Integration of Seismic and Well Log Data Using Acoustic Impedance for Lithology and Hydrocarbon Evaluation of “Ovi” Field, Niger Delta

  • Akpono Ejovi E P.O. BOX 756, 25 Buba Maruwa Road, Satellite Town, Lagos. Nigeria
  • Amigun John O. Department of Applied Geophysics, Federal University of Technology, P.M.B 704, Akure. Nigeria
Keywords: Hydrocarbon, Acoustic Impedance, Inversion, Crossplotting.

Abstract

This research work is aimed at using acoustic impedance as means of predicting lithology and hydrocarbon away from well control of “Ovi” Field hence providing a detailed evaluation of the hydrocarbon potential of the area. The methodology used involves identification of hydrocarbon bearing reservoirs from well logs using Gamma ray and resistivity logs, wells correlation, petrophysical analysis, well to seismic tie, horizon and fault mapping, generation of structural maps, acoustic impedance crossplot analysis and seismic inversion using model based approach. Three reservoir sand were mapped within the Agbada Formation. From the crossplot of acoustic impedance against gamma ray, porosity and water saturation, the acoustic impedance ranges from 24500-27500 (ft/s)*(g/cc) for shale and 17500-24500 (ft/s)*(g/cc) for sand based on the saturating fluids, the results also shows that acoustic impedance have a linear relationship with water saturation, while porosity have an inverse relationship with acoustic impedance for the study area. Average acoustic impedance maps for reservoir tops generated from the inverted seismic data indicated areas of low acoustic impedance corresponding to hydrocarbon bearing zones that were not detected on the time maps. The result provided detailed information about the subsurface lithology and hydrocarbon saturation away from well control of the study area.

References

. Avadhani, V.L., Anandan, M., Thattacherry, B.J., Murthy, K.S., Gariya, B.C., and Dwivedi A.K., (2006). Acoustic impedance as a lithological and hydrocarbon indicator: The Leading Edge. Vol.25, No.07, p.854-858.

. Badri, M., Svendsen, M., and Egan, M., (2002). Reducing drilling risk through improved seismic imaging. Utilizing new signal-sensor acquisition technology: AAPG Annual International Meeting, Cairo, Egypt.

. Doust, H., and Omatsola, E.M., (1990). Niger Delta, in, Edwards, J. D., and Santogrossi, P.A., eds., Divergent/passive Margin Basins, AAPG Memoir 48: Tulsa, American association of Petroleum geologist, p.239-248.

. Evamy, B.D., Hareboure, J., Kamerling, P., Knaap, W.A., Molloy, F.A., and Rowlands, P.H., (1978). Hydrocarbon habitat of Tertiary Niger Delta: American Association of Petroleum Geologist Bulletin, Vol 682, p.277-298.

. Hampson and Russell Software Services Ltd., (1999). STRATA.

. Mitchele, L.W., Turtle, R., Charpentier., and Michael, E.B., (1999). The Niger Delta petroleum system: Niger Delta Province, Nigeria, Cameroon and Equatorial Guinea, Africa. USGS. Denver Colorado, Open/file report 99-50-H.

. Murat, K., (1972). Stratigraphy and paleogeology of crateous and lower tertiary in Southern Nigeria: Proceeding first conference on African Geology, Ibadan 1970, proceeding, Hs: Ibadan University press, p.251-266.

. Short, K.C and Stauble, J., (1967). Outline geology of the Niger Delta: American Association of Petroleum Geologist Bulletin, vol.5, p.761-779.

. Shrestha, R. K., and Boeckmann, M. K. (2002, October). Stochastic seismic inversion freservoir modeling. In 2002 SEG Annual Meeting, p.2

. Singh, H., Subbrayudu, K.,Mohorana, A., Singh, M.K., and Kumar, A., (2013). A deterministic approach to reservoir characterization through quantitative interpretation: A case study from heara field, western offshore India: Society of petroleum geophysics 10th biennial international conference and exposition, p.427.

. 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.

Published
2019-07-24
Section
Articles