Nanoparticle Catalysts Upgrade Heavy Oil for Continuous-Steam-Injection Recovery
Authors: Wilson Adam 
Published: April 2017

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 179699, “Heavy-Oil Upgrading and Enhanced Recovery in a Continuous Steam-Injection Process Assisted by Nanoparticulated Catalysts,” by C.A. Franco, L.  Cardona, S.H. Lopera, J.M. Mejía, and F.B. Cortés, National University of Colombia at Medellín, prepared for the 2016 SPE Improved Oil Recovery Conference, Tulsa, 11–13 April. The paper has not been peer reviewed.

The production of heavy and extra-heavy oil is difficult because of its rheological properties caused by high asphaltene content. Upgrading these unconventional oils requires large amounts of energy, decreasing the production’s cost-effectiveness. Nanoparticulated catalysts have been shown to improve enhanced recovery of these oils by altering their physicochemical properties, including asphaltene content. This paper presents an investigation into the effect of catalytic nanoparticles on the efficiency of recovery from continuous steam injection.

Introduction

Several in-situ techniques have been used to enhance heavy- and extra-heavy-oil recovery with the objective of upgrading the oil and improving its viscosity and mobility. These techniques include thermal processes, such as steam-assisted gravity drainage, and cold techniques, such as treatments with diluents. Cold processes improve the crude oil by dilution or destabilization and deposition of asphaltene components in the reservoir with solvents that have a direct effect on viscosity. This paper evaluates the use of nanoparticulated catalysts in steamflooding.

The nanoparticles were selected through batch-adsorption experiments. A methodology was developed for evaluating the effect of the nanoparticulated catalyst in continuous vapor injection. Oil recovery was evaluated by use of a slimtube filled with a nonconfined sandpack in steam-injection scenarios in the absence and presence of a water-based nanofluid. A displacement test was conducted by (1) constructing the base curves, (2) estimating the oil recovery by continuous injection of vapor in the absence of the nanofluid, and (3) identifying the influence of the nanoparticles on the enhanced recovery of oil.

Results suggested that functionalized nanoparticles lead to higher adsorption of asphaltenes, higher degrees of asphaltene self-association, and lowered temperature of n-C7 asphaltene steam gasification. Oil recovery increased to 46% for the system assisted by nanoparticles in comparison with that from vapor injection without the nanoparticles. The °API value of the oil increased from 7.2 to 12.1 °API. A reduction of 59% in oil apparent viscosity was also observed. Additionally, analysis of n-C7 asphaltene and residue content demonstrated that nanoparticles are an excellent alternative for heavy- and extra-heavy oil upgrading in processes involving vapor injection. n-C7 asphaltene content decreased by 5.2 percentile points after vapor injection in the presence of nanoparticles com-pared with the unaltered extra-heavy oil. Also, residue content decreased 47%. Improved oil recovery by nanoparticle injection could be attributed to three main reasons: (1) wettability alteration of the porous media, (2) viscosity reduction because of reduction of the asphaltene aggregate, and (3) crude-oil upgrading.