How similiar is drilling for oil vs. drilling for water?

Question

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Answer 1

you dril for something underground in both

Answer 2

The geology is different, for water drilling you have to find the water table and usually there is no "water derrick," the hole is dug and a well is put in.  You want the similarities though, and obviously, they both are intended to get a valuable resource from the ground.  The other way they are similar is porbably that you have to to a test drill to see if there is anything at all I guess.