Advancing Reservoir Simulation: Reservoir-Wellhead Coupling in an Innovative Simulator Based on a Plugin Architecture

Resumo

This paper presents an implicit reservoir-wellhead coupling methodology using vertical lift performance (VLP) tables in the GSIM simulator, developed through a Petrobras-PUC-Rio R\&D partnership. Addressing critical production system pressure drops affecting hydrocarbon recovery, it is a first step in implementing integrated reservoir-surface simulation. By extending GSIM's plugin architecture, the work focused on the residual and Jacobian matrix terms in Newtonian iterations, making use of Inflow Performance Relationships (IPR) and Tubing Performance Relationships (TPR) for nodal analysis. The methodology introduces multidimensional VLP table interpolation validated against CMG's IMEX simulator. Single-layer cases showed excellent agreement with IMEX, while multilayer configurations exhibited small transient discrepancies resolving over time, confirming GSIM's system replication capability. The implementation enables accurate wellhead specifications while preserving GSIM's plugin-based flexibility. This advancement provides a robust open-source platform for integrated reservoir-to-surface modeling, enhancing production system simulation accuracy and demonstrates how explicit tubing pressure loss consideration improves forecasting reliability in field development.