scholarly journals Experimental Study on Expansion Characteristics of Core-Shell and Polymeric Microspheres

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Pengxiang Diwu ◽  
Baoyi Jiang ◽  
Jirui Hou ◽  
Zhenjiang You ◽  
Jia Wang ◽  
...  

Traditional polymeric microsphere has several technical advantages in enhancing oil recovery. Nevertheless, its performance in some field application is unsatisfactory due to limited blockage strength. Since the last decade, novel core-shell microsphere has been developed as the next-generation profile control agent. To understand the expansion characteristic differences between these two types of microspheres, we conduct size measurement experiments on the polymeric and core-shell microspheres, respectively. The experimental results show two main differences between them. First, the core-shell microsphere exhibits a unimodal distribution, compared to multimodal distribution of the polymeric microsphere. Second, the average diameter of the core-shell microsphere increases faster than that of the polymeric microsphere in the early stage of swelling, that is, 0–3 days. These two main differences both result from the electrostatic attraction between core-shell microspheres with different hydration degrees. Based on the experimental results, the core-shell microsphere is suitable for injection in the early stage to block the near-wellbore zone, and the polymeric microsphere is suitable for subsequent injection to block the formation away from the well. A simple mathematical model is proposed for size evolution of the polymeric and core-shell microspheres.

2005 ◽  
Vol 13 (7) ◽  
pp. 721-726
Author(s):  
Shunsheng Cao ◽  
Xiaobo Deng ◽  
Bailing Liu

Core-shell microspheres ranging in average diameter from 12.829 to 15.039 μm, with a poly butyl methacrylate (BMA) core, and a poly 3-(methacryloxypropyl)-trimethoxysilane (MATS) shell, were prepared with methanol as the dispersion medium, by a successive seeding method under kinetically controlled conditions. To date, although some of particles (PSi/PA) have been prepared by seeded emulsion polymerisation, only a few core/shell (PA/PSi) microspheres have been reported the literatures. To prepare core/shell (PA/PSi), the core was first synthesized by dispersion polymerisation and to form seeds; addition of MATS monomer was started after 90~95% conversion of the BMA. The reaction was prolonged for another 12 h to achieve complete consumption of MATS monomer. Microspheres; containing hydrophilic PBMA as the core and hydrophobic PMATS as the shell, were successfully formed through the free radical of surface in the core. The particles morphology and size distribution were examined using a Transmission electron microscope and a Malvern Master Sizer/E particle size analyser, respectively.


2015 ◽  
Vol 8 (1) ◽  
pp. 58-63
Author(s):  
Wang Chunsheng ◽  
Sun Yingfan ◽  
He Chenglin ◽  
Zhang Haipeng ◽  
Du Qiuying

Under the constraints of high temperature and heterogeneity, the common profile control agent can not effectively plug the steam channeling. To address this issue, it is necessary to develop the high temperature resistance steam channeling plugging agent to improve the steam suction profile in the heavy oil reservoir. This paper used Simple Variable Method to optimize the content of the components of the high temperature resistant plugging agent. Static performances evaluation aims to study the influence rules of the formation condition (temperature, salinity and pH value). Dynamic evaluation is used to study its performance (plugging ratio, residual resistance factor, scouring resistance and thermal stability) in the sand-filled pipe to testify its applicability. The ratio of the component and the injection sequence are shown as follows: 0.03% coagulant +2.2% cross-linking agent I + 1.2% cross-linking II + 6% high efficient main agent. The evaluation experiment results show that the gel can resist at least 280ºC, the plugging ratio is above 93.1%. The plugging ratio only have a 8.43% reduction after scoured by 15 PV steam (280ºC). After a 10-day thermal stability experiment (280 ºC), the plugging ratio is still above 80%. The result indicated that the plugging agent is suitable for the improvement of steam suction profile. The suggested way of injection is also provided.


