Some Practical Examples Of Difficult Well Test Problems

Five practical examples of difficult field well test cases are examined. The source of the difficulty ranges from purely non-uniqueness problems in parameter estimation to several grades of severity of anomalous wellbore pressure and temperature behaviors. The examples include both gas and gas-lifted oil wells and demonstrate that regardless of the source(s) of the difficulty, they inevitably lead to a wrong or an extraneous solution. The examples show that non-uniqueness prone data lack clearly defined infinite acting radial flow segment on the log-log derivative profile, and that anomalous pressure responses inherently exhibits equally puzzling temperature profiles.