Heat oil in soup pot. Add celery, onion and leek and cook over medium heat until softened, about 5 minutes. Add wheat berries and tomato paste and cook, stirring, until the grains are coated and shiny, about 30 seconds. Add 1 quart of the broth, the beans, the thyme and basil, and bring to a boil. Simmer over low heat for 30 minutes.