Arno Zang – författare

Stress Field of the Earth’s Crust is based on lecture notes prepared for a course offered to graduate students in the Earth sciences and engineering at University of Potsdam. In my opinion, it will undoubtedly also become a standard reference book on the desk of most scientists working with rocks, such as geophysicists, structural geologists, rock mechanics experts, as well as geotechnical and petroleum en- neers. That is because this book is concerned with what is probably the most pe- liar characteristic of rock – its initial stress condition. Rock is always under a natural state of stress, primarily a result of the gravitational and tectonic forces to which it is subjected. Crustal stresses can vary regionally and locally and can reach in places considerable magnitudes, leading to natural or man-made mechanical failure. P- existing stress distinguishes rock from most other materials and is at the core of the discipline of “Rock Mechanics”, which has been developed over the last century. Knowledge of rock stress is fundamental to understanding faulting mechanisms and earthquake triggering, to designing stable underground caverns and prod- tive oil fields, and to improving mining methods and geothermal energy extraction, among others. Several books have been written on the subject, but none has atte- ted to be as all-encompassing as the one by Zang and Stephansson.

Mechanical properties and fluid transport in rocks are intimately linked as deformation of a solid rock matrix immediately affects the pore space and permeability. This may result in transient or permanent changes of pore pressures and effective pressures causing rock strength to vary in space and time. Fluid circulation and deformation processes in crustal rocks are coupled, producing significant complexity of mechanical and fluid transport behavior. This often poses severe technical and economic problems for reservoir and geotechnical engineering projects involved in oil and gas production, CO2 sequestration, mining and underground waste disposal. For example, the depletion of hydrocarbon and water reservoirs leading to compaction may have adverse effects on well production. Solution/precipitation processes modify porosity and affect permeability of aquifers and reservoir rocks. Fracture damage from underground excavation will critically influence the long-term stability and performance of waste storage.Part I of this topical volume covers mainly the nucleation and evolution of crack damage in rocks, new or modified techniques to measure rock fracture toughness and a discussion of upscaling techniques relating mechanical and fluid transport behaviour in rocks at different spatial scales.Part II, to be published later in 2006, will include studies investigating the coupling of rock deformation and fluid flow.

Mechanical properties and fluid transport in rocks are intimately linked as deformation of a solid rock matrix immediately affects the pore space and permeability. The coupling of fluid circulation and deformation processes in crustal rocks results in significant complexity of the mechanical and fluid transport behavior. This often poses severe technical and economic problems for reservoir and geotechnical engineering projects involved in oil and gas production, CO2 sequestration, mining and underground waste disposal. The volume results from the 5th Euroconference on Rock Physics and Geomechanics, which was held in Potsdam, Germany in September 2004. Part I of the topical volume mainly contains contributions investigating the nucleation and evolution of crack damage in rocks, new or modified techniques to measure rock fracture toughness and a discussion of upscaling techniques relating mechanical and fluid transport behavior in rocks at different spatial scales.Part II contains contributions discussing fluid flow and transport in rocks as observed on the laboratory scale and in boreholes. The evolution of rock damage pertinent to the stability of underground excavations is studied and scaling relations of elastic properties and seismic events are discussed.