Development of a Fracturing Nanofluid with Dual Purpose: Increasing Heavy Oil Mobility and Reducing the Reservoir Damage Associated at the Remaining Fracture Fluid

Abstract

This work aims to develop a fracturing nanofluid with a dual purpose: i) to increase heavy crude oil mobility and ii) to reduce formation damage caused by the remaining fluid. Three commercial nanoparticles were evaluated: two fumed silica of different sizes and one type of alumina. They were acidified and basified, obtaining nine nanoparticles (NPs) by the surface modification, characterized by TEM, DLS, Z Potential and Total Acidity. The effect of adding nanoparticles at different concentrations onto the linear gel and heavy crude oil was determined by their rheological behavior. Also, there was assessed the alteration of the rock wettability by contact angle for all NPs and concentrations. Based on these results, the nanoparticle with better performance was the neutral fumed silica of 7 nm at 1000 mg/L. These were used to make a fracturing nanofluid from a commercial fracturing fluid (FF). Both of them were evaluated through their rheological behavior overtime at high pressure following the API RP39 test and quantitative measurements of the rock sample wettability changes. Displacement tests also were performed on proppant and rock samples at reservoir conditions: pressure and temperature. Finally, there was evaluated the rheological behavior of the crude oil recovered in the displacement test. It was possible to conclude that the inclusion of nanoparticles allowed obtaining a reduction of 10 and 20% in the two breakers used in the commercial fracture fluid formulation. An alteration of the rock wettability was achieved, where the rock sample became up to 50% more wettable to water. Moreover, there was a diminution of 53% in the damage caused by the remaining fracturing fluid to the oil effective permeability in the proppant medium. In the rock sample, a decrease of 31% of this kind of damage was observed. Increases of 28 and 18 % in the crude oil recovery were noticed in the proppant and the rock sample, respectively. Finally, there was a reduction of 40% in the crude oil viscosity, showing the effectiveness of adding nanoparticles to fracturing fluids for increasing oil mobility and reducing the formation damage.