Place the carrots, celery, onion, and olive oil in a 6-quart Dutch oven or soup pot. Allow the carrots, celery, and onion simmer over medium heat for 10 minutes or until the onions are translucent.
Combine milk and half-n-half in a separate bowl
Add the garlic cloves, chicken stock, water, and add half of the milk and cream to the mixture.
Add the pepper, dried oregano, bay leaf, and chicken. Mix until combined. Allow the soup to simmer over medium heat for 15 minutes.
Whisk together ½ cup flour with the remaining milk and cream mixture. until smooth. Place into the soup mixture and whisk until combined. Use a mini-cuisinart or immersion blender to smooth out if necessary.
Place the long grain and wild rice and the seasoning packet into the soup and mix until combined. Allow the soup to simmer for 20 minutes or until the rice is tender. Add salt and pepper to taste.
Serve and garnish with fresh scallions.
