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IODP Expeditions 367 and 368

South China Sea Rifted Margin


Daily Science Report for 22 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: This morning we successfully completed the drilling of the 992 m long 10.75 inch casing string into the seafloor at 0915 h. We pulled the bit up to 976 mbsf, recovered the subsea camera system at 1115 h, then continued to recover the drill string, until the bit was back onboard at 2230 h. The last 1.5 h of the day were spent flushing and storing away the mud motor and underreamer, and reinstalling the upper guide horn in the moonpool area. At our noon crossover, the scientific party received a presentation on the scientific objectives at Site U1503 and an update on the operations plan based on the latest approval by EPSP to RCB core from 990 to 1060 m, then to drill ahead to 1360 m, and finally to RCB core from 1360 m to our target depth of ~1800 m. Review of the Site U1502 reports continues.


Daily Science Report for 21 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: The crew successfully completed the replacement of the clutch diaphragm of the drawworks at 0415 h. Then they continued to lower the drill string from 2379 to 3856 mbsl. As the drill pipe was lowered to the seafloor, they stopped every 25 stands to fill the pipe with seawater to equalize the pipe’s inside pressure with that of the surrounding water. At 0745 h, with the bit at 3856 mbsl, they deployed the underwater camera to inspect the reentry cone assembly and reenter the hole. Hole U1503A was reentered at 1005 h and the rig crew worked the 10¾ inch casing downhole to 908.2 m by midnight. We held a meeting to discuss the scientific results from Site U1502, and the scientists submitted all the site reports to the Co-Chief Scientists and Expedition Project Manager for review.


Daily Science Report for 20 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: At 2300 h a tugboat (M/V Taikoo) arrived on site and delivered the critical spares for the drawworks clutch. The transfer was completed by 2330 h and the rigfloor crew began repairs immediately. Scientists began to submit the Site U1502 reports.


Daily Science Report for 19 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: Drilling and coring operations are on standstill until the replacement parts (low clutch diaphragms) are delivered to the ship on Saturday night, 20 May. Scientists continue writing up the Site U1502 reports.


Daily Science Report for 18 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: We completed assembling the stinger and latched it into the casing hanger. We then lowered the casing and the drill string to 2378.7 mbsl, where we had to stop because their combined weight (430,000 lb) was too high to continue their deployment without using the low clutch of the drawworks. At this point there is nothing more that can be done on the rigfloor until the replacement parts (low clutch diaphragms) are delivered to the ship. Scientists continue writing up the Site U1502 reports.


Daily Science Report for 17 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: The assembling of the 989 m long casing was completed and the casing was hung off the moonpool doors at 1830 h. Following this, the mud motor and underreamer were assembled and function-tested in the moonpool, and the rig crew started to assemble the rest of the drill string that will be used to drill the casing in Hole U1503A. Scientists continue collecting, analyzing, and writing up the data from Site U1502. At 1100 h, we held the science summary meeting for Site U1502 with the participation of the Expedition 367 scientists.


Daily Science Report for 16 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: By 0100 h, the tricone bit had extended Hole U1503A from 864.5 to 902.8 m when the mechanic detected a leak in the drawworks clutch diaphragm that had been replaced earlier in the expedition. Consequently, the decision was made to recover the drill string before the clutch completely failed. The bit was pulled back to 97.6 m inside the hole by 0430 h. A 13 ft wide reentry cone was launched from the moonpool, free-falling all the way down to the seafloor. Following, the subsea camera was deployed to the sea bottom to inspect the landing of the reentry system and confirm that it had landed in the correct position, which it had. Then the bit was pulled up to just above the internal aperture of the reentry cone, which was tagged at 3867.7 m below sea level. Before retrieving the underwater camera system, we conducted required routine rig servicing, which consisted of slipping and cutting 215 ft of drilling line. The subsea camera was brought back onboard at 1045 h, and we continued to recover the drill string until the bit cleared the rotary table at 1655 h. The rest of the day was spent making up the 10.75 inch casing string. Spare diaphragms to repair the drawworks clutch are scheduled to arrive in Hong Kong on 18 May, then be delivered to the ship by boat. While waiting for these to arrive, assembly of the casing string and the stinger will continue as planned. Scientists are documenting the Site U1502 data in the site reports and preparing presentations for tomorrow’s science summary meeting.


