Title : An integrated and scalable workflow for evaluating polymer flooding and conformance control strategies in heterogeneous waterflooded reservoirs
Abstract:
Mature waterflooded reservoirs frequently exhibit channeling and preferential flow pathways that reduce sweep efficiency, accelerate water breakthrough, and leave significant volumes of recoverable oil unswept. Although Polymer Flooding and Conformance Control technologies have individually demonstrated their potential to improve recovery, these technologies are commonly evaluated as independent processes, limiting the ability to quantify their combined impact on reservoir performance. As a result, important interactions between flow-diversion and mobility-control mechanisms may not be fully captured during project evaluation and design.
This paper presents an integrated and scalable workflow for evaluating Chemical EOR opportunities in heterogeneous and channelized reservoirs. The proposed methodology combines dynamic reservoir characterization, tracer-assisted connectivity assessment, laboratory-based chemical calibration, reservoir simulation, uncertainty analysis, and optimization within a unified decision-support framework. Designed to support technology screening, development planning, and performance forecasting, the workflow provides a repeatable approach that can be applied across mature waterflooded assets exhibiting significant permeability heterogeneity and thief-zone behavior.
A distinguishing feature of the workflow is the integrated evaluation of Polymer Flooding and Colloidal Dispersion Gel (CDG) technologies within a common simulation framework. Individual Conformance Control and Polymer Flooding scenarios are first evaluated independently and subsequently assessed as a sequential development strategy. This approach enables the quantification of both the individual and combined contributions of flow diversion and mobility control to overall recovery performance. In the integrated strategy, CDG treatments reduce water mobility within thief zones, improve injectant distribution, and create more favorable conditions for subsequent polymer injection, resulting in improved sweep efficiency.
Connectivity uncertainty is explicitly incorporated throughout the evaluation process. Multiple reservoir connectivity scenarios are generated, calibrated to historical production performance, and independently validated using tracer-response data to ensure consistency with injector-producer communication patterns. These alternative reservoir representations are then propagated through forecasting and optimization workflows to quantify their impact on recovery predictions and development decisions.
Results demonstrate that reservoir connectivity remains a significant source of uncertainty in Chemical EOR forecasts. Nevertheless, the integrated CDG-Polymer strategy consistently ranked as the highest-performing development alternative across all evaluated connectivity scenarios. Compared with conventional waterflooding, the combined flow-diversion and mobility-control approach increased cumulative oil production by 3.6–4.0%, while outperforming standalone Conformance Control and standalone Polymer Flooding cases. These results confirm that addressing channeling prior to polymer injection enhances injectant distribution and enables a more effective utilization of polymer-based mobility control. The analysis further indicates that once conformance and mobility-control mechanisms are effectively established, operational management becomes an increasingly important contributor to incremental recovery.
Beyond a specific field application, the proposed workflow establishes a practical and transferable methodology for evaluating Chemical EOR opportunities in heterogeneous reservoirs. By integrating connectivity characterization, chemical-process modeling, uncertainty management, and optimization within a single framework, the methodology supports more informed decision-making and reduces technical risk in the design and assessment of Polymer Flooding and Conformance Control projects.
