IODP Expedition 395E
Complete South Atlantic Transect Reentry Installations
Daily Science Report for 31 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 251 nmi at an average speed of 10.5 kt, completing 4805 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 30 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: Today the ship transited 277 nmi at an average speed of 11.5 kt, completing 4554 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 29 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: Today the ship transited 273 nmi at an average speed of 11.4 kt, completing 4277 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 28 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 263 nmi at an average speed of 11.0 kt, completing 4004 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 27 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: Today the ship transited 278 nmi at an average speed of 11.6 kt, completing 3741 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 26 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: Today the ship transited 274 nmi at an average speed of 11.4 kt, completing 3463 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 25 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 259 nmi at an average speed of 10.8 kt, completing 3189 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 24 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: Today we passed the halfway point of the transit to Reykjavík. The ship transited 252 nmi at an average speed of 10.5 kt, completing 2930 nmi of the total 5761 nmi transit.
Daily Science Report for 23 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 251 nmi at an average speed of 10.5 kt, completing 2678 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 22 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 252 nmi at an average speed of 10.5 kt, completing 2427 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 21 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 249 nmi at an average speed of 10.4 kt, completing 2175 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 20 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 256 nmi at an average speed of 10.7 kt, completing 1926 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 19 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 258 nmi at an average speed of 10.8 kt, completing 1670 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 18 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 246 nmi at an average speed of 10.3 kt, completing 1412 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 17 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 275 nmi at an average speed of 11.5 kt, completing 1166 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 16 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: Today, the ship transited 274 nmi at an average speed of 11.4 kt, completing 891 nmi of the total 5761 nmi transit to Reykjavík.
Daily Science Report for 15 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 290 nmi at an average speed of 12.1 kt, completing 617 nmi of the total 5761 nmi transit to Reykjavík. In the Chemistry Laboratory, ion chromatograph, spectrophotometer, and titration measurements were completed on interstitial water samples from Cores U1561A-1H to 6H.
Daily Science Report for 14 May 2021
Location: In transit to Reykjavík, Iceland.
Science Update: The ship transited 274 nmi at an average speed of 11.4 kt, completing 327 nmi of the total 5761 nmi transit to Reykjavík. Physical property and paleomagnetic measurements have been completed on Cores U1561A-1H to 9X. The two cores which were shot from beneath the seafloor, in failed attempts to establish the mudline depth, have now been identified as U1561B-1H and U1561C-1H. They were also measured on some instruments, but will be used with caution because they likely contain some push-in sediment.
Daily Science Report for 13 May 2021
Location:
- Hole U1561A (30°43.2902′S, 026°41.7162′W, water depth 4909.5 mbsl, proposed Site SATL-55A)
- In transit to Reykjavík, Iceland
Science Update: We raised the drill bit from 4894 meters below sea level (mbsl) and it cleared the rig floor at 1150 h, ending operations at Hole U1561A. From 1230 to 1730 h we deployed the subsea camera to 4881 mbsl to detorque the camera’s umbilical cable. We then secured the rig floor for transit, raised the thrusters, and at 1806 h began the sea passage to Reykjavík, Iceland. The transit is expected to take ~22 d.
Daily Science Report for 12 May 2021
Location: Hole U1561A (30°43.2902′S, 026°41.7162′W, water depth 4909.5 mbsl, proposed Site SATL-55A)
Science Update: Cores U1561A-2H to 6H advanced from 6.7 to 46.2 meters below seafloor (mbsf). Core 6H struck basaltic hard rock, which bent the advanced piston corer (APC) cutting shoe. This was unexpected because the main basement seismic reflector is interpreted to be at ~126 mbsf at this site. We switched to the extended core barrel (XCB) and Cores U1561A-7X to 9X advanced from 46.2 to 48.9 mbsf. Cores U1561A-1H to 9X recovered 45.4 m (93%). At 2245 h we stopped coring to prepare for the transit to Reykjavík. We raised the drill bit, clearing the seafloor at 2355 h.
Daily Science Report for 11 May 2021
Location: Hole U1561A (30°43.2906′S, 26°41.7150′W (preliminary), water depth 4909.5 mbsl, proposed Site SATL-55A)
Science Update: Having completed reentry installations in Holes U1560B, U1557D, and U1556B for the South Atlantic Transect, some operations time remained before we need to depart for Reykjavík on the morning of 14 May. In consultation with the Expedition 390/393 Co-Chief Scientists, it was decided to core a single hole at nearby alternate Site SATL-55A, where the sediment/basement contact is ~126 meters below sea floor (mbsf).
