Natural Gamma Ray Theory

25 Questions | Total Attempts: 115

SettingsSettingsSettings
Please wait...
Natural Gamma Ray Theory

Quiz Description


Questions and Answers
  • 1. 
    Select all of the following that apply to gamma rays.
    • A. 

      Spontaneously emitted from the nucleus of an atom

    • B. 

      Positively charged

    • C. 

      No atomic mass

    • D. 

      Low energy electromagnetic radiation

    • E. 

      No electrical charge

  • 2. 
    Select all of the following reasons that might result in different count rates for two different tool designs.
    • A. 

      Type of crystal used

    • B. 

      Different tool housings

    • C. 

      Half-lives of radioactive material

    • D. 

      Different crystal material

  • 3. 
    Which of the following is not a potential application of the natural gamma ray measurement of the NGRT, D4TG, or GTET?
    • A. 

      Assists in determining formation lithology

    • B. 

      Determination of diameter of invasion

    • C. 

      Determination of volume of shale

    • D. 

      Well-to-well correlation

    • E. 

      Depth control

  • 4. 
    Which of the following elements are primarily responsible for natural gamma radiation?
    • A. 

      Potassium, uranium, and calcium

    • B. 

      Americium, uranium, and potassium

    • C. 

      Thorium, uranium, and potassium

    • D. 

      Polonium, potassium, and thorium

    • E. 

      Uranium, thorium and americium

  • 5. 
    What type of detector is used in the NGRT, D4TG, and GTET?
    • A. 

      Sodium iodide (Nal)

    • B. 

      Bismuth germinate (BGO)

    • C. 

      Cesium iodide (Csl)

    • D. 

      Sodium Chloride (NaCl)

  • 6. 
    Which of the following best describes the process by which a gamma ray is detected?
    • A. 

      A gamma ray interacts with the scintillation crystal to produce a small pulse of light. This light pulse enters the photo-multiplier tube and strikes a photo-sensitive cathode, emitting electrons. The electrons are multiplied as the avalanche through a series of dynodes, resulting in an electrical pulse that represents one gamma ray detected.

    • B. 

      A gamma ray interacts with the scintillation crystal to produce electrons. These electrons enter the photo-multiplier tube and strike a photo-sensitive cathode, emitting a pulse of light. This pulse of light is amplified as passes through a series of dynodes, resulting in an electrical pulse that represents one gamma ray detected.

  • 7. 
    The GAPI unit is defined as:
    • A. 

      1/2000th the difference in measured count rates between the high and low intervals of the API test pit

    • B. 

      1/200th the difference in measured count rates between the high and low intervals of the API test pit

    • C. 

      1/200th the sensitivity of the standard tool as measured in the API test pit

    • D. 

      100% of the thorium blanket calibrator's value

  • 8. 
    Which of the following lithologies would likely result in the highest gamma ray count rate at a detector?
    • A. 

      Limestone

    • B. 

      Dolomite

    • C. 

      Shale

    • D. 

      Sandstone

  • 9. 
    Which of the following tools is necessary if the specific concentrations of potassium, uranium, and thorium within a rock must be known?
    • A. 

      Spectral Density Logging Tool (SDL)

    • B. 

      Natural Gamma Ray Tool (NGRT, D4TG, or GTET)

    • C. 

      Compensated Spectral Natural Gamma Tool (CSNG)

    • D. 

      Dual Spaced Neutron Tool (DSNT)

  • 10. 
    Halliburton tools are calibrated at the wellsite using:
    • A. 

      The API test pit

    • B. 

      Thorium blankets

    • C. 

      Halliburton test wells

    • D. 

      Uranium blankets

  • 11. 
    Half-life is defined as:
    • A. 

      The period of time required for a radioactive material to lose one-half of its radioactivity

    • B. 

      The period of time needed for radioactive material to gain one-half of its radioactivity

    • C. 

      The period of time required before radiation emitted from radioactive material is at a safe level

  • 12. 
    The count rate measured by a natural gamma ray tool is proportional to:
    • A. 

      The total amount of potassium in the formation

    • B. 

      The total amount of potassium, uranium and thorium in the formation

    • C. 

      The energy level of potassium, uranium and thorium in the formation

    • D. 

      The total amount of only uranium and thorium in the formation

  • 13. 
    Natural gamma ray tools such as the NGRT, D4TG, and GTET provide measures of the amount of naturally occurring gamma radiation emitted by a formation.
    • A. 

      True

    • B. 

      False

  • 14. 
    The most fundamental use of natural gamma ray tool is to assist in determining formation ________.
    • A. 

      Lithology

    • B. 

      Porosity

    • C. 

      Permeability

    • D. 

      Resistivity

  • 15. 
    Which of the following contains the largest quantity of the radioactive elements potassium, uranium, and thorium?
    • A. 

      Deep water marine shales

    • B. 

      Deltas

    • C. 

      Lake environments

    • D. 

      River bottoms

  • 16. 
    Potassium, with a half life of 1.3 billion years, ultimately decays to the stable element ______.
    • A. 

      Argon

    • B. 

      Lead

    • C. 

      Aluminum

    • D. 

      Barium

  • 17. 
    An electron volt (e) is a unit of energy equal to the kinetic energy acquired by an electron passing through a potential difference of 1 volt.
    • A. 

      True

    • B. 

      False

  • 18. 
    Uranium decays to the stable element ______.
    • A. 

      Lead

    • B. 

      Argon

    • C. 

      Aluminum

    • D. 

      Barium

  • 19. 
    Thorium decays to the stable element ______.
    • A. 

      Lead

    • B. 

      Argon

    • C. 

      Aluminum

    • D. 

      Barium

  • 20. 
    The more dense the crystal, the ______ its counting efficiency.
    • A. 

      Better

    • B. 

      Worse

  • 21. 
    Larger crystals measure _____ count rates.
    • A. 

      Higher

    • B. 

      Lower

    • C. 

      The size doesn't matter

    • D. 

      According to women, size does matter

  • 22. 
    The NGRT uses a(n) ____ crystal while the D4TG uses a(n) _____ crystal.
    • A. 

      4-inch, 8-inch

    • B. 

      8-inch, 4-inch

    • C. 

      3-inch, 6-inch

    • D. 

      6-inch, 3-inch

  • 23. 
    Crystals with larger diameters measure _____ count rates.
    • A. 

      Higher

    • B. 

      Lower

    • C. 

      Diameter doesn't effect count rate

  • 24. 
    The engineering unit for a gamma ray measurement is the Gamma API (GAPI).
    • A. 

      True

    • B. 

      False

Back to Top Back to top