Abstract
According to the results of a series of high pressure experimentation, following empirical equation was proved to be valid between porosity n and strength σs.
n=Aoe-bσs……(1)
where Ao and b are constants or coefficients. This equation is quite compatible with equation (6) derived from well-known compaction eqution (2) and indicates a close relation between "strength coefficient, b" and compaction coefficient c.
In was pointed out that the strength coefficient b is an indication of somewhat softness of the rock structure against failure and hence closely related to strength of boundness or cementation of rock. Since the boundness or cementation of the clastic rocks is formed probably by strong effect of both pressure and temperature, therefore the coefficient b can be a parameter to indicate accumulative energy related to the above factors acted upon the rocks concerned during long geological age.
By this reason, further, the coefficient b could be an indication of physical potentiality for oil and gas fields. To prove this idea, strength coefficients b were studied in several oil-bearing sedimentary basins in Japan. The results are given in Tab. 3, which are agreeable with geological data and mode of occurrence of oil and gas.
