Borehole (Downhole or THP) pressure survey based on the pressure response to the periodic flow rate variations (also called "cycles" or "pulses" ).
The usual practise is to create 3 - 5 pulses.
The pressure response is recorded in
- the same well where the flowrate is varying ( and in this case is called Self-Pulse Test)
or
- in the offset well (an in this case is called Pressure Pulse Interference Test)
In case of harmonic pulsations and sufficiently long pressure-rate delay and a simple diffusion model (single-bed homogeneous reservoir without boundary) the test data can be approximated by analytical model: