Experimental and numerical investigation of polymer pore-clogging in micromodels

Abstract

Polymers have been used effectively in the Oil & Gas Industry for a variety of field applications, such as enhanced oil recovery (EOR), well conformance, mobility control, and others. Polymer intermolecular interactions with the porous rock, in particular, formation clogging and the associated alterations to permeability, is a common problem in the industry. In this work, fluorescent polymers and single-molecule imaging are presented for the first time to assess the dynamic interaction and transport behavior of polymer molecules utilizing a microfluidic device. Pore-scale simulations are performed to replicate the experimental observations. The microfluidic chip, also known as a "Reservoir-on-a-Chip" functions as a 2D surrogate to evaluate the flow processes that take place at the pore-scale. The pore-throat sizes of an oil-bearing reservoir rock, which range from 2 to 10 nm, are taken into consideration while designing the microfluidic chip. Using soft lithography, we created the micromodel from polydimethylsiloxane (PDMS). The conventional use of tracers to monitor polymers has a restriction due to the tendency of polymer and tracer molecules to segregate. For the first time, we develop a novel microscopy method to observe the dynamic behavior of polymer pore-clogging and unclogging processes. We provide direct dynamic observations of polymer molecules during their transport within the aqueous phase and their clustering and accumulations. Pore-scale simulations were carried out to simulate the phenomena using a finite-element simulation tool. The simulations revealed a decline in flow conductivity over time within the flow channels that experienced polymer accumulation and retention, which is consistent with the experimental observation of polymer retention. The performed single-phase flow simulations allowed us to assess the flow behavior of the tagged polymer molecules within the aqueous phase. Additionally, both experimental observation and numerical simulations are used to evaluate the retention mechanisms that emerge during flow and how they affect apparent permeability. This work provides new insights to assessing the mechanisms of polymer retention in porous media.

Novel fabrication of mixed wettability micromodels for pore-scale studies of fluid–rock interactions

“…Paper also enables rapid, precise, and real-time analysis of fluid transport and phase behavior. [40][41][42][43][44] Micromodel substrates are utilized as 2D proxies to represent the complex 3D porous structures found in rocks, simplifying the analysis of porescale mechanisms. These 2D models, despite not completely replicating 3D flow and transport effects like the percolation threshold, offer a controlled environment with precise pore geometries.…”

Microfluidic devices, materials, and recent progress for petroleum applications: A review

“…The fine transparency of PDMS is one of the main reasons for the application of this material in microfluidic devices. Due to the contact angles of PDMS (110 ) and glass (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), this structure enables the emulation of reservoir rocks with a mixed state of wettability. [9,16,67] Previously, Olmos and colleagues developed a novel and low-cost method of PDMS microdevices fabrication using a reusable photopolymer mould.…”

“…Silicon glass offers high precision and resolution in fabrication, a good thermal conductivity; nevertheless, silicon wafers possess a high cost and complexity in bonding. [192] PDMS-glass is suitable for LPLT applications, and the recreation of mixed wettability conditions considering the contact angle of PDMS (110 ) and glass (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), even though PDMS is a porous material that can retain particles in its structure.…”

“…Thus, microfluidics appears as a useful technology for the oil and gas industry. In this field, microfluidics devices have been implemented to perform fluid characterization such as deposition, [18] remediation, [19] solubility, [20] chemical composition of asphaltenes, [21] formation of microemulsions, [22,23] pore-clogging, [24] interfacial tensions (IFT), [25] enhanced oil recovery treatments such as injection of polymers, surfactants, and nanoparticles, [26][27][28] separation of emulsions, [22] and the effect of ions [29] on their stability.…”

Acrylamide-Based Active Quadripolymer as an Efficient and Robust Foam Enhancer for Gas Mobility Control

“…First of all, the addition of conventional polymers, such as hydrolyzed polyacrylamide (HPAM), will hamper the foamability of surfactants; besides, the elevated reservoir temperature and high salinity can significantly lower the apparent viscosity of the majority of the commercially available polymers, which presumably makes the PEF less compelling. Furthermore, the effect of polymers on foam flow in porous mediums has not been fully elucidated yet …”