Chap. 11] 



GEOPHYSICAL WELL TESTING 



849 



SEDIMENTARY ROCKS" 



Very dry sand 0.8 



Sand with 11.3% moisture.. 2.7 



Quartz sand (dry) 1.0 



Quartz sand (moist) 8.2 



Red sandstone (dry) 2.5 



Red sandstone (moist) 6.0 



Clays (dry) 2.5 



Clays (moist) 3.5 



Molasse sandstone, 5 = 2.06 3.0 



Molasse sandstone, 6 = 2.57 8.1 



Alpine limes 4.9 



Limestone 5.2 



Clayey lime, S = 2.59 6.7 



Clayey lime, S = 2.71 8.1 



Lime 8.8 



"Nagelflue," 8 = 2.03 5.9 



"Nagelflue," 5 = 2.73 9.0 



IGNEOUS AND MET AMORPHIC ROCKS 



Granite, S = 2.66 7.6 



Granite, 8 = 2.6 9.8 



Granite, 5 = 2.66 8.1 



Basalt, 8 = 2.97 6.7 



Aare granite 4.0 



Rof na porphyry 5.5 



Serpentine 8.4 



Gneiss .- 5.3 



Andesite 3.1 



Obsidian 1.9 



Marble 5.2 



Slate 5.7 



Phyllite 7.0 



Lava, 8 = 2.62 4.0 



Traprock, Calumet & Hecla 3.4 



Porphyry 8.4 



Andesite 6.9 



Trachyte, 8 = 2.55 4.6 



Trachyte, 8 = 2.4 3.0 



Garnet schist 6,5 



Calcareous phyllite 4.7 



Lava, 8 = 2.83 4.6 



The values for sedimentary, igneous, and metamorphic rocks indicate 

 that the thermal conductivity is greatly dependent on porosity and 

 moisture. From molecular theory, the following relation has been de- 

 duced,^^ in which c is thermal conductivity, V; is longitudinal wave 

 velocity, and 5 is density: 



c-lO' == vf-S'.lO"''. 



Since approximately V/ = VE/5, the conductivity 



c=E-6.10~^ (11-5) 



where E is Young's modulus. This relation has probably not been tested 

 experimentally on rocks. However, calculations made for various ho- 

 mogeneous rocks and for representative values of E and 5, give reasonable 

 figures for the heat conductivity. The high heat conductivities of igneous 

 and metamorphic rocks are in good agreement with high elastic moduli 

 and densities. 



Thermal rock conductivities may be measured in the laboratory by ab- 

 solute or relative procedures. An absolute method, illustrated in Fig. 

 ll-20a, provides a heater and a plate of constant temperature on both 

 sides of a specimen. Holes of small diameter are drilled into it and are 



"Largely after H. Reich, Handb. Exper. Phys., 25(3). 

 " See also Van Orstrand, A.A.P.G. Bull., 18(1), 19 (Jan., 

 " N. M. Thornton, Phil. Mag., 6, 38, 705, 707 (1919). 



1934). 



