The application of nanoparticles to stabilise colloidal disperse systems
Elchin F. Veliyev, Azizagha A. Aliyev
Abstract
Today, due to the increase in the number of mature oil fields methods of in-situ fluid diversion acquire special relevance. The presence of highly permeable zones or channels in the reservoir, inevitably appearing during long-term reservoir development, in its turn reduces the waterflood efficiency and creates areas that are practically unaffected by it. To solve this situation, one has to decrease the permeability of high-permeability zones and redistribute filtration flows into zones not affected by waterflooding. The most widespread working agents used for this purpose are various gel compositions. In the presented work a colloidal-dispersed gel composition with the addition of TiO2 nanoparticles was formulated. The rheological studies of the obtained compositions were carried out, the thermal stability and zeta potential were studied. The obtained results were confirmed by sandpack experiments. The addition of nanoparticles decreased the interfacial tension and increased the rheological stability, zeta potential and RF/RRF values of colloidal dispersion gels. The critical concentration of nanoparticles in CDG was defined as 1000 ppm. Pseudoplastic behavior of the system, low thermochemical degradation and 47% decrease in surface tension at the liquid/air interface were observed. The decrease in average particle size did not exceed 10%. The presence of nanoparticles increased the zeta potential of the colloidal system by 43% and its thermal stability. The RF/RRF values were 173% and 59% higher compared to the reference composition. A kinetic gelation mechanism of colloidal dispersed gels in the presence of TiO2 nanoparticles was proposed.