Dictionary:Time-average equation

From SEG Wiki
Jump to: navigation, search
Other languages:
English • ‎español

1. An empirical equation stating that the transit time through a rock with matrix velocity Vm and porosity that is filled with fluid of velocity Vf is approximately


This relation works well in clean consolidated formations with uniformly distributed pores. In formations containing vugs, the sonic log may not reflect the secondary porosity, and in unconsolidated formations, this relationship may overestimate porosity. The formula may be empirically modified to give better values. Also called Wyllie relationship[1].

2. A generalization of the foregoing equation for other constituents, weighting the velocity of each according to its volume fraction.



External links

find literature about
Time-average equation
SEG button search.png Datapages button.png GeoScienceWorld button.png OnePetro button.png Schlumberger button.png Google button.png AGI button.png
  1. Wyllie, M. R. J.; Gregory, A. R.; Gardner, L. W. (1956). "Elastic Wave Velocities in Heterogeneous and Porous Media". GEOPHYSICS 21 (1): 41–70. doi:10.1190/1.1438217.
  2. Whaley, J., 2017, Oil in the Heart of South America, https://www.geoexpro.com/articles/2017/10/oil-in-the-heart-of-south-america], accessed November 15, 2021.
  3. Wiens, F., 1995, Phanerozoic Tectonics and Sedimentation of The Chaco Basin, Paraguay. Its Hydrocarbon Potential: Geoconsultores, 2-27, accessed November 15, 2021; https://www.researchgate.net/publication/281348744_Phanerozoic_tectonics_and_sedimentation_in_the_Chaco_Basin_of_Paraguay_with_comments_on_hydrocarbon_potential
  4. Alfredo, Carlos, and Clebsch Kuhn. “The Geological Evolution of the Paraguayan Chaco.” TTU DSpace Home. Texas Tech University, August 1, 1991. https://ttu-ir.tdl.org/handle/2346/9214?show=full.