Wellbore-reservoir coupled simulation study for CO₂ flooding in oil reservoirs
Abstract
CO₂ flooding can simultaneously enhance oil recovery and enable geological carbon storage. This study develops a tNavigator-based coupled wellbore-reservoir CO₂ flooding model to examine tubing-head-to-downhole pressure conversion and early gas breakthrough through a high-permeability channel. A three-dimensional isothermal compositional model represents reservoir flow, while vertical flow performance (VFP) tables constructed using the Beggs-Brill correlation describe wellbore multiphase flow and pressure conversion. The coupled VFP relationships, well flow equations, and reservoir mass-conservation equations are solved using the adaptive implicit method (AIM) implemented in tNavigator, enabling bidirectional interactions among wellbore pressure variation, downhole boundary conditions, and reservoir dynamic parameters. A continuous high-permeability channel between injectors and producers is incorporated to characterize reservoir heterogeneity. Simulations under fixed injection rate and fixed tubing-head pressure conditions are conducted to analyze the influences of injection and production rates, porosity and streak permeability on CO₂ migration and flooding performance. The results show that injection and liquid production rates dominate the inter-well pressure difference and control gas breakthrough. Reservoir porosity primarily governs reservoir storage and pressure buffering capacity, while streak permeability determines CO₂ preferential migration velocity. Under tubing-head pressure constraints, actual injection and production performances are co-regulated by tubing-head pressure limits, wellbore pressure loss and reservoir injectivity/deliverability. The proposed model provides a numerical framework for investigating wellbore-reservoir interactions and gas-channeling risks in heterogeneous reservoirs with high-permeability channels. Quantitative validation against field measurements or controlled experimental data will be undertaken in future work.
Copyright (c) 2026 Bujie Ding, Huanying Ma, Jincang Li, Kaifang Jin, Tao Zou, Hui Zhao, Jiaxu Liu, Siyuan Chen, Xi Ouyang, Xiang Rao

This work is licensed under a Creative Commons Attribution 4.0 International License.
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