the sinking of boreholes in oil-and gas-bearing regions to obtain the geological and geophysical parameters required for prospecting.
Parametric drilling is an integral part of the first stage of prospecting. Borehole locations are selected on the basis of regional geological and geophysical research data. The holes are usually bored to depths of 3–5 km; sometimes they are bored to more than 7 km. Core samples are taken from 10–20 percent of the total borehole depth. They are used to determine physical parameters, such as reflectivity, refractivity, and density and electrical, magnetic, and acoustic properties. They also reveal such data as the composition of rocks and the precise location of stratigraphic boundaries.
Parametric drilling and other types of regional exploration reveal the details of the geological structure of the earth’s crust and the zones likely to contain accumulations of oil, gas, and other minerals. Such tests largely determine the course of further prospecting.