Daily Science Report for 15 May 2017

Location: Hole U1503A (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E; water depth 3867.7 mbsl)

Science Update: We spent the day drilling ahead with a 14.75 inch tricone bit in Hole U1503A, deepening the hole from 203.1 to 864.5 m with an average rate of penetration of 49 m/h. We have accumulated 15.8 h on the bit. We plan to drill ahead to 1000 m then install a reentry system and a 10.75 inch casing to ~990 m in the same hole. Scientists are analyzing and documenting the Site U1502 data and preparing presentations for the crossover meeting.


Daily Science Report for 14 May 2017

Location:
Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)
In transit
Arrived at Site U1503 (proposed Site SCSII-9B, 18°8.6298′N, 116°18.8460′E, water depth 3873 mbsl)

Science Update: Following the recovery of the drill string from Hole U1502B, the rig floor was secured, the thrusters were raised, and the short journey to the next site began. We arrived at Site U1503 (scientific prospectus Site SCSII-9B) at 1000 h, but we were unable to position the JOIDES Resolution over the site coordinates until ~1130 h because a research vessel (R/V Shiyan 2) operated by the South China Sea Institute of Oceanology, Chinese Academy of Sciences, was deploying an ocean bottom seismometer (OBS) at the same location as part of a seismic survey the ship was conducting in the area. Following the departure of the research vessel, the JOIDES Resolution lowered the thrusters and a seafloor positioning sonar beacon was deployed as the ship was positioned over the site coordinates. A precision depth recorder (PDR) water depth of 3873.1 m was established and rigging preparations began on the drill floor. A 14.75 inch bottom-hole assembly (BHA) was made up and the drill string was lowered to the seafloor. Hole U1503A was spudded at 2000 h, and by midnight we had drilled without recovery to 191.8 m. Our plan is to continue drilling to 1000 m, then install a reentry system and 10.75 inch casing to ~990 m in Hole U1503A.


Daily Science Report for 13 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: The drill string was raised and the end of the pipe was positioned at 747.3 m (23.6 m below the bottom of the casing to avoid a ledge in the formation we had encountered just below the casing when lowering the RCB coring assembly for the first time). The rig floor was prepared for logging and a modified triple combo tool string was rigged up and lowered through the drill pipe into the open hole at 0200 h. The tool descended smoothly to the bottom of the hole where it encountered 45 m of fill. We conducted our main pass upwards collecting magnetic susceptibility, sonic velocity, density (with caliper), neutron porosity, and gamma radiation data. Once the tool was back aboard, we raised the end of the pipe to 259.3 m inside the casing for the vertical seismic profile (VSP) experiment. The Versatile Seismic Imager (VSI) tool string was rigged up next and run into the casing at 1445 h; as it made its way down and outside the casing it encountered an obstruction just ~3 m below the casing shoe. Therefore, only six VSP stations inside casing could be logged (at 629, 589, 549, 450, 359, and 290 m), recording clear wave forms at all the stations. The VSI tool string was retrieved and rigged down by 2200 h. The rest of the day was spent recovering the drill pipe.


Daily Science Report for 12 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: We completed coring operations in Hole U1502B with RCB Cores 33R to 37R sampling from 896.1 m to the final depth of 920.8 m at 1800 h. We recovered 22.7 m (92%) of basalt showing a gradual transition from greenish-gray, highly altered phyric sheet and pillow lavas, with abundant quartz, calcite, and sulfides veins, to moderately altered, bluish gray, aphyric sheet lavas in the two lowermost cores.

Following the retrieval of the last core, we started preparing the hole for wireline logging. We circulated the hole with a 30-barrel mud sweep and conducted a wiper trip with the top drive to 718.3 m sand back to bottom. No obstructions were found. We released the bit at the bottom of the hole and started to pull the end of the pipe to logging depth by midnight.