2019 ◽  
Vol 9 (23) ◽  
pp. 5119
Author(s):  
Yongqiang Bi ◽  
Jianlong Xiu ◽  
Ting Ma

To study the feasibility of polymer-producing bacteria Enterobacter cloacae (E. cloacae) FY-07 and surfactant-producing bacteria Pseudomonas aeruginosa WJ-1 combined profile control and flooding, the compatibility of FY-07 and WJ-1 was evaluated using laboratory experiments. The results showed that the growth and metabolism of WJ-1 was not significantly affected by the FY-07 in the degradation medium, and the surface tension of fermentation broth was reduced from 70 mN/m to 30 mN/m. FY-07 enhanced the degradation of WJ-1, increasing the ratio of C14- to C15+ from 0.37 to 0.67. The core-flooding experiments indicated the oil recovery of 17.4% when both FY-07 and WJ-1 were injected into the system, as against to 10.4% and 7.9% for FY-07 and WJ-1, respectively, when injected alone. The results demonstrate a good compatibility between the FY-07 and WJ-1 strains and highlight the application potential of stain FY-07 and strain WJ-1 compound flooding for enhancing the oil recovery in heterogeneous reservoirs.


2008 ◽  
Vol 8 (3) ◽  
pp. 1464-1467 ◽  
Author(s):  
Weiping Qin ◽  
Dan Zhao ◽  
Jisen Zhang ◽  
Jishuang Zhang ◽  
Yan Wang ◽  
...  

The core–shell titania (TiO2) hybrid spheres embedded with tris(dibenzoylmethanato)phenanthroline [Eu-(DBM)3phen] complex clusters were fabricated by a modified Stöber method. Under ultraviolet excitation (355 nm), the hybrid spheres exhibit the characteristic luminescence of the Eu3+ ions. The experimental results indicate that the titanic shell has different influences on the two fluorescent centers of Eu3+ ions. The emission from the centers on the complex surfaces was greatly enhanced when incorporated into titania spheres.


2020 ◽  
Vol 312 ◽  
pp. 80-85
Author(s):  
Ilya Gavrilin

In this work, germanium nanowires (GeNWs) were fabricated by galvanostatic electrodeposition using In nanoparticles from water solutions at different temperatures. It was found that in the temperature range from 10°C to 60°C there was no significant change in the structure of GeNWs, and the average diameter was about 40 nm. The growth time of GeNWs increases linearly with increasing temperature of the electrolyte solution. However, the structure of GeNW obtained at a solution temperature of 90°C has changed. It was shown that these GeNWs have a core-shell structure: the core is a crystalline Ge phase containing In atoms, and the shell is Ge oxides (hydroxides).


2009 ◽  
Vol 79-82 ◽  
pp. 385-388 ◽  
Author(s):  
Ting Feng Tan ◽  
Shi Rong Wang ◽  
Shu Guang Bian ◽  
Xiang Gao Li

Hollow TiOX nano-spheres have been successfully prepared using hollow core-shell latex particles as template, which involves the deposition of inorganic coating on the surface of hollow core-shell latex particles and subsequent removal of the latex particles by calcinations in air or ammonia gas. The formation route of hollow core-shell polymer particles is presented as follows: Firstly, poly-methyl methacrylate (PMMA) seed emulsions are prepared as the 'core'. Subsequently, the outer shell poly(styrene-co-methyl methacrylate) (PS-co-MMA) particles wrap on the surface of the core, the microspheres with core-shell have been prepared. Finally, Ti(OBu)4 is used as precursor for the preparation of hollow TiOX nanospheres. Transmission electron microscopy (TEM) and atom force microscopy (AFM) images of seed emulsions show they have the uniform size of about 470 nm. TEM of hollow core-shell polymers particles show they have an average diameter of about 500 nm. X-ray diffraction (XRD) analysis of TiO2 sample calcined presents that the strong absorptions is coordinated with the standard chart of rutile TiO2. TEM of TiO2 and TiO show hollow spheres well-dispersed with the diameter range of 300-400 nm and 350-400 nm, respectively. The density (in the atmospheric pressure, 20 °C) of TiO2 and TiO hollow spheres was 2.49 and 2.37 g∙mL-1, respectively. The Zeta potentials were 6.20 mV and 20.39 mV, respectively. Uniform hollow spheres show low density and good electrophoretic displays. The electrophoretic mobilities of white TiO2 and black TiO hollow spheres in tetrachloroethylene show they are suitable for electronic paper as background and display particles, respectively. It is anticipated that this method would present a potential toward the road of large-scale industrial production of TiOx hollow spheres.


