A Sample‐Freezing Drive Shoe for a Wire Line Piston Core Sampler

Abstract

Loss of fluids and samples during retrieval of cores of saturated, noncohesive sediments results in incorrect measures of fluid distributions and an inaccurate measure of the stratigraphic position of the sample. To reduce these errors, we developed a hollow drive shoe that freezes in place the lowest 3 inches (75 mm) of a 1.88‐inch‐diameter (48 mm), 5‐foot‐long (1.5 m) sediment sample taken using a commercial wire line piston core smapler. The end of the core is frozen by piping liquid carbon dioxide at ambient temperature through a steel tube from a bottle at the land surface to the drive shoe where it evaporates and expands, cooling the interior surface of the shoe to about ‐ 109°F (‐ 78°C). Freezing a core end takes about 10 minutes. The device was used to collect samples for a study of oil‐water‐air distributions, and for studies of water chemistry and microbial activity in unconsolidated sediments at the site of an oil spill near Bemidji, Minnesota. Before freezing was employed, samples of sandy sediments from near the water table sometimes flowed out of the core barrel as the sampler was withdrawn. Freezing the bottom of the core allowed for the retention of all material that entered the core barrel and lessened the redistribution of fluids within the core. The device is useful in the unsaturated and shallow saturated zones, but does not freeze cores well at depths greater than about 20 feet (6 m) below water, possibly because the feed tube plugs with dry ice with increased exhaust back‐pressure, or because sediment enters the annulus between the core barrel and the core barrel liner and blocks the exhaust.

Comparison of surficial CO2 efflux to other measures of subsurface crude oil degradation

“…Cores were collected in vertical profiles through the unsaturated zone to below the water table from sites 1b, 2, 3, and 4 during July 26 to 28, 2010 (Table A.2), using a freezing drive shoe (Murphy and Herkelrath, 1996). At these sites, three sample locations for methanotrophs were selected to lie above, within, and below the methanotrophic zone.…”

“…Briefly, Bemidji crude oil samples (except for the archived oil) were collected using a freezing drive shoe (Murphy and Herkelrath, 1996) on July 27 to 28, 2010, for sites 2 to 4 and July 17, 2008, for site 5. The samples were extracted using dichloromethane (DCM) from two separate oil-contaminated sediment samples taken from each site.…”

Silicates, Silicate Weathering, and Microbial Ecology

“…Cores were collected from the microbially active anoxic region of the contaminated Bemidji aquifer using a frozen-shoe, wire-line core barrel (Murphy and Herkelrath 1996). The core material and the selected mineral type were transferred to triplicate sterile serum bottles in an anaerobic chamber, nished with a 1:1 mixture of formation water and sterile anaerobic water, and amended with toluene.…”

Effects of a Dual‐Pump Crude‐Oil Recovery System, Bemidji, Minnesota, USA

“…Using the methods described by Hess et al () and Murphy and Herkelrath (), about 15 soil cores were collected with a freeze shoe apparatus at both the north and south oil pools (Figure ). The cores were analyzed in order to measure the vertical distribution of oil, air, and water saturation within each core.…”