Daily Science Report for 11 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: RCB coring in Hole U1502B continued with Cores U1502B-27R to 32R sampling from 868 to 896.1 m with good recovery (20.7 m, 74%). Core recovery increased in the last three cores, which averaged 94%. Our plan is to continue deepening the hole until tomorrow at 1800 h, when we will stop RCB coring and rig up to conduct downhole measurements.

Cores U1502B-23R to 32R were described and measured for petrophysical properties. Geochemical analyses are ongoing. The cores described today consist of massive sparsely plagioclase-rich phyric basalt that is moderate to highly altered. The basalt also contains quartz, carbonate, sphalerite, and iron oxide veins.


Daily Science Report for 10 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: We had just recovered Core U1502B-24R from 858.6 m when the drawworks clutch diaphragm that had been replaced 21 d earlier in the expedition failed at 0115 h. The driller was able to pull the pipe up into the casing and set the top drive back, then attach the circulating head to the drill pipe to maintain circulation. The clutch diaphragm was replaced with our final spare and tested by 0945 h. The driller began to lower the pipe back into the hole, washing and reaming as he worked his way back to the bottom of the hole, where 3 m of fill were found. The hole was cleared with a 20-barrel mud sweep and the center bit was retrieved. We restarted coring at 1630 h, and Cores U1502B-25R and 26R (from 858.4 to 868 m) were retrieved before midnight with 82% recovery. Scientists continue collecting, analyzing, and writing up the data from Holes U1502A and U1502B.


Daily Science Report for 9 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: We lowered the drill string to just above the seafloor, deployed the underwater camera system, and reentered Hole U1502B at 0240 h. The subsea camera was recovered, and we continued lowering the drill string and bit through the casing to 728.3 m (~4.5 m below the casing shoe) where we met resistance. We deployed a center bit, circulated high viscosity mud, and washed/reamed the hole to bottom (846.8 m). We installed the sinker bars to retrieve the center bit, then we deployed an RCB core barrel to begin coring at 1400 h. By midnight we had penetrated from 846.8 to 858.4 m (Cores U1502B-22R through 24R), recovering 6.5 m (56%). Core U1502B-22R recovered only a few basalt pebbles in the core catcher, interpreted to be fall-in from inside the hole, and Core U1502B-22R recovered 3.21 m of continuous greenish gray and bluish gray pillow basalt.


Daily Science Report for 8 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: After recovering Core U1502B-21R from 846.8 m, we stopped coring to change the RCB bit, which had accumulated 48.8 rotating hours. Before pulling the bit up, we circulated the hole with 45 barrels of mud, then we started to pull the bit back into the casing and out of the hole. We had significant overpull (up to 60 klb) between 740.3 and 728 m, but the bit was pulled back into the casing without problems. We lowered the underwater camera system to observe the reentry funnel. While we were still in the hole, we could see the drill pipe clearly in the center of a sediment mount created by the drill cuttings, and the reentry funnel’s concentric black stripes were not visible. We pumped seawater through the bit and cleared the cone. We continued to retrieve the drill pipe until the bit was back on the rig floor at 1345 h. A new bit and a mechanical bit release (MBR) were installed, and the crew began lowering the bit back to the seafloor.

Like the previous cores, Core U1502B-21R sampled moderately to highly altered greenish gray to bluish gray pillow basalts. Quartz, epidotes, calcite, and sulfides veins are common. Scientists continued collecting, analyzing, and writing up the data from Holes U1502A and U1502B.


Daily Science Report for 7 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: RCB coring in Hole U1502B sampled from 825.1 to 846.8 m (Cores U1502B-17R to 21R) with very good recovery (21.9 m, 81.9%). Cores U1502B-17R to 20R were described today and consist of moderately to highly altered greenish gray to bluish gray basalt. Veins of quartz, epidotes, calcite, and sulfides are common. Scientists continue collecting, analyzing, and writing up the data from Site U1502.

