To operate this or any other unit, manufacturer’s instructions should be carefully read before attempting to perform testing. Extreme caution should be used in running this test. Equipment should be cleaned and maintained in good working condition (Figure5).
Figure 3
Low-Temperature/Low-Pressure Filtration Apparatus
Figure 4 Bleeder Valve
Step 1. Plug heating jacket cord into correct voltage for the unit.
Step 2. Place metal thermometer in hole on outside from of heating jacket. Adjust thermostat and preheat jacket to 10×F above desired test temperature.
Step 3. While jacket is heating, check o-rings (3) on the following components and replace if worn or distorted:
• High-Pressure Regulator
• Lid/Valve
• Cell Body
(See Figures 6, 7 and 8 for details.)
Step 4. Stir mud sample 10 minutes with a high-speed mixer.
Step 5. Close valve A by turning black knob clockwise.
Step 6. Turn handle counterclockwise on high pressure regulator, then load CO2 cartridge into cham-ber (Figure6).
Step 7. Close valve B and pour stirred mud sample into cell, leaving 1/2 in. from the top lip to allow for expansion. Position o-ring in groove inside cell body. Place filter paper on top of o-ring (Figure7).
Figure 5 HTHP Filtration Unit
Step 8. Open valve C and seat lid/valve assembly. Lubricate threads of allen screws with silicone grease and tighten (Figure8).
Step 9. Close low-pressure shut-off valve.
Figure 6
Two Types of Puncture Pin Assemblies
Figure 7 Assembly of Cell Body
Step 10. Invert cell. (The lid/valve assembly is now at the bottom.) Carefully, install cell assembly into heating jacket.
Caution: The Heating Jacket is hot!
Transfer thermometer from the jacket to the thermometer well located on top of HTHP cell body (Figure9).
Step 11. Slip high-pressure regulator (0-1500 psi) onto top of valve B and lock into place with steel ring.
Step 12. Slip low-pressure regulator (0-200 psi) on bottom of valve C. Lock into place with steel ring.
Be sure bleeder valve on low-pressure regulator is in the horizontal (closed) position.
Step 13. With valves B and C closed, apply 100 psi to both the high-pressure regulator and the low-pressure regulator by turning regulator handles clockwise.
Step 14. Open valve B. This is done to maintain 100 psi back pressure in the cell body while heating to the desired temperature. Heating time should not exceed 1 hour (Figure10).
Figure 8 Assembled Cell Body
Step 15. When desired temperature is reached, increase pressure on high-pressure regulator to 600 psi by turning regulator handle clockwise.
Step 16. Open valve C. Start timer immediately at this point! Collect filtrate for 30 minutes, maintaining test temperature within ±5×F (Figure11).
Step 17. At the end of 30 minutes close valve. Carefully open valve D and collect filtrate. Leave valve open until low-pressure gauge reads 0 psi.
Step 18. Note the total volume of filtrate, test temperature and pressure, and cell heat-up time.
Because most HTHP filter presses have a filter area of 3.5 in.2, the filtrate volume collected must be doubled to correct to API standard 7.1 in.2 Calculate and record the API HTHP fil-trate as follows:
Figure 9
Cell Body Into Heating Jacket
Note:If pressure on low-pressure regulator rises above 100 psi during the test, cautiously reduce pressure by drawing off a portion of filtrate using valve D located on bottom of filtrate collec-tion chamber.
API HTHP Filtrate = 2 cm( 3 filtrate collected)
Figure 10
Valve Positions During Heat-Up
Figure 11
Valve Positions During Filtration
Step 19. Unplug unit and allow cell and contents to cool to room temperature before proceeding to dis-assembly procedure.
Step 20. After HTHP cell assembly and contents are cooled to room temperature, proceed with disas-sembly and cleaning procedure. Valves B and C should already be in the closed positions (Figure12).
Step 21. To bleed pressure from the high-pressure (top) regulator, be sure valve B is closed. Turn reg-ulator handle clockwise and carefully open valve A. Bleed pressure until CO2 cartridge is expended and high-pressure gauge reads 0 psi (Figure13).
Step 22. To bleed pressure from the low-pressure (bottom) regulator, be sure that valve C is closed.
Turn regulator handle clockwise and carefully open valve D. Bleed pressure until CO2 car-tridge is expended and low-pressure gauge reads 0 psi (Figure14). The pressure on the high-pressure gauge and the low-pressure gauge should now read 0 psi. If not, carefully bleed pressure until both gauges read 0 psi, then remove regulators.
Step 23. Remove cell from heating jacket and place in sink. Carefully open valve C and bleed pres-sure trapped in the cell. Now, open valve B. All prespres-sure should now be released (Figure14).
Note:CAUTION - Throughout the disassembly procedure, always assume there could be trapped high pressure in the HTHP unit.
Figure 12
Valve Positions at End of Test
Figure 13
Valve Positions to Bleed Pressure
Figure 14
Removing Top and Bottom Pressure Regulators after Bleed Down
Step 24. Remove Allen screws, being careful to point the top assembly away from your body in case any pressure may be trapped (Figure15).
Step 25. Open cell and carefully remove filter paper and cake from screen, being careful not to disturb the filter cake. Wash excess mud from cake with a small, gentle stream of water.
Step 26. Measure and report thickness of filter cake to nearest 1/32 of an inch. Describe condition of the cake.
Step 27. Discard the mud. Clean the cell. Cleaning includes removal of valves B and C to prevent mud from drying in the cell assembly, which could cause valves to plug in future tests.
Figure 15 Opening the Cell Body
Note:If Allen Screws are tight, DO NOT attempt to remove them because the cell may contain trapped pressure! This requires special procedures to unplug valves C and B.