Improved Exploration Potential in Shallow Gas-charged Channels through Constrained Data-driven Velocity Model Building and Imaging of 4-C Data: Case Study from Niger Delta Shallow Marine Environment

Ogagarue D.O.^1,

¹Department of Earth Science, Federal University of Petroleum Resources, Effurun, Nigeria

Cite this paper

Ogagarue D.O.. Improved Exploration Potential in Shallow Gas-charged Channels through Constrained Data-driven Velocity Model Building and Imaging of 4-C Data: Case Study from Niger Delta Shallow Marine Environment. Journal of Geosciences and Geomatics. 2018; 6(3):165-170. doi: 10.12691/JGG-6-3-7

Abstract

Imaging of the shallow Pliocene channels in a legacy streamer 3D seismic dataset acquired in a Niger Delta shallow marine environment posed a serious challenge due to the presence of shallow gas-charged zones in the dataset, making the data sub-optimal for further exploration and field development. Acquisition of modern high quality 3D streamer data over the area was no longer feasible owing to dense facilities and field activities in the area. To maximize exploration potential especially of the deeper targets, a high density multicomponent seismic dataset was acquired over the area. Processing of the converted wave derived from the multicomponent data was very challenging due to the special binning requirement which relied heavily on the accuracy of the ratio of the compressional to converted wave velocities. This paper focuses on the velocity model building and imaging of the converted wave to adequately resolve the lateral inhomogeneities associated with the gas-charged channels. Comparison of the imaged result to the legacy data shows significant improvement in imaging over the gas zone with the converted wave data. The result is important for evaluation of the remaining exploration potential in the area and could also be useful in seismic reservoir characterization for field development. Constraining the velocity model building and imaging in the most efficient way to benefit the data-driven process is the main goal of this study.

Keywords

converted wave, c wave, velocity model building, imaging, gas channel, Niger delta

Copyright

This work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

References

[1]	Veeken, P.H., 2007, Seismic stratigraphy, basin analysis and reservoir characterization, vol. 37, Elsevier, Oxford, UK, 509p.
[2]	Inyang, C., 2009, AVO analysis and impedance inversion, Master Thesis, the Faculty of the Department of Earth and Atmospheric science, University of Houston.
[3]	Court, J., 2009, Simultaneous inversion of pre-stack seismic data for quantitative interpretation, simian and sienna fields, Egypt, Master Thesis, School of Earth and Environment, the University of Leeds.
[4]	Mancinin F., Li, X., Zio;kowski, A. and Pointer, T., 2999, Interpreting velocity ratios from 4C seismic data and well logs in the presence of gas and anisotropy, SEG Technical Program Expanded Abstracts 21(1).
[5]	Stewart, R.R., Gaiser, J.E., Brown, R.J. and Lawton, D.C., 1999, Converted wave seismic exploration: a tutorial, CREWES Research Report, vol. 11. Elsevier, Oxford, UK, 509p.
[6]	Aliu, U. and L. Novelli (1974). Outlines of Niger Delta. In: C. Ancel, E. Couve de Murville, C. Dadrian, D. Deines, J. Goetz, A. Misk, J. Moore, D. Parker, J. Trassard, and K. Weiss, (eds.), Well Evaluation Conference Nigeria, 2nd. Edition. Schlumberger Publication, p. 15.
[7]	Doust, H. and Omatsola, E., 1990, Niger Delta, in, Edwards, J.D. and Santogrossi, P.A., eds., Divergent/passive Margin Basins, AAPG Memoir 48: Tulsa, AAPG, p. 239-248.
[8]	Stacher, P., 1995, Present understanding of the Niger Delta hydrocarbon habitat, in, Oti, M.N. and Postma, G., eds., Geology of Deltas: Rotterdam, A.A. Balkema, p. 257-267.