2013 ◽  
Vol 716 ◽  
pp. 413-417 ◽  
Author(s):  
Lei Li ◽  
Xue Mei Gao ◽  
Guang Lun Lei ◽  
Xiao Dong Wei

In order to solve the deep profile control problem and improve oil recovery of the oilfield, a novel profile control agent pore-scale polymer elastic microspheres (PSPEMs) was synthesized. The swelling property of PSPEMs in aqueous solution was analyzed. Core flow test and double-tube sand pack models were used for studying profile control and flooding performance of PSPEMs in oil formation. The results show that PSPEMs have good swelling property in aqueous solution with high salinity, high temperature and high pressure. Fig 5 and Fig 6 show that PSPEMs are better than polyacrylamide polymer on profile control. Table 1 indicates PSPEMs can improve water injection profile of heterogeneous formation effectively and plug the high permeable layer first. The higher the concentration of PSPEMs, the shorter the time it spends to realize profile control. The results also confirm that use proper concentration of PSPEMs, the profile control efficiency can increase enormously.


2021 ◽  
Vol 9 ◽  
Author(s):  
Lifei Dong ◽  
Miao Wang ◽  
Jie He ◽  
Mingchen Ding ◽  
Hun Lin

The particle system is one of the widely used profile control agents in many oilfields, and the matching relationship between the particle and the reservoir pore throat is significant for the profile control effect. In order to enhance oil recovery after water breakthrough in the Fuyu oilfield, a self-assembled particle with some branches on the surface, compounded by inverse emulsion polymerization and added, is introduced as the profile control agent in this paper. Then the permeabilities of the water channel and the oil remaining area in the Fuyu oilfield are achieved after the statistic analysis of 1,022 cores from the practical reservoir. Furthermore, the oil restarting pressure in the oil remaining area and the self-assembled particle plugging strength in the water channel are tested. Finally, the adaption of the self-assembled particle and effect of profile control in the Fuyu oilfield are evaluated by comparing the oil restarting pressure and the plugging strength. The results show that the self-assembled particles can be gathered together easily by the force of the ionic bond, which is good for water channel plugging. The permeability of the water channel in the Fuyu oilfield ranges from 1,000 mD to 1,500 mD. The oil restarting pressure increases with the decreasing of permeability, and the increasing rate grows rapidly when it drops below 50 mD. Comparing the oil restarting pressure with the plugging strength, a self-assembled particle with a diameter of 20–40 μm in the water channel with a permeability of 1,265.7 mD can provide sufficient plugging strength to restart the remaining oil in the oil remaining areas with a permeability over 3.38 mD. The matched window of the self-assembled particle is wider than a normal particle in the Fuyu oilfield.


2015 ◽  
Vol 1083 ◽  
pp. 15-20 ◽  
Author(s):  
Ming Tian

Nowadays, the earth’s available oil reserves decreases gradually while a great demand for oil is increasing.To improve oil recovery technique, the development of new profile control agent has important scientific significance and application value. A new copolymer of acrylamide (AM) and Isobutane-Ethylhexyl acrylate (2-EHA) was synthesized as profile control agent by free radical copolymerization. FT-IR and 1H-NMR were used for the structure characterization. Thermo gravimetric analysis, Core/Sand pack experiments and water drive displacement tests of copolymer particles were used to evaluate the properties. The results showed that the copolymer particles had good thermal stability, alkaline resistance, anti-salt property and excellent blocking property as profile control agent.


2012 ◽  
Vol 602-604 ◽  
pp. 732-738
Author(s):  
Ming Tian ◽  
Yong Jun Xu

In order to enhance oil recovery and avoid the profile control agents degradation in the alkali/surfactant/polymer composite solution in the oil layer, the copolymer of AM (basic monomer), 2-EHA (salt resistance monomer with large lateral group) and VTEOS(temperature tolerance monomer) was prepared by free radical copolymerization method as the profile control agent. FT-IR and 1H-NMR were used for the structure characterization. Thermo gravimetric analysis, Core/Sand pack experiments and water drive displacement tests of copolymer particles were used to evaluate the properties. The results shows that the copolymer particles have good thermal stability, alkaline resistance, anti-salt property and excellent blocking property as profile control agent.


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