In this paper, we present the results
of the rheometric properties
of a guar-based fracturing fluid containing amino-acid clay stabilizers.
Four amino acids, glycine, proline, alanine, and arginine were selected
for the study. KCl, a conventional clay stabilizer, was also used
for comparison. The fracturing fluid was prepared using tap water
(97.3 wt %), guar gum (0.4 wt %), ethylene glycol (0.1 wt %), potassium
carbonate (0.2 wt %), and a clay stabilizer (2 wt %). A Discovery
Hybrid rheometer with a bob-in-cup measuring system was used to determine
the fluids’ viscoelastic and temperature-dependent properties
under both static and dynamic oscillatory conditions. The static tests
were employed at varying shear rates of 0.001–1000 s–1 from 25 to 90 °C, mimicking both room and reservoir conditions.
For the oscillatory measurements, amplitude and frequency sweep tests
were done at a strain ranging from 0.001 to 100% and a frequency ranging
from 0.01 to 100 rad/s. The rheological characterizations of the fracturing
fluids confirmed that amino acids did not negatively affect the base
fluid’s viscoelasticity, flow behavior, shear-thinning properties,
and pumpability, including its damping factor. Glycine and alanine
enhanced the shear-thinning property of the base fluid by 4 and 5%,
respectively. All the stabilized fluids displayed significant upsurges
in their elasticity as the frequency was increased from 0.01 to 100
rad/s. Proline, glycine, and alanine improved the base fluid elasticity
by reducing its damping factor value by 0.37, 0.20, and 0.14, respectively.
Alanine on the other hand increased the base fluid’s damping
factor value by 0.12. This study provides new insights into the rheological
abilities of hydraulic fracturing fluids containing amino acid additives
and how their presence in the fracturing fluid contributes to the
effective transportation and dropping of proppants. These insights
are necessary for evaluating the effects of additives on the fracturing
fluid gel structure, proppant carrying and packing capacity, gelling
time, temperature stability, and, more importantly, its structural
stability.