scholarly journals Comparison of laboratory and in situ compressional-wave velocity measurements on sediment cores from the western North Atlantic

1979 ◽  
Vol 84 (B2) ◽  
pp. 687 ◽  
Author(s):  
Brian E. Tucholke ◽  
Donald J. Shirley
Geophysics ◽  
1985 ◽  
Vol 50 (5) ◽  
pp. 775-784 ◽  
Author(s):  
William D. Daily ◽  
Wunan Lin

We report laboratory measurements of electrical resistivity ρ, water permeability k, and compressional wave velocity [Formula: see text] for both intact and fractured Berea sandstone samples as functions of temperature from 20°C to 200°C and effective pressure [Formula: see text] from 2.5 MPa to 50 MPa. For the intact sample, [Formula: see text] increases from 3.52 km/s to 4.16 km/s as [Formula: see text] goes from 3 to 50 MPa. With increasing temperature, [Formula: see text] decreases at rates of about 3 percent per 100°C at [Formula: see text] of 5 MPa and about 1.5 percent per 100°C at [Formula: see text] of 38 MPa. Data from the fractured sample are qualitatively similar, but velocities are about 10 percent lower. For both intact and fractured samples, ρ increases less than 15 percent as [Formula: see text] increases from 2.5 MPa to 50 MPa. Although both samples show a larger decrease in resistivity with increasing temperature, most of this change is attributed to the decrease in resistivity of the pore fluid over that temperature range. For both samples, k decreases with increasing pressure and temperature. The intact sample permeability varies from 23 mD at 3 MPa and 20°C to less than 1 mD at 50 MPa and 150°C. The permeability of the fractured sample varies from 676 mD at 3 MPa and 20°C to less than 1 mD at 40 MPa and 190°C. The effect of the fracture on k vanishes after several pressure cycles and above about 100°C. These laboratory data are used to demonstrate the possibility of using resistivity and velocity measurements to estimate in‐situ permeability of a reservoir.


Geophysics ◽  
1961 ◽  
Vol 26 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Andris Viksne ◽  
Joseph W. Berg ◽  
Kenneth L. Cook

Compressional wave velocities through 36 synthetic sandstone cores were measured and related to several of their physical properties, namely, porosity, manufacturing pressure, grain contacts, and amount of cement. The cores were composed of Ottawa sand grains averaging 0.12 mm in diameter and commercial Grefco cement; the manufacturing pressure was varied from 4,000 to 10,000 psi; the cement content by volume was varied from 10 to 100 percent; the effective porosities ranged between 2.1 and 30.4 percent; and the compressional wave velocities ranged between 9,170 and 17,420 ft.sec. All velocity measurements were taken at room temperature and atmospheric pressure using cores that contained only air in the pore space. The results are presented in graphic form, showing the relationship between the compressional wave velocity and manufacturing pressure, porosity, and cement content. For Grefco cement contents between 10.0 and 17.5 percent, the compressional wave velocity is controlled by the manufacturing pressure and the porosity. A change in manufacturing pressure of 1,000 psi changed the compressional wave velocity by one percent for cores having porosities of about 23 percent and by about 3 percent for cores having porosities of about 28 percent. A decrease in porosity of one percent increased the velocity by an average of 1.4 percent for effective porosities between 23 and 26 percent. The velocity is also dependent, to a great extent, on the number of grain contacts which is intimately associated with the manufacturing pressure, and the cement content which is intimately associated with the porosity. For cement contents greater than 17.5 percent by volume, the sand grains float in the cement, and the analogy between the synthetic sandstone cores and natural sandstones is questionable.


Author(s):  
Jack K. Odum ◽  
William J. Stephenson ◽  
Kathy Goetz-Troost ◽  
David M. Worley ◽  
Arthur D. Frankel ◽  
...  

Geophysics ◽  
1972 ◽  
Vol 37 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Joel S. Watkins ◽  
Lawrence A. Walters ◽  
Richard H. Godson

The relation of in‐situ compressional‐wave velocities to porosities, determined by seismic refraction for unsaturated near‐surface rocks from different areas in Arizona, New Mexico, and California, is grossly similar to relations determined by other investigators for water‐saturated rock and unconsolidated sediments. The principal difference is that in the porosity range 0.0–0.2, compressional waves travel somewhat more slowly in unsaturated rocks than in water‐saturated rocks, and much more slowly, in the porosity range 0.2–0.8. The function, ϕ=−0.175 ln (α)+1.56, where ϕ is the fractional porosity and α is the compressional‐wave velocity, was obtained as a least squares fit to the experimental data. Bulk densities are reported for all samples; moisture contents are reported in some instances.


2011 ◽  
Vol 96 (10) ◽  
pp. 1425-1432 ◽  
Author(s):  
Q. Zhang ◽  
F.-G. Li ◽  
C.-Y. Sun ◽  
Q.-P. Li ◽  
X.-Y. Wu ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document