Temporary Plugging Performance of an Intelligent Liquid Gel with Magnetorheological Fluid

Abstract

Liquid gel temporary plugging agents were widely applied in many oilfield operations, such as temporary plugging for well workover, diverting re-fracturing for old wells, separate layer fracturing for horizontal well. In this work, an intelligent liquid gel based on magnetorheological fluid (MRF) was developed with hydrophilic magnetic Fe3O4 nanoparticles, dispersant polyvinylpyrrolidone (PVP), and stabilizer SiO2 nanoparticles. The hydrophilic magnetic Fe3O4 nanoparticles were prepared by virtue of chemical co-precipitation and double-layer surfactant coating methods, and characterized by scanning electron microscope (SEM), infrared spectrometer (IR). And then, the performances of the MRF liquid gel were investigated, such as magneto-rheological properties, bearing capacity, and core permeability damage. The results showed that MRF liquid gel under magnetic field is consistent with Bingham fluid. When the magnetic field intensity is 0.73T, the yield strength reaches at 74.453 kPa. With an increase of magnetic field intensity, the core plugging property of MRF liquid gel becomes better. The breakthrough pressure of MRF liquid gel can reach 15.81 MPa at magnetic field intensity of 0.6T and the plugging rate is higher than 97%, while the core permeability damage rate is less than 5.5%. Theoretically, the low-damage MRF temporary plugging agent can be controlled in real time by applying an external magnetic field, providing a new method for oilfield temporary plugging operations.KeywordsIntelligent liquid gelFe3O4 nanoparticleMagnetorheological fluidMagnetic field intensityTemporary plugging