EOS Model Tuning for Downhole Fluid Contamination Analysis

The patent segments the fluid sampling process into distinct phases: initial contaminated samples followed by cleaner samples after pump-out. It also segments the analysis by creating separate pump-out curves for different fluid properties (density, GOR, resistivity) to independently characterize and correct for contamination effects in each property measurement.

The patent applies preliminary action by collecting and analyzing pump-out curve data during the early contaminated phase to establish baseline contamination characteristics. This preliminary information is then used to correct measurements taken during subsequent cleaner sampling phases, allowing accurate determination of reservoir fluid properties despite initial contamination.

The patent introduces pump-out curves as an intermediary tool that mediates between the contaminated sample measurements and the true reservoir fluid properties. By creating reference curves showing how fluid properties change during the pump-out process, the system can interpolate and correct API gravity measurements to account for drilling fluid contamination effects.

The patent monitors and utilizes changes in multiple fluid parameters (density, gas-to-oil ratio, resistivity) simultaneously during the pump-out process. By tracking how these parameters evolve and diverge at different contamination levels, the system can identify the transition from contaminated to clean samples and correct API gravity measurements based on the observed parameter trajectories.