We secured the rig floor for transit and raised the thrusters. At 0114 h we started the 13 nmi transit to the north, arriving at Site U1561 (proposed Site SATL-55A) at 0324 h. We lowered the thrusters and entered dynamic-positioning mode at 0349 h. The advanced piston corer/extended core barrel (APC/XCB) bottom-hole assembly (BHA) was made up and lowered to the seafloor. The water depth was 4963 meters below sea level (mbsl) according to the 12 kHz precision depth recorder (PDR) chirp reflection, which was deeper than the anticipated water depth of 4857 mbsl. The BHA took weight at 4927 mbsl, so we raised the drill bit to 4917 mbsl and then to 4912 mbsl to attempt mudline cores, both of which returned full and did not recover a mudline. The drill bit was raised to 4907 mbsl for a third attempt. Hole U1561A was spudded at 2335 h and Core U1561A-1H recovered 6.7 m, establishing a seafloor depth of 4909.5 mbsl.
Daily Science Report for 10 May 2021
Location: Hole U1556B (30°56.5244′S, 26°41.9472′W, water depth 5001.8 mbsl (updated), proposed Site SATL-53B)
Science Update: At 0915 h, the seas had subsided enough to lower the subsea camera to the seafloor safely. We observed that the top of the reentry cone was level with the seafloor, and tagged it to determine a water depth of 5001.8 meters below sea level (mbsl) for Hole U1556B. This depth is 4.6 m shallower than the mudline depth at Hole U1556A. At 1225 h we reentered Hole U1556B with the cementing bottom-hole assembly (BHA). A circulation test showed that the formation had sealed around the casing, hence there was no need to cement the base of the hole. We raised the BHA, which cleared the seafloor at 1240 h and reached the rig floor at 2359 h, ending operations at Hole U1556B for this expedition.
Daily Science Report for 9 May 2021
Location: Hole U1556B (30°56.5244′S, 26°41.9472′W, water depth 5006.4 mbsl, proposed Site SATL-53B)
Science Update: From midnight to 0200 h, we lowered the cementing bottom-hole assembly (BHA) from 4408 to 4922 m below sea level (mbsl) and installed the top drive. The average ship heave for the day was 3 m, which was too high to deploy the subsea camera, so for the rest of the day we waited on weather. The seas were forecast to become calmer on 10 May.
Daily Science Report for 8 May 2021
Location: Hole U1556B (30°56.5244′S, 26°41.9472′W, water depth 5006.4 mbsl, proposed Site SATL-53B)
Science Update: We continued to raise the drill bit up to the ship from a depth of 2386 m below sea level (mbsl). From 0245 to 1200 h we disassembled the bit, underreamer, and mud motor that had been used to drill in the casing in Hole U1556B, and then assembled the bottom-hole assembly (BHA) for cementing. After stowing the casing deployment equipment, we lowered the cementing BHA to 4408 mbsl.
Daily Science Report for 7 May 2021
Location: Hole U1556B (30°56.5244′S, 26°41.9472′W, water depth 5006.4 mbsl, proposed Site SATL-53B)
Science Update: From midnight to 1530 h we drilled in the 10¾ inch casing string from 85.3 to 282.3 meters below seafloor (mbsf) in Hole U1556B. At 282.3 mbsf, the weight of the casing was no longer supported by the drill string, indicating that the casing had landed. At 1630 h we released the casing from the hydraulic release tool (HRT). We filled the hole with 75 bbl of heavy mud, and then raised the drill bit, clearing the seafloor at 1920 h. By midnight we had raised the bit to 2386 meters below sea level (mbsl). Seas are forecast to continue to rise over the next 48 h, which may affect our ability to deploy the subsea camera for reentry with the cementing string.
We conducted a virtual ship tour with a class from the Austin Community College in Texas.
