Quantification of Transportation of Deformable Gel Particles in Porous Media

Abstract Channeling is a ticklish problem of water-flooding in mature reservoirs. Deep fluid diversion (DFD) using deformable gel particle (DGP) has shown promising conformance control and improvement of sweep efficiency for enhancing oil recovery. The transport behaviors of DGP including shearing, plugging, deformation, and breakage are significantly complicated. It is extremely different from percolation of fluid and sand-removal problems. Although some empirical models or knowledge have been reported in literature, there have been few quantitative investigations or mechanistic interpretations to such behaviors. Without a good understanding of these behaviors, reliable modeling and optimization of DGP treatment would be impossible. Therefore, quantification of DGP transport behaviors in porous media is extremely essential. In this paper, we first conducted a set of experiments to measure the characteristics of DGP passing through and the breakage using variable-diameter capillary. Then, the corresponding derivation of DGP passing through the throat was demonstrated based on the elastic mechanics theory. After that, experiments of DGPs transport in porous media were conducted to study the shearing behavior and plugging capacity for different scenarios. Finally, the oil displacement experiments of parallel sand cores with different permeabilities and viscosities were carried out using different DGPs to validate and apply the above quantitative achievements. The results show that the pressure gradient for DGP passing through exponentially increases as the diameter ratio of DGP to throat. It is also a function of elastic modulus, Poisson's ratio, the diameter ratio of DGP to throat, and friction coefficient according to the derivation. Moreover, the derived model has a good agreement with the experimental results. There is a critical diameter ratio of DGP to throat, above which the DGP will break under an enough pressure. Both resistance factor and sheared DGP diameter are the function of flow rate, the diameter ratio of DGP to throat, and initial diameter. The above models can be used to choose optimal DGP size and injection parameters for a certain scenario. The experimental results of oil displacement support the quantitative achievements very well. This work provides a solid mechanistic theory for modeling DGP flooding and offers a useful guidance to the design of DGP flooding in field applications.