Abstract: A downhole tool and method for performing a base log sigma measurement of a formation. The tool comprising a nuclear source for irradiating the formation and a detector for obtaining a sigma measurement of the irradiated formation. The tool is mounted close to a drill bit arranged to drill a borehole into the formation and is capable of determining a base log sigma measurement of the formation while drilling into the formation.

Abstract: Systems and methods for stabilizing the gain of a gamma-ray spectroscopy system are provided. In accordance with one embodiment, a method of stabilizing the gain of a gamma-ray spectroscopy system may include generating light corresponding to gamma-rays detected from a geological formation using a scintillator having a natural radioactivity, generating an electrical signal corresponding to the light, and stabilizing the gain of the electrical signal based on the natural radioactivity of the scintillator. The scintillator may contain, for example, naturally radioactive elements such as Lutetium or Lanthanum.

Abstract: Systems, methods, and devices for thermally protecting a scintillator crystal of a scintillation detector are provided. In one example, a thermally-protected scintillator may include a scintillator crystal and a thermal protection element, which may partially surround the scintillator crystal. The thermal protection element may be configured to prevent the scintillator crystal from experiencing a rate of change in temperature sufficient to cause cracking or non-uniform light output, or a combination thereof.

Abstract: An apparatus and method for determining the density and other properties of a formation surrounding a borehole using a high voltage x-ray generator. One embodiment comprises a stable compact x-ray generator capable of providing radiation with energy of 250 keV and higher while operating at temperatures equal to or greater than 125° C. In another embodiment, radiation is passed from an x-ray generator into the formation; reflected radiation is detected by a short spaced radiation detector and a long spaced radiation detector. The output of these detectors is then used to determine the density of the formation. In one embodiment, a reference radiation detector monitors a filtered radiation signal. The output of this detector is used to control at least one of the acceleration voltage and beam current of the x-ray generator.

Abstract: Apparatus for determining properties of a borehole and a formation around the borehole. The apparatus comprising a source for generating nuclear particles, a detector for measuring a effect of the nuclear particles on a fluid flowing in the borehole and a second detector for measuring an effect of the nuclear particles on the formation. The source is arranged to generate the nuclear particles in a manner that enables the measuring of the first and the second detector to be performed simultaneously.

Abstract: A well logging instrument includes a source of high energy neutrons arranged to bombard a formation surrounding the instrument. A scintillator sensitive to gamma radiation resulting from interaction of the high energy neutrons with the formation is disposed in the instrument. A neutron shielding material surrounds the scintillator. A neutron moderator surrounds the neutron shielding material. An amplifier is optically coupled to the scintillator.

Abstract: A downhole tool for performing measurement of a formation. The tool comprising a housing surrounding a source for generating neutrons and a detector for detecting the neutrons. A shield is located outside of, or embedded in, the housing and focuses the neutrons.

Abstract: An apparatus and method for determining the density and other properties of a formation surrounding a borehole using a high voltage x-ray generator. One embodiment comprises a stable compact x-ray generator capable of providing radiation with energy of 250 keV and higher while operating at temperatures equal to or greater than 125° C. In another embodiment, radiation is passed from an x-ray generator into the formation; reflected radiation is detected by a short spaced radiation detector and a long spaced radiation detector. The output of these detectors is then used to determine the density of the formation. In one embodiment, a reference radiation detector monitors a filtered radiation signal. The output of this detector is used to control at least one of the acceleration voltage and beam current of the x-ray generator.

Abstract: An apparatus and method for determining the density and other properties of a formation surrounding a borehole using a high voltage x-ray generator. One embodiment comprises a stable compact x-ray generator capable of providing radiation with energy of 250 keV and higher while operating at temperatures equal to or greater than 125° C. In another embodiment, radiation is passed from an x-ray generator into the formation; reflected radiation is detected by a short spaced radiation detector and a long spaced radiation detector. The output of these detectors is then used to determine the density of the formation. In one embodiment, a reference radiation detector monitors a filtered radiation signal. The output of this detector is used to control at least one of the acceleration voltage and beam current of the x-ray generator.

Abstract: Apparatus and method for detecting subsurface radiation phenomena. An elongated support member, adapted for disposal within a wellbore traversing a subsurface formation, includes a recess along its longitudinal axis. A pad is linked to the support member. The pad is configured with a surface correspondingly shaped to fit in juxtaposition with the support member recess. The pad is adapted for movement into and out of the recess such that an exposed surface of the pad can extend away from the support member. The pad also includes one or more radiation detectors and is adapted with shielding material on its sides near the exposed surface to prevent radiation reflected from the recess from reaching the detector(s) from the area near the exposed surface.

