This paper presents the use and value of information obtained from interference testing performed during the early production of Kashagan field. Numerous field examples of the interference and pulse tests are presented along with their implications for improving reservoir characterization and modeling. Design aspects of the conducted tests and an approach to address uncertainties in the pressure data are also described.
A significant amount of important interference data was captured during the start-up and subsequent ramp- up of Kashagan field. This included local well to well interference and pulse testing as well as an extended test that covered a larger area of the field. However, operational activities at observer wells complicated the available data and necessitated application of a pressure correction methodology. This methodology had to account for the inherent uncertainty in the interpretation of the data. Moreover, to increase our confidence in the interpretation, a dedicated pulse test was performed in the specific part of the field. Finally, responses from all observation wells were integrated and analyzed to capture big picture learnings from the early interference testing program.
When results of the interpreted interference response from all observers were combined, several groupings of wells became apparent. This helped to understand the degree of connectivity in various areas of the field. For dynamic model calibration, it was preferable to have a range of interference responses for each well to reflect uncertainty in the data. Therefore, so called "early" and "late" response curves were developed for each well. Overall, the collected and analyzed interference data was very useful in reducing uncertainty during this early period and will be used to optimize reservoir management decisions and future phases of the field development.
Results presented in this paper can be used by practicing engineers as another great example for advocating the use of permanent downhole gauges (PDHGs) and importance of proper planning and execution for the interference and pulse tests.