Paradigm Shift of the Deep Marine Fan Deposit (Ultra-Tight) Gumai Sand Reservoir’s Development Upon Recently Known Subsurface Heterogeneity and Uncertainty in Tempino Field, Jambi, Indonesia

This study focuses on gaining a deeper understanding of the Gumai sand reservoir in the Tempino Field, which is known for its complexity due to its heterogeneity and low quality properties. The research draws from insights gleaned from the drilling of six recent wells, shedding light on key factors that have a substantial impact on reservoir behavior and development strategies. One of the central findings of this study is the importance of rock typing. Historically, a simplistic single-rock-type model was used in reservoir characterization. However, the research demonstrates that this approach was inadequate in capturing the reservoir's complexity. By utilizing electrical open-hole logs and taking into account limited core analysis data, the study identifies three distinct rock types within the Gumai sand reservoir. This discovery is a significant departure from conventional practices and underscores the necessity of considering heterogeneity when dealing with sand reservoirs. Furthermore, the study delves into fracture pressure measurements and their implications. The discrepancy in fracture pressure data, observed at an equivalent depth of 1100 meters among the latest five wells, is discussed. This discrepancy is closely linked to the behavior of hydrocarbon production. It's a reminder that understanding fracture pressure is critical when evaluating a reservoir's behavior and productivity. One of the noteworthy findings pertains to well T-220, which was positioned at the peak of the Gumai sand reservoir's closure. While based on a study conducted in 2022, it was expected to have the highest oil production rate, the actual results were disappointing. Even after a workover job with remedial cementing, the production behavior remained subpar. This observation highlights the importance of rock typing and how it directly correlates with the reservoir's production behavior. In essence, this research offers a novel and different approach to managing a mature field with diverse, low-quality sand reservoir properties. It challenges the conventional paradigm by advocating for a more nuanced understanding of the heterogeneous sand reservoir. By acknowledging the presence of distinct rock types within the reservoir and accounting for their impact on production behavior, the study paves the way for more effective field development strategies.