... to be heterogeneous and contain complex fracture systems, sedimentary rocks are thought to be relatively fracture free and predictable over large distances. The site characterisation for a repository at a depth of 500 m with a footprint of 2 km2 in either of these formations would require sig- nificantly different...

... ABSTRACT ABSTRACT: The discrete fracture network (DFN) approach is attractive for applications in which the geometry and properties of discrete fractures play a significant role in hydraulics, geomechanics, and resource assessment. This paper describes the development of approaches...

...1 INTRODUCTION The conventional modeling of fractured reservoir concerns the numerical modeling of flows in the re- servoir. The main steps of the fluid flow study are the characterization of the fracture networks, the in- tegration of the data in a realistic geological models and the up-scaling...

... in numerical modelling studies for stabil- ity analysis and design and are also important in studying tectonic stresses for the prediction of earth quakes and seismic events. In situ stress measurement techniques currently in use include borehole fracturing methods such as hy- dro-fracturing (Fairhurst 1964...

... ABSTRACT ABSTRACT: The X-ray computed tomography (CT) technique was used to characterize a variable aperture sandstone rock fracture. The introduced relative fracture aperture measurement method from demountable mechanical strain gauge (DEMEC) eliminated some of the drawbacks in previously...

... ABSTRACT ABSTRACT: A semi-analytical hydraulic fracture model for injection of a compressible substance (biosolids) is developed. The approach is a modification of the Perkins-Kern-Nordgren (PKN) hydraulic fracture model modified with a pseudo-dynamic leak-off function that describes...

... called COSFLOW which incorporates unique features that make it ideal for the simulation of interaction between rock fracture, aquifer interference, and water flow in coalmine environment. Both the deformation and the hydraulic conductivity of rock mass are described using an equivalent continuum approach...

... of both step-paths and intact rock fracture in rock slopes. A combined finite element-discrete element code, ELFEN, is used to illustrate the factors influencing step-path failure in uniaxial laboratory specimens containing pre-existing weakness planes. Based on the results of the laboratory simulations...

... Characterization Engineering dulle airport site stability subvertical joint fracture bedding plane excavation geological model 1 INTRODUCTION Estimating the support pressure for a rock cut de- pends on the assumed failure mode and that failure mode is a function of the rock mass and its geologi- cal...

... and reduces the propagation of the overburden movement to the surface. A systematic laboratory study was carried out to investigate the flow properties of flyash grouts and their injectability into open fractures. To facilitate this study, a laboratory injection rig was designed and constructed. A series...

... Upstream Oil & Gas mass behavior synthetic rock mass discrete fracture network synthetic rock mass model strength cohesion increment fracture lift 2 reservoir geomechanics particle rock mass strength brittleness fragmentation Reservoir Characterization Simulation SRM sample...

... ABSTRACT ABSTRACT: A fracture mechanics numerical code, FRACOD, has previously been developed to predict the explicit fracturing process such as fracture initiation and fracture propagation in rock masses. It has been used in studying borehole breakouts, tunnel stability, and rock mass...

... ABSTRACT ABSTRACT: Closure of hydraulic fractures yields the in-situ stresses, net pressure and fracture geometry. A series of laboratory model experiments using sand samples is conducted with the aid of X-ray CT technique. The observation and analysis of CT images provide the visualized...

... Reservoir Characterization alteration uniaxial compressive strength Eberhardt kaolinite structural geology uniaxial compression alteration grade granite fracture boundary crack amplitude engineering behaviour kaolinised granite Upstream Oil & Gas initiation secondary mica...

... analysed for borehole breakouts and drilling- induced tensile fractures to ascertain the orientation of the contemporary horizontal stresses. Orientations were consistent across the basin, with a regional mean maximum horizontal stress orientation of approximately 105°N. Over 80% of the mean borehole...

... relevance, the pres- ence of an additional phase, either gaseous, liquid or both, often controls the behaviour of multi- fracturing rock systems. Examples of such interac- tion include (i) Fracture induced in rock masses by the presence of fluid flow and (ii) Generation of gas pressure fields due...

... and interpret fault or fracture behavior in stress models. Limit equilibrium models are often used to inves- tigate structural failure along the walls of ore passes. This is justified, provided that there are clearly de- fined wedges formed along the excavation. This im- plies that the major fractures...

... at the tips of pre-existing cracks decreases as confinement increases, and at some point crack initiation in shear prevails (Bobet & Einstein 1998a). Wing (tensile) and secondary (shear) cracks have been observed to initiate at the tips of pre-existing fractures in rock and rock-type specimens loaded...

... strongly upon the natural fracture network of the rock mass, there is an associated need for improving the characterization of the in situ fragmentation. In-situ fragmentation is defined as the blocks that are naturally present in the rock mass before any mining activity occurs. In the various forms...

... analysis of subsequent surface subsidence. Most natural rocks subjected to engineering analysis are quasi-brittle; failure in such rocks is a result of brittle fracture initiation and propagation. The brittle fracture is the process by which sudden loss of strength occurs across a plane following little...