Driving Tangguh’s First Turbidite Reservoir Development Through New Well Data Integration

Abstract

The Tangguh JV has been producing gas from Bintuni Bay since 2009 from Jurassic Marginal Marine reservoir. The secondary reservoir in Tangguh is the Paleocene Deepwater Turbidite mainly present in Wiriagar Deep (WD) field. This reservoir has been extensively studied but due its complexity and poorer quality compared to the Jurassic, development of this reservoir was not prioritized at first. Poor seismic quality due to karstified overburden made it difficult to image. Evaluation is heavily derived by geology data resulted in robust subregional understanding. The WD Paleocene field consists of four zones, each zone has different Architectural Elements and characteristics including its reservoir quality (Mardani & Butterworth, 2016). It represents classic deepwater turbidite basin evolution, where at the bottom it has deepwater lobes reservoir, then evolves to slope channels overlying it. And lastly covered by shelf and clinoform channel at the top. Slope channel interval is the main development target in the Paleocene reservoir. To inform the best development scenario the subregional understanding needs to be improved. Five development wells targeting Jurassic reservoir closely spaced to each other were drilled in offshore part WD field during 2019-2020. It gave important data for appraising the Paleocene reservoir. Detailed Reservoir Depositional Environment (RDE) map were generated to give guidance in placing the future wells. This RDE map shows where is the on axis, off axis and margin of the slope channel. Integrating subregional understanding with evaluation of this latest data, continued with cellular reservoir model building, and finalized with reservoir simulation, informing the optimum development scenario for the first turbidite reservoir development in Tangguh. Two wells will be drilled in 2022 as part of this program. This development will be a steppingstone to evaluate reservoir performance before expanding the development to onshore and unlock the WD Paleocene field’s full potential.