Contamination estimation of formation samples

Abstract

Contamination estimation of a mud filtrate or reservoir sample requires a robust handle on the properties of mud filtrate at downhole conditions. Coupling acquired data with downhole measured data provides a robust estimation of contamination by encompassing the entire available data. Downhole density of the mud filtrate sample may be estimated based on a characteristic of the mud filtrate sample. A density of a formation fluid of the reservoir may be determined using a formation tester tool. The contamination of the formation fluid may be estimated based on the clean fluid density and the estimated mud filtrate density by, for example, using a material balance equation or ratio. An estimated pump-out time for the formation fluid may be determined based on the estimated contamination and a trend of the estimated contamination of the formation fluid.