SPE Thailand Monthly Technical Meeting – November 2024 : A Tale of 3 DSTs: Evolution of strategies

Abstract:

This presentation covers story of 3 DSTs (Drill-Stem-Tests) that were conducted from different wells in the same carbonate reservoir. The first DST was carried out in 2019 in the discovery well. This was followed by two more wells in 2021 and 2024 with the aim to adequately characterize the reservoir before proceeding to development. This aims to cover the unique challenges faced with both DST operation and PTA (pressure transient analysis) interpretation, and how the techniques and strategies of DSTs were refined to reasonably characterize this carbonate reservoir. In the discovery well 2019, operational problems resulted in suboptimal DST acquisition and PTA data were uninterpretable. Extensive root cause analysis followed, and possible areas of improvement (both operational and acquisition strategy) were identified. In the 2nd DST conducted in 2021, the data quality was improved, but the interpretation was still a challenge as the well never came out of spherical flow regime. Interpretation could still be carried out to make development decisions. In the 3rd DST performed in 2024, a different zone was tested where the refined strategy provides a very good quality data. New interpretation challenges were observed requiring unconventional approach to obtain the most benefit out of these data.