Abstract: An apparatus can measure characteristics of a formation surrounding a borehole. The apparatus includes a tool body having a neutron measurement section. The neutron measurement section includes a neutron source and a neutron detector arrangement spaced in an axial direction from the neutron source The apparatus also includes a density measurement section having a gamma ray source and a gamma ray detector arrangement spaced in an axial direction from the gamma ray source. The neutron measurement section and the density measurement section are positioned in the tool body so that the sections overlap in the axial direction and are azimuthally spaced apart in the tool body. The tool body also includes shielding to block a direct signal path from the neutron source to the gamma ray detector arrangement and to block a direct signal path from the gamma ray source to the neutron detector arrangement.

Abstract: A method of formation evaluation using a pulsed neutron tool. The approach removes the effect of formation hydrogen index (HI) from the nuclear response of the tool. It can be used for gas detection and quantification, as well as for other fluids. It can also be used to improve a formation hydrogen index (HI) measurement.

Abstract: The disclosure includes an arrangement of X-ray generator(s) (210), X-ray detector(s) (214), and/or X-ray calibration device(s) for performing X-ray measurements, such as attenuation and/or photo electric factor measurements, on formation core samples (204) in a downhole environment under conditions including limited space and operations at high pressure and temperature.

Abstract: A neutron detecting device using a neutron-reactive material as the source of charged particles to feed conventional dynode-based electron multiplier which not gas-filled (i.e., with 3He). The detector comprises a neutron-reacting material that produces charged particles, coupled with an electron multiplier that is known for use in photomultipliers. The neutron-reacting material is deposited on a substrate at the entrance to the electron multiplier. Charged particles from the neutron-reacting material impinge on the first dynode of the electron multiplier, where, in turn, electrons are generated. The secondary electrons are collected by a second dynode, and the charge so collected is amplified in each succeeding dynode stage in a cascade effect. The charge pulse from the anode is processed by subsequent pulse processing electronics and counting electronics to provide a count rate that is proportional to the neutron flux incident on the neutron-reacting material.

Abstract: A method and apparatus for obtaining neutron images of a rock formation are provided. The neutron images can be obtained from a tool which need not rotate to obtain neutron data from a plurality of azimuthal orientations.

Abstract: A nuclear measurement tool for determining properties of a formation penetrated by a borehole fluid. The tool comprising: a nuclear source for irradiating the formation and a a plurality of nuclear sensors each operating with a different depth of investigation into the formation. The tool further comprising processing means for receiving the data from the nuclear sensors and based thereon determining the properties of the formation by taking into account the penetration of the borehole fluid.

Abstract: Methods and related systems are described for the detection of nuclear radiation. The system can include a tool body adapted to be deployed in a wellbore and a scintillator material that intrinsically generates radiation. The scintillator material is mounted within the tool body. A photodetection system is coupled to the scintillator material, and mounted within the tool body. Features in a spectrum associated with a scintillation material's intrinsic radioactive decay are used for the determination of one or more parameter's of the response function of the radiation detector system.

Abstract: Methods and systems for determining whether a tool has been deployed below a drill pipe are provided. A downhole tool can measure various characteristics, which then can be analyzed to determine the likelihood of a tool having been deployed below the drill pipe. For example, density and porosity measurements can be affected by the presence of casing or drill pipe, and thus such measurements can provide an indication of whether the tool has been deployed below the drill pipe.

Abstract: A method is provided to detect neutrons using a boron-shielded gamma-ray detector, which will detect the 0.48-MeV prompt gamma ray due to the 10B (n,?)7Li reaction. The gamma ray detector can be a proportional gas counter, a scintillation based detector, or a semiconductor detector. Monoenergetic prompt gammas will produce a sharp peak in the pulse height spectrum of a gamma-ray spectroscopy detector. By surrounding a gamma detector with a layer containing 10B, we can measure the gamma signal and neutron signal at the same time and at the same physical location in an instrument. The approach can be used to measure neutron porosity simultaneous with gamma-ray counting or spectroscopy at the same location as long as the 0.48-keV gamma-ray from the neutron reaction does not interfere with the gamma-ray measurement.

Abstract: Disclosed is a radiation logging tool, comprising a tool housing; a compact generator that produces radiation; a power supply coupled to the compact generator; and control circuitry. Embodiments of the compact generator comprise a generator vacuum tube comprising a source generating charged particles, and a target onto which the charged particles are directed; and a high voltage supply comprising a high voltage multiplier ladder located laterally adjacent to the generator vacuum tube. The high voltage supply applies a high voltage between the source and the target to accelerate the charged particles to a predetermined energy level. The compact generator also includes an electrical coupling between an output of the high voltage supply and the target of the generator vacuum tube to accommodate the collocated positions of the generator vacuum tube and the high voltage power supply.

