A Literature Survey of Drilling Fluids and Densifiers

A literature search was conducted to investigate potential choices in drilling fluids and densifiers for use in deep ice core drilling programs. Previous practice has been to employ fuel (DF-A, kerosene or JP-4) and a heavy chlorinated solvent (PCE or TCE) to increase the density (specific gravity) from about 0.85 to 0.92.

Ethyl alcohol has been used by the Soviets. However, it does not satisfy hydrophobicity requirements and will attack ice grain boundaries as well as to affect oxygen isotope measurements.

Many other compounds are presently available which meet the general drilling requirements but fail to meet the criteria required to acquire a high quality ice core which will be sampled for chemical analysis. Also, many fluids are unacceptable because of their high toxicity.

This literature search of nearly 250,000 compounds and synthesis of data resulted in 15 compounds which may be considered for use as a drilling fluid or fluid densifier.