Pre-stack seismic inversion based on a genetic algorithm: A case from the llanos basin (Colombia) in the absence of well information

  • Edward Moncayo Petrobras Colombia
  • Nadejda Tchegliakova Universidad Nacional de Colombia, Bogotá ,Colombia
  • Luis Montes Universidad Nacional de Colombia, Bogotá ,Colombia
Keywords: Seismic inversion, Channel lithology, Genetic algorithm, Llanos basin


The Llanos basin is the most prolific of the Colombian basins; however few stratigraphic plays have been explored due to the uncertainty in determining the lithology of the channels. Inside a migrated 2D section, a wide channel was identified inside a prospective sandy unit of the Carbonera Formation, composed by intercalations of sand and shale levels, and considered a main reservoir in this part of the basin. However, the lithology filling the channel was unknown due to the absence of wells. To infer the channel lithology, and diminish the prospective risk a model based pre-stack seismic inversion was proposed.
However, without well logs available along the line, the uncertain initial model diminishes reliance on the inversion. To circumvent this impasse, a seismic inversion with a genetic algorithm was proposed. The algorithm was tested on synthetic seismograms and real data from an area of the basin, where well logs were available. The error analysis between the expected and the inverted results, in both scenarios, pointed out a good algorithmic performance. Then, the algorithm was applied to the pre stack data of the 2D line where the channel had been identified.
According to the inverted results and rock physics analysis of wells near the seismic line with comparative geology, classified the channel was described as to be filled by silt, shale and probably some levels of shaly sands, increasing the exploratory risk because this lithology has low porosity and permeability, contrary to the producing reservoirs in neighbor fields, characterized by clean sands of high porosity. The algorithm is useful in areas with few or no borehole logs.


Pre-stack seismic inversion based on a genetic algorithm: A case from the llanos basin (Colombia) in the absence of well information

Anderson, P. (2009). Comparing post-stack AVO inversion to prestack inversion for estimating rock properties. Fron. +
Innova. CSPG CSEG CWLS Convention: 669-672.

Castaño, K., Ojeda, G. & Montes, L. (2011). Thin-layer detection using spectral inversion and a genetic algorithm. Earth Sci. Res. J., 15 (2), 121-128.

Fatti, J., Smith, G., Vail, P., Strauss, P. & Levitt, P. (1994). Detection of gas in sandstone reservoirs using AVO analysis: A 3D case history using geostack technique. Geophysics, 59 (9), 1362-1376.

Gardner, G., Gardner, L. & Gregory, A. (1974). Formation velocity and density - the diagnostic basics for stratigraphic traps. Geophysics, 39 (6), 770-780.

Gassmann, F. (1951). Elastic waves through a packing of spheres. Geophysics, 16 (4), 673-685.

Guerrero, J., Vargas, C. & Montes, L. (2010). Reservoir characterization by multiattribute analysis: The Orito field case. Earth Sci. Res. J., 14 (2), 173-180.

Koefoed, O. (1955). On the effect of Poisson’s ratio of rock strata on the reflection of plane waves. Geophysical Prospecting, 3 (4), 381-387.

Labat, K., Macé, D., Bourgeois, A., Froidevaux, P., Pichard, M. & Tonellot, T. (2005). Which factors is the prestack stratigraphic inversion very sensitive to?. SEG Expanded
Abstracts, 250-254.

Mallick, S. (1999). Some practical aspects of prestack waveform inversion using a genetic algorithm: An example from the east Texas Woodbine gas sand. Geophysics, 64 (2), 326-336.

Mavko, G., Mukerji, T. & Dvorkin, J. (1998). The rock physics handbook: Tools for seismic analysis in porous media. Cambridge: Cambridge University Press.

Mitchell, M. (1998). An introduction to genetic algorithm. Reading: The MIT press.
Puryear, C. & Castagna, J. (2008). Layer-thickness determination and stratigraphic interpretation using spectral inversion: Theory and application. Geophysics, 73 (2), 37-48.

Robinson, E. & Treitel, S. (2000). Geophysical signal analysis. Tulsa: SEG Books.

Rua, N., Jian-hua, Y., Shuai-qi, D. & Yang-guang, L. (2009). Wave impedance inversion in coalfield based on immune genetic algorithm. Procedia Earth and Planetary Science,
1 (1), 929-935.

Sen, M. (2006). Seismic Inversion. Texas: Richardson. S. of Petrol. Eng. Villegas, M., Bachu, S., Ramon, J. & Underschultz, J. (1994).

Flow of formation waters in the Cretaceous–Miocene succession of the Llanos Basin, Colombia. AAPG Bull, 78: 1843–1862.
How to Cite
Moncayo, E., Tchegliakova, N., & Montes, L. (2012). Pre-stack seismic inversion based on a genetic algorithm: A case from the llanos basin (Colombia) in the absence of well information. CT&F - Ciencia, Tecnología Y Futuro, 4(5), 05-20.


Download data is not yet available.
Scientific and Technological Research Articles

More on this topic