INFLUENCE OF KEROGEN TYPE AND TOC CONTENT ON MULTIPHASE PRIMARY MIGRATION

Primary migration of fluids out of source rocks is modeled in this pap er as a multiphase fluid flow. Pressure changes created in the source rock through the cracking of organic matter, and porosity reduction du e to rock compaction and kerogen cracking, are the two driving forces for primary migration considered here. This approach links cracking sc hemes and kinetics with the porosity evolution of the source rock duri ng geological times, through mass and volume balance equations. Fluids created and trapped inside the source rock become separated into seve ral fluid phases, according to their pressure, temperature and bulk co mposition. Each phase is expelled according to its own mobility. At a given pressure and temperature, the composition and the amount of the expelled fluids vary greatly, depending on: (1) the cracking schemes a nd kinetics (e.g. Type II vs Type III kerogens); (2) the source rock r ichness (TOC).