ALBERT

Description: 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 the following groups: Group 1, sediment consisting of more than 80% clay (material 2 μm or less in size); Group 2, sediment containing from 60 to 80% clay‐size material; Group 3, silty clays with less than 60% clay; and Group 4, silts and clays that have a significant sand‐size fraction present (more than 5% sand). The permeabilities of the groups ranged from 10−5 to 10−10 cm/s with 35% 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 =en(15.05)‐27.37. for Group 2, k=en(14. 18)‐26.50. for Group 3, k= en(15.59)‐26.65. for Group 4 k=en(17.51)‐26.93.and for all data, k = en(14.30)‐26.30; wherc n is the porosity (in decimals) 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.

Description: During U.S. Department of Interior, Bureau of Land Management (BLM) public hearings held in 1973, 1974 and 1975 prior to Texas Outer Continental Shelf (OCS) oil and gas lease sales, concern was expressed by the National Marine Fisheries Service, scientists from Texas A&M and the University of Texas and private citizens over the possible environmental impact of oil and gas drilling and production operations on coral reefs and fishing banks in or adjacent to lease blocks to be sold. As a result, certain restrictive regulations concerning drilling operations in the vicinity of the well documented coral reefs and biostromal communities at the East and West Flower Gardens were established by BLM, and Signal Oil Company was required to provide a biological and geological baseline study of the less well known Stetson Bank before a drilling permit could be issued. Considering the almost total lack of knowledge of the geology and biotic communities associated with the South Texas OCS banks lying in or near lease blocks to be offered for sale in 1975, BLM contracted with Texas A&M University to provide the biological and geological baseline information required to facilitate judgments as to the extent and nature of restrictive regulations on drilling near these banks which might be required to insure their protection. In pursuit of this, scientists from Texas A&M University were to direct their attention toward assessments of ground fish populations, unique biological and geological features, substratum type and distribution, and the biotic and geologic relationships between these banks and those farther north.