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Estimating Elastic Impedance from Seismic Inversion Method:A Study from Nova Scotia Field, Canada


Affiliations
1 Department of Geophysics, Institute of Science, Banaras Hindu University, Varanasi 221 005, India
 

In the present study, elastic impedance (EI) inversion is performed to estimate subsurface elastic properties in inter-well regions. These elastic properties are helpful to discriminate gas-bearing formation from gasfree formation, as well as overpressure zone. Seismic reflection data from the Penobscot Scotia shelf, Canada are used for the analysis which is performed in two steps. First, the method is tested with noise-free synthetic data, as well as with addition of 5%, 10%, 20% and 30% Gaussian noise. The analysis shows that efficacy of EI inversion decreases by 3.4% with addition of 30% noise in the data compared to noise-free data. In the second step, EI inversion is applied to the real data and variation of EI is estimated for near- and far-angle stack gathers. The analysis demonstrates that the inverted results follow the well-log curve satisfactorily. The results also show higher resolution images for the far-stack data compared to the nearstack data. Incidentally, it is noticed that the area of study does not contain any major gas or overpressure zones. As of now, the analysis has been performed for small datasets of the region. Robustness of the method needs to be tested with more data from other parts of the region as well.

Keywords

Elastic Impedance, Gas Formation, Modelbased Inversion, Overpressure Zone.
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  • Estimating Elastic Impedance from Seismic Inversion Method:A Study from Nova Scotia Field, Canada

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Authors

S. P. Maurya
Department of Geophysics, Institute of Science, Banaras Hindu University, Varanasi 221 005, India

Abstract


In the present study, elastic impedance (EI) inversion is performed to estimate subsurface elastic properties in inter-well regions. These elastic properties are helpful to discriminate gas-bearing formation from gasfree formation, as well as overpressure zone. Seismic reflection data from the Penobscot Scotia shelf, Canada are used for the analysis which is performed in two steps. First, the method is tested with noise-free synthetic data, as well as with addition of 5%, 10%, 20% and 30% Gaussian noise. The analysis shows that efficacy of EI inversion decreases by 3.4% with addition of 30% noise in the data compared to noise-free data. In the second step, EI inversion is applied to the real data and variation of EI is estimated for near- and far-angle stack gathers. The analysis demonstrates that the inverted results follow the well-log curve satisfactorily. The results also show higher resolution images for the far-stack data compared to the nearstack data. Incidentally, it is noticed that the area of study does not contain any major gas or overpressure zones. As of now, the analysis has been performed for small datasets of the region. Robustness of the method needs to be tested with more data from other parts of the region as well.

Keywords


Elastic Impedance, Gas Formation, Modelbased Inversion, Overpressure Zone.

References





DOI: https://doi.org/10.18520/cs%2Fv116%2Fi4%2F628-635