Investigation into the migration of polymer microspheres (PMs) in porous media: Implications for profile control and oil displacement

Pu, Wanfen; Zhao, Shuai; Wang, Song; Wei, Bing; Yuan, Chengdong; Li, Yibo

doi:10.1016/j.colsurfa.2018.01.018

Cited by 72 publications

(25 citation statements)

References 30 publications

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“…In the oilfield, researchers apply the PMs to plug the porous media in the reservoir to expand the swept volume of injected water and improve oil recovery, which is called in-depth conformance control technology (Liu et al, 2016). However, the effect of in-depth conformance control technology with PMs depends on whether the particle size of PMs matches the throat's diameter (Pu et al, 2018). At present, the selection method of PMs is based mainly on the matching coefficient that comes from the ratio of the particle size with the throat diameter .…”

Section: Introductionmentioning

confidence: 99%

Research on a Fractal Dimension Calculation Method for a Nano-Polymer Microspheres Dispersed System

et al. 2021

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Polymer microspheres (PMs) are a kind of self-similar volume expansion particle, and their fractal dimension varies with hydration swelling. However, there is no unique fractal dimension calculation method for their characteristics. A new model is established in this paper, which is particular to calculate the fractal dimension of PMs. We carried out swelling hydration experiments and scanning electron microscope (SEM) experiments to verify the new model. The new model and the box-counting model were used to calculate the fractal dimensions of PMs based on the hydration experiment results. Then, a comparison of the calculation results of the two methods was used to verify the validity of the model. Finally, according to the new model calculation results, the fractal dimension characteristics of PMs were analyzed. The research results indicate that the new model successfully correlates the cumulative probability of the PMs dispersed system with the fractal dimension and makes fractal dimension calculation of PMs more accurate and convenient. Based on the experiment results, the new model was used to calculate the fractal dimension of PMs and the box-counting model, and its findings were all 2.638 at initial state hydration and 2.739 and 2.741 at hydration time as of day 1. This result verifies the correctness of the new model. According to the hydration swelling experiments and the new model calculation results, the fractal dimension is linear correlated to the average particle size of PMs and the standard deviation average particle size. This means the fractal dimension of PMs represents the space occupancy ability and space occupancy effectiveness.

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Section: Introductionmentioning

confidence: 99%

Research on a Fractal Dimension Calculation Method for a Nano-Polymer Microspheres Dispersed System

et al. 2021

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“…Micron-sized and nano-sized polymer microspheres are suitable for high and low-permeability cores, respectively [26]. In terms of the in-depth oil displacement mechanism, polymer microspheres are elastic and can reach in-depth strata through elastic deformation and breakthrough, thereby achieving in-depth fluid diversion [27][28][29]. Micron-sized polyacrylamide elastic microspheres can resist the water flow by throat plugging through the mechanisms of trapping plugging, stacking plugging, and bridging plugging [30,31].…”

Section: Introductionmentioning

confidence: 99%

The Reservoir Adaptability and Oil Displacement Mechanism of Polymer Microspheres

Niu

et al. 2020

Polymers

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Polymer microsphere profile control is a promising approach for the profile control of heterogeneous reservoirs. Matching between polymer microspheres and the reservoir pore throat is crucial for profile control. In this study, the range of the optimal matching factor Ra between polymer microspheres and core porosity was divided through core permeability limit experiments, and the dynamic migration laws and shut-off patterns of microspheres were studied using 9-m-long cores and microscopic models. The oil displacement effect and mechanism of microspheres were analyzed using three cores in parallel. The “injectability limit” and “in-depth migration limit” curves were divided by Ra into three zones: blockage (Ra < 1.09 ± 0.10), near-well profile control (1.09 ± 0.10 < Ra < 5.70 ± 0.64), and in-depth fluid diversion (Ra > 5.70 ± 0.64). During migration in porous media, the microspheres gradually enlarged in size and thus successively shut off in four forms: multi-microsphere bridging shut-off, few-microsphere bridging shut-off, single-microsphere shut-off, and elastic shut-off. Microspheres with a rational combination of sizes versus those with a single particle size further enhanced reservoir oil recovery under certain reservoir conditions. Through “temporary shut-off–breakthrough–temporary shut-off,” the polymer microspheres were able to change the fluid flow rate and streamlines, mobilize residual oils, and enhance the oil recovery rates.

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“…33,34 Polymer microspheres are elastic and can reach deep strata through elastic deformation and breakthrough, thereby achieving deep fluid diversion. [33][34][35][36] Polymer microspheres have blocking-passing-blocking characteristics and can form pressure pulses in reservoirs, which promote the displacement of blindend residual oil or surface-attached residual oil, enhancing oil recovery. 37 The matching relationship between polymer microspheres and rock pores is a dominant factor affecting the profile control effect.…”

Section: Introductionmentioning

confidence: 99%

“…Compared with organic profile control agents, inorganic gel coatings possess a higher heat resistance, salt resistance, and sealing performance, but the viscosity of injection liquids containing inorganic gel coatings is similar to that of water, which easily pollutes low-permeability oil zones of reservoirs. [33][34][35][36] Polymer microspheres have blocking-passing-blocking characteristics and can form pressure pulses in reservoirs, which promote the displacement of blindend residual oil or surface-attached residual oil, enhancing oil recovery. Polymer microspheres are an emerging and promising deep profile control technology.…”

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confidence: 99%

Migration characteristics and deep profile control mechanism of polymer microspheres in porous media

Niu

2019

Energy Science & Engineering

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The performance and migration characteristics of polymer microspheres in porous media and the mechanism of deep profile control for oil displacement were studied by theoretical analysis, instrument detection, and physical simulation to further improve oil recovery. Polymer microspheres were expansive in water and nonexpansive in oil. The polymer microspheres with short expansion times possessed excellent mechanical shear resistance. According to the matching factor (Ra), resistance factor, and residual resistance factor, the migration of polymer microspheres in porous media was divided into four periods: transportation (Ra > 2.41), bridging plugging (1 < Ra < 2.41), elastic plugging (Ra < 1), and fatigue (microsphere breakage). The resistance factor and residual resistance factor of the polymer microspheres during the bridging and elastic plugging periods were larger than those during other periods. The deep oil displacement profile can be controlled by adjusting the occurrence positions (distance from the injection end) of these two periods. Increasing the injection rate during the transportation and bridging plugging periods and decreasing the injection rate during the elastic plugging period made elastic plugging occur farther from the injection end while maintaining the resistance factor and residual resistance factor at high levels. Aimed at the remaining oil accumulation area, the optimal profile control depth of oil displacement (distance from the injection end) of polymer microspheres in porous media can be regulated by changing the injection rate to enhance oil recovery. The simultaneous migration and expansion of polymer microspheres is the main mechanism of microsphere fluid diversion in porous media.

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Investigation into the migration of polymer microspheres (PMs) in porous media: Implications for profile control and oil displacement

Cited by 72 publications

References 30 publications

Research on a Fractal Dimension Calculation Method for a Nano-Polymer Microspheres Dispersed System

Research on a Fractal Dimension Calculation Method for a Nano-Polymer Microspheres Dispersed System

The Reservoir Adaptability and Oil Displacement Mechanism of Polymer Microspheres

Migration characteristics and deep profile control mechanism of polymer microspheres in porous media

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