Abstract

This work presents a methodology to optimize well completions in a complex carbonate oil rim offshore characterized by heterogeneous plays with highly variable oil viscosity under a strong aquifer and overlying a gas condensate reservoir. Maximizing sustainable oil production was the prime objective while minimizing gas condensate production and honoring water production constraints. Integrating multizone electric interval control valves (eICVs) with a continuous choke and dynamic modeling enabled determining optimal well depth, length, and control strategy.

A cloud-enabled, derivative-free optimization utilized to handle simulation-based objective functions required more than 100 independent control variables per trial. Advanced reservoir and well modeling addressed the high viscosity gradient of the fluid, and a robust algorithm was used to traverse the multidimensional solution surface efficiently.

The proposed strategies, which are complex and computationally expensive, provided meaningful insights for future investment and operational decision-making. The cloud infrastructure ran 3,360 processors simultaneously, with each individual simulation requiring 32 parallel processors. The integration of optimization workflows with multiple eICVs providing continuous choking and monitoring capabilities provided the flexibility necessary to address the challenges of this offshore oil rim by integrating different critical objectives into the solution.

The cloud-based derivative-free optimization demonstrates the feasibility of achieving longer (and sustainable) oil production while honoring strict constraints. The requirement to track heavier oil was necessary to minimize unavoidable, but less valuable, gas condensate production. Strategic well and intelligent completion design delivered a 74% reduction in water while extending oil rim production in comparison with an openhole benchmark. The study showed that a horizontal drain and both proactive and reactive water management with flow control strategies are key requirements for sustainable oil rim production in this challenging carbonate reservoir.

Novel insights into optimization strategies with continuous choking eICVs in heterogeneous plays with oil viscosity variation with depth can significantly impact the concept selection phase of field developments. The use of advanced computational resources (cloud computing) and modeling techniques combined with an emphasis on nonintuitive proactive and reactive control provides valuable insight into addressing technical challenges associated with reservoir characteristics and production management throughout the well`s life.