Abstract: Borehole logging methods for estimating a parameter of interest using nuclear radiation. Methods include estimating a water saturation of the formation from gamma radiation from at least the formation detected in the borehole using a radiation detector, the gamma radiation responsive to a pulsed neutron source and resulting from at least one of: (i) decay of nitrogen-16 formed by activation of oxygen-16, and ii) inelastic scattering of neutrons from oxygen. This may include using at least one processor to: obtain a gamma ray count measurement, representing gamma rays from one of: (i) the decay of nitrogen-16 (ii) and the inelastic scattering, and estimate the water saturation using the gamma ray count measurement and a model comprising a relationship between measured gamma ray counts and modeled gamma ray counts from each of a fully water saturated formation and a minimally water saturated formation.

Abstract: Borehole logging methods for estimating a parameter of interest using nuclear radiation. Methods include estimating a water saturation of the formation from gamma radiation from at least the formation detected in the borehole using a radiation detector, the gamma radiation responsive to a pulsed neutron source and resulting from at least one of: (i) decay of nitrogen-16 formed by activation of oxygen-16, and ii) inelastic scattering of neutrons from oxygen. This may include using at least one processor to: obtain a gamma ray count measurement, representing gamma rays from one of (i) the decay of nitrogen-16 (ii) and the inelastic scattering, and estimate the water saturation using the gamma ray count measurement and a model comprising a relationship between measured gamma ray counts and modeled gamma ray counts from each of a fully water saturated formation and a minimally water saturated formation.

Abstract: The present disclosure relates to borehole logging methods and apparatuses for estimating formation properties using nuclear radiation, particularly an apparatus and method for estimating amounts of silicon and/or oxygen in the formation. The method may include using nuclear radiation information from at least one nuclear radiation detector to estimate at least one parameter of interest. The method may include separating a gross nuclear radiation count into separate nuclear radiation components. The method may also include reducing an error in the estimated formation properties due to speed variations of a nuclear radiation source that activates the silicon and oxygen in the formation. The apparatus may include at least one nuclear radiation detector. The apparatuses may include an information processing device to perform the methods.

Abstract: Borehole logging methods for estimating a parameter of interest using nuclear radiation. Methods include estimating a water saturation of the formation from gamma radiation from at least the formation detected in the borehole using a radiation detector, the gamma radiation responsive to a pulsed neutron source and resulting from at least one of: (i) decay of nitrogen-16 formed by activation of oxygen-16, and ii) inelastic scattering of neutrons from oxygen. This may include using at least one processor to: obtain a gamma ray count measurement, representing gamma rays from one of: (i) the decay of nitrogen-16 (ii) and the inelastic scattering, and estimate the water saturation using the gamma ray count measurement and a model comprising a relationship between measured gamma ray counts and modeled gamma ray counts from each of a fully water saturated formation and a minimally water saturated formation.

Abstract: Borehole logging methods for estimating a parameter of interest using nuclear radiation. Methods include estimating a water saturation of the formation from gamma radiation from at least the formation detected in the borehole using a radiation detector, the gamma radiation responsive to a pulsed neutron source and resulting from at least one of: (i) decay of nitrogen-16 formed by activation of oxygen-16, and ii) inelastic scattering of neutrons from oxygen. This may include using at least one processor to: obtain a gamma ray count measurement, representing gamma rays from one of: (i) the decay of nitrogen-16 (ii) and the inelastic scattering, and estimate the water saturation using the gamma ray count measurement and a model comprising a relationship between measured gamma ray counts and modeled gamma ray counts from each of a fully water saturated formation and a minimally water saturated formation.

Abstract: Borehole logging methods for estimating a parameter of interest using nuclear radiation. Methods include estimating a water saturation of the formation from gamma radiation from at least the formation detected in the borehole using a radiation detector, the gamma radiation responsive to a pulsed neutron source and resulting from at least one of: (i) decay of nitrogen-16 formed by activation of oxygen-16, and ii) inelastic scattering of neutrons from oxygen. This may include using at least one processor to: obtain a gamma ray count measurement, representing gamma rays from one of (i) the decay of nitrogen-16 (ii) and the inelastic scattering, and estimate the water saturation using the gamma ray count measurement and a model comprising a relationship between measured gamma ray counts and modeled gamma ray counts from each of a fully water saturated formation and a minimally water saturated formation.

Abstract: Borehole logging methods and apparatuses for estimating formation properties using nuclear radiation, particularly an apparatus and method for estimating amounts of silicon and/or oxygen in the formation. Methods include estimating a formation property using an oxygen estimate and at least a formation lithology. The method may include using nuclear radiation information from at least one nuclear radiation detector generate the oxygen estimate. The apparatus may include at least one nuclear radiation detector. The apparatuses may include an information processing device to perform the methods.

