Deeprock rotary drilling method is most common.

Nonetheless, Petrobras has made strides to lessen Brazil's dependence on foreign oil through the development of advanced offshore drilling methods.

The majority of large diameter water supply wells, especially deep wells completed in bedrock aquifers, were completed using this drilling method.

The vertical drilling method however, in which a cannon was slowly lowered over a turning drill, was very delicate, very time consuming and rather imprecise.

Compared with the traditional drilling method, the advantages of air abrasion are many and include the following:

It is introduced through the stationary drilling method, unaccompanied by footwork.

Three-step, or horizontal drilling method, which combines the stationary strike, advance step, and back-step.

Opponents of the drilling method criticised the Cuomo administration for exaggerating the economic benefits.

The new drilling methods, said Dr. Ehrlich of Rensselaer, "are very careful."

He never patented the drilling method he pioneered, and lost his modest earnings from the oil business speculating on Wall Street.