Main boring diameter for petroleum well is 20-30 cms in diameter, while
the depth of the oil well may be about __________ kms.
(A) 0.1 to 0.5
(B) 1.5 to 4.5
(C) 7.5 to 12.5
(D) 15-20
the depth of the oil well may be about __________ kms.
(A) 0.1 to 0.5
(B) 1.5 to 4.5
(C) 7.5 to 12.5
(D) 15-20