A quality control protocol for gas condensate fluid samples

Several quality control (QC) methods have been introduced for gas condensate fluid samples in the literature. However, a comprehensive protocol to check the quality and validity of reservoir fluid samples and their analysis results is absent. This paper introduces a robust protocol which involves diagnostic methods consisting of using appropriate plots to identify outlying data and general trends in different properties, checking stabilization of flowing parameters during conditioning and sampling period, applying suitable criteria for selection of the best gas and oil samples in laboratory, QC of recombination of fluids and composition analysis, evaluating experimental data by material balance, and using appropriate fluid property correlations. This protocol is further applied to the fluid samples taken from a gas condensate field located in the Middle East. This stepwise protocol evaluates the existing data from well conditioning, fluid sampling, recombination and PVT experiments. This careful and thorough examination identifies the representative fluid samples and, moreover, clarifies the flaws of unrepresentative samples. It also helps avoid occurrence of errors in the future fluid sampling and experimental analysis. Such a comprehensive quality control protocol could be utilized extensively in the industry as a part of a fluid characterization project.