The Captain flew flags at half mast in remembrance of IODP Supervisor of Operations Mike Storms, who passed away on 6 May.


Daily Science Report for 6 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: RCB coring in Hole U1502B continued from 796.4 to 825.1 m (Cores U1502B-11R to 16R) with very good recovery (24.6 m, 85.5%). Cores U1502B-11R to 16R sampled sparsely to highly plagioclase-phyric basalt. Veins of quartz, epidotes, and sulfides are common. Scientists continued collecting, analyzing, and writing up the data from Site U1502.


Daily Science Report for 5 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: RCB coring in Hole U1502B penetrated from 757.9 to 796.4 m with an overall recovery of 23.4 m (Cores U1502B-6R to 10R; 60.8%). We switched to half advances (4.6 m) with the RCB at Core U1502B-9R (786.7 to 791.3 m) to improve recovery. Cores U1502B-6R through 9R consist of highly brecciated and altered basalts, with occasional centimeter to decimeter-size chert and claystone clasts. Micropaleontological examination of samples from a semiconsolidated sandstone interval in Core U1502B-3R revealed abundant, well preserved abyssal agglutinated foraminifera.

No other microfossils have been found, and no age determination has been possible for Hole U1502B cores. As a reference point, the base of Hole U1502A, at 750.7 m, is late Oligocene based on biostratigraphic markers.


Daily Science Report for 4 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: After lowering the drill string to 3732 m, the subsea camera was deployed at 0115 h. We paused rig floor operations until 0245 h to conduct required routine rig servicing (drill line slip and cut) before we started to search for the Hole U1502B reentry funnel. It took us 3.5 h to find it and position the bit over the funnel, and we reentered Hole U1502B at 0615 h. We retrieved the camera and lowered the bit down through 715.3 m of casing where we encountered fill. We installed the top drive and conducted a 20 barrel mud sweep to clear the hole. We lowered the bit to 727.7 m and started RCB coring. By the end of the day we had cored from 727.7 to 757.9 m (Cores U1502B-2R to 5R), recovering 7.9 m (26.2%).

The recovered sequence yielded a variety of sedimentary and igneous rocks. Cores U1502B-2R and 3R consisted of claystone, brownish yellow breccia, gray limestone, and dark to light greenish gray clast-rich clay with magmatic components. Cores 4R and 5R sampled coarse sandstone overlying hydrothermally altered and brecciated metadolerite. At our noon crossover, we held the science summary meeting for Hole U1502A, with the participation of the Expedition 367 scientists.


Daily Science Report for 3 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: After yesterday’s successful installation of the 723.7 m long casing string into the seafloor, we recovered the drill string and the camera system. The drill bit was back on the rig floor at 1130 h. After taking apart the drilling assembly, we flushed the mud motor, underreamer, and bit with fresh water, and then prepared the rig floor for RCB coring. We started assembling the RCB coring BHA at 1530 h, and the rest of the day was spent lowering it to the seafloor. Scientists continued to finalize reports and prepare presentations for tomorrow’s science summary meeting for Hole U1502A.


Daily Science Report for 2 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: Today we successfully drilled the 723.7 m long casing string into the seafloor. Immediately after this was completed, we deployed the go-devil to activate the casing running tool, which released the casing at 2220 h. During the last hour of the day we began pulling the drill string out of the hole. The scientists received a presentation on casing installation, and they continue to analyze and prepare presentations of their Hole U1502A results.


Daily Science Report for 1 May 2017

Location: Hole U1502B (proposed Site SCSII-17A, 18°27.8798′N, 116°13.8409′E)

Science Update: The day started while we made up the stinger BHA and then latched it to the mudskirt in the moonpool. The “stinger” consists of the entire drilling assembly, including the pipe, drill collars, mud motor, underreamer, and drill bit that goes inside the casing to drill it in. As the drill pipe was lowered to the seafloor, we stopped every 20 stands to fill the pipe with water to equalize the pressure. We then stopped at 3744 mbsl to deploy the underwater camera so that we could observe drilling in the casing. While the camera was being lowered, the drill crew picked up the top drive and spaