Preparation, swelling properties, and displacement performance of functional amphiphilic microspheres

Abstract

Because polymers containing benzyl chloromethyl groups are easily modified for functional production, the dispersion polymerization of acrylamide, 4-vinylbenzyl chloride, and N,N-methylene bisacrylamide in dimethylformamide initiated with a,a-azobisisobutyronitrile was carried out to produce amphiphilic microspheres containing benzyl chloromethyl groups. The structure of the amphiphilic microspheres was determined by IR and 1 H-NMR spectroscopy. The polymerization conditions, the temperature, amount of crosslinking agent, and initiator included, were optimized. The size distribution of the microspheres after swelling equilibrium ranged from 4 to 62 lm. The swelling behavior of the microspheres was also investigated. The increase in temperature and the decrease in salinity caused a gradual increase in the swelling ratio. The prepared microspheres were transported uniformly in porous media when the permeability was 0.436 lm 2 . The oil displacement experiments indicated that amphiphilic microspheres had the ability to enhance oil recovery under homogeneous and heterogeneous conditions but was more suitable for heterogeneous formation.

Preparation and properties of novel pH-sensitive core−shell microspheres for enhanced oil recovery

“…The pH‐sensitive core−shell microspheres were prepared via a two‐step process. The synthesis of the microsphere core which has a benzyl chloride group on the surface is described in our previous work . As an example, the ATRP of acrylic acid sodium (AANa) from the core surface was carried out according to the following steps.…”

“…Enlightened by this, we reported the preparation of a crosslinked polyacrylamide microsphere whose surface contained the reactive benzyl chloride group as an initiator site of atom transfer radical polymerization (ATRP) . In this paper, we describe the synthesis of a pH‐sensitive core−shell microsphere with crosslinked polyacrylamide as core and non‐crosslinked polyacrylic acid as shell.…”

Preparation and Characterization of Hydrophobic-Associated Microspheres for Deep Profile Control in Offshore Oilfields

“…Excess water production can easily cause rock structure destruction and form the macroscopic throats or high-permeability channels in these reservoirs, especially near the wellbore [1][2][3]. This problem can be solved by deep profile modification to further improve water flooding efficiency.…”

“…Recent researches have been carried out on the profile control mechanism of microspheres [8][9][10]. Slow swelling rate of microspheres avoids blocking in the zone close to the wells and increases core injectivity [3,11]. Deformability of microspheres is conducive to shear resistance and deep migration [12,13].…”

“…N-dodecyl poly(etheroxy) acrylate (DEA; C 12 H 25 (OCH 2 CH 2 ) n OCOCH=CH 2 ) has also been reported as a polymerizable nonionic surfactant. Compared to ordinary hydrophobic association monomers, DEA with surface activity could improve the emulsion stability and solid content [3]. Moreover, it could form bilayer membranes in the presence of a small amount of an ionic surfactant and onion-like multilayer lamellar in water above the Krafft point (50°C) [25].…”