Nanosilica-Based Loss Circulation Composition to Cure Moderate to Severe Losses

Abstract

The loss circulation composition comprising a combination of a nanoparticle-based dispersion and a chemical activator has been designed to treat moderate to severe losses. The nanomaterial used is an environmentally friendly nanosilica-based dispersion. The composition is designed to give delayed gelling of the nanoparticle-based dispersion. A major advantage of this technology is its ability to place the composition into the target loss circulation zone before the nanoparticle-based dispersion gels up. Premature gelling of the nanoparticle-based dispersion would avoid premature setting of the treatment fluid before it reaches the target zone. The newly developed system can be used effectively up to 300 °F. In this paper, experiments have been performed with three different types of nanoparticles differing in their surface charges and particle sizes. Two negatively charged nanoparticle-based dispersions with a particle size of 5 nm and 17 nm, respectively, and one positively charged nanoparticle-based dispersion with a particle size greater than 17 nm have been evaluated as loss circulation materials. Two different types of chemical activators, one organic and the other inorganic, have been used in this study, and their effect on the gelling time has been evaluated. The gelling time experiments have been done at four different temperatures viz. 150 °F, 200 °F, 250 °F, and 300 °F. The effect of activator concentration and different shear rates on the gelling time of the three nanoparticle-based dispersions has been studied. Permeability plugging tests have been performed using 2 mm slotted disks to evaluate the effectiveness in controlling moderate to severe losses.