Equation comparison for saturation water in carbonate reservoir: Case study Miocene carbonate baturaja reservoir, North West Java Basin

Abstract

There are several mathematical equation for calculate the saturation water in the reservoir. But, the best fit equation for carbonate reservoir is still poor understanding. The change of facies and diagenesis that reflect to its grain size, grain density and pore type will also give effect to water saturation equation.
The reservoir interval of the study is Miocene Carbonate Baturaja, North West Java Basin. The first step of the study is identify the carbobate facies of reservoir, diagenesis and pore type from the petrography, XRD and SEM data then calculate porosity data using well log data. After the facies, diagenesis, pore type and the porosity are identified, the value of m, n and a will be easily calculate for saturation water calculation input. Five equation are used to calculate the saturation water of the reservoir Archie (1985), Simandoux (1963), Indonesia (1971), Waxman-Smith (1968) and Dual Water (1977).
Grainstone, wackstone and packstone are the facies in the reservoir interval. By compare the saturation water equation and validate with saturation water from core data the best fit saturation water equation is Indonesia (1971) equation.