Heat a very large pot over medium-high heat and add the oil. Add the celery, onions
and garlic and cook, stirring frequently, until the vegetables are tender, 10 to 15 minutes. Add the potatoes, clam juice and the liquid from the canned clams. Bring to a boil. Lower the heat and simmer
, uncovered, until the potatoes
are tender, about 20 minutes.
In a large bowl, combine the half-and-half and flour and whisk until smooth. Slowly stir the half-and-half mixture into the chowder, stirring constantly. Add the clams and increase the heat to bring the mixture back to a boil. Boil 2 minutes. Lower the heat and stir in the Worcestershire sauce. Season with salt and pepper and serve.