A Comprehensive Review of Pre-Darcy Flows in Low-Permeability Porous Media

TL;DR

This paper provides a comprehensive review of pre-Darcy flow in low-permeability porous media, covering theories, experiments, and models, with implications for energy, environmental, and waste management applications.

Contribution

It synthesizes existing knowledge on pre-Darcy flow, highlighting experimental methods, findings, and modeling approaches, and discusses future research challenges.

Findings

Pore geometry and fluid type influence pre-Darcy flow onset.

Experimental techniques vary across geomaterials and conditions.

Models help interpret nonlinear flow behavior at low pressures.

Abstract

This paper reviews theories, experimental data, and modeling methods for pre-Darcy flow in low-permeability porous media, where Darcy velocity shows nonlinear dependence on pressure gradients at sufficiently low pressures, a deviation from Darcy's law. It begins by explaining the fundamental mechanisms of pre-Darcy flow, focusing on its unique characteristics like non-linear pressure gradients and fluid-rock interactions. Next, the paper compiles experimental studies on low-permeability geomaterials such as tight sandstones, shales, and clays, detailing methodologies employed, including core sample preparation, permeability measurement techniques, and threshold pressure gradient assessments. The experiments' findings, showing how pore geometry, fluid type, and pressure conditions affect pre-Darcy flow onset, are discussed. The review then covers empirical and theoretical models, plus simulation methods developed for interpreting data on pre-Darcy flow. It concludes by highlighting challenges in conducting and interpreting these experiments, suggesting directions for future research. This comprehensive analysis aims to assist those studying fluid dynamics in low-permeability geomaterials and has implications for applications like shale oil and gas recovery, contaminant transport in low-permeability aquifers, and geological nuclear waste disposal.