Articles

 

BOLETÍN DE LA SOCIEDAD GEOLÓGICA MEXICANA

Vol 61, Núm. 3, 2009, P. 356-366.

Generación de petróleo mediante experimentos de pirólisis: revisión sobre el conocimiento actual

Petroleum generation through pyrolisis experiments: a review

Demetrio Marcos Santamaría Orozco1*, Myriam Adela Amezcua Allieri1 y Teresita de Jesús Carrillo Hernández1

1 Instituto Mexicano del Petróleo. Eje Central Lázaro Cárdenas No. 152, Col. San Bartolo Atepehuacan. C. P. 07730. México, D. F. *E–mail: This email address is being protected from spambots. You need JavaScript enabled to view it. .

Abstract

The hydrocarbon generation process is a complex issue that involves several aspects. The petroleum generation models have been changing their approaches, although from the beginning, it has been supposed that the petroleum comes from organic matter transformation that is trapped into the source rocks. To simulate the chemical reactions of petroleum formation at laboratory, they have been carried out several pyrolysis experiments in their different modalities. However, the temperatures and pressures of the lab experiments are always different from those that occur in nature, therefore matches or calibrations are necessary to make the estimation of the real temperature to which each event happened. The frst numerical models of generation considered that, as the temperature increases, the kerogen generated bitumen and this last generated oil and gas. With the increment of temperature, the complex compounds of petroleum were cracked through a series of frst order parallel reactions and velocity constants. Later, it was discovered that liquid and gas hydrocarbons were not only generated, but also pre–coke and coke. The temperature affected the physical–chemical properties, and the kinetic parameters were obtained through the distribution of the activation energy and only one frequency factor. The variations in the composition of the kerogen–derived products were due to poli–condensation and aromatization processes. The models began to consider different fractions of the petroleum, and then they became more precise, due to the consideration of multicompound kinetics. The most recent models consider the saturated and aromatic fractions, including resins and asphaltenes compounds. Recently, models have included the iso and cycloalkanes, as well as the alkyl aromatics. The software that simulates the hydrocarbon generation in 1D, 2D and 3D up to now considers 14 chemical classes for the multicompound modeling. It is expected that every time there will be more chemical classes that are involved in the kinetic models and their results will be good to predict the quality and quantity of hydrocarbons before drilling a new well and finding a reservoir.

Key words: petroleum generation, kerogen, numerical modeling, compositional kinetics, hydrocarbons.