A new simulator has been developed to model displacement processes in fractured reservoirs, in particular the block-block interaction in gravity particular the block-block interaction in gravity drainage processes. This block-block interaction forces oil draining from a matrix block into the fracture system to be absorbed by the underlying matrix block whenever this is possible. Otherwise the oil flows through the fracture network. Block-block interaction influences both the initial production rates and the resulting hydrocarbon distribution in the reservoir. Simulation of fractured reservoirs with this type of interaction between matrix blocks makes high demands upon the simulator, both in terms of memory requirements and speed. The simulator hence uses dynamic memory management and an efficient grid-block partitioning scheme that reduces the memory partitioning scheme that reduces the memory requirements significantly. In addition, this scheme enables a high degree of vectorisation on a Cray computer. The simulator can be used for a variety of reservoir geometries: dual porosity, dual porosity/ permeability, reservoirs with block-block interaction permeability, reservoirs with block-block interaction and unfractured reservoirs. Introduction Numerical simulation of fractured reservoirs is usually based on the dual-porosity concept. A fractured reservoir is modelled using two interacting continua, one for the matrix and one for the fracture system. In this way detailed knowledge about the individual fractures is not required as long as meaningful average fracture and matrix properties can be defined. The matrix contains most of the oil and the fractures contribute most to the fluid flow conductivity. Therefore the transmissibility between matrix blocks is often neglected and the matrix is treated as a source to the fracture system. However, to model the ultimate recovery from a dual porosity system correctly, it is necessary to take the capillary contacts between the matrix blocks into account. When capillary contacts exist, the ultimate recovery is the same as if the blocks form an homogeneous column. The rate at which depletion occurs is, of course, lower than in the homogeneous case, this being a result of the small area of the capillary contacts. This effect is modelled by a dual permeability approach with reduced transmissibilities between the matrix blocks. Fractured reservoir research in Shell has shown that in a vertical stack of oil-saturated matrix blocks surrounded by gas, the blocks do not drain independently: oil draining from one matrix block into the fracture system will be absorbed (by gravity and capillary forces) by the underlying matrix block whenever this is possible. Otherwise the oil flows through the fracture network. This type of block-block interaction is considered a crucial factor in describing the behaviour of fractured reservoirs. P. 373
Most of cyclists’ fatalities originate from collisions with motorized vehicles. It is expected that automated vehicles (AV) will be safer than human-driven vehicles, but this depends on the nature of interactions between non-automated road users, among them cyclists. Little research on the interactions between cyclists and AVs exists. This study aims to determine the main factors influencing cyclists’ crossing intentions when interacting with an automated vehicle as compared to a conventional vehicle (CV) using a 360° video-based virtual reality (VR) method. The considered factors in this study included vehicle type, gap size between cyclist and vehicle, vehicle speed, and right of way. Each factor had two levels. In addition, cyclist’s self-reported behavior and trust in automated vehicles were also measured. Forty-seven participants experienced 16 different crossing scenarios in a repeated measures study using VR. These scenarios are the result of combinations of the studied factors at different levels. In total, the experiment lasted 60 min. The results show that the gap size and the right of way were the primary factors affecting the crossing intentions of the individuals. The vehicle type and vehicle speed did not have a significant effect on the crossing intentions. Finally, the 360° video-based VR method scored relatively high as a research method and comparable with the results of a previous study investigating pedestrians’ crossing intentions confirming its suitability as a research methodology to study cyclists’ crossing intentions.
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