During the past quarter of a century, the exploitation of oil and gas reserves, associated with thick sequences of very fine-grained and coarsegrained rocks in the Tertiary Basins, have become increasingly important for fulfilling the world's energy needs. Many exploration and reservoir development problems have arisen which demand an analytical solution. The solution of many scientific and technological problems associated with these geologically young basin sediments requires knowledge of the origin, maintenance, and distribution of abnormally high pore-fluid pressures, chemical changes induced in the interstitial water by compaction, origin and migration of hydrocarbons, temperature gradients, clay minerals phase changes, and subsidence of the surface. Successful drilling to depths greater than 20,000 ft in these sediments and the amounts of hydrocarbons discovered and produced depend to a great extent on our knowledge of the physical and mechanical properties and deformation characteristics of the sediments and the interrelationships among the various properties of sediments and associated interstitial fluids.