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Environmental Earth Sciences

, 75:1442 | Cite as

Experimental investigation of factors affecting compressional and shear wave velocities in shale and limestone of Ewekoro formation of Southern Nigeria sedimentary basin

  • Adio Olufemi AbatanEmail author
  • Olukayode D. Akinyemi
  • Joseph A. Olowofela
  • Godwin A. Ajiboye
  • Felix Kolawole Salako
Original Article

Abstract

Compressional V p and shear V s velocities measurements were taken out on fluid-saturated shale and limestone obtained from the Ewekoro quarry of Southern Nigeria sedimentary basin at constant differential pressure of 50 MPa with porosities ranging from 0.32 to 0.53% and 0.01 to 0.35 for limestone and shale, respectively, while the volume of clay content C ranges from 0 to 60% and 0 to 40% for limestone and shale, respectively. Correlation coefficient for the velocities of both clean samples and those with clay minerals ranged from 0.972 to 1.000 and 0.971 to 1.000, respectively, with limestone having the lesser for both. A very small amount of clay, about 0.21 and 0.23, reduced the elastic modulus of limestone and shale, respectively. For water-saturated shaly samples, V s was more sensitive to porosity and clay content than V p . Consequently, velocity ratios V p /V s also showed a reasonable degree of correlations with clay content and porosity. For both limestone and shale studied, the presence of porosity is the most important parameter in reducing velocities followed by clay content due to the softening of its matrix. This study established that wave velocities are functions of porosity and clay content of porous shale and limestone of Ewekoro formations.

Keywords

Porosity Clay content Compressional wave velocity Shear wave velocity Shale Limestone 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Adio Olufemi Abatan
    • 1
    Email author
  • Olukayode D. Akinyemi
    • 2
  • Joseph A. Olowofela
    • 2
  • Godwin A. Ajiboye
    • 3
  • Felix Kolawole Salako
    • 3
  1. 1.Science Laboratory Technology DepartmentMoshood Abiola PolytechnicAbeokutaNigeria
  2. 2.Physics DepartmentFederal University of AgricultureAbeokutaNigeria
  3. 3.Soil Science DepartmentFederal University of AgricultureAbeokutaNigeria

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