Mudrocks, Shales, Silica Deposits and Evaporites

Mudrocks and shales are the most abundant lithologies in most sedimentary basins. They are important because shales includes source rocks for oil and gas, but recently large reserves of gas have been found in shales. Shales may therefore be reservoir rocks because they may have significant porosity and some (although small) permeability to flow gas. The rising production of oil and gas from shales (shale gas and shale oil) in recent years has led to a new interest in the primary composition and the properties of mudstones and shales as functions of the burial depth and temperature. The seismic image for sandstones also depends on the properties of adjacent shales.