Study of crosslinked copolymer nanospheres with temperature resistance, salinity resistance, and deep profile control

2017 ◽  
Vol 134 (40) ◽  
pp. 45131 ◽  
Author(s):  
Ming Zhou ◽  
Xincheng Nie ◽  
Lei Zhou ◽  
Liutong Hou ◽  
Jinzhou Zhao ◽  
...  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Qin Yu ◽  
Xiangguo Lu ◽  
Yubao Jin ◽  
Cui Zhang ◽  
Kuo Liu ◽  
...  

Microspheres have excellent sealing performances such as injectivity, bridging-off, deep migration, and deformation performances, but their plugging effects are limited by the fast swelling rate and poor viscoelasticity. In this study, we synthesized a novel modified microsphere with polymerizable surfactant monomers and cationic monomers. We investigated the influence factors on the swelling performance and rheological properties of the microspheres and explored the ways to improve the plugging performance of hydrophobic-associating microspheres. The association behaviors in aqueous media of poly(acrylamide-co-methacry loyloxyethyl trimethyl ammonium chloride-co-n-dodecyl poly(etheroxy acrylate) P(AM-DMC-DEA) are proven to be mediated by the DEA content. Moreover, the hydrophobic association interaction has a strong effect on the performance of microspheres such as swelling properties, the rheological performance, and plugging properties. The swelling properties of microsphere studies exhibited the slow swelling rate. The rheological performance measurements showed significant improvements; yield stress, and creep compliance increased rapidly from 404 to 2060 Pa and 3.89 × 10−4 to 1.41 × 10−2 1/Pa, respectively, with DEA content in microspheres rising from 0.0% to 0.22%. The plugging properties of microspheres were enhanced by the slow swelling performance and good viscoelasticity.


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 381 ◽  
Author(s):  
Bin Xu ◽  
Huiming Zhang ◽  
He Bian

Delayed crosslinking polymer gel systems are widely utilized in deep profile control processes for water production control in oilfields. In this paper, a kind of delayed crosslinking amphiphilic polymer gel system with adjustable gelation time based on competitive inclusion was prepared and its delayed crosslinking gelling properties were studied. The amphiphilic polymer of P(acrylamide (AM)–sodium acrylate (NaA)–N-dodecylacrylamide (DDAM)) was synthesized and it showed much better salt resistance, temperature resistance, and shear resistance performance compared with hydrolyzed polyacrylamide (HPAM). Phenol can be controlled released from the the cavity of β-cyclodextrin (β-CD) ring in the presence of the hydrophobic group used as the competitive inclusion agent in the amphiphilic polymer backbone. Accordingly, the gelation time of the delayed crosslinking amphiphilic polymer gel system is closely related to release rate of the crosslinker from the the cavity of β-CD ring. This study screened an amphiphilic polymer with good salt resistance and temperature resistance performance, which can be used in high temperature and high salinity reservoirs, and provided a feasible way to control the gelation time of the polymer gel system by the competitive inclusion method.


Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1021
Author(s):  
Daiyin Yin ◽  
Shuang Song ◽  
Qi Xu ◽  
Kai Liu

The matrix/fracture conductivity of a fractured low-permeability reservoir is variable, and its heterogeneity is serious. When carrying out deep profile control measures, it is difficult to inject under the premise of ensuring the plugging effect. According to the characteristics of the fractured low-permeability reservoir in Chaoyanggou Oilfield, the polymer/chromium ion deep profile control system was optimized via a viscosity evaluation experiment, liquidity experiment and oil displacement experiment. The experimental results show that the high molecular weight main agent/low concentration system and low molecular weight main agent/high concentration system can meet the gel strength requirement. The evaluation results of the injection ability and plugging performance of the fractured low-permeability core show that a high molecular weight profile control system is difficult to inject, while a low molecular weight profile control system has a poor plugging performance and high cost after simulated shear. Therefore, the formulation of the profile control system was determined to be a polymer with a molecular weight of 16 million g·mol−1 as the main agent with a concentration of 1000–1500 mg·L−1. As assisting agents, the concentrations of thiourea, NaCl and NaHCO3 were 900 mg·L−1, 800 mg·L−1 and 700 mg·L−1, respectively. The plugging rate of the system was 87.6%, and the resistance coefficient was 19.2. Finally, a fractured low-permeability core model with parallel long cores was designed, and the optimal profile control system was used for the core oil-displacement experiment. Compared with the water-flooding experiment, the plugging rate can be increased by 6.9–8.0%.


2013 ◽  
Vol 734-737 ◽  
pp. 1272-1275
Author(s):  
Ji Hong Zhang ◽  
Zhi Ming Zhang ◽  
Xi Ling Chen ◽  
Qing Bin He ◽  
Jin Feng Li

Nanometer microspheres injection is a new deep profile control technology. Nanometer microspheres could inflate with water, resulting in plugging step by step in reservoirs, which could improve the swept efficiency in the reservoir and enhance oil recovery. By using non-homogeneous rectangular core, oil displacement efficiency experiment was conducted for studying the influence of different injection methods on the effect of injection nanometer microspheres. The experimental result shows that, compared with development effect of single-slug injection or triple-slug injection, the one of double-slug injection is better. Nanometer microspheres can enhance oil recovery significantly in medium and low permeability reservoir.


2014 ◽  
Vol 908 ◽  
pp. 46-50
Author(s):  
Yu Li Liu ◽  
Yi Qin

Organic phenolic gel is commonly used to be a deep profile control agent which applies to use in the high water cut oilfields where heterogeneity is severe, improve the contradiction of inter-reservoir layer and inner layer, expand water sweeping zone, and achieve the purpose of stable oil production and water control. Organic phenolic weak gel is mainly affected by the concentration of each component and reaction temperature. In this paper, formaldehyde was replaced by urotropin, which is not only delaying the gelation time, but also avoiding pollution. In addition, a water-soluble phenolic resin oligomer has been synthesized by the method of two-step alkali catalysis with appropriate mole ratio as an auxiliary crosslinking agent. Considering the concentration of each reactant as the factor, the orthogonal experiments have been designed to optimize the traditional organic HPAM-phenolic weak gel. We have found that the optimized weak gel has a better stability, longer gelation time, better salt resistance and environment friendly. It can better meet the needs of oilfield deep profile control.


2021 ◽  
Vol 252 ◽  
pp. 02078
Author(s):  
Wei Zhou ◽  
Daiyin Yin ◽  
Yazhou Zhou

The problem of injected water channeling along fractures exists in the process of water injection in fractured low permeability reservoir, aimed at this problem, deep profile control technology applies to plug fractures to improve the recovery of low permeability reservoir. In this paper, partially hydrolyzed polyacrylamide (HPAM) is used as water-plugging/profile-modifying agent and phenolic resin as crosslinker agent. Several profile control systems are tested to find the one which is suitable for fractured low permeability reservoirs. The performances of profile control systems are evaluated, and effects of formation water salinity, that of shearing rate and that of temperature on the performance are studied. Finally, in order to study effects of this profile control system on displacing oil, flowability experiment and core displacement experiment are applied. It shows that with the increase of salinty of prepared water and the increase of the shearing rate, the viscosity of this system decreases. With the increase of temperature, the gelling time shortens, the viscosity increases, but the stability weekens. This kind of profile control system has a good effect on plugging fractures of low permeability cores. After water flooding, this kind of profile control system is injected into cores, the recovery ratio can increase 3.5%. So the profile control system composed of HPAM/ phenolic resin can apply to deep profile control in fractured low permeability reservoir to enhance oil recovery.


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