Cryogenic Drilling

Task Description

This task provides a temporary method for stabilizing the borehole while drilling. Prevention of bore-
hole collapse is an important con-
sideration when drilling in uncon-
solidated sandy or gravelly sedi-
ments and in particular when drilling horizontal wells.

In cryogenic drilling, horizontal or vertical holes are drilled using super-cooled air as the drilling fluid, allowing holes to be stabil-
ized by freezing a ring of soil around the borehole during the drilling process (Figure 2.2). It re-
sults in a minimum alteration of the soil as well as minimization of surface wastes due to the fact that

liquid and volatile contaminants are frozen in place, and the re-
turns are limited to air and the volume of soil excavated from the hole. This method also precludes the need for the use of drilling liquids or hole stabilization additives.

Technology Needs

Many DOE and industrial sites are contaminated with toxic sub-
stances that have leaked into the near surface soils. In order to characterize and remediate these sites, boreholes must usually be drilled. One of the difficulties that arises in the drilling of near-
surface boreholes in unconsolidat-
ed formations is the poor stability of the borehole. This can be an acute problem in drilling hori-