Seismic imaging of faults and fault zones: insight through modelling for improved interpretation
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- Master theses 
Faults and fault zones in the subsurface can create problems in reservoir production and well placement if gone un-detected because of restriction of fluid flow or affecting the ability of the reservoir to hold fluids. In seismic interpretation it is hard to map out the full extent of faults and fault zones, meaning there is room for erroneous interpretations. The imaging of faults and fault zones are largely dependent on size, throw and the stratigraphy bounding the fault or fault zone. Models with a range of geometries associated with normal faulting have been created, these are drag, parallel faulting, vertical fault overlap, imbricate fault systems and fault lenses. Using simple generic models and further creating more complex models from plaster models provides a mean of increasing the structural complexity. By populating the models with elastic parameters from well 34/10-41 S of the Brent group it is possible to model these structures to see their seismic equivalent. A total of 20 models have been created with varied complexity and structural geometry. By using a 2D Point Spread Function based modelling approach it is possible to take both generic models and segments from plaster models of faults and fault zones to further asses how the models are imaged seismically. These models have been modelled at different scales and with varied geophysical parameters to see how this affects the seismic response. The generated seismic sections show that high angles of incidence, a low dominant frequency, a decrease in angle of maximum illumination or increase in noise further worsens the ability to detect faults in the subsurface and properly map out the extent of faults and fault zones. Furthermore, illumination or reflectivity issues further worsens the detectability of faults and fault zones. The findings of this study coupled with previous knowledge to an interpreter may help assess fault and fault zone geometries in the subsurface, as well as helping to understand how scales and geophysical sensitivity affects the respective geometries.