Convert Gamma Counts to Uranium Equivalent Grade

RockWorks | Borehole Manager | P-Data | CPS - eU308 - I-Data

Use this program to read a P-Data column containing Gamma counts per second (or milli- or micro-second) and translate them to Uranium Grade values, which will be recorded in the I-Data or P-Data table. The translation can be for a single well or all enabled boreholes.

Feature Level: RockWorks Standard and higher

Menu Options
Step-by-Step Summary

Menu Options

• Conversion Options
  • Gamma (P-Data) Track: Click here to select the existing P-Data column that contains the Gamma measurements, in counts per second, millisecond, or microsecond.
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  • Output (Equivalent Grade) Track
    • I-Data: Click in this radio button if the output data is to be recorded in the I-Data table. Click to the right to select the I-Data track where the output measurements are to be recorded.
      ! Any existing data will be overwritten.
      ! If you need to add a new track to the I-Data table, click the rectangular button to access the I-Data Types Table.

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    • P-Data: Click in this radio button if the output data is to be recorded in the P-Data table. Click to the right to select the P-Data track where the output measurements are to be recorded.
      ! Any existing data will be overwritten.
      ! If you need to add a new track to the P-Data table, click the rectangular button to access the P-Data Types Table.

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  • Sample Interval: Click here to type in the depth interval at which to perform resampling. For example, if you enter "1", the Gamma measurements will be translated to Uranium Grade values at 1-foot or meter depth increments.
    ! Note: Saving eGrade data to a new P-Data column assumes that the Sample Interval is the same as the spacing between the original gamma values.
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  • Constants
    • Defined within Locaton Table: Select this option if the constants (Dead-Time, K-Factor, Water-Factor, Casing-Factor) are defined within the Location table.
      ! Note: If you're using the Location table, the fields must already exist, and they must be named DeadTime, KFactor, WaterFactor, CasingFactor. The Display label for the fields can contain spaces, but the field name itself must not.

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    • Defined as Follows: Choose this option to enter the constrants in the prompts. In this case the same constants will be used for all boreholes.

    • The K-Factor can be defined with an unlimited number of decimal places.

  • Dead Time Units: Choose whether they are recorded as seconds, milliseconds, or microseconds by clicking in the appropriate radio button. This will apply to constants defined either in the Location tabs or in the menu, above.
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• Apply to
  • All Boreholes (Enabled and Disabled): Choose this if the calculations are to occur for all boreholes.
  • Only Enabled Holes: Choose this option if the calculations are to occur only in boreholes which are currently enabled.
  • Currently Highlighted Borehole (Single Borehole): Choose this if the program is to perform the computations for a single borehole. The currently-selected borehole is displayed here, click another from the list to change the active hole.
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Step-by-Step Summary

1. Access the RockWorks Borehole Manager program tab.
2. Verify that you have your Gamma data entered for one or more wells, in a P-Data track.
3. Create, if necessary, a column in the I-Data table or P-Data table where the Uranium Grade computations will be stored. If there is any existing data in this column, it will be overwritten. See Defining the I-Data Columns or Defining the P-Data Columns for more information.
4. Select the Borehole Operations | P-Data | CPS - eU308 - I-Data menu option.
5. Enter the requested program settings, described above.
6. Click the Continue button to proceed.

   RockWorks will read the contents of the input Gamma (P-Data) Track and perform the following computations, recording the output in the indicated I-Data or P-Data column.

   For each depth increment (as defined by the original sampling interval):

   If the dead-time input units are set to micro or milli-seconds the dead-time is converted to seconds.

   The "deadtime_adjusted_counts" are computed by the following equation:

   deadtime_adjusted_counts = raw_counts / abs ( 1 - ( raw_counts * deadtime ) )

   Finally, the uranium grade is computed by the next equation (a variation of the 2KN equation):

   uranium_grade = deadtime_adjusted_counts * k_factor * water_factor * casing_factor * ( 1 / interval_thickness )

   Next, the data is resampled (via a spline algorithm) at intervals equal to the specified "Sample Interval". If not for this resampling procedure, the interval_thickness value within the preceding equation would be invalid (i.e. the interval thickness would be greater than the distance between the original points).

   This approach assumes that the original raw-count data was sampled at regular intervals (i.e. via a wireline tool that sampled at a constant rate).

You can now display the Uranium grade as an I-Data bargraph or a P-Data curve on striplogs, and use the I-Data or P-Data tools to interpolate solid models of the grade data.

See also

• Adding this program to your Playlist
• Adding this program to your Favorites
• Save/load/view menu settings
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Back to P-Data Menu Summary

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