Natural Gamma Ray Theory
(291).jpg "Natural Gamma Ray Theory - Quiz")
Quiz Description
- 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
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