Analysis and Interpretation of Well Test Performance at Arun Field, Indonesia

Abstract

Abstract This paper presents a comprehensive field case history of the analysis and interpretation of all of the available well test data from the giant Arun Gas Field (Sumatra, Indonesia). Arun Field has estimated recoverable reserves on the order of 18–20 TCF and has 110 wells - 78 producers, 11 injectors, 4 observation wells, and 17 abandoned. Approximately 100 well tests have been performed, and the analysis and interpretation of these data suggests strong existence of condensate accumulation near the wellbore as well as a "regional pressure decline" effect caused by competing production wells. We demonstrate and discuss the analysis/interpretation techniques for wells that exhibit condensate banking and non-Darcy flow. We found that the 2-zone radial composite reservoir model is effective for diagnosing the effects of condensate banking at Arun Field. We also demonstrate the development and application of a new solution for the analysis and interpretation for wells that exhibit "well interference" effects. Our new solution treats the "interference effect" as a regional pressure decline and this proposed solution accurately represents the well interference effects observed in many of the well tests obtained at Arun Field. Furthermore, this solution is shown to provide a much better interpretation of well test data from a multiwell reservoir system than the existing approaches-i.e., assumption of no-flow or constant pressure boundaries, data truncation, etc.