Chapter 11 - Pore-Scale Modeling and Simulation in Shale Gas Formations

Abstract

Pore-scale modeling is essential for understanding the transport and storage mechanisms of hydrocarbons in shale formations, as well as the estimation of petrophysical properties, the prediction of long-term hydrocarbon production, and reserve estimation. It is well-known that organic-rich shale formations consist of numerous nanometer-sized pores ranging from 1nm to several hundred nanometers. Transport, storage, and phase behavior of hydrocarbons in nanoscale shale pores behave significantly different to that in conventional rock pores due to the effects of extreme confinement and dynamic adsorption/desorption. To overcome the challenges in traditional laboratory experiments, pore-scale modeling and simulation have become an alternative and feasible way to characterize the petrophysical and fluid properties in shale. This chapter discusses the hydrocarbon transport and storage mechanisms in shale nanopores, pore-scale modeling approaches, and predicted properties based on simulation results. This chapter is not a detailed review of the pore-scale approaches in terms of model developments and simulation setups but aims to establish a basic overview of the applicability of a couple of commonly used pore-scale methods in shale formations. We focus on two microscopic-scale approaches, i.e., Monte Carlo simulation and Molecular Dynamics simulation approaches, and one mesoscopic approach, i.e., the lattice Boltzmann method, as well as their applications in shale nanopores.