Physical and Numerical Simulation of an Extra-Heavy Crude Oil Downhole Upgrading Process Using Hydrogen Donors Under Cyclic Steam Injection Conditions

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractPhysical simulation experiments of a Downhole Upgrading Process showed that use of a hydrogen donor additive (tetralin) in the presence of methane (natural gas) and the mineral formation under steam injection conditions (280°C and residence times greater than 24 h) led to an increase of at least three degree in API gravity of the treated Extra-Heavy Crude Oil, three-fold viscosity reduction and, approximately, 8% decrease in the asphaltene content with respect to the original crude. In the present work, a continuous bench scale plant was used at different temperatures (280-315°C) and residence times (24-64 h) for carrying out kinetic studies. A reaction model involving four pseudo-components (light, medium, heavy and asphaltene fractions) was used and the kinetic parameters (pre-exponential factors and activation energies) were determined. Using these data, compositionalthermal numerical simulations were carried out and validated using the bench scale data. The results showed a good match between the calculated and experimental °API gravities of the upgraded crude oil (average relative error 4%) Using the previous model, the Downhole Upgrading Process was numerically simulated under cyclic steam injection conditions (injection of 2500 bbl/d of 1:1 steam/tetralin with 75% quality steam) for 20 days, followed by 10 days of soaking period) in a typical Orinoco Basin reservoir (9°API). The simulation runs showed the production of 12°API upgraded crude oil, accumulated over a 100 day-cycle. However, a reduction in the percentage of conversion of tetralin was observed (0.8%) in comparison with the bench scale experiments (3%), which was attributed to gravitational segregation of the steam coupled with low mixing efficiency of the hydrogen donor with the extra-heavy crude oil at reservoir conditions.

Enhance Oil Recovery for Steam Flooding: Low-Temperature Oxidative Decomposition of Heavy Oil with Air Injection

“…It can be found that after the reaction, yield of low boiling point fraction changes a little, but that of high boiling point fraction decreases significantly. This is because during the aquathermolysis reaction, heavy component in heavy oil translates into light component due to breakage of carbon bonds and hydrogen ion joining. , Oxidative decomposition reaction occurs with the existence of water and O 2 in no. 3.…”