Production Performance of a Retrograde Gas Reservoir: A Case Study of the Arun Field

The Arun field is one of the world`s giant retrograde gas reservoirs. Approximately 10 years after production began, a significant loss in well productivity occurred in some of the wells. The study shows that this productivity loss was due to near wellbore condensate accumulation, and documents its effects on production and pressure transient response. A radial, single well, compositional model was used to study this effect and confirm that the productivity loss was due to liquid accumulation. The model was also used to predict the future performance of the well. The model matches well production data and the pressure transient response of affected wells. This work identifies near wellbore condensate accumulation as an extremely important factor to consider when predicting future well performance as some of the productivities are reduced by 50%. The work also details how production data and well test analysis can be used to quantify the effects of near wellbore condensate accumulation on well productivity.