EFFECT OF PRESSURE ON THE KINETICS OF KEROGEN PYROLYSIS

Laboratory experiments on three different source rock samples indicate that pressure effects on generation kinetics are measurable but minor . Pressure effects are quantified in terms of an activated volume whic h is analogous to the use of activation energy to quantify temperature effects. Although the three shales had slightly different activated v olumes, a value of 27 cm3/mol is recommended as typical for the activa ted volume of the transformation of kerogen to products. With this act ivated volume, a 1380 bar pressure corresponds to about a 7-degrees-C increase in generation temperature. Since generation commonly occurs a t pressures less than 1380 bar, the effects of pressure on generation timing appear minor and well within the range of uncertainty from othe r causes.