Abstract: The present disclosure relates to borehole logging methods and apparatuses for estimating formation properties using nuclear radiation, particularly an apparatus and method for estimating amounts of silicon and/or oxygen in the formation using exposure time information. The method may include using nuclear radiation information from at least one nuclear radiation detector to estimate at least one parameter of interest. The method may also include reducing an error in the estimated formation properties due to speed variations of a nuclear radiation source that activates the silicon and oxygen in the formation. The apparatus may include at least one nuclear radiation detector. The apparatuses may include an information processing device to perform the methods.

Abstract: A method of estimating at least one property of an earth formation includes: constructing a matrix model of a formation; constructing a shale model of the formation, the shale model including an estimation of a concentration of at least one trace element; combining the first model and the second model to generate a formation model; and comparing measured pulsed neutron data with the mixed model to estimate the at least one property.

Abstract: A method of calculating a porosity of a geological formation includes determining a bulk pore volume and a movable fluid pore volume in the geological formation in which drilling mud including a mud filtrate is introduced, calculating a porosity of the formation based on a bulk pore volume, and correcting the porosity based on the movable fluid volume in the geological formation.

Abstract: Method and apparatus for evaluating an earth formation using a pulsed neutron source comprising of dual beams of oppositely directed hydrogen isotopic ions with timing and focal characteristics of each beam set to accomplish a beam-to-beam focusing interaction to a selected position that extends axially along a sealed tube. This makes it possible to generate pulsed neutrons from a plurality of positions.

Abstract: A method for estimating a property of an earth formation, the method includes: conveying a carrier through a borehole penetrating the earth formation; irradiating the formation with neutrons from a neutron source disposed at the carrier; detecting a first signal from the formation due to the irradiating using a first radiation detector, the first signal being related to a saturation of a fluid in the formation; detecting a second signal from an element in the formation due to the irradiating using a second radiation detector, the second signal being related to an element emitting the second signal in the formation; and estimating the property from the first signal and the second signal.

Abstract: A method for estimating a parameter of interest of an earth formation having a fluid contained in pores of the earth formation, the method includes: conveying a carrier through a borehole penetrating the earth formation; irradiating the earth formation with neutrons from a neutron source disposed at the carrier; measuring radiation emitted from the earth formation resulting from the irradiating using at least one detector; calculating or determining a mathematical parameter from radiation measured by the at least one detector; predicting values of the mathematical parameter over a range of values of an earth formation property; and comparing the mathematical parameter to the predicted values to estimate the parameter of interest.

Abstract: In one aspect, the present disclosure provides an apparatus for determining formation density. One embodiment of the apparatus includes a bottomhole assembly having a drill bit attached to end thereof for drilling through a formation, a first sensor in the drill bit configured to provide first signals for determining a first density of the formation proximate to the drill, a second sensor distal from the first sensor configured to provide signals for determining density of a second density of the formation, and a processor configured to determine the formation density from the first density and the second density.

Abstract: A method for estimating a concentration of carbon dioxide (CO2) in a formation penetrated by a borehole, the method includes: conveying a carrier through the borehole; irradiating the formation with neutrons from a neutron source disposed at the carrier; detecting photons from the formation resulting from the irradiating; and estimating the concentration of CO2 from data acquired from the detecting.

Abstract: An instrument for performing measurements downhole, includes an irradiator oriented to irradiate sub-surface materials surrounding the instrument, the irradiator including at least one neutron source disposed proximate to a moderator for providing a source of inelastic gamma photons and also disposed proximate to a material for providing a source of capture gamma photons; and a first detector and a second detector, each detector for detecting gamma rays and oriented in a relationship to the irradiator for receiving gamma photons from at least one of the irradiator and the formation. A method for irradiating sub-surface materials is provided.

Abstract: A method of calculating a porosity of a geological formation includes determining a bulk pore volume and a movable fluid pore volume in the geological formation in which drilling mud including a mud filtrate is introduced, calculating a porosity of the formation based on a bulk pore volume, and correcting the porosity based on the movable fluid volume in the geological formation.

Abstract: A method for performing a measurement of a property downhole includes: using an instrument including an irradiator including a pulsed neutron generator, a moderator and a material including a high cross section for capturing thermal neutrons downhole, generating inelastic gamma photons from neutron interactions in the moderator and generating capture gamma photons from neutron interactions in the material; irradiating sub-surface materials proximate to the instrument with the inelastic gamma photons and the capture gamma photons; detecting radiation scattered by the sub-surface materials; and estimating the property according to the detected radiation. A system is also disclosed.

Abstract: Method and apparatus for evaluating an earth formation using a pulsed neutron source comprising of dual beams of oppositely directed hydrogen isotopic ions with timing and focal characteristics of each beam set to accomplish a beam-to-beam focusing interaction to a selected position that extends axially along a sealed tube. This makes it possible to generate pulsed neutrons from a plurality of positions.

Abstract: In one aspect, the present disclosure provides an apparatus for determining formation density. One embodiment of the apparatus includes a bottomhole assembly having a drill bit attached to end thereof for drilling through a formation, a first sensor in the drill bit configured to provide first signals for determining a first density of the formation proximate to the drill, a second sensor distal from the first sensor configured to provide signals for determining density of a second density of the formation, and a processor configured to determine the formation density from the first density and the second density.