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Site U14021

R.D. Norris, P.A. Wilson, P. Blum, A. Fehr, C. Agnini, A. Bornemann, S. Boulila, P.R. Bown, C. Cournede, O. Friedrich, A.K. Ghosh, C.J. Hollis, P.M. Hull, K. Jo, C.K. Junium, M. Kaneko, D. Liebrand, P.C. Lippert, Z. Liu, H. Matsui, K. Moriya, H. Nishi, B.N. Opdyke, D. Penman, B. Romans, H.D. Scher, P. Sexton, H. Takagi, S.K. Turner, J.H. Whiteside, T. Yamaguchi, and Y. Yamamoto2

Background and objectives

Integrated Ocean Drilling Program (IODP) Site U1402 was chosen as the location for the engineering test of the Motion Decoupled Hydraulic Delivery System (MDHDS). The MDHDS is a new downhole tool delivery system that is deployed by wireline and uses drill string pressure to advance a penetrometer (or other downhole tool) into the formation at the bottom of the borehole. After hydraulic deployment of the penetrometer, the bottom-hole assembly (BHA) is completely decoupled from the BHA; this eliminates the adverse effects of ship heave. The motivation for this engineering development is discussed by Flemings et al. (in press) and in “Background and Objectives: Motion Decoupled Hydraulic Delivery System sea trials” in the “Expedition 342 summary” chapter (Norris et al., 2014a).

Site U1402 is at the same location as Ocean Drilling Program (ODP) Leg 174A Site 1073 (Fig. F1). At this location, the continental slope is smooth and draped by sediments from the Hudson apron, and the water depth is 639 m. During Leg 174A, advanced piston corer (APC) cores were taken to 215 m below seafloor (mbsf). Sediments within the uppermost 200 mbsf were dominated by silty clay (Shipboard Scientific Party, 1998).

The former Site 1073 was chosen because the lithology was well understood from previous drilling (Fig. F2). The mudstone lithology was known to be appropriate for deployment of a penetrometer. Finally, previous work had inferred the presence of excess pressures in this location (Dugan and Flemings, 2000) (Fig. F2), and thus a scientific goal was to directly document the presence of overpressures.

Approximately 2 days of ship time were dedicated to testing the MDHDS. When time allowed, some piston cores were also taken.

1 Norris, R.D., Wilson, P.A., Blum, P., Fehr, A., Agnini, C., Bornemann, A., Boulila, S., Bown, P.R., Cournede, C., Friedrich, O., Ghosh, A.K., Hollis, C.J., Hull, P.M., Jo, K., Junium, C.K., Kaneko, M., Liebrand, D., Lippert, P.C., Liu, Z., Matsui, H., Moriya, K., Nishi, H., Opdyke, B.N., Penman, D., Romans, B., Scher, H.D., Sexton, P., Takagi, H., Turner, S.K., Whiteside, J.H., Yamaguchi, T., and Yamamoto, Y., 2014. Site U1402. In Norris, R.D., Wilson, P.A., Blum, P., and the Expedition 342 Scientists, Proc. IODP, 342: College Station, TX (Integrated Ocean Drilling Program). doi:10.2204/iodp.proc.342.103.2014

2Expedition 342 Scientists’ addresses.

Publication: 3 March 2014
MS 342-103