Method and system for evaluation of gamma-gamma well logging data in mineral exploration
A calibration site for a gamma-gamma well logging tool for use in mineral exploration, the calibration site having a column consisting of a plurality of blocks of known densities; and a borehole through the column configured to accept the gamma-gamma well logging tool. Further, a method for calibrating a gamma-gamma well logging tool at the calibration site, the method including lowering the gamma-gamma well logging tool into a column consisting of a plurality of blocks of different known densities and having a borehole therein to receive the gamma-gamma well logging tool; raising the gamma-gamma well logging tool at a set rate; capturing a radiation count at a sensor of the gamma-gamma well logging tool; converting the radiation count to a recorded density for a particular depth at a computing device; and comparing the recorded density at each position of the column with the known densities.
1. A calibration site for a gamma-gamma well logging tool for use in mineral exploration, the calibration site comprising:
a column including a plurality of blocks of known densities; and
a borehole through the column configured to accept the gamma-gamma well logging tool.
2. The calibration site of claim 1 wherein each of the plurality of blocks has a different, known density, and wherein the plurality of blocks is stacked so a lowest density block is on top and a highest density block is on the bottom of the stack.
3. The calibration site of claim 2 , wherein the densities of plurality of blocks is selected to span a range of densities of lithologies encountered in mineral exploration.
4. The calibration site of claim 3 , wherein the densities of each block in the plurality of block range from 1.5 g/cm3 to 4.5 g/cm3.
5. The calibration site of claim 2 , wherein each block in the plurality of blocks is homogenous for a density.
6. The calibration site of claim 5 , wherein each block of the plurality of blocks is comprised of at least one of cement, grit, gravel, water, Styrofoam, and iron ore.
7. The calibration site of claim 2 , wherein a horizontal plane is formed between each of the blocks in the column.
8. The calibration site of claim 1 , wherein the borehole includes a casing.
9. The calibration site of claim 1 , further comprising a bunker for storage of a radioactive source for the gamma-gamma well logging tool.
10. The calibration site of claim 1 , further comprising a pulley system for the gamma-gamma well logging tool.
11. A method for calibrating a gamma-gamma well logging tool at a calibration site comprising:
lowering the gamma-gamma well logging tool into a column including a plurality of blocks of different known densities and having a borehole therein to receive the gamma-gamma well logging tool;
raising the gamma-gamma well logging tool at a set rate;
capturing a radiation count at a sensor of the gamma-gamma well logging tool;
converting the radiation count to a recorded density for a particular depth at a computing device; and
comparing the recorded density at each position of the column with the known densities.
12. The method of claim 11 , wherein the plurality of blocks is stacked so a lowest density block is on top and a highest density block is on the bottom of the stack.
13. The method of claim 12 , wherein the densities of plurality of blocks spans a range of densities of lithologies encountered in mineral exploration.
14. The method of claim 12 , wherein the densities of each block in the plurality of block range from 1.5 g/cm3 to 4.5 g/cm3.
15. The method of claim 11 , wherein each block in the plurality of blocks is homogenous for a density.
16. The method of claim 11 , wherein a horizontal plane is formed between each of the blocks in the column.
17. The method of claim 16 , further comprising comparing a density curve within a transition influence zone between two blocks with a theoretic density curve.
18. The method of claim 11 , wherein results from the calibration are used as reference curves in geophysical well logging operations.
19. The calibration site of claim 1 , further comprising a gamma-gamma well logging tool that comprises a radiation source, a short sensor and a long sensor, wherein the short sensor and long sensor have different but known spacing from the source.
20. The method of claim 11 , wherein the gamma-gamma well logging tool comprises a radiation source, a short sensor and a long sensor, wherein the short sensor and long sensor have different but known spacing from the source.
21. A system comprising:
a column including a plurality of blocks of known densities;
a gamma-gamma well logging tool comprising a radiation source, a short sensor and a long sensor, wherein the short sensor and long sensor have different but known spacing from the source; and
a borehole through the column configured to accept the gamma-gamma well logging tool.