Generation of Pseudo Velocity Logs from Resistivity Logs and an Applied Example from Thrace

Year 2017, Volume: 3 Issue: 2, 5 - 7, 01.11.2017

Züheyr Kamacı Güler Yenilmez

Abstract

This study used the well-log data belonging to
two wells in the Thrace region drilled by the Turkish Petroleum Company (TPAO).
A scale function was created from the correlation of sonic and resistivity logs
in only one of these wells and the non-linear equation it defined was obtained
to derive a pseudo velocity log. With the aid of this equation, a pseudo
velocity log was derived for the second well drilled in the area using only
resistivity log values. Additionally the % error values were calculated for
both wells and the similarities between them investigated.

The true sonic logs and derived pseudo velocity
logs from both wells were compared in the study. For both wells, the logs were
observed to be similar. This study reveals that for any area with the aid of
the non-linear equation based on the correlation between sonic and resistivity
logs taken from one well, pseudo velocity logs can be derived using only
resistivity log values for other wells in the region without requiring new
sonic log measurements. 

Keywords

pseudo velocity log, sonic log, scale function

References

• [1] Archie, G. E., “The Electrical Resistivity Log as an Aid in Determining Some Resorvoir Characteristics”, AIME trans. (Petroleum Development and Technology), 146, (1942) 54-62
• [2] Faust, L. Y., “Seismic Velocity as a Function of Depth and Geologic Time”, Geophysics, 16, (1951) 192-206.
• [3] Faust, L. Y., “A Velocity Function Including Lithology Variations”, Geophysics, 18, (1953) 271-88.
• [4] Wyllie, M.R.J., Gregory, H.R. and Gardner, L.W., “Elastic Waves in Heterogeneous and Porous Media”, Geophysics 21, (1956) 41-70.
• [5] De Witte, A.J., “Saturation and Porosity from Electric Logs in Shaly Sands”, Oil and Gas Journal, 55(9), (1957) 89-97.
• [6] Kim, D. Y., “Synthetic Velocity Log”. Paper Presented at 33rd Annual Intern. SEG Meeting, 1964 New Orleans.
• [7] Rudman, A.J., J.F.Whaley, R.F.Blakely, M.E.Biggs, “Transformation of Resistivity to Pseudovelocity Logs”, AAPG Bull., 59, (1975) 1151-65.
• [8] Rudman, A.J., J.F.Whaley, R.F.Blakely, M.E.Biggs, “Geologic Note: Transformation of Resistivity to Pseudovelocity Logs”, AAPG Bull., 60, (1976) 879-82.
• [9] Rudman, A.J., “Interrelationship of Resistivity and Velocity logs”,in Developments in Geophysical Exploration Methods-3, Chapter-2 , (1982) pp.33-59.
• [10] Bussian,A.E., “Determination of the Relationships of Electrical Resistivity, Sound Velocity and Density/Porosity of Sediments and Rock by Laboratory Techniquies and Well Logs from Deep Sea Drilling Project Sites 415 and 416 off the Coast of Morocco”. Initial Reports ofthe Deep Sea Drilling Project, 50, (1983) 305-318.
• [11] Dos Santos, W.L.B., T.J.Ulrych, O.A.L.De Lima, “A New Approach for Deriving Pseudo-velocity Logs from Resistivity Logs”. Geophysical Prospecting, 36, (1988) 83-91.
• [12] Nafe, J. E., C.L.Drake, “Variations with Depth in Shallow and Deep Water Marine Sediments of Porosity, Density and the Velocities of Compressional and Shear Waves”, Geophysics, 22, (1957) 523-52.
• [13] Nafe, J. E., C.L.Drake, “Physical Properties of Marine Sediments in The Sea”, Vol. 3, Ed. N. M. Hill. Interscience, 1963 New York, 794-815p.
• [14] Kamacı, Z., 1988. “Sismik Geçiş-Zaman Loglarının Elektrik Özdirenç Loglarından Türetilmesi”. TMMOB Jeofizik Mühendisleri Odası Jeofizik Dergisi, 2(2), (1988) 185-199.
• [15] Yenilmez, G., “Rezistivite Loglarından Yalancı Hız Loglarının Elde Edilmesi : Bir Uygulama Örneği”. 72s., 2011, SDÜ Fen Bilimleri Enstitüsü.Isparta