Heat oil in a pot over medium heat. Add onion and celery; cook, stirring occasionally, until softened, 4 to 6 minutes. Add garlic, thyme, and parsley; cook, stirring, until fragrant, about 10 seconds.
Stir in carrots. Add water and broth; bring to a high simmer over high heat. Reduce heat to maintain a high simmer and cook until very tender, about 25 minutes.