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2015  (Vol. 6, No. 2)

Abstract

Polymer degradation is an important challenge associated with polymer flooding operations during Enhanced Oil Recovery (EOR). Non-associating polymers lose their viscosity under harsh reservoir conditions such as high temperature and salinity. This makes for an inefficient recovery process under such conditions. Polyacrylamide based associating polymers has been an area of ongoing research as the use of different hydrophobic co-monomers with acrylamide monomers yields associating polymers with improved rheological properties. In this paper, an associating polymer made up of acrylamide (AM) and N-dodecylacrylamide (N-DDAM) was synthesized via micellar copolymerization with the amount of N-dodecylacrylamide co-monomer varied for each synthesized polymers. The characterization of the synthesized polymer was carried out through viscometric measurement using an Ubbelohde Viscometer to determine the molecular weight of the polymers. The rheological behavior of the polymers under shear stress, temperature and salinity was investigated using a Bohlin Rheometer. Improved rheological properties were observed with increasing amount of the N-dodecylacrylamide co-monomer. The effect of the N-dodecylacrylamide content can be seen in the improved resistance to salinity, shear and temperature comparable with most hostile environments of oil reservoirs. These enhanced polymeric properties turn out to be more evident when the N-dodecylacrylamide content increases which leads to larger hydrophobic blocks on the polymer backbone. The presence of these N-dodecylacrylamide blocks on the polymer backbone increases its molecular weight thereby improving its viscous property

 

Keywords: Associating Polymers, Enhanced Oil Recovery, Polymer Flooding

Submitted
 Accepted
April 2015
July 2015
 
Hossein Ramezani Ali-Akbari, Roohollah Dehghani Firouz-Abadi

Corresponding Author: Hossein Ramezani Ali-Akbari

Vol. 06 (02), 2015, 042-058
Abstract

In this paper, the nonlinear vibration of single-walled carbon nanotubes (SWCNTs) embedded in a Kelvin-Voigt foundation is studied. The SWCNT is considered as an elastic Euler-Bernoulli beam with von- Kármán type geometrical nonlinearity. Then, the governing equation of motion is derived based on the Hamilton’s principle. The nonlocal elastic field theory is utilized to introduce the small-scale effect into the equation of motion. Using the Galerkin method, the equation of motion is reduced to a nonlinear ordinary differential equation and solved by an asymptotic perturbation method called Krylov-Bogolubov-Mitropolskij (KBM) method. Two analytical formulas for the fundamental frequency and displacement field are derived. The obtained results for the case of simply-supported boundary conditions are reported and the effects of amplitude, residual stresses, and viscoelastic foundation are addressed and discussed.


Keywords: Single-walled carbon nanotubes, Nonlinear vibration, Nonlocal elastic field theory, Asymptotic perturbation method



Submitted
 Accepted
June 2015
 July 2015