Abstract: Methods and systems to determine and regulate the gain of gamma-ray detectors in tools equipped with neutron sources are provided. Gain regulation may be based on the gamma ray background generated in the tool by interaction of neutrons with the nuclei of some elements constituting the tool structure. Some chemical elements that are used in construction of the tool's mechanical parts and structure result in characteristic gamma ray lines in a measured energy spectrum. These lines can be used to calibrate the energy scale of the response of the detector, without any added calibration radio isotopic source.

Abstract: Methods for pre-treating packaging materials of particular composition for use in conjunction with a scintillation crystal are disclosed. The packaging materials may comprise a reflecting material, an elastomer, a reflecting fluorocarbon polymer, a polymer or elastomer loaded with a reflecting inorganic powder (including a reflecting inorganic powder comprising a high reflectance material selected from the group comprising Al2O3, TiO2, BN, MgO, BaSO4 and mixtures thereof), or a highly reflective metal foil selected from the group comprising Ag and Al that is chemically compatible with the scintillator crystal. The scintillator crystal may comprise a crystal selected from the group comprising NaI(Tl), LaBr3:Ce, La—Cl3:Ce, La-halides, and La-mixed halides.

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 insert apparatus for use in a test formation for a downhole nuclear spectroscopy tool includes an outer liner, and an inner liner defining a cylindrical borehole having a diameter such that the downhole nuclear spectroscopy tool is receivable therein. There is fill material between the outer liner and the inner liner, the material including a formation base material and an elemental standards material. The outer liner, the inner liner, and the fill material are configured such that an elemental standard measurement derived from a test using the insert apparatus is equivalent to an elemental standard measurement from a selected formation.

Abstract: The invention provides a hermetically sealed scintillation crystal package with a window made of a ruggedized material such as ALON (aluminum Oxynitride) or Spinel ceramic (MgAl2O4) where the window is sealed to an external metallic housing part by a brazing or soldering process and the external housing part is welded to the housing containing the scintillation crystal.

Abstract: Systems, methods, and devices for inelastic gamma-ray logging are provided. In one embodiment, such a method includes emitting neutrons into a subterranean formation from a downhole tool to produce inelastic gamma-rays, detecting a portion of the inelastic gamma-rays that scatter back to the downhole tool to obtain an inelastic gamma-ray signal, and determining a property of the subterranean formation based at least in part on the inelastic gamma-ray signal. The inelastic gamma-ray signal may be substantially free of epithermal and thermal neutron capture background.

Abstract: The present disclosure describes a scintillation crystal having the general formula RE(1?y)MyF3XA3(1?x), wherein RE is selected from the group consisting of La, Gd, Y, Lu, or mixtures thereof; A is selected from Cl, Br or I, and M is an activator ion selected from the group consisting of Ce3+, Pr3+ or Eu3+ and combinations thereof containing two or all three activator ions and further optionally comprising Ho, Er, Tm, or Yb also in the 3+ oxidation state. We also disclose a scintillation detector including a scintillation crystal, and downhole tools and methods of oil exploration utilizing such scintillation crystals.

Abstract: Logging-while-drilling tools incorporating an electronic radiation generator, such as an electronic X-ray generator, and a method for using the same are provided. One example of such a logging-while-drilling tool may include a circumferential drill collar, a chassis disposed radially interior to the drill collar, and an electronic X-ray generator and an X-ray detector disposed within the chassis. The electronic X-ray generator may emit X-rays out of the logging-while-drilling tool into a subterranean formation. The X-ray detector may detect X-rays that return to the logging-while-drilling tool after scattering in the subterranean formation, which may be used to determine a density and/or a lithology of the subterranean formation.

Abstract: A method and apparatus for obtaining neutron images of a rock formation are provided. The neutron images can be obtained from a tool in a logging-while-drilling system but which need not rotate to obtain neutron data from a plurality of azimuthal orientations.

Abstract: A tool having a neutron source, a gamma ray detector, and a photomultiplier tube is provided. The gamma ray detector and the photomultiplier tube are at least partially surrounded by a layer of boron. The tool is used to make measurements, and the number of prompt gamma rays emitted by the boron is determined from the measurements. The number of neutrons detected may be inferred using the determined number of prompt gamma rays. The tool may also have a layer of neutron absorbing material different from boron or a layer of heavy metal at least partially surrounding the boron. The tool may be a logging tool used to delineate a porous formation and to determine its porosity. The tool may have a plurality of gamma ray detector/photomultiplier tube pairs and those pairs may be used to determine a formation hydrogen index and/or a borehole hydrogen index.