In a large stock pot, over high heat, add the oil. When the oil is hot, add the onions, carrots, and celery. Saute for 2 to 3 minutes. Add the remaining ingredients and bring to a boil. Reduce the heat to low and simmer for about 2 hours. Remove the stock from the heat and skim off any scum that is on the surface. Strain the stock through a large fine-mesh sieve. Discard the bones and vegetables.