BAKER HUGHES - Drilling Fluids Reference Manual

Water Based Drilling Fluids
The instrument is now calibrated and you are ready to proceed with the analysis of your sample.
Calibration Procedure for Orion Model 290A
1. Connect electrode to meter.
2. Press (power) key to turn on meter.
3. Press the (mode) key until the CONC mode indicator is displayed.
4. Place the Fluoride Selective Electrode into the 10 standard.
5. Press (2nd cal). CALIBRATE and the time and date of the last calibration will be
displayed. After a few seconds P1 will be displayed indicating the meter is ready for the
first standard.
6. When the reading is stable use the scroll keys to enter the value of the standard. To enter
a value, press the ∧ or ∨ key. The value will flash. Press the key again and the decimal
point will. flash. Position the decimal then press (yes). {Standard value is 10} Continue
for each digit on the display. There are 4 1/2 digits plus a polarity sign and decimal point.
The display will freeze for three seconds then P2 will be displayed in the lower field.
7. Rinse electrode and place into second standard. When the reading is stable enter the value
of the second standard {100} using the ∧ or ∨ and (yes) keys. The reading will freeze for
three seconds then P3 will be displayed.
8. Press (measure). The electrode slope will be displayed for a few seconds then the meter
will advance to MEASURE mode.
9. Rinse electrode and place into sample. Wait for a stable reading, then record fluoride
concentration directly from the main meter display. Record ALPLEX concentration from
the Fluoride electrode correlation chart.
Sample Preparation for Analysis
1. Place 30 ml of 0.010 M (100 Standard) into a plastic graduated cylinder.
2. Transfer the 30 ml of solution to a plastic beaker.
3. With a plastic pipette, add 0.5 ml of sample (mud filtrate) to the beaker and swirl the
contents to ensure proper mixing.
4. With 3ml pipette or 10cc syringe, add 3 ml of Acetic Acid/Potassium Acetate Buffer to
the beaker.
5. Swirl the solution to ensure proper mixing.
ALLOW THE SOLUTION TO SIT FOR 5 MINUTES PRIOR TO TESTING.
* Repeat steps 1-5 for each sample analysis.
Sample Analysis
1. Rinse the electrode with distilled water between each analysis.
2. Blot probe dry, do not wipe dry.
3. Prepare samples as previously described in “D” above. Place the electrode in the sample
and record sample readings after 1 minute.
4. Check calibration every 4 hours by analyzing the 100 standard.
Reference Manual
Baker Hughes Drilling Fluids
3-92 Revised 2006