A Workflow for Multi-Scale Modeling and Simulation of Transport Phenomena in Woodford Shale Rock Matrix

Abstract

One of the most significant challenges facing the development of shale oil and gas resources worldwide is an inadequate understanding of complex flow and transport processes within shale reservoirs. For that reason, a proper understanding of the multi-scale transport phenomena within these highly heterogeneous formations is crucial from both scientific and economic perspective.Because anisotropy of shale rock exists across multiple scales, determining changes in pores distribution has proven to be difficult. Recent studies have indicated that shale rock pores significantly vary in number, size (from nano-, through micro-and meso-, to macro-pores), and kind (organic and inorganic). Thus far, the role of pore network and, more specifically, what pores contribute the most to the hydrocarbons storage or the production process, is not well understood and remains largely unknown. Hence, it is vital to address the need for understanding of how well different pores are connected and how they create possible flow pathways for the hydrocarbons migration.Here we present a comprehensive modeling and simulation framework for Woodford shale rock that links and correlates two most important parameters for characterizing flow in shale rock reservoirs: porosity and permeability. First, multi-scale 3D models are reconstructed from FIB-SEM, nano-and micro-XRM images of the Woodford shale rock specimen. Through this process, the mineralogy, porosity, and pore size distribution of the sample are obtained. Second, newly created 3D representations of the shale rock matrix are used as an input to the direct and indirect CFD solvers to simulate fluid flow and determine the shale rock permeability. Visualization of the resulting models revealed the full detail of the shale rock geometry and mineralogical composition.This work provides a guidance for reconstruction of realistic geometries, as well as a template for many different simulation studies relevant to unconventional reservoir characterization.