CHEMICAL KINETIC-MODEL OF HYDROCARBON GENERATION, EXPULSION, AND DESTRUCTION APPLIED TO THE MARACAIBO BASIN, VENEZUELA

This paper describes the development and application of a compositiona l chemical model of hydrocarbon generation, expulsion, and destruction for the Cretaceous La Luna Formation source rock of the Maracaibo bas in, Venezuela, Applications include both laboratory and geological set tings, Laboratory pyrolysis experiments were used to study bulk oil ge neration, expulsion, and associated changes in composition of the kero gen, extractable organic matter, and expelled and unexpelled hydrocarb ons. The laboratory experiments were also used to determine kinetic pa rameters to quantitatively describe organic reactions, via a computer model that also includes simulation of pressure-driven primary expulsi on, over widely varying conditions, We show that the chemical model ac curately simulates the experimental results, Thermal history models fo r wells in the Maracaibo basin were used to simulate hydrocarbon gener ation and pore pressure development in the La Luna Formation and expul sion into nearby Cretaceous reservoirs, Results of the modeling indica te that both compaction disequilibrium and organic maturation play imp ortant roles in the development of excess pore pressure in the La Luna Formation. The model simulation of the variation of indicators such a s Rock-Eval parameters and extract and oil compositions shows generall y good agreement with measurements from remaining kerogen, oils, and e xtracts recovered from the La Luna Formation and from nearby Cretaceou s reservoirs.