1887

Abstract

Summary

Shear modulus should be the same despite saturation, but it is observed that the saturated shear modulus is often lower than the dry one, and this is described as shear weakening effect. In many areas, e.g. reservoir engineering, problems such as permeability changes can occur through shear weakening. "Buntsandstein", Grey Berea Sandstone, limestone, dolomite and granite samples were taken to determine mass, porosity, permeability, compressional and shear wave velocity over time. Porosity and permeability values did not change. Vp and vs were determined in the laboratory with an ultrasonic device. The samples were measured dry and saturated (1000ppm NaCl), hence shear and bulk modulus were calculated. Vp and mass over time is presented, increasing mass does not increase vp consistently. Shear and bulk modulus over time is figured, thereby it can be seen that the often cited shear weakening effect occur on the limestone and granite samples. Shear weakening was expected for the limestone samples due to the complicated pore structures, but it was not predictable for granite samples. Probably an explanation could be that granite contains a mineral that is able to adsorb and/or release water which influences the shear modulus, thin sections may provide information.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.201601281
2016-05-30
2024-03-28
Loading full text...

Full text loading...

References

  1. Gegenhuber, N., Steiner-Luckabauer, C.
    [2012] Vp/Vs automatic picking of ultrasonic measurements and their correlation of petrographie coded carbonates from Austria. 74th EAGE Conference and Ex. Copenhagen.
    [Google Scholar]
  2. Gegenhuber, N., Pupos, J.
    [2015] Rock physics template from laboratory data for carbonates. J. Appl. Geophys. 114, 12–18.
    [Google Scholar]
  3. KhazanehdariJ., Sothcott, J.
    [2003] Variation in dynamic elastic shear modulus of sandstone upon fluid saturation. Geophysics68, 472–481.
    [Google Scholar]
  4. Rogen, B., FabriciusI., JapsenP., Hoier, C, Mavko, G., Pederson, J.
    [2005] Ultrasonic velocities for North Sea chalk samples: influence of porosity, fluid content and texture. Geophys. Prospect. 53, 481–496.
    [Google Scholar]
  5. Sharma, R., Prasad, M., Batzle, M., VegaS.
    [2011] Sensitivity of elastic properties to fabric heterogeneity in carbonate rocks. SPE/DGS Saudi Arabia section, Technical Symposium and Ex..
    [Google Scholar]
http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609.201601281
Loading
/content/papers/10.3997/2214-4609.201601281
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error