The core flow tester is a core equipment used in petroleum exploration and development to simulate formation conditions, analyze rock permeability and fluid flow characteristics. Its working principle is based on Darcy's law, which states that the flow velocity of fluid in porous media is proportional to the pressure gradient and inversely proportional to the fluid viscosity. During the experiment, fluids (such as oil, water, or chemical oil displacement agents) are injected into the core holder at a constant pressure or flow rate. By measuring the pressure difference between the inlet and outlet of the core, fluid flow rate, and time parameters, combined with the geometric dimensions (length, diameter) and porosity of the core, absolute permeability, relative permeability, and reservoir sensitivity indicators can be calculated. For example, in the permeability measurement experiment, the system collects real-time pressure difference and flow data through high-precision pressure sensors and electronic scales, and generates permeability curves through software processing, with an error controlled within ± 3%.

The core system components include:

Injection system: composed of a horizontal flow pump, an intermediate container, and pipe valves, responsible for accurately injecting fluid into the core at a flow rate of 0.01-10mL/min, ensuring flow stability (repeatability accuracy ± 1%).

Simulation system: including core clamp (pressure resistance of 50MPa, temperature resistance of 180 ℃), constant temperature box (temperature control accuracy of ± 1 ℃), ring pressure pump and back pressure system, simulating formation confining pressure, temperature and fluid flow state.

Measurement system: using a pressure transmitter with 0.1% F · S accuracy, pt100 temperature probe, and electronic balance (accuracy 0.01g), real-time measurement of pressure, temperature, and flow parameters.

Data acquisition and processing system: Through data acquisition cards, industrial computers, and specialized software, parameters are synchronously collected and raw data reports, analysis curves, and database files are automatically generated. It supports Darcy's law calculation, permeability curve fitting, and reservoir sensitivity evaluation.