Calculated recovery of mineralization values of oil and gas bearing reservoir water in their mixtures with drilling mud filtrates

Abstract

During drilling of wells using water-based drilling fluids, the filtrate can penetrate the aquifer and distorts the chemical composition and mineralization of reservoir water. Water mineralization of oil and gas bearing reservoir is used in the Archie-Dakhnov equation to calculate the oil and gas saturation coefficient. As a result, any distortion in mineralization values leads to inaccuracies in the saturation coefficient and the estimated volume of hydrocarbon reserves.

The aim of this study is to develop a methodological approach that employs genetic coefficients of water to restore the mineralization of reservoir water mixed with drilling fluid filtrates when information about the drilling fluids is available. The initial data is the chemical composition and mineralization of waters from reservoirs accessed by exploration wells. The authors of this paper applied data on chemical composition and mineralization of filtrates from drilling mud used to penetrate the aquifers. For data processing, a methodological approach based on the analysis of changes in the sodium-chloride genetic coefficient was applied to restore formation water mineralization values in their mixtures with drilling fluid filtrates. In conclusion, the authors outlined the sequence of steps for applying this approach and the requirements for the initial data needed.