Physicochemical properties of potential low-temperature drilling fluids for deep ice core drilling

Abstract

Drilling fluids are added to deep ice boreholes to facilitate control pressure and remove chips. The drilling fluids currently in use are not intelligent choices for the future from safety, environmental, and technological standpoints. Two potential fluid types, namely, low-molecular weight dimethylsiloxane oils (DSOs) and lowmolecular-weight fatty-acid esters (FAEs), were suggested to replace the drilling fluids currently in use. For this study, six types of liquids (DSO-3,0cs, KF96-2,0cs, ethyl butyrate, n-propyl propionate, n-butyl butyrate, and n-amyl butyrate) were selected because of their appropriate density-viscosity properties. These liquids were tested for properties such as electrical conductivity, thermal conductivity, and compatibility with plastics. The results indicated that the electrical conductivities of all the liquids were very small (b 0.003 μS/cm), and an electric field applied in the electromechanical drills was not sufficient to ionize the liquid. The thermal conductivities of all the tested liquids were considerably less than that of water. However, n-propyl propionate indicated the best performance in terms of the cooling ability at subzero temperatures. The effect of FAEs on O-rings swelling was stronger than that of the DSOs. The potential drilling fluids had absolutely no influence on polytetrafluoroethylene (PTFE) O-rings; hence, they could be considered as the ideal sealing material. Tests indicated that low-molecular-weight DSOs and FAEs were both applicable as drilling fluids for deep ice core drilling. It is suggested that the final decision should be confirmed by field-based and practical experiments in test boreholes.

Icephobic materials: Fundamentals, performance evaluation, and applications

“…As a consequence, ice accretion is a great threat to the flight safety and even gives rise to many crashes taking place in recent years. The ice accretion produces the troubles far more than this, and also brings many inconveniences to our daily lives, resulting in the enormous economic loss every year [11][12][13][14][15][16][17]. To prevent or to suppress the ice build-up, researchers and engineers have made a great deal of effort to understand the physicochemical mechanisms of freezing, and developed many anti/de-icing strategies over the last decades [18][19][20].…”

Adaptation of the Winkie Drill for subglacial bedrock sampling

“…Water cannot be used for the circulation fluid in polar drilling applications for the obvious reason that it would freeze in the borehole. A considerable amount of research has gone into the selection of a drill fluid that meets the requirements of polar drilling (Talalay, 2011; Sheldon and others, 2014; Liu and others, 2016). The decision to use Isopar K was based on the material properties of the fluid as well as its low toxicity, availability, cost and previous experience (IDP successfully used Isopar K at the WAIS Divide drill project).…”