Quantitative Characterization of Foam Transient Structure in Porous Media and Analysis of Its Flow Behavior Based on Fractal Theory

Abstract

Foam fluid is widely used in petroleum industry, so the behavior of the foam fluid flow in porous media directly affects the application effect of foam. However, the foam flow pattern in porous media is difficult to be established because of its dynamic change of interface structure and unpredictable boundary condition. In this work, the transient structural changes of the foam fluid in porous media are quantitatively characterized, and the flow behavior is analyzed based on fractal theory and visual experiments. First, the foam fractal characteristics are verified, and the fractal dimension is calculated. Results show that the foam fractal dimension is between 1.5 and 2.0, and the foam flow can be divided into three stages: gas–liquid two-phase flow, foam unstable flow stage, and foam stable flow stage. In addition, the evaluation indices of foam performance in porous media are proposed to evaluate the influencing factors, namely, the fractal dimension in stable stage D foam‑s and the time needed to reach stability T s. The analysis shows that the larger concentration of the surfactant and the lower permeability correspond to smaller D foam‑s and the larger temperature corresponds to larger D foam‑s, and D foam‑s of the nitrogen foam is smaller than that of the carbon dioxide foam. T s is the opposite. Last, the relationship between fractal dimension, pressure, and gas saturation is discussed. Qualitative analysis shows that the larger the displacement pressure, the smaller the foam fractal dimension and the higher the gas saturation, the smaller the foam fractal dimension. This paper provides a new method to explore the flow behavior of foam flow in formation, which has a certain significance for guiding the field application of the foam fluid.

Complexity and self-organized criticality in liquid foams. A short review

“…Foams can be considered as complex systems in several ways, for instance focusing in the fractal structure of foams [ 53 , 54 ] and foams flowing through porous media [ 55 ] and in Hele Shaw radial cells [ 56 ] (see §4, Fig. 8 ) or even the fractal-like patterns in chaotic light scattering by foams [ 57 ].…”

Automatic structural analysis of bioinspired percolating network materials using graph theory

“…[26,27] A similar challenge also emerges in foams with a stochastic distribution of interconnected micropores made from polymers, ceramics, and metals, [28] whose architectures are congruent to PNNs. [29] The need for the comprehensive structural quantification of materials with aperiodic stochastic architectures inclusive of both 'local' and 'global' structural patterns becomes, thus, general and fundamental. A closely related problem is the lack of computational tools and algorithms to enumerate the materials with non-crystalline architecture that would be rapid and accurate.…”

Flow Characteristics of Foam in Fracture Networks

“…Steinsbø et al and Haugen et al , evaluated the potential of foam to control fluidity through oil displacement experiments of pregenerated foam flooding in carbonate cores. Wang et al and Chen et al injected pregenerated foam into parallel fractures to study foam structure and rheology. Gauteplass et al and Buchgraber et al used a microscope to observe foam flow in a silicon micromodel in real time and captured numerous details of this process.…”