Water Saturation Sensitivity
Calculates the uncertainty range on Sw. i.e P10,P50 and P90.
Software Platform: Geolog
Developer: Steve Cuddy
Submission Date: 09/29/2015
Calculates the uncertainty range on Sw. i.e P10,P50 and P90.
Software Platform: Geolog
Developer: Steve Cuddy
Submission Date: 09/29/2015
Petrophysical analysis should always be accompanied with uncertainty ranges on the results. The operator needs P10, P50 and P90 HCIIP values in order to place a value a field.
To reduce uncertainty the operator also needs to understand the relative contribution of the matrix parameters, a, m, n and Rw.
This loglan, based on Chen and Fang’s paper provides all these. The method is based on the general formula for error propagation and partial differentiation to calculate the standard deviation in water saturation from which the 80% confidence level (P10 and P90) is derived.
The inputs are m, n, Rw, porosity and Rt and an estimate of their associated uncertainty. P10, P50 and P90 Sw calculated. If these results are used to created P10, P50, P90 Sw vs. Height functions the operator can populate the reservoir model and determine P10, P50, P90 OIIP or GIIP.