Acrylic acid hydrogel synthesis in high pressure CO2 mixtures for EOR applications

FACUNDO MATTEA; JUAN MANUEL MILANESIO; JUAN IGNACIO RAMELLO; MIRIAM STRUMIA

Viña del Mar

Conferencia; IV Iberoamerican Conference on Supercritical Fluids (PROSCIBA 2016); 2016

Pontificia Universidad Católica de Chile - Universidad Técnica Federico Santa María

The use of polymers and hydrogels for enhanced oil recovery (EOR) provides and additional chance to extract between 5 to 30% of oil from drilled reservoirs. The most relevant fluid properties in this technology are viscosity, interfacial tension and density. In order to obtain a high displacement efficiency and sweep efficiency the mobility index (M) between the oil and aqueous solution must be optimized. The value of M depends mainly on the permeability and viscosity of the aqueous phase. These properties can be adjusted by the addition of a polymer or hydrogel with tune the relative mobility of the final solution.In this work a hydrogel based on acrylic acid crosslinked with N N?- methylene bisacrylamide was synthesized in a batch high pressure reactor using CO2 and an aqueous solution of the reactive species. The reaction conditions were set to 15 MPa and 90ºC using benzoyl peroxide (BP) or Azobisisobutyronitrile (AIBN) as initiator, compared to the same reaction in a single CO2 based fluid phase. The thermodynamics and phase equilibria involved both reaction schemes during the initial conditions of these reactions has been studied with the aid of an adequate equation of state like PC-SAFT. The resulting materials have been characterized and compared by rheometry, density measurements, and swelling indexes.This work represents the starting point for the modelling and optimization of materials with better properties for EOR technology, such as hydrogels based on a combination of acrylic acid and acrylamide.