Perforation, fracture fall-off, and formation leak-off tests satisfy ERCB Initial Pressure requirements. These simplified tests, now in common usage, provide an economical alternative to traditional methods. There are several different scenarios, depending on your completion operation logistics. One method is basically over-balanced perforating and monitoring the subsequent pressure fall-off feed into the reservoir. Another is to land a horizontal multi-stage frac’ string, open the toe hydro-port, and monitor the pressure fall-off feed into the reservoir. A third method is to complete the multi-stage fracture treatment, clean-up some, land recorders and pump, then monitor the pressure fall-off for a few weeks before starting the pump – then pulling recorders during the first pump change.
All of these tests are analyzed using impulse or closed-chamber theory to generate a p*. The fall-off does not have to pass the 2 kPa Rule, nor does the well have to be shut-in >14 days. Subsurface pressure measurements are required, with a minimum 8 h of data. The Board will accept PAS files flagged as analyzed with an input extrapolated reservoir pressure (p*):
~TEST DATA,INTRP.,Y,Test Interpretation Present
~PRESSURE RESULTS – SUMMARY,PEXTR.KPAA,9558.00,Representative Extrap/ False Pressure
What’s not specifically clear in G40 is that Pressure Transient Analysis (PTA) is acceptable for estimating Initial Pressure Oil and Initial Pressure Gas conditions. Please give us a call to discuss tactics specific to your completion operations.