Answer to Question 1Offshore drilling is more expensive and more dangerous. It includes jack-up rigs, drill ships, semisubmersible rigs,
and fixed platforms.
Answer to Question 2 Cable toolthis early method used a chisel to loosen the soil, then rotary drills used bits to break through the
rock and soil.
Directional drillsdrill the shaft at an angle
Special drills called turbodrills or electrodrillsrotate and bend, directing the cutting bit.