Daily Science Report for 6 May 2021
Location: Hole U1556B (30°56.5244′S, 26°41.9472′W, water depth 5006.4 mbsl, proposed Site SATL-53B)
Science Update: After we finished welding the reentry cone, we lowered it through the moonpool. The assembly, comprising the 10¾ inch casing string, reentry cone, and drilling stinger, was lowered down to 4994 m below sea level (mbsl). At 1300 h, we started to lower the subsea camera; while it was descending, we slipped and cut 115 ft of drilling line as part of regular maintenance. We started Hole U1556B at 1655 h (Hole U1556A was drilled during Expedition 390C in October 2020), and by 2000 h we had drilled in the casing to 75.5 m below sea floor (mbsf). By then, the cable to the subsea camera was wrapped around the drill pipe eight times, which is more than usual, so we paused drilling and slowly raised the subsea camera to the ship. It was back aboard at 2245 h. We resumed drilling, and by the end of the day we had reached 85.3 mbsf. The target depth is 286.2 mbsf.
Daily Science Report for 5 May 2021
Location: Site U1556 (30°56.5244′S, 26°41.9472′W, water depth 5006.4 mbsl, proposed Site SATL-53B)
Science Update: During the night, the JOIDES Resolution offset from Hole U1557D to Site U1556 in dynamic-positioning mode, travelling 3.6 nmi in 12.5 h at an average speed of 0.3 kt. At the same time, we continued to raise the drill string up to the rig floor. We had disassembled the bottom-hole assembly and the Dril-Quip casing running tool by 0630 h. In preparation for installing casing, we made up the hydraulic release tool (HRT) and set it aside in the derrick. We then assembled 284.2 m of 10¾ inch casing and landed it on the base of the reentry cone in the moonpool. From 1700 to 2215 h, we assembled the stinger (comprising a 9⅞ inch bit, underreamer, and mud motor), tested it in the moonpool, and lowered it down through the casing. The same assembly had been used to drill Hole U1560B earlier in the expedition. The HRT running tool was attached and bolted to the base of the reentry cone. Finally, we constructed the reentry cone and welded it to the base.
Daily Science Report for 4 May 2021
Location: Hole U1557D (30°56.4546′S, 26°37.7898′W, water depth 5010.66 mbsl, proposed Site SATL-56A)
Science Update: We lowered the casing string down to 4978 m below sea level (mbsl), and at 1000 h we started to lower the subsea camera. We reentered Hole U1557D at 1245 h, and lowered the casing string to 554 m below seafloor (mbsf). At that depth we engaged the top drive to allow rotation, if required, and continued lowering the casing to its full depth of 571.6 mbsf at 1535 h, landing the top of the casing in the existing reentry cone. There was no circulation in the hole while pumping, showing that the formation had sealed around the casing, and that the base of casing would not need to be cemented. We released the casing from the Dril-Quip running tool, and cleared the reentry cone at 1600 h. The subsea camera was raised aboard at 1830 h. By the end of the day, we had raised the drill string to 1668 mbsl.
Daily Science Report for 3 May 2021
Location: Hole U1557D (30°56.4546′S, 26°37.7898′W, water depth 5010.66 mbsl, proposed Site SATL-56A)
Science Update: After we had filled the hole with heavy 12 ppg mud, we pulled the drill bit out of the hole, clearing the seafloor at 0315 h and reaching the rig floor at 1430 h. We assembled the casing running tool and set it aside in the derrick, and then assembled the casing string, which took the remainder of the day.
Daily Science Report for 2 May 2021
Location: Hole U1557D (30°56.4546′S, 26°37.7898′W, water depth 5010.66 mbsl, proposed Site SATL-56A)
Science Update: Today we continued to drill Hole U1557D and prepare it for casing installation. We started at 500.6 m below seafloor (mbsf), reached the basement contact at 566.6 mbsf at 0830 h, and reached the target depth of 576.6 mbsf at 1600 h. We then swept the hole of cuttings by pumping 50 bbl of high viscosity mud. Next we made a wiper trip to clear the hole of obstructions and infill. We racked the top drive and raised the drill bit to the base of the 16 inch casing (60 mbsf), then lowered the drill bit back down to 524.1 mbsf. At that point, we reinstalled the top drive and rotated the drill bit down, encountered infill at 568.1 mbsf, and then washed it out down to the hole depth of 576.6 mbsf. We made another sweep of the hole with 50 bbl of high viscosity mud, and then filled the hole with 12 ppg heavy mud to help reduce any caving of the borehole walls.
Daily Science Report for 1 May 2021
Location: Hole U1557D (30°56.4546′S, 26°37.7898′W, water depth 5010.66 mbsl, proposed Site SATL-56A)
Science Update: Throughout the day we continued to drill a 14¾ inch hole from 135.7 m below sea floor (mbsf), and we reached 500.6 mbsf by midnight. The target depth is 10 m into basement, ~574 mbsf.