Shale

Subsurface Science and Engineering

Thomas Dewers, Jason Heath, Marcelo Sánchez

• Publisher: American Geophysical Union
• Year: 2019
• ISBN:
  9781119066897
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Geology & Earth Sciences

Advances in theories, methods and applications for shale resource use

Shale is the dominant rock in the sedimentary record. It is also the subject of increased interest because of the growing contribution of shale oil and gas to energy supplies, as well as the potential use of shale formations for carbon dioxide sequestration and nuclear waste storage.

Shale: Subsurface Science and Engineering brings together geoscience and engineering to present the latest models, methods and applications for understanding and exploiting shale formations.

Volume highlights include:

• Review of current knowledge on shale geology
• Latest shale engineering methods such as horizontal drilling
• Reservoir management practices for optimized oil and gas field development
• Examples of economically and environmentally viable methods of hydrocarbon extraction from shale
• Discussion of issues relating to hydraulic fracking, carbon sequestration, and nuclear waste storage

Book Review: I. D. Sasowsky, University of Akron, Ohio, September 2020 issue of CHOICE, CHOICEconnect, A publication of the Association of College and Research Libraries, A division of the American Library Association, Connecticut, USA

Shale has a long history of use as construction fill and a ceramic precursor. In recent years, its potential as a petroleum reservoir has generated renewed interest and intense scientific investigation. Such work has been significantly aided by the development of instrumentation capable of examining and imaging these very fine-grained materials. This timely multliauthor volume brings together 15 studies covering many facets of the related science. The book is presented in two sections: an overview and a second section emphasizing unconventional oil and gas. Topics covered include shale chemistry, metals content, rock mechanics, borehole stability, modeling, and fluid flow, to name only a few. The introductory chapter (24 pages) is useful and extensively referenced. The lead chapter to the second half of the book, "Characterization of Unconventional Resource Shales, " provides a notably detailed analysis supporting a comprehensive production workflow. The book is richly illustrated in full color, featuring high-quality images, graphs, and charts. The extensive index provides depth of access to the volume. This work will be of special interest to a diverse group of investigators moving forward with understanding this fascinating group of rocks.

Summing Up: Recommended. Upper-division undergraduates through faculty and professionals.

Part I
Shale and Clay Overview

1
Mudrock Components and the Genesis of Bulk Rock Properties: Review of Current Advances and Challenges

Kitty L. Milliken¹ and Nicholas W. Hayman²

¹ John A. and Katherine G. Jackson School of Geosciences, Bureau of Economic Geology, The University of Texas at Austin, Austin, TX, USA

² John A. and Katherine G. Jackson School of Geosciences, Institute for Geophysics, The University of Texas at Austin, Austin, TX, USA

ABSTRACT

Fine‐grained sediment (mud) and lithified equivalents (mudrock, mudstone, and shale) contain components similar to ones in coarser sedimentary materials, albeit of such small size that high‐resolution imaging is required to observe them. Such imaging reveals that fine‐grained sedimentary rocks display diversities of grains, pores, and diagenetic features that actually exceed the variations of components in common sandstones and limestones. Mudrock diversity reflects the extraordinary range of grain and pore sizes, which extend from detrital grains and authigenic crystals in the <1–100 μm fraction to the nanomaterials (crystals and pores) in the matrix surrounding the silt‐size fraction. Prediction of bulk‐property evolution in fine‐grained materials lags current process understanding in coarse materials but a view is emerging that while there are similarities, there are also contrasts between the responses of coarse and fine materials to changing conditions in the subsurface. Mechanical and chemical processes that operate on submicrometer pores and crystals very likely proceed to different limits, at different rates, and even by entirely different mechanisms than do comparable processes in coarser materials. This paper reviews current knowledge about mudrock components, and explores some of the gaps that exist in our understanding of microscale properties and processes in Earth's most abundant sedimentary material.

1.1. INTRODUCTION

Mudrocks, the overall class of fine‐grained sedimentary rocks, contain grain assemblages composed by weight or volume of >50% particles that are <62.5 μm. Mudrocks include fissile shales, nonfissile mudstones, siltstones, and even claystones; bulk mineralogies of mudrocks span nearly the entire range of compositions displayed by sandstones and limestones. At the scale of a core or a hand specimen, it is easy to gain the impression that many mudrocks are homogeneous and uniform (Fig. 1.1). Data at both small and large scales challenge this view (e.g., Ilgen et al., 2017; Milliken and Curtis, 2016). For example, permeability in shale varies over 13–15 orders of magnitude, perhaps the largest range of any measured natural property (Bryant, 2002; Dewhurst et al., 1999). Mechanical behavior in fine‐grained sediments also varies tremendously as the combined effects of compaction and cementation drive lithification of mud to mudstone (Storvoll and Bjorlykke, 2004; Storvoll et al., 2005), ultimately producing rocks with bulk mechanical properties that approach those of solid crystals of quartz or feldspar (Kumar et al., 2015). The wide range of mudrock properties is expressed in the spatial and temporal complexity of hydrocarbon production from them; 30‐year economic tiers in the Barnett Shale of the Fort Worth Basin vary around eightfold in production and more productive wells show strong spatial clustering (Gulen et al., 2013).

Figure 1.1 Homogeneous black shale. Although subtle variations in texture and color can be discerned in this short section of black shale, describing cores of this type from visual description alone is challenging.

Microscopic examination of mudrocks readily shows that their profound heterogeneities are rooted in large variations in the abundance and sizes of basic mudrock components such as grains, cements, and pores. Imaging based on field‐emission scanning electron microscopy, for example, including high‐resolution secondary electron imaging, elemental X‐ray mapping, and scanned cathdoluminescence imaging have expanded the scale at which mudrock components can be imaged well into the submicrometer range, opening new potentials for both qualitative and quantitative characterization. Newer methods for the preparation of flat surfaces with minimal mechanical damage (specifically ion‐milling, by broad‐beam and focused‐beam methodologies) have figured prominently in imaging advances (Curtis et al., 2011; Desbois et al., 2009; Loucks et al., 2009; Milliken and Curtis, 2016). Several advances have also had significant impact on the examination of mudrock components at the submicron scale. These include: (i) advances in SEM automation (Goergen et al., 2014; Saif et al., 2017), (ii) imaging with X‐ray tomography (Dewers et al., 2012), (iii) and neutron scattering (Radlinski et al., 2004a), (iv) novel applications of rock‐mechanics expe...

Table of contents

• Cover
• Table of Contents
• CONTRIBUTORS
• PREFACE
• ACKNOWLEDGMENTS
• Part I: Shale and Clay Overview
• Part II: Unconventional Oil and Gas
• INDEX
• End User License Agreement