# Study of Constrained Velocity Inversion of Seismic Data in North Sumatra Basin

## DOI:

https://doi.org/10.5614/j.eng.technol.sci.2021.53.1.5## Keywords:

complex structure, constrained velocity inversion, interval velocity, North Sumatera Basin, seismic processing, velocity analysis## Abstract

Interval velocity analysis increases the precision of seismic velocity data with a complex structure and a high variation of velocity both laterally and vertically. In this study, interval velocity analysis was performed by applying the exponential asymptotically bounded function approach. An exponentially asymptotically bounded function was applied to calculate the interval velocity obtained from the root mean square velocity of seismic data using the Dix equation for conversion. To control this operation, a velocity constraint was applied in the interval velocity conversion. The velocity constraint used was the velocity trend gained from the root mean square velocity. This method is called constrained velocity inversion. In this study, interval velocity analysis using constrained velocity inversion was applied to seismic data from the North Sumatra Basin area. The seismic data interpretation resulted from the interval velocity analysis using constrained velocity inversion described the subsurface structure clearly. A corresponding anomaly at a time depth from 2000 ms to 2400 ms in the seismic time-domain data indicated a fault beneath an anticline. This result indicates that the interval velocity analysis of seismic data is more rigorous than the root mean square velocity analysis.

### Downloads

## References

Irawan, S. & Sismanto, Applying the Horizon Based Tomography Method to Update Interval Velocity Model, Identify the Structure of Pre-Stack Depth Migration 3D and Estimate the Hydrocarbon Reserve in SBI, Jurnal Teknologi, 69(6), pp. 53-58, 2014.

Fagin, S., Model-Based Depth Imaging, SEG Course Notes Series 10, Tulsa, 2002.

Fauzatun, S., Improvement of Interval Velocity Model on Pre-Stack Depth Migration 3D with Residual Depth Moveout Horizon Based Tomography Analysis on "SF', Universitas Diponegoro, Indonesia, 2008.

Yilmaz, O., Circumventing Velocity Uncertainty in Imaging Complex structures: The Leading Edge, SEG, 37, pp. 14-18, Anaheim, California, 2018.

Ravve, I. & Koren, Z., Exponential Asymptotically Bounded Velocity Model, Presented at Annual International Meeting, SEG, 2004.

Pertamina & BEICIP, Hydrocarbon Potential of Western Indonesia, 1985. (Unpublished)

Wicaksono, B, Setyoko, J. & Panggabean, H., The North Sumatera Basin: Geological and Petroleum System Review, Lemigas-PSG, Presented May 12-15 at CCOP, Krabi, 2006.

Geosciences Indonesia Servis., Seismic Data Results, 2015 (unpublished).

Gerritsma, P.H.A., Time to Depth Conversion in the Presence of

Structure, Geophysics, 42, pp. 760-772, 1997.

Van der Made, P.M., Determination of Macro Subsurface Models by Generalized Inversion, Ph.D. Dissertation. Delft University, Netherlands, 1988.

Toldi, J.L., Velocity Analysis without Picking, Geophysics, 54, pp. 191-199, 1989.

Zijlstra, D.M., Van der Made, P.M., Bussemaker, F. & van Riel, P., Effective Depth Conversion: A North Sea Case Study in Fagin, S.W., Seismic Modeling of Geology Structure, Society of Exploration Geophysicists, Houston, Texas, United States, 1991.

Dix, C. H., Seismic Velocities from Surface Measurement, Geophysics, 20, pp. 68-86, 1955.

Harlan, W.S., Constrained Dix Inversion, Landmark Graphics, 1999.

Ravve, I. & Koren, Z., Constrained Velocity Inversion, Presented at Annual International Meeting, SEG, Huston, Unites States, 2005.

Slotnick, M.M., On Seismic Computation with Application: Part I, Geophysics, 1, pp. 9-22, 1936.

Huston, C.E., Seismic Path, Assuming A Parabolic Increase of Velocity versus Depth, Geophysics, 4, pp. 242-246, 1939.

Faust, L.Y., Seismic Velocity as a Function of Depth and Geologic Time, Geophysics, 16, pp 192-206, 1951.

Al Chalabi, Instantaneous Slowness versus Depth Function, Geophysics, 62, pp. 270-273, 1974.

Yilmaz, O., Seismic Data Processing, Society Exploration Geophysics, Tulsa Oklahoma, United States, 2001.

Sripanich, Y. & Fomel, S., Fast Time to Depth Conversion and Interval Velocity Estimation with Weak Lateral Variations, SEG International Exposition and 87th Annual Meeting, Huston, Texas, United States, 2017.

Rocha, D.C. & Porsani, M.J., Non-Linear Inversion of Interval Velocities, Thirteenth International Congress of The Brazilian Geophysical Society, Rio de Janeiro, Brazil, 2013.

## Downloads

## Published

## How to Cite

*Journal of Engineering and Technological Sciences*,

*53*(1), 210105. https://doi.org/10.5614/j.eng.technol.sci.2021.53.1.5