Production drilling at WAIS Divide

Abstract

ABSTRACT. The deep ice-sheet coring (DISC) drill was used for production ice-core drilling at WAIS Divide in Antarctica for six field seasons between 2007 and 2013. Continuous ice-core samples were obtained between the snow surface and 3405 m depth. During the 2012/13 austral summer, the DISC drill's newly designed replicate ice-coring system was utilized to collect nearly 285 m of additional high-quality core samples at depths of high scientific interest. Annual progress graphs are described, as well as milestones achieved over the course of the project. Drilling operations, challenges encountered, drill fluid usage, drilling results, and the drill crew's experiences with the DISC drill and replicate coring system during production drilling are described and discussed in detail. Core-processing operations are described briefly, as well as the logistical undertaking of the DISC drill's deployment to Antarctica.

Core handling and processing for the WAIS Divide ice-core project

“…The WAIS Divide drilling operation is discussed by Slawny and others (2014) and is not discussed in detail here. However, for the purposes of this paper, it is important to describe the sequence of events inside the drilling arch at the end of each drill run.…”

Ice-core drilling problems and solutions

“…To solve the problem of ice sticking the maximum concentration of cuttings in the fluid would be presumably no higher than 1-2%. This was obliquely confirmed during drilling operations at WAIS Divide where drilling was stopped~50 m above the base of the ice sheet at a temperature of~-6°C at the bottom (Slawny et al, 2014). The DISC drill performed well in these warming conditions presumably because the flow rate of~300 L min − 1 of the DISC drill pump aided by continuously flushing the drill head with cooled drilling fluid.…”

“…Later, a similar drill head was used in an attempt at subglacial rock sampling at NorthGRIP, Greenland (see Fig. 33 in Talalay, 2013) and to retrieve lost hardware bits in the WAIS Divide borehole (Slawny et al, 2014).…”

DISC drill and replicate coring system: a new era in deep ice drilling engineering

“…All aspects of the DISC and replicate coring production drilling are summarized in Slawny and others (2014).…”