In a large pot, combine 6 cups of water, the shrimp shells, onion, celery and bay leaves. Bring to boil and then simmer for 2 hours. When soup is done, in a medium large pan over medium heat, add 4 tablespoons of butter, green onions and garlic, sautéing for 2-3 minutes. Add thyme, oregano, rosemary, cayenne, crushed red pepper, black pepper and salt, mixing well. Stir in Worcestershire sauce, liquid smoke, ketchup, beer, soup stock and 2 tablespoons butter. Simmer for about 5 minutes or until sauce begins to thicken. Add peeled shrimp and cook until shrimp is pink, 2-3 minutes. Do not overcook. Serve over a bed of rice or pasta with lots of crusty bread for dunking.