In a large casserole or soup pot, heat the oil over medium heat. Once hot add the onion and cook for 5 to 6 minutes until softened. Incorporate 1 cup each of the celery, carrot, and leeks (reserving half a cup of each for later use), cook for 3 to 4 minutes until the vegetables have wilted. Make room in the middle of the pot and add the garlic, chipotles in adobo, and chile de arbol, cook for a minute, then mix with the vegetables and cook for another minute. Add the tomatoes, the juices from the oysters, salt, and oregano and cook for about 6 to 7 minutes, until it is all simmering and thickening a bit. Add the broth, once it comes back to a simmer, continue simmering for another 10 minutes. Turn off heat.

Once it cools off a little, puree in batches in the blender until completely smooth. If you want a very silky soup, strain back into the soup pot.

Bring the pureed soup back to a simmer over medium heat, add the remaining half a cup each of the celery, carrot, and leeks and cook for 4 to 5 minutes. Incorporate the shucked oysters, cook for 1 minute until barely cooked through and turn off the heat.

Ladle into soup bowls, garnish with cilantro and offer your guests a quartered lime to squeeze in fresh juice before they eat.