Why is Saint Patrick considered to be the patron saint of engineers? An exhaustive search on the web, that lasted a good ten minutes, revealed the following:
Saint Patrick is credited with fostering the development of arts and crafts and introducing the knowledge of the use of lime (think limestone reservoir rock) as mortar in Ireland. He is also responsible for the initial construction of clay (think shale) churches in Ireland in the 5th century A.D. Another of St. Patrick's achievements was teaching the Irish to build arches of lime mortar instead of dry masonry. These beginnings of ceramic (think proppant) work developed into organized crafts, and that's how St. Patrick became the patron saint of engineers.