InterPore2026

Lab Evaluation of Long-Distance Propagation of CO2 Foam for Deep Mobility Control

22 May 2026, 11:50

15m

Oral Presentation (MS01) Porous Media for a Green World: Energy & Climate MS01

Speaker

William Rossen (Delft University of Technology)

Description

Foam is a valuable tool for maximizing CO2 sweep in subsurface applications. Maximizing sweep increases capillary and solution trapping of CO2 in carbon sequestration and maximizes oil recovery in combined sequestration/enhanced oil recovery applications (Rossen et al., 2024), which improves the economics of the sequestration process. Long-distance CO2-foam propagation is essential for maximizing CO2 sweep. Long-distance propagation is challenging at the low velocities and low pressure gradients deep in a reservoir (Ashoori et al., 2012). We apply a multi-diameter coreflood method (left figure) to evaluate long-distance foam propagation. This technique allows determination of critical conditions governing CO2-foam propagation in terms of minimum pressure gradients and velocity thresholds needed for foam generation, mobilization and stability maintenance (Yu et al., 2020). We also quantify the correlations between foam-propagation thresholds and influential factors for prediction of field behavior.
A multi-diameter coreflood approach allows determining the thresholds for foam generation, propagation and stability in place in different steps in the three sections of the core, following a particular injection-velocity sequence (Yu et al., 2020). In an increasing, or decreasing, velocity sequence, the sudden abrupt increase, or drop, in pressure gradient in one of the core sections indicates the critical pressure gradient and velocity required for foam generation, propagation or maintaining stability (right figure).
Foam propagation results from two processes: mobilizing bubbles behind the displacement front and bubble generation at the front, needed to compensate for bubble collapse there (Ashoori et al., 2012). Published data for N2 foam show that long-distance N2-foam propagation at deep reservoir velocity and pressure-gradient conditions is extremely challenging (Yu et al., 2020). This is because the minimum pressure gradient needed for N2 foam mobilization, e.g. 33 bar/m in a 2.5-darcy Bentheimer core (right figure), and higher in lower-permeability formations, is not attainable far from an injection well. We find CO2-foam propagation is much easier. In a 1052-mD core, the minimum pressure gradient needed for CO2 foam generation is only 0.06 bar/m (easily attainable throughout a formation). The minimum for foam propagation is still problematic: 4.1 bar/m.
However, our data show that the minimum pressure gradients required for CO2 foam generation and propagation are strongly affected by surfactant type. A surfactant that reduces CO2-brine surface tension is expected to reduce the critical thresholds needed for foam generation and propagation. This would provide a direction for manipulating CO2 foam generation and mobilization conditions to improve its long-distance propagation deep into reservoirs.
The multi-diameter coreflood approach provides a technique for evaluating field-scale long-distance foam propagation in the lab. This approach can be used to determine the critical velocity and pressure-gradient conditions for foam generation, propagation and stability maintenance. The measured quantitative critical thresholds reduce the uncertainty in the prediction of CO2-foam propagation distance. The finding that a low-tension surfactant reduces the foam-propagation thresholds provides a way for extending CO2-foam propagation for its deep applications in enhanced oil recovery.