NSO-A Field Revaluation Using IPM Suites: A Case Study of Mature Production Data History Match

摘要

The NSO-A Gas Field is a large gas field located in Aceh, Indonesia that has been producing since July 1999 and still continue producing gas with field depletion not as rapid as predicted, it was known that reservoir pressure measurements indicated the field was not depleting as rapidly as expected and wells were maintaining their plateau rates longer than earlier models, so that it necessary to re-evaluate the availability of oil and gas reserves contained in the NSO-A field structure. Previous studies were revisited, it is stated that geomechanical testing of Malacca limestone cores indicate that the rock has high compressibility and suffers elastic and significant plastic deformation when mechanical stresses are increased. This paper adopted the previous study and add updated mature production data to be used in material balance history match with field production to evaluate fluid initial in place estimation. This methodology uses the combination between GAP (Network Modelling Tool), MBAL (Material Balance Tool), and PROSPER (Well Modelling Tool) which gives satisfaction result in OGIP, Aquifer Size, and Controlling mechanism determination while using limited static data in the early production period. Without proper calibration, this models could lead to misleading of in-place estimation. The combination of these modelling tool has proved to be very reliable and has resulted in better reservoir evaluation. This approach requires the accuracy of of individual well testing and production history data in order to be reliable an accurate. The model shows a bigger OGIP to be around 3 TCF (11% higher than volumetric) with 220000 RB/PSI/DAY aquifer influx. Material balance model were very useful to giveses a credence that possibly aside from rock compaction mechanism, active aquifer influx as an other major drive mechanism that is essential to match with the field performance history. This paper should help the engineers step by step to perform reservoir evaluation using limited static pressure data availability, but still able to give a reliable result to achieve history matched for in-place volume estimation and well performance prediction.