Synergistic effects of polymer and bentonite clay on rheology and thermal stability of foam fluid developed for hydraulic fracturing

Demand for foam fracturing fluids is ever-increasing because of its nondamaging characteristics, less water requirement, combined with efficient proppant carrying capacity. The present study reported the synergistic effects of bentonite clay and polymer (guar) on rheology and stability of the foam prepared with surfactant (sodium dodecyl sulfate). Bentonite clay, which is never considered so far for improving quality of foam fracturing fluid, was found to provide improved foam rheology at reduced polymer concentration. Static and dynamic rheology with microscopic study showed the improvement of apparent viscosity, viscoelasticity, thermal stability, and morphology of foam on addition of bentonite clay. Addition of bentonite reduced the doses of polymer with similar proppant suspension capacity, which could be preferred over conventional gelled foam to reduce formation damage incurred by insoluble guar in the very low permeability unconventional reservoirs like shale gas, coal bed methane, or water-sensitive formations. (c) 2017 Curtin University and John Wiley & Sons, Ltd.