(636d) Chemical Kinetic Modeling Study of Heavy Hydrocarbons in Naturally Fractured Reservoirs through in-Situ Upgrading Technology

In Situ Upgrading Technology is new thermal-catalytic oil recovery technique that uses hydrogen for improving chemical properties of heavy oils contained in reservoirs, thus increasing recovery efficiencies. A chemical kinetic study was carried out to test hydroprocessing reactions within the matrix and fractures of a carbonate core pack at different temperatures and residence times.

The key elements involved in the present hydro-catalytic oil recovery process are ultra-dispersed catalytic particles, a hot fluid made of vacuum residue as a nano-catalyst carrier and low flow of hydrogen reactant. The study was conducted in a continuous mode, carried out in a laboratory unit that uses a carbonate core pack elementally representing a Mexican oil reservoir. The core pack set up was built up having pressure, temperature, rock characteristics and oil in place similar to real Mexican reservoirs. Cores were saturated with crude oil at 100 ^oC and 1100 psig; then a hot fluid with ultra-dispersed catalytic particles was percolated at 350 ^oC and 1450 psig to irreversibly deposit the catalyst particles over the rock. After a critical nano-catalyst deposition was built inside the core pack, a hot fluid without catalyst was flowed through the core under varying conditions of residence time and temperature, keeping the pressure constant (1450 psig). Collected products were characterized using Gas chromatography Simulated Distillation, P-Value stability test, Micro Carbon Residue and, Sulfur and Nitrogen elemental contents to assess the extent of hydroprocessing.

Experimental results showed stable and high quality recovered oils. The P-Value of the most severe condition was 1.95, comparable with the original value of the crude oil in place (2.0). A low tendency of the studied Mexican oil to produce coke was observed during the In Situ Upgrading test by passing many pore volumes of the VR with a micro-carbon of 24.24% through the core-pack. The oil coming out of the core-pack showed a micro-carbon residue of 17.15 % wt. under the most severe upgrading conditions (350^oC, 1450 psig, and 72 h residence time). This oil resulting from VR shows no much difference compared to 16 %wt. measured for the original oil in place.

The present work provides insights into the oil reactions occurring in the matrix and fractures of the rock during the process In Situ Upgrading, providing important clues about interactions between the rock, the hot fluids contained in the reservoir and hydrogen reagent.