“Blue Whale 1,” the world’s largest and most advanced ultra-deep-water semi-submersible drilling rig was built by Yantai CIMC Raffles Offshore Limited in east China's Shandong Province. The 42000-ton oil platform has cost $700 mil. more
[pdf] The first offshore mobile drilling platform was the Breton Rig 20, first operated in 1949. This rig had evolved from the inland drilling barges which were used to drill in marshes and protected waters in up to 10 feet of water. The Breton Rig 20 was 160 feet by 85 feet, and could work in 20 feet water depth.
[pdf] The answer ranges from just a few thousand dollars for a manual rig to several hundred thousand for a high-capacity commercial unit. The right rig for you depends on your drilling needs, budget, and long-term goals. Choosing the right rig is about more than price.
[pdf] 
