A Comprehensive and Systematic Reservoir Performance Prediction Workflow in Tangguh Ubadari Field, Delivering a Confidence in Unlocking Resource Progression and Prediction Forecast

Tangguh Field is located in Bintuni Bay, Papua Barat Province, Indonesia. Tangguh development was commenced following successful exploration program in 1990s. Tangguh has been on production since 2009 through development of 2 LNG trains (Kasim, Titus, Roberts, & Bulling, 2000). Tangguh integrated full field development includes the third LNG train S/U 2023, and development of Ubadari Field and Vorwata EGR/CCUS which Plan of Development (POD) was approved by Government of Indonesia (GoI) in August 2021. Decision to develop Ubadari field is based upon successful drilling of Uba Deep-1 appraisal well in 2018, which supports larger resources in Lower Roabiba reservoir. Ubadari development will be able to mitigate the risk of production shortfall ca 2025 once Tangguh major fields start to decline, as well as to contribute on meeting Indonesia’s growing energy demand. Ubadari development will open opportunity to develop some marginal economic prospects in Western Berau area. The selected development scenario consists of two offshore platforms with five wells, and one export pipeline. Gas from Ubadari Field will be produced directly to Train-3 Onshore Receiving Facilities (ORF) through a new offshore pipeline and tie-in connection to Tangguh fence. To date, there is no production from Ubadari Field, therefore predicting reservoir performance considering subsurface uncertainties is very critical to underpin the development plan. A bp’s proprietary Top Down Reservoir Modelling (TDRMTM) tool-based workflow has been successfully implemented. The workflow considers ranges of reservoir descriptions from limited static data and short Drill Stem Test (DST)/pressure data from exploration/appraisal wells, along with some global analog data, to underpin the evaluation of the system energy, driving mechanism, reservoir connectivity and drainage to predict reservoir performance. The workflow has enabled robust resource progression and development planning, particularly associated with the well count and location, with healthy exploration of subsurface uncertainties.