2. Conditions and limits

In practice SNP works well depending on a number of geological factors. Firstly a binary-impedance model is assumed that expects sands to have one impedance and shales another. The geological environment should be relatively simple, e.g. complex geology should not represent in the reservoir. Also it assumes no interferences between the reservoir and events below or above. Picking the zero-crossings should be clear because calculation of average band-limited impedance is very sensitive to picking accuracy. A maximum pay thickness of the reservoir is applied as a limit, and detuning the average amplitudes is based on the 100% net-to-gross response to ensure the proportional relationship between net-to-gross and average band-limited impedance.