Electrohydraulic Fracturing Of Rocks

This book presents a new fracturing technique that should be considered as a potential alternative, or a companion technique, to hydraulic fracturing of tight gas reservoirs and low permeability rock masses. As opposed to hydraulic fracturing which generates a few numbers of large cracks, electro-hydraulic fracturing induces diffuse micro-cracking and fragmentation of rocks. Laboratory tests demonstrate that increases of permeability by two orders of magnitude can be reached, without major cracking in tested specimens. This book discusses the principles of this new technique, reports experiments which have been developed is order to prove the concept and finally describes the numerical model from which the potentialities of this technique in representative reservoir conditions can be assessed.

Much of the research on fracture of rocks or rock-like materials conducted over the past two decades may be considered as "academic studies" of the general phenomenon of fracture. Yet, the understanding of this phenomenon is fundamental if a material is used in any engineering design, whether the aim is to prevent failure of the structure or to promote it. Fracture theories existing are generally empirical and derived from experimental results of laboratory test with simple boundary conditions. Because of the basic weakness of rock intension and because in general the environmental stresses in rock mechanics are compressive most of these theories consider fracture under compressive stress conditions. The Coulomb-Navier-, the Mohr-, the Griffith and the McClintock and Walsh criteria are typical examples and will be considered in the following. In addition the tendency during the past was in making accurate experiments under conditions of homogeneous stresses. To obtain information about the fracture behaviour with unequal principal stresses systems have to be used which involve inhomogeneous stresses. This case is of particular interest, since in practical rock mechanics we may expect conditions of highly inhomogeneous stresses. However, a consideration of such situations involve additional assumptions like the applicability of the theory of elasticity for calculating the stress field, which may be open to question. A distinction has to be made between fracture initiation and fracture propagation, since a detailed observation of the total fracture process in rock was possible by means of "stiff" and "servo-controlled" loading systems.

Scientific understanding of fluid flow in rock fractures--a process underlying contemporary earth science problems from the search for petroleum to the controversy over nuclear waste storage--has grown significantly in the past 20 years. This volume presents a comprehensive report on the state of the field, with an interdisciplinary viewpoint, case studies of fracture sites, illustrations, conclusions, and research recommendations. The book addresses these questions: How can fractures that are significant hydraulic conductors be identified, located, and characterized? How do flow and transport occur in fracture systems? How can changes in fracture systems be predicted and controlled? Among other topics, the committee provides a geomechanical understanding of fracture formation, reviews methods for detecting subsurface fractures, and looks at the use of hydraulic and tracer tests to investigate fluid flow. The volume examines the state of conceptual and mathematical modeling, and it provides a useful framework for understanding the complexity of fracture changes that occur during fluid pumping and other engineering practices. With a practical and multidisciplinary outlook, this volume will be welcomed by geologists, petroleum geologists, geoengineers, geophysicists, hydrologists, researchers, educators and students in these fields, and public officials involved in geological projects.

‘Tensile Fracturing in Rocks’ presents field observations on fracturing of sedim- tary rocks and granite outcrops from various provinces in three continents. It also combines results of recent experiments conducted at different laboratories around the world with current theories on fracturing. In treating faults, this book limits itself to faults that are associated with joint sets produced by definable causes and occasi- ally to cases where interaction between the two types of fracture – faults and joints – is not clear. The book’s subject matter is divided over six chapters, which are briefly described below. Chapter 1 summarizes current key concepts in fracture physics. It starts with a pr- entation of the elastic theory of fracture, and concentrates on the results of linear el- tic fracture mechanics. The chapter touches also upon other fracture properties, e.g., crack nucleation, dynamic fracturing and slow fracturing processes. Nucleation is - dressed by statistical mechanics methods incorporating modern approaches of th- mal and fiber bundle processes. The analyses of dynamic fracturing and slow fract- ing focus on the differences, as compared to the linear elastic approach. The cont- versy in interpreting experimental dynamic results is highlighted, as are the surface morphology patterns that emerge in fracturing and the non-Griffith crack extension criterion in very slow fracturing processes.

This book highlights the latest progress in pulsed discharge plasmas presented by front-line researchers worldwide. The science and technology surrounding pulsed discharge plasmas is advanced through a wide scope of interdisciplinary studies into pulsed power and plasma physics. Pulsed discharge plasmas with high-power density, high E/N and high-energy electrons can effectively generate highly reactive plasma. Related applications have gathered strong interests in various fields. With contributions from global scientists, the book elaborates on the theories, numerical simulations, diagnostic methods, discharge characteristics and application technologies of pulsed discharge plasmas. The book is divided into three parts with a total of 35 chapters, including 11 chapters on pulsed discharge generation and mechanism, 12 chapters on pulsed discharge characterization and 12 chapters on pulsed discharge applications (wastewater treatments, biomedicine, surface modification, and energy conversion, etc). The book is a must-have reference for researchers and engineers in related fields and graduate students interested in the subject.

World population growth and the related increase in the demand for food and other goods has intensified agricultural production throughout the world. Some of today's technologies are characterized by relatively low productivity and high consumption of energy resources. The Handbook of Research on Energy-Saving Technologies for Environmentally-Friendly Agricultural Development is a comprehensive research publication that provides insight into new technologies that create efficient and environmentally-friendly energy potential sufficient for the organization of industrial and social-economic activity in rural areas. Highlighting a variety of topics such as economic development, renewable energy, and climate change, this book is ideal for agricultural business executives, engineers, scientists, environmentalists, entrepreneurs, academicians, researchers, students, and those working in the agro-industrial and housing and communal services sectors.

In the past two or three decades, fractured rock domains have received increasing attention not only in reservoir engineering and hydrology, but also in connection with geological isolation of radioactive waste. Locations in both the saturated and unsaturated zones have been under consideration because such repositories are sources of heat and potential sources of groundwater contamination. Thus, in addition to the transport of mass of fluid phases in single and multiphase flow, the issues of heat transport and mass transport of components have to be addressed.