The PREL-300 provides a modern instruction focused measuring instrument that allows
the student to go through the experimental process in structured transparent steps.
The student then builds on his basic knowledge of relative permeability and can
extend it to predicting reservoir performance.
Samples are hand loaded and experimental operating conditions are established manually,
thus re-enforcing the previously learned theory. Instructions on the calculation
of unsteady state permeability by the Welge method are included.
is based on Darcy’s law allowing the student to make effective liquid permeability
measurements on core plugs and is designed to allow the establishment of a single
liquid phase in a clean and dried core plug. The relative permeability measurement
typically commences with a base permeability of Ko at Swir, the beginning of the
drainage phase. The displacing fluid (typically a lab brine) is then flowed through
the rock at a known pressure and flow rate.
The experiment is then conducted to
a water cut of 99 percent or some other predetermined endpoint. The effluent is
measured as a function of time, using the provided volumetric flasks and stopwatch.
This allows the effective permeability for each phase to be determined. Once the
effective permeability for each phase has been determined then the relative permeability
at any given water saturation is determined.
The instrument is forgiving in its operation and requires neither mercury nor significantly
elevated confining pressures to operate, enhancing user safety. The dual injection
system allows for the unsteady state displacement of one fluid with another at pressures
up to 1500 psig.