Simulated thermal maturation of type I and III kerogens in the presence, and absence, of calcite and montmorillonite

The effects of a mineral matrix on hydrocarbon generation from different types of kerogen were examined. Simulated thermal maturation of type I*, III/a and III/b kerogens, alone and mixed with minerals, was investigated using anhydrous pyrolysis.Both calcite and montmorillonite modified the products of simulated thermal maturation of the kerogens. Montmorillonite slightly reduced, and calcite slightly enhanced the formation of oil-like products from the coals (type III/a and III/b kerogens). At higher levels of maturation, however, the catalytic effect of calcite resulted in cracking of the pyrolysates. For retention of the pyrolysis products of type I kerogen, montmorillonite proved to be a very active matrix whereas the products were less affected by calcite. The amount of soluble bitumen extracted from heated type I kerogen was higher in the presence of minerals than in their absence. On the contrary, the amount of soluble bitumen obtained from heated type III/a kerogen was smaller in the presence of minerals. In the case of type III/b kerogens this effect of minerals changed as a function of the temperature of simulated thermal maturation.