Chandler Engineering AMETEK 7200, Инструкция по эксплуатации

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2-16 SECTION 2 – OPERATING INSTRUCTIONS
while at a test temperature of 150°C, this final pressure would be approximately 73 psi (0.5
MPa, 500 kPa, 5 bar, 4.9 atm.).
1. The CHA vessel is filled with the cement slurry sample and placed in the oven.
2. H
2
O confining pressure is applied to the slurry until thermal equilibrium is reached
between the slurry and the oven.
3. The CHA vessel is closed by closing the H
2
O Confining Valve with the Gas
Injection Valve closed.
4. The cement temperature reaches a constant temperature before increasing, reaches a
maximum, and finally decreases to approach the oven temperature.
Cell Open (Constant H
2
O Confining Pressure) Until Gas Injection
This procedure involves setting the gas injection pressure lower than the H
2
O Confining
Pressure (at 250 psi and 300 psi, respectively).
1. Fill the vessel with the cement slurry and pressurize with the H
2
O Confining Pressure
(300 psi) and preset the Gas Injection Pressure (250 psi). The Gas Injection valve is
not opened now.
2. Allow the cement slurry temperature to reach the oven temperature.
3. Once the pore pressure above the sample reaches the preset Gas Injection Pressure
(250 psi), close the H
2
O Confining valve and open the Gas Injection valve to allow
the gas to enter the cell throughout the remainder of the test. The open Gas Injection
valve allows gas to enter at the preset gas injection pressure.
4. The amount of gas which enters the cell (as measured by the N
2
Flow Rate meter) is
used to estimate the total shrinkage and will assist with determining if gas migration
is occurring.
The CHA-Control software can be set to automatically open and close these valves as
described, at whatever value of Minimum Pore Pressure you enter.
Stop the test after the cement completes its hydration, as monitored by the Cement
Temperature decreasing and approaching the Oven Temperature.
Interpretation of Results
After gas injection starts, if the pore pressure increases (especially if it becomes equal to the
gas injection pressure), then gas migration has occurred.
If the pore pressure continues to decrease (especially if it approaches 0 psig), then no gas
migration has occurred.
The flow rates can be used as raw data used to make an approximate calculation of the
shrinkage or expansion of the cement, and of the volume of gas which entered the sample.
See Figure 11 and Figure 12 below for examples.