Experiments on method for washing drill cuttings: evaluation of soaking, stirring, and milling effects

Abstract

Effects of soaking, stirring, and milling were investigated to standardize the washing method used for drill cutting samples. Drill cuttings are fragments of solid material ground by a drill bit at the bottom of a hole. They are recovered on the ship in riser drilling as a component of the circulating drilling mud. Removal of drilling mud from the surface of cutting samples must be done before cutting samples are analyzed. Cutting samples from IODP Expedition 337 were used in test experiments. The samples were analyzed before and after soaking, stirring, and milling with XRD, XRF, an elemental analyzer and a carbonate analyzer. Results show that Na and K contents are reduced by the removal of drilling mud. However, changes that occur after 6 h of soaking are rather minor. These results suggest that stirring of cuttings in heated seawater at 40℃ for 6 h after quick washing is effective for XRF and TOC analyses.