Hydraulic fracturing
is a well stimulation technique involving
the fracturing of bedrock formations by a pressurized liquid, in which
proppants are added to keep the fracture open after the fracturing
operation. The scale discrepancy between the rock specimen and the
proppant may bring deviations in the analysis of proppant embedment
depth if the fluid-deteriorated formation is treated as an isotropic
medium. This study tries to uncover the origins of these deviations
through numerical and analytical analyses. The fluid-deteriorated
formation is first modeled as a layered rock to obtain equivalent
elastic parameters under isotropic conditions. Then, the equivalent
parameters are used in the numerical modeling of proppant embedment.
The numerical simulations indicate that the simplification of the
fluid-deteriorated formation into an isotropic rock results in an
underestimation of the proppant embedment depth, and this deviation
increases with the scale contrast between rock specimens and proppants.
Hertz contact theory is utilized to explain this deviation. As a promising
technique, the nano/micro-indentation is also proposed to depict the
fluid-deterioration effect along the depth. This study provides methods
for the calibration of mechanical parameters of fluid-deteriorated
rocks in the analysis of proppant embedment.