Abstract: An apparatus and method for determining the density and other properties of a formation surrounding a borehole using a high voltage x-ray generator. One embodiment comprises a stable compact x-ray generator capable of providing radiation with energy of 260 keV and higher while operating at temperatures equal to or greater than 125° C. In another embodiment, radiation is passed from an x-ray generator into the formation; reflected radiation is detected by a short spaced radiation detector and a long spaced radiation detector. The output of these detectors is then used to determine the density of the formation. In one embodiment, a reference radiation detector monitors a filtered radiation signal. The output of this detector is used to control at least one of the acceleration voltage and beam current of the x-ray generator.

Abstract: An electron acceleration portion of a Betatron having a vacuum chamber with an interior wall spaced from an exterior wall with a main electron orbit located approximate to the exterior wall and the interior wall. An electron injector has an anode structured and arranged adjacent a wall selected from the group consisting of the interior wall and the exterior wall that is shaped so as to not impede the main electron orbit. There is at least one electron deflection plate disposed approximate an anode end of the anode and the main electron orbit. There can be two electron deflection plates spaced apart that form a gap of a width effective to receive emitted electrons from the electron injector. Such that, there is a voltage potential between the two electron deflection plates that is effective to deflect emitted electrons towards the main electron orbit.

Abstract: A Betatron having a toroidal passageway disposed in a cyclical magnetic field with a main electron orbit circumnavigating the toroidal passageway. Within the toroidal passageway is a first electrode that is spaced apart from a second electrode. The combination of the first electrode and the second electrode define a central space having a first opening and a second opening. A cathode is disposed within the central space. This cathode has a first electron emitter aligned to inject electrons through the first opening and a second electron emitter aligned to inject electrons through the second opening. Electrons injected in a proper direction are accelerated in the main electron orbit. At a time of maximum electron acceleration, the electrons are deflected and impact a target that generates x-rays on impact.

Abstract: Method and system for analyzing electrical pulses contained in a pulse train signal representative of the interaction of x-ray bursts with a nuclear detector configured for subsurface disposal. The pulse train signal is sampled to form a digitized signal. The total energy deposited at the detector during an x-ray burst is determined from the digitized signal, and a count rate of x-ray pulses from the burst is determined. A subsurface parameter is determined using the total energy deposit.

Abstract: A well logging instrument includes a source of high energy neutrons arranged to bombard a formation surrounding the instrument. A scintillator sensitive to gamma radiation resulting from interaction of the high energy neutrons with the formation is disposed in the instrument. A neutron shielding material surrounds the scintillator. A neutron moderator surrounds the neutron shielding material. An amplifier is optically coupled to the scintillator.

Abstract: The invention relates to methods and apparatus for determining a downhole parameter in an underbalanced drilling environment which include: selectively activating a first fluid flowing from the formation through a wellbore while under balanced drilled; detecting the activated first fluid, and determining a depth at which said fluid enters the wellbore.

Abstract: A nuclear tool includes a tool housing; a neutron generator disposed in the tool housing; and a solid-state neutron monitor disposed proximate the neutron generator for monitoring the output of the neutron generator. A method for constructing a nuclear tool includes disposing a neutron generator in a tool housing; and disposing a solid-state neutron monitor proximate the neutron generator for monitoring the output of the neutron generator.

Abstract: A nuclear tool includes a tool housing; a d-D neutron generator disposed in the tool housing; a d-T neutron generator disposed in the tool housing; and, optionally, a control circuit for controlling pulsing of the d-D neutron generator and the d-T neutron generator. A method for well-logging using a nuclear tool includes disposing the nuclear tool in a wellbore penetrating a formation; pulsing a d-D neutron generator to emit neutrons at a first energy level into the formation; pulsing a d-T neutron generator to emit neutrons at a second energy level into the formation; and measuring signals returning from the formation.

Abstract: The invention relates to methods and apparatus for determining a downhole parameter in an underbalanced drilling environment which include: selectively activating a first fluid flowing from the formation through a wellbore while under balanced drilled; detecting the activated first fluid; and determining a depth at which said fluid enters the wellbore.

Abstract: An apparatus and method for determining the density and other properties of a formation surrounding a borehole using a high voltage x-ray generator. One embodiment comprises a stable compact x-ray generator capable of providing radiation with energy of 260 keV and higher while operating at temperatures equal to or greater than 125° C. In another embodiment, radiation is passed from an x-ray generator into the formation; reflected radiation is detected by a short spaced radiation detector and a long spaced radiation detector. The output of these detectors is then used to determine the density of the formation. In one embodiment, a reference radiation detector monitors a filtered radiation signal. The output of this detector is used to control at least one of the acceleration voltage and beam current of the x-ray generator.