Heat oil in a large (4-5 qt.) soup pot over medium heat. Add carrots, onions, celery, and bell pepper, then season with a little salt and pepper. Cook until tender and onions are translucent, about 5 minutes. Add kale and sauté until wilted. Add garlic, thyme, rosemary, bay leaf, and chopped tomatoes and cook for 1 more minute. Add chicken broth and water, scraping the bottom of the pot to loosen any vegetables.