0102030405
Liquid Steady-state Permeameter For Core And Cement Testing
Testing Principle
Steady-State Method: Suitable for medium-to-high permeability rock types, such as sandstone and conglomerate, with relatively high permeability. By applying a steady pressure differential across the core, a fluid (liquid or gas) is forced through the core at a steady rate, and permeability is calculated based on Darcy's law.
Pulse Method: Suitable for low-permeability cores, such as shale, mudstone, and tight sandstone. A pressure pulse is momentarily applied to one end of the core, and the pressure decay over time is recorded at both ends. Permeability is calculated from the pressure decay curve, without the need for a steady flow rate.
Testing Process
Steady-State Method
1. Sample Preparation: Select a representative rock sample and process it into a standard plunger shape (or other regular shape). Parameters such as length and diameter are measured, and cross-sectional area is calculated. The sample is cleaned and dried to remove impurities and fluid from the pores. Vacuuming is performed as necessary to ensure unobstructed pores.
2. Connecting the Experimental Apparatus: Load the sample into the core holder and secure it tightly, ensuring that fluid flows only axially through the sample (to avoid side leakage). Connect a displacement system (such as a constant pressure/constant flow pump), pressure sensor, and flow meter to form a closed flow path.
3. Permeability Measurement: Introduce the experimental fluid (such as nitrogen) and adjust the displacement pressure to ensure a steady flow through the sample. After the flow rate and inlet and outlet pressures stabilize, record the inlet and outlet pressures (usually atmospheric), fluid flow rate, and experimental temperature.
4. Calculate the permeability: Using Darcy's law, substitute the measured data for the permeability.
Pulse Method
1. Steady-state Permeameter Sample Preparation: For the steady-state method, the core must be fully saturated with the fluid (usually a liquid such as kerosene).
2. Experimental Apparatus: Connect the core to a reservoir at both ends. One end serves as the pulse port (for rapid pressurization) and the other as the reference port (with a known volume). Seal the system and remove any bubbles.
3. Apply the Pulse: Apply a pressure pulse to the pulse port by rapidly opening a valve (to increase the pressure momentarily). After closing the valve, record the pressure curve at both ends over time (this typically takes several minutes to several days, but may take longer for low-permeability cores).
4. Calculation of permeability The permeability is calculated based on the pressure decay equation (based on diffusion theory) combined with parameters such as core size, fluid viscosity, and reservoir volume.
Equipment composition
(1) Constant flow pump: 1 set,
working pressure 40MPa,
flow rate: 0.01 ~ 10ml / min, flow accuracy 1%;
(2) Intermediate vessel: Volume 500ml,
pressure 42MPa, 316L stainless steel, 2 pieces;
(3) Core holder: 1, can hold core size of Φ 25mm × (25-100) mm, pressure resistance of 42MPa, 316L stainless steel material;
(4) Manual metering pump: 1 set, with pressure of 40MPa; According to Darcy's law, the device can carry out core liquid permeability experiment and displacement experiment
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