Synthesis and performance evaluation of temperature and salt-resistant organic/inorganic composite copolymers

ABSTRACT

Ordinary polymers have poor adaptability in high-temperature and high-salt reservoir environments due to their properties. Organic/inorganic composite copolymer microspheres have the advantages of both of them, which are expected to break through their applicability limitations in such oil reservoirs. Therefore, its preparation and performance have always been of great concern to researchers. In this paper, AM/AMPS/Si-St ternary copolymers were synthesized by precipitation polymerization; then modified nano-silica particles were added to synthesize AM/AMPS/Si-St/g-SiO₂ organic/inorganic composite quaternary copolymers. FT-IR and SEM characterized the copolymers to confirm that they were prepared successfully. Experiments were carried out to investigate the concentration and ratio of monomers, which showed that the Weissenberg effect could be avoided. The number of polymer molecules could be stabilized under AM concentration of 12 wt%, AM/AMPS/Si-St ratio of 8:1:1, nano silica of 3.3% and the modification conditions of KH570:SiO₂ = 1:1. The experiments of temperature and salt resistance of two copolymers were evaluated and compared were conducted by using viscosity and particle size as parameters. The results showed that quaternary copolymers could increase the viscosity retention rate by about 10% compared with ternary copolymers under high content of Na⁺ and Mg²⁺. When the two copolymers were placed at 150°C, the appearance and morphology of the terpolymer changed obviously. Through the SEM image of the quaternary copolymers, it could be seen that although the spherical shape of the microsphere had been gradually lost, no degradation occurred, and the stable time of the modified microspheres had been effectively extended.

KEYWORDS:

• Composite copolymer microspheres
• viscosity retention rate
• temperature and salt resistance
• modified inorganic nano-silica

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Author contributions

Yunbao Zhang: Conceptualization, Methodology, Validation, Formal analysis, Project administration, Writing – review & editing, Supervision.

Jiamei Quan: Data curation, Investigation, Visualization, Writing – original draft, Writing – review & editing.

Chengzhou Wang: Conceptualization, Investigation, Resources, Supervision.

Wentao Li: Data curation, Writing – original draft, Formal analysis

Ruofei Du: Investigation, Validation

Hongchao Dong: Data curation, Resources

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, Jiamei Quan. The data are not publicly available due to their containing information that could compromise the privacy of research participants.

Additional information

Funding

Study on the Working Mechanism of Adaptive Nanofluids Based on Reversible Wettability in Cross scale Shale Reservoirs.No.: LH2022E021; International cooperative scientific research project of “Chunhui Plan” of the Ministry of Education: HZKY20220311 (research on the mechanism of improving the recovery efficiency of cross scale shale reservoirs based on adaptive fluorescent nano fluids with reversible wettability)