Continuous 1D Capillary Pressure Modelling for Enhanced 3D Saturation Modelling

Reservoir engineers use capillary pressure to compute the original hydrocarbon in place and to estimate the ultimate recovery using fluid flow simulation. Traditionally, capillary pressure data are obtained from the special core analysis (SCAL). SCAL is a time consuming and expensive procedure. As a result: only few measurements of capillary pressure can be done and capillary pressure measurement support size (core plug) is a lot smaller than the modelling support size (simulation cell) where the capillary pressure is intended to be used. Therefore, 3D saturation modelling based on limited SCAL data will generate a 3D saturation model with high uncertainties. In this work, we developed a novel methodology, based on Thomeer formalism and optimization techniques, for 1D capillary pressure estimation using “standard” log data. With this methodology, capillary pressure will cover a larger volume of the reservoir than the volume covered by the SCAL. The scale issue due to the gap between the core plug size and the simulation cell size will be substantially reduced. The estimated capillary pressure, covering wells with log data, can be used to build 3D saturation models with lower uncertainties compared to 3D saturation models based on SCAL measurement only.