GO/NO GO Free Fluid Test after Conditioning in HPHT Consistometer

The free fluid test described in API RP 10B-2 is modified slightly to provide a test which determines free fluid content under closely simulated job conditions. The modified test is performed according to the following procedure:

  1. Prepare the slurry according to Section 6.A.1 Thickening Time.
  2. In a pressurized consistometer, stir the slurry at atmospheric pressure for a time period equivalent to the batch-mix time or to the average time that the slurry is held in a tank during the pumping operation. Maintain the slurry temperature at the average slurry temperature anticipated at surface during the job. Within 5 minutes of mixing the sample, begin the acquisition program on the consistometer.
  3. Ramp up the temperature and pressure to BHCT and BHP over a 60 min interval. Alternatively, this ramp time can be adjusted to meet job-specific placement requirements. Allow the slurry to stabilize and condition at BHCT and BHP with constant motor speed (150 +/- 15 rpm) and 30 min.
  4. After the 30 min conditioning period, the motor is stopped for 20 min.
  5. After 20 min, the motor is re-initiated. A consistency reading less than 20 BC higher than the pre- shutdown reading is typically acceptable. A consistency reading more than 30 BC higher than the pre-shutdown reading indicated the possibility of settling or significant gelation.
  6. After 10 min, the motor is shutdown. Keeping the motor off, the slurry is cooled down to 190 degFas soon as possible and removed from the cell.
  7. The slurry is removed from the consistometer cup, careful to blot any excess oil in contact with diaphragm/slurry.
  8. A density trend is measured from slurry in top third, middle third, and bottom third of cylinder.
  9. The standard paddle is removed from the cylinder, with careful observation of potential settling/gelation behavior on the bottom portion of the paddle. The density trend and settling observations are annotated on the reporting sheet.
  10. The slurry is vigorously stirred with a spatula to re-homogenize the slurry before the free fluid test.
  11. After stirring, the remaining slurry is poured into 250-mL graduated cylinder up to 250-mL mark. Dimensions of cylinder should meet API RP10B-2 specifications.
  12. Incline the cylinder at 45 deg angle and allow the cylinder to sit under ambient PVT conditions for 2 hours, as per API RP 10B-2.
  13. Measure the supernatant fluid which exists at the top of the graduated cylinder after the slurry stands quiescent for two hours. This volume equals the free fluid content. Free fluid calculations follow API RP 10B-2 guidelines.
  14. Check the cylinder for signs of sedimentation.

Things to Report:

  1. GO/NO GO BC reading before and after 20 min shutoff
  2. Slurry density from top third, middle third, and bottom third of cylinder.
  3. Sedimentation observed on bottom of paddle and approximate height.
  4. Supernatant fluid collected on top of 250-mL cylinder after 2-hr API free fluid test.
  5. % free fluid as calculated using API RP 10B-2.