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[en] The risks related to developing an industry that is likely to have harmful effects on the environment and the population's health are said to be 'emergent'. They often stem from advances in new technology, but they might also follow from long-time practices that have sooner or later proven to be a danger owing to new scientific knowledge or changes in how public opinion perceives them. An example of the latter: the French perception of risks related to tapping unconventional hydrocarbons by applying processes that have been used for more than a decade in the United States. Serious questions, relayed by citizens and public authorities, have been raised about this new resource's environmental impact
[en] Overgrowths of hydraulic fracture height occur in reservoirs without stress barriers. It may decrease the efficiency of hydraulic fracturing, pose harm to well production, and increase the possibility of groundwater pollution. Hence, fracture height containment methods are recommended to restrain the overgrowths of fracture height. To enhance the effect of artificial barrier technology, it is improved by replacing the sand or the ceramic used for bridging the fracture tips by gel particles. This innovative technology could be named “artificial gel-barrier technology”. Experiments show that the design of artificial gel-barrier technology is more convenient and controllable, since the dilatability and the gelling performance of the selected gels are mainly controlled by salinity. Experiments also show that the break-through pressure of the gel-barrier is much larger than that of the classical barrier. Numerical simulations reveal that the artificial gel-barrier technology is more helpful and efficient than classical barrier technology. This improved technology has been applied to fracturing operations in Tahe oilfield of China; 73% of these operations were more efficient and the performances of these wells were better than those of adjacent wells.
[en] A model for computing the impact of blast energy irradiated into the three-dimensional space of the enclosing medium is suggested, which makes it possible to predict the parameters of the action of an arbitrary blast source on an arbitrarily located watched object. As a consequence, it becomes possible to optimize safe conditions of the building process under virtually any conditions of blasting
[en] We have developed and illustrated an approach for geomechanic modeling of elastic wave generation (microsiesmic event occurrence) during incremental fracture growth. We then derived properties of effective point seismic sources (radiation patterns) approximating obtained wavefields. These results establish connection between geomechanic models of hydraulic fracturing and microseismic monitoring. Thus, the results of the moment tensor inversion of microseismic data can be related to different geomechanic scenarios of hydraulic fracture growth. In future, the results can be used for calibrating hydrofrac models. We carried out a series of numerical simulations and made some observations about wave generation during fracture growth. In particular when the growing fracture hits pre-existing crack then it generates much stronger microseismic event compared to fracture growth in homogeneous medium (radiation pattern is very close to the theoretical dipole-type source mechanism)
[en] The paper represents a physical blasting model in laboratory scale along with a photographic approach to describe the distribution of blasted rock materials. For this purpose, based on wobble probability distribution function, eight samples each weighted 100 kg,were obtained. Four pictures from four different section of each sample were taken. Then, pictures were converted into graphic files with characterizing boundary of each piece of rocks in the samples. Error caused due to perspective were eliminated. Volume of each piece of the blasted rock materials and hence the required sieve size, each piece of rock to pass through, were calculated. Finally, original blasted rock size distribution was compared with that obtained from the photographic method. The paper concludes with presenting an approach to convert the results of photographic technique into size distribution obtained by seine analysis with sufficient verification
[en] This book introduces gunpowder blasting, which consists of ten chapters. It deals with conception of gunpowder on the history of gunpowder, difference between gunpowder and general materials and classification of gunpowder, reaction of gunpowder, shock wave and detonation, on properties, material velocity and structure, test method on gunpowder and an article processed with heat, gunpowder such as igniter charge, carlit and slurry gunpowder, propellant and an article processed with heat, blasting on basics and Bench cut, blasting operations and security blasting construction and using of gunpowder.
[en] The authors give an assessment of the effect exerted by blasting on the intensity of geodynamic and seismic events. The key regularities of distribution of shocks under blasting of rock blocks are found. The scope of the experimental research embraces determination of seismic velocities on the ground surface in mining area in Gornaya Shoria.
[en] The steel parts to be dismantled are subcooled in the areas where they are to be separated, so that they break because of the brittleness produced due to stresses introduced by explosive charges. (orig.)
[de]Die zu zerlegenden Stahlteile werden in den vorgesehenen Trennstellenbereichen unterkuehlt, so dass sie aufgrund der damit erreichten Sproedigkeit infolge der mittels Sprengladungen eingebrachten Spannungen brechen. (orig.)
[en] More recent public discourse has taken place regarding the potential correlation between seismic activity and hydraulic fracturing in shale gas reservoirs. Public fears about the risk of seismicity stem mainly from past earthquakes induced by conventional deep injections because the two types of projects share similar mechanisms of rock failure and fault activation. Although previous earthquake risks associated with fluid injection were not serious, the situation would be far more problematic if hydraulic fracturing in a shale gas reservoir triggered a similar-sized earthquake due to potential environmental issues. In fact, almost all documented injection-induced earthquakes have been associated with long-duration and high-volume injection rather than short-term (hours) pressurization (e.g., hydraulic fracturing). In general, hydraulic fracturing operations mostly induce microseismic events through rock failure and activation of small fractures. Although shale reservoirs in tectonically active zones pose a high risk of inducing large-magnitude seismic activities, the internal geological conditions and external stimulation conditions are impossible to be satisfied simultaneously to trigger activation of an entire fault and to result in a destructive earthquake during hydraulic fracturing operations.