Large-diameter, long-interval tubing conveyed perforation (TCP) operations are an important part of modern deepwater completion design. Safe and cost-effective designs require an understanding of the interdependence between a large set of static and dynamic parameters that characterize the downhole processes affecting a complex well completion. Typically, it is impractical to measure such parameters in a downhole environment. For this reason, physics-based modeling and numerical simulation of transient processes such as static/dynamic underbalance, perforation cleanup, and shock loading are a critical component of the design process. A significant challenge is that these downhole processes are typically modeled with a dynamically coupled system that includes the reservoir, wellbore, perforation tunnel, tool string and fractures, leading to long simulation times. This is not desirable due to the fact that a single design must satisfy constraints over a large design parameter space, and therefore requires many simulations. This paper introduces a fast computational tool based on dominant flow physics of the perforating process. The new model is benchmarked and verified against current industry-standard dynamic simulators, as well as computational fluid dynamic (CFD) packages. The novelty of this approach is based on physics at the right scale, resulting in a computational efficiency improvement and simulation times at least an order of magnitude less than other industry-standard simulators. Results for numerical examples representing downhole perforating scenarios provide unique insight into underbalance (i.e., using pressure transients), and subsequent cleanup mechanisms. In this study, a new fast computational model of the perforation process has been developed based on dominant physics. The benefits of this novel approach include design parameters that are closely tied to the flow physics, and simulation results that are easily interpreted for enhanced perforating job design. Ultimately, these benefits enable the completion engineer to make more informed and faster decisions during the design of a perforating job.
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