Experimental Study of Microscopic Displacement Efficiency of Polymer Microspheres Using Low-Field NMR

Zhou, Yuanlong; Jiang, Hanqiao; Wang, Chuan; Li, Ben

doi:10.1080/01932691.2013.825569

Cited by 8 publications

(1 citation statement)

References 3 publications

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“…Zhao et al [24] and Dai et al [25] characterized the matching relationship between polymer microspheres and rock core pores by using the matching factor and found that polymer microspheres achieved the best shut-off and in-depth fluid diversion effects only within a certain range of the matching factor. 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].…”

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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