gamma rays and the tool gamma rays may be detected using a gamma ray detector. The tool gamma rays from the different parts of the tool may have a substantially similar spectral shape. As such, a processor may be used to analyze the spectra of the tool gamma rays using a single tool background standard, thereby simplifying the analysis and improving the precision of the results.

Abstract: Methods and apparatus are provided for determining the content of a first element in a formation which cannot otherwise be determined via a capture spectrum measurement. The methods and apparatus utilize the inelastic spectrum measurement of the first element and the inelastic and capture spectrum measurements of at least a second element. The methods and apparatus have particular application to determining the carbon content of a formation although they are not limited thereto. The inelastic and capture spectrum measurements of silicon are useful in making such determinations, although other chemical elements may be used as the second element.

Abstract: Methods and apparatus are provided for determining the content of a first element in a formation which cannot otherwise be determined via a capture spectrum measurement. The methods and apparatus utilize the inelastic spectrum measurement of the first element and the inelastic and capture spectrum measurements of at least a second element. The methods and apparatus have particular application to determining the carbon content of a formation although they are not limited thereto. The inelastic and capture spectrum measurements of silicon are useful in making such determinations, although other chemical elements may be used as the second element.

Abstract: Logging method and tool string for identifying and determining the concentrations of subsurface formation elements next to a borehole, by (i) using a low energy neutron source (either a chemical source, e.g. a .sup.252 Cf, or a deuterium-deuterium electronic source), and (ii) detecting and counting the delayed gamma rays resulting from the activation by the neutrons of atoms of at least one element of interest (e.g. aluminum). Two gamma ray detectors may also be disposed on either side of the low energy neutron source, for detecting and counting the prompt gamma rays resulting from the capture of neutrons by atoms of elements, such as Si, Ca, Fe, S, H, or Cl, Gd, Ti, or K.The low energy neutron source is used for both the "activation" and the "capture" measurements. The tool string may also include a natural gamma ray tool for the determination of uranium, thorium and potassium, and for measuring the background to be subtracted from the gross Al activation measurement.

Abstract: A golf accessory for retrieving golf balls, repairing divots and placing ball markers, the accessory including a planar member having a ball holder section formed on one side and a flexible ball guide section on the opposite side for biasing the ball into the holder, the guide section including a pair of tapered tines for repairing divots and placing golf ball markers on the green.