Production Data Analysis in a Gas-Condensate Field: Methodology, Challenges and Uncertainties

Production data analysis techniques have been widely used for estimating reservoir properties such as gas in place and average pressure. Knowledge of this information is crucial for proper reservoir management. The present study discusses the roadmap, challenges and uncertainties for analyzing production data in an Iranian gas-condensate offshore field.
This work is an integrated study involving the quality check of production data, platform process simulation, orifice simulation, modeling choke performance, well modeling, and Rate Transient Analysis (RTA). The study is an inverse analysis which starts from production platform and continues down to the reservoir. To perform data analysis, we propose five general steps which are: Data gathering/extraction/quality check, well rate determination, well bottom hole pressure estimation, layer rate allocation, and reservoir property estimation. In this study, these steps are discussed elaborately. Furthermore, challenges of each step are presented and discussed. In addition, the required input and also missing data for each step is mentioned. Also, to cope with lack and/or uncertainties of data, feasible solutions are proposed for the current field situation as well as future developments. This paper can help petroleum engineers to know where to start and how to proceed to get to the final step of the analysis, i.e. estimating field gas in place. It also provides insights into challenges and uncertainties of the production analysis in gas-condensate.