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Petroleum Migration and Accumulation
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
A fault is a fracture or discontinuity in rock brought about by the movements of rock due to geological stress. A fault line on a rock surface is geological traceable line and it can be seen. The fault line is a perpendicular or oblique straight line (linear). It may also have a concave or convex shape. A fault may range from a few millimeters to thousands of km. Faults are formed as the earth’s crust deforms due to stress. Stress is caused by plate tectonics. When the stress is greater than the strength of the rock, the rock breaks and a fault is formed. A fault line is produced when a crack develops in the rock due to the displacement of rock layers relative to each other. The fault line becomes the boundary between the two plates, such as the subduction zone, or between two blocks of strata.
Geological Structures
Published in F.G.H. Blyth, M. H. de Freitas, A Geology for Engineers, 2017
F.G.H. Blyth, M. H. de Freitas
Near the Earth’s surface, hard rocks which have undergone compression may have failed in shear, with the production of single fault, or groups of faults forming a fault pattern. Three main kinds of faults are formed, namely thrust faults, normal faults, and wrench faults. Where the dominant compression was horizontal and the vertical load small, the shear fractures formed intersect as shown in Fig. 8.19, the acute angle between them facing the maximum principal stress; faults having this kind of orientation are the thrusts or thrust faults. Where the greatest stress was vertical (Fig. 8.19) the shear planes are steeply inclined to the horizontal, and faults formed under such stress conditions are normal faults. Thirdly, when both the maximum and minimum stresses were horizontal and the intermediate stress vertical (Fig. 8.19), the resulting fractures are vertical surfaces and correspond to wrench faults. The two wrench faults of a pair are often inclined to one another at an angle between 50° and 70°.
Plane failure
Published in Duncan C. Wyllie, Christopher W. Mah, Rock Slope Engineering, 2017
Duncan C. Wyllie, Christopher W. Mah
Seismic sources. Earthquakes are the result of fault movement, so identification of seismic sources includes establishing the types of faults and their geographic location, depth, size and orientation. This information is usually available from publications such as geological maps and reports prepared by government geological survey groups and universities, and any previous projects that have been undertaken in the area. Also, the identification of faults can be made from the study of aerial photographs, geological mapping, geophysical surveys and trenching. On aerial photographs, such features as fault scarplets, rifts, fault slide ridges, shutter ridges and fault saddles, and off-sets in such features as fence lines and road curbs (Cluff et al., 1972) may identify active faults. In addition, records of seismic monitoring stations provide information on the location and magnitude of recent earthquakes that can be correlated to fault activity.
Simulation with Monte Carlo methods to find relationships between accumulated mechanical energy and atomic/nuclear radiation in piezoelectric rocks with focus on earthquakes
Published in Radiation Effects and Defects in Solids, 2022
Abouzar Bahari, Saeed Mohammadi, Mohammad Reza Benam, Zahra Sajjadi
Modern ideas on the mechanism of earthquakes began with the elastic rebound theory of H. F. Reid. According to this theory, the immediate source of an earthquake is a sudden release of elastic strain energy accumulated in the rock mass surrounding a pre-existing fracture in the earth's crust, known as a fault (46). Faults themselves occur when rocks break due to the forces acting on them. Stress may build up over a period of many years until the fault suddenly moves perhaps a few centimeters, or even a few meters. When this happens, it releases a huge amount of energy in an earthquake (47). Therefore, an earthquake is happened when either a pre-existing fault moves, or when an intact block of rock is under a huge stress value and suddenly it breaks, creating the faults. If we suppose that the stress is applied on a giant block of a brittle rock like granite, the elastic energy stored in the block can cause the earthquake.
Optimization of injection-withdrawal schedules for underground gas storage in a multi-block depleted gas reservoir considering operation stability
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Jun Zhou, Jinghong Peng, Guangchuan Liang, Jianhua Sun
UGS in a depleted gas reservoir mainly consists of underground system and aboveground system (Figure 1). The underground system includes reservoir, caprock and faults. The reservoir is a rock layer with certain porosity and permeability that can store natural gas. Caprock is the low permeability rock layer above the reservoir that protects the gas from escaping upward. Fault refers to the structure in which the earth’s crust is fractured by force, and the rock blocks are relatively displaced along both sides of the fault surface. Faults disrupt the continuity of the rock layer, so they prevent the flow of natural gas in a reservoir. According to the location of faults in the reservoir, they can be divided into boundary faults and internal faults. Due to the existence of internal faults, a complete reservoir can be divided into several disconnected RBs. Besides, the aboveground system has valve groups, gathering pipeline, compressor unit and dehydration unit. Injection-withdrawal wells connect the underground system and the aboveground systems.
Intermittent sensor fault detection for stochastic LTV systems with parameter uncertainty and limited resolution
Published in International Journal of Control, 2020
Junfeng Zhang, Panagiotis D. Christofides, Xiao He, Fahad Albalawi, Yinghong Zhao, Donghua Zhou
With the rapid development of advanced control and computer technologies, the modern engineering systems have become more automated and complicated. Meanwhile, the increased complexity and automation tend to make the systems more vulnerable. Any faults may have the potential to cause a host of safety, environmental and economic problems, which could even turn into disasters. Therefore, the fault detection technology has received extensive attention from both academia and industry over the past decades (Brás, Rosa, Silvestre, & Oliveira, 2015; Floquet, Barbot, Perruquetti, & Djemai, 2004; Franze & Famularo, 2012; Hajshirmohamadi, Davoodi, Meskin, & Sheikholeslam, 2016; Hwang, Kim, Kim, & Seah, 2010; Jing & Hua, 2008; Ríos, Punta, & Fridman, 2017; Zhang, Zhao, Li, & Liu, 2010).