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IODP Expedition 384

Engineering Testing


Daily Science Report for 6 August 2020

Location: Hole U1555D (60°13.680′N, 28°29.902′W; water depth 1516 m; proposed Site REYK-13A)

Science Update: Deployment of the drill string with the 12¼ inch PDC bit and mud motor for the fourth drilling test was completed and drilling in Hole U1555D began at 0245 h. The top of the basement was encountered at 0800 h, with the bit at 189.0 m driller’s depth below seafloor (DSF). The remainder of the day was spent drilling ahead and by 2400 h the bit was at 217.6 m DSF.


Daily Science Report for 5 August 2020

Location: Hole U1555D (60°13.680′N, 28°29.906′W; water depth ~1516 m; proposed Site REYK-13A)

Science Update: Drilling in Hole U1555C with the 12¼ inch TCI bit, Rhino XS hydraulically expandable reamer and mud motor, continued until 1045 h, when the underreamer had reached 20 h of operation and the bit was at 225.8 m driller’s depth below seafloor (DSF). The drill string was retrieved and cleared the rig floor at 1745 h, ending the third drilling test and operations in Hole U1555C.

From 1930 h to 2400 h, the crew made up a 12¼ inch PDC bit and mud motor, assembled the bottom-hole assembly, and began to deploy the drill string for the fourth drilling test of the expedition.


Daily Science Report for 4 August 2020

Location: Hole U1555C (60°13.682′N, 28°29.932′W; water depth 1516 m; proposed Site REYK-13A)

Science Update: For the third test, the rig floor crew continued making up the 12¼ inch TCI bit with the Rhino XS, 12¼ inch to 14½ inch hydraulically expandable reamer and the mud motor. A flow test confirmed expansion of the reamer at 45–50 strokes/min. The drill string was deployed and drilling in Hole U1555C began at 0645 h. At 1000 h, the pumping rate was increased to 60 strokes/min to expand the cutting blocks of the reamer, with the bit at 130.6 m driller’s depth below seafloor (DSF). At 1225 h we reached the top of the basement at 186.6 m DSF. At the end of the day, the bit was at 206.1 m DSF.


Daily Science Report for 3 August 2020

Location: Hole U1555C (60°13.681′N, 28°29.927′W; water depth 1516 m; proposed Site REYK-13A)

Science Update: We continued drilling in Hole U1555B with the 12¼ inch Kymera hybrid bit from 199.0 m driller’s depth below seafloor (DSF). At 1600 h and a bit depth of 210.8 m DSF, we decided to terminate drilling based on the low rate of penetration (<1 m/h) over 6 h. The drill string was retrieved and the bit cleared the rig floor at 2225 h, ending Hole U1555B operations. The Kymera hybrid bit returned intact but showed significant damage.

For the third test, the rig crew began making up a 12¼ inch TCI bit with a Rhino XS, 12¼ inch to 14½ inch hydraulically expandable reamer (Schlumberger), the mud motor, and the bottom-hole assembly.

Final measurements and observations continued in the Core Laboratory on Site U1554 cores.


Daily Science Report for 2 August 2020

Location: Hole U1555A (60°13.682′N, 28°29.944′W; water depth 1516 m; proposed Site REYK-13A)

Science Update: We continued waiting on weather until 1200 h, when the heave became consistently safe for operations to continue. Deployment of the drill string with the second test bit, a 12¼ inch Kymera hybrid bit, was completed and drilling in Hole U1555B began at 1400 h. The sediment was penetrated at the same controlled rate of ~40 m/h as was done in the first test with the TCI bit. At 2030 h we encountered the hard basement formation at 186.6 m driller’s depth below seafloor (DSF). By the end of the day we had reached 199.0 m DSF.

Routine split core measurements of the Site U1554 cores were completed except for the magnetic remanence measurements, which are carried out very methodically for the core orientation testing objective.


Daily Science Report for 1 August 2020

Location: Site U1555 (60°13.682′N, 28°29.949′W; water depth 1512 m; proposed Site REYK-13A)

Science Update: We completed the retrieval of the drill string by 0245 h. For the second bit test, a 12¼ inch hybrid bit was assembled with a mud motor and flow tested. The bottom-hole assembly was made up and the drill string was deployed to 1426 m below the rig floor by 0915 h. Wind and heave had picked up to levels unsafe for rig operations and the rest of the day was spent waiting on weather.

The IODP JRSO staff continued Site U1554 core characterization with section half and discrete sample measurements.