A specific implementation of Well Testing based on recording and interpretation of borehole (downhole or THP) pressure response to the pre-designed flow rate variations (also called "cycles" or "pulses" ) at one or more disturbing wells inducing pressure pulse propagation across the field.
The usual practise is to create 3 – 5 pulses.
The pressure response can be recorded in
- the same well where the flowrate is varying (called Self-Pulse Test)
or
- the offset well (called Pressure Pulse Interference Test)
In case of harmonic pressure pulsations and sufficiently long pressure-rate delay and a simple diffusion model (single-bed homogeneous reservoir without boundary) the pressure response can be approximated by analytical model. In this case the pressure data at receiving wells are being detrended and then matched to analytical model.
In case of periodic but non-harmonic pulsations one can use top-hat Fourier filter to decompose the harmonic components from total response and then apply harmonic pulsations interpretation models.
In case of non-periodic pressure pulsations with pressure contamination caused by interference with routine production and maintenance field activity, the complexity of pressure variation at receiving end maybe very high and the concept of "cycles" may not apply at all.
In this case the actual pressure responses should be decoded by specialized algorithms from receiving data records and then matched by diffusion model.
This type of tests is called Pressure Pulse-Code Test but this approach is equally applicable to simple periodic pulsations.