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P-SV Numerical modelling and AVO of the Cardium conglomerate in the Carrot Creek field of central Alberta, Canada
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ashraf Abdalla |
| Abstract | This work implements the use of numerical seismic modelling to investigate modeconverted Pto SV-reflected wave traveltimes and the amplitude versus offset (AVO) response of reflectors from the Cardium Conglomerate in the Carrot Creek Field of central Alberta, Canada. Field data represented by 12 km of 3-component reflection seismic collected over 2 lines and numerous well logs are provided as the data base for the area. Synthetic events that closely represent Cardium reflections based on kinematics were obtained and gave a good idea about the structure velocity of the area. Cardiumreflections were studied in terms of AVO using the conventional processing parameters. Further analysis of AVO effects on Cardium boundaries were conducted by considering substantial differences in Poisson's ratio between the Cardium layer and the surrounding media. All modelling results demonstrate the importance of considering Poisson's ratio in AVO studies. Poisson's ratio has a strong effect on changes in reflection coefficient as a function of the incident angle. With substantial differences of Poisson's ratio across the reflecting interface, polarity reverse may occur depending on the velocity contrast between the two media. In this specific area where the Cardium Conglomerate exists as thin interval, considerable difficulties are experienced in resolving independent formation boundaries. In investigating possible Poisson's ratios for one medium, it is found that the medium boundaries can have the same response for the different cases assumed. Event tuning is also shown to be a result of considering Poisson's ratio. INTRODUCTION Numerical modelling is widely used as a useful way to investigate and understand many of the problems in Exploration Seismology. The current study uses numerical modelling, as its tool, to investigate P-SV wave arrival and Amplitude Versus Offset (AVO) on surface seismic data recorded in the Carrot Creek area of central Alberta, Canada. P-SV wave arrival P-waves traveling through the subsurface media and reflecting off a boundary produce SVwaves in addition to the P-wave (same type wave) reflections. This indicates that the same source (P-wave source) can be used to record the two-component data; i.e. P-P waves and P-SV waves. The mode-converted wave (P-SV) image acquired by inline horizontal (radial) -component recording provides another seismic image in addition to that obtained from the conventional vertical component. Wood (1979) showed through amplitude response curves from model data that PSV raypaths are commonly the largest amplitude converted wave reflections. He claimed that these amplitudes are more dependent on shear velocity contrast than on compressional velocity contrast. Garrota (1987) also considered and confirmed the previous observation by stating that the energy in a P-SV reflection resulting from wave-mode conversion upon |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.crewes.org/ForOurSponsors/ResearchReports/1989/1989-10.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
