Automatic Laboratory Porosity Meter for Core Testing
Primary Purpose
Measuring Porosity
The main goal is to calculate the effective porosity, which is the volume of the interconnected pores that can contain and transmit fluids (like oil, gas, or water). This is different from total porosity, which includes isolated pores.
The formula for porosity (φ) is:
φ = (Pore Volume / Bulk Volume) × 100%
The instrument provides a highly accurate measurement of the pore volume , which is used in this calculation.
Technical Parameters
Item: Automatic porosity meter for core testing
Power Supply: 50Hz, AC 220v
Power Supply: 50Hz, AC 220v
Testing Range: ≥1%
Working Pressure: 0.02-0.5 MPa
Working Temperature: Room Temperature
Test gas: Helium
Core Size: Maximum diameter 1 inch, maximum length 2.5 inches
Pressure Sensor Accuracy: 0.1% FS (Full Scale)
Testing Range: ≥1%
Why Helium Gas
Helium is the ideal gas for this measurement due to its unique properties:
Small Molecular Size: Helium atoms are tiny and can penetrate even very minute micropores that other gases or liquids cannot access.
Inert Nature: Helium is non-reactive and won't adsorb onto the rock surface or react with the sample, which could alter the measurement.
Ideal Gas Behavior:
It behaves very closely to an ideal gas across a wide range of temperatures and pressures, making the calculations based on gas laws (like Boyle's Law) extremely accurate.
Frequently Asked Questions (FAQ)
Q1: What is the primary measurement principle of this Manual Core Porosity Meter?
A: The instrument operates on Boyle’s Law Gas Expansion (Helium / Nitrogen Isothermal Expansion):
Gas Injection: Helium gas is injected into a reference cell of precisely calibrated volume, then expanded into the core sample chamber (matrix cup).
Non-Destructive: Helium molecules penetrate the finest pore throats without damaging or altering the delicate rock matrix, providing a 100% non-destructive measurement.
Q2: Why choose a Manual Porosity Meter over an Automatic system?
A:Superior Cost-Efficiency: Provides high-precision research-grade data at a fraction of the cost of fully automated systems.
Low Maintenance & High Reliability: Uses robust manual needle/ball valves and simplified pneumatic lines, eliminating electronic solenoid valve failures and complex motor-driven maintenance.
Ideal for Field Labs & Teaching: Perfect for mobile field laboratories, remote well site units, and university/training labs where straightforward mechanical operation and high durability are required.
Q3: How do operators prevent leakages and ensure data accuracy during manual operation?
A:Zero-Leakage Valve System: Equipped with industrial-grade, low-dead-volume micro-metering valves and high-seal O-ring assemblies designed specifically for helium gas confinement.
High-Precision Transducers: Integrated temperature-compensated digital pressure transducers ensure stable readings down to ±0.05\%$Full Scale (F.S.).
Visual Equilibrium Monitoring: Operators can easily verify pressure stabilization on the digital display before recording values, eliminating operator-induced premature reading errors.
Q4: What core sample sizes and shapes can be tested?
A: The system includes a modular matrix cup assembly with precision stainless steel volume-reduction inserts to support standard and customized samples:
Plug Diameters: Standard 1" (25.4 mm) and 1.5" (38.1 mm) core plugs.
Sample Lengths: Accommodates core lengths up to 3" (76.2 mm).
Irregular Samples: Can also test drill cuttings or irregular core fragments using dedicated small-volume matrix cup inserts and calibration billets.
Q5: What is the measurement range, precision, and testing speed?
A:Porosity Range: 0.1% to 50%+, capable of testing tight sandstones, carbonates, and unconventional shales.
Volume Accuracy: ≤ 0.1% of measured volume.
Repeatability: Better than ±0.05\% across successive test runs.
Testing Time: Approximately 2 to 4 minutes per sample, depending on sample permeability and pressure equilibrium time.
Q6: How are bulk volume and final porosity values calculated?
A:Grain Volume (Vg): Calculated directly from pressure readings using Boyle's Law equation during gas expansion.
Bulk Volume (Vb): Determined via precise digital caliper measurement, mercury immersion, or liquid displacement.
Data Calculation Software / Spreadsheet: We provide an automated Excel calculation template and desktop software. Simply input the pressure readings and sample dimensions to instantly derive Pore Volume (Vp) and Effective Porosity (hi).
Q7: Which international testing standards does this instrument comply with?
A: The equipment fully conforms to core petrophysical testing standards recognized worldwide:
API RP 40: Recommended Practices for Core Analysis (American Petroleum Institute).
ASTM D4404: Standard Test Method for Determination of Pore Volume and Pore Volume Distribution.
SY/T 5336: Practices for Core Analysis in Petroleum and Natural Gas Industries.
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