Permeability of Unconsolidated and Consolidated marine Sediments, Gulf of Mexico: ABSTRACT

Abstract

Permeability of a large number of natural marine sediment samples from the Gulf of Mexico was determined through the use of laboratory consolidation tests. The samples were divided into groups as follows. Group 1, sediment consisting of more than 80 percent clay (material 2µ or less in size); Group 2, sediment containing from 60 to 80 percent clay-size material; Group 3, silty clays with less than 60 percent clay; Group 4, silts and clays that have a significant sand-size fraction present (more than 5 percent sand). The permeabilities of the groups ranged from 10-5 to 10-10 cm/sec with 35 ppm normal seawater being used as the saturating fluid. A statistical analysis of the natural log of permeability versus porosity was used to develop the permeability prediction equation for each of the groups listed. The equation for Group 1 is k = eP(15.05) - 27.37, for Group 2 k = eP(14.18) - 26.50, for Group 3 K = eP(15.59) - 26.65, for Group 4 k = eP(17.51) - 26.93), and for all data k = eP(14.30) - 26.30, where P is the porosity (in decimal) and k is the coefficient of permeability. These equations are useful for predicting changes in permeability with depth in fine grained sediments of the Gulf of Mexico. The ability to predict permeability in a continuous sequence, where the deposition history is known, may explain the large variations that we see in the physical properties in sediments similar in grain size and mineralogy. End_of_Article - Last_Page 2207------------