Influence of Proppant Size on the Proppant Embedment Depth

Area of Science:

• Geotechnical Engineering
• Petroleum Engineering
• Materials Science

Background:

• Hydraulic fracturing uses pressurized liquid to fracture bedrock, with proppants preventing fracture closure.
• Scale discrepancies between rock and proppant can cause analysis deviations when fluid-deteriorated formations are modeled as isotropic.

Purpose of the Study:

• To investigate deviations in proppant embedment analysis due to the simplification of fluid-deteriorated rock formations.
• To develop methods for calibrating mechanical parameters of fluid-deteriorated rocks for accurate proppant embedment analysis.

Main Methods:

• Modeling fluid-deteriorated formations as layered rocks to derive equivalent elastic parameters.
• Numerical simulations of proppant embedment using derived equivalent parameters.
• Analytical explanation using Hertz contact theory.
• Proposal of nano/micro-indentation for characterizing fluid-deterioration effects.

Main Results:

• Simplifying fluid-deteriorated rock to an isotropic medium leads to underestimation of proppant embedment depth.
• The underestimation of embedment depth increases with the scale contrast between rock specimens and proppants.
• Hertz contact theory explains the observed deviations in embedment analysis.

Conclusions:

• The study provides essential methods for calibrating mechanical parameters of fluid-deteriorated rocks.
• Accurate analysis of proppant embedment requires accounting for the anisotropic nature of deteriorated rock formations.
• Nano/micro-indentation shows promise for detailed characterization of rock deterioration.