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5 Find antonyms in the text for the following words.
soft formations clay
disadvantage plain
rotary drilling top
simple hard-rock formation
quiet

6 Say whether the following statements are true or false.

1 The two drilling techniques are rotary drilling and directional drilling
2 Colonel Drake and George Bissel drilled the Oil Creek site.
3 Cable-tool rigs had more parts and a cable tool had a powered bullwheel mounted in derrick.
4 At Drake’s rig, a 10-horsepower (4.5 – watt) steamboat engine powered the walking beam.
5 Cable-tool drilling worked very well in the hard-rock formations such as those in eastern U.S.,
the Midwest, and California.
6 A far bigger problem than bailing, that led to cable-tool drilling's demise, was that the cable-tool
technique didn't work in soft formations like clay or loose sand.
7 The wall cake created by circulating drilling fluid prevented formations from collapsing.
8 The pump moves the clean mud back down the hole.
9 As you now know, one disadvantage of a rotary rig is that workers have to worry about soft
formations caving in on the bit and sticking it.
10 Drilling mud or drilling fluid can be a liquid, a gas, or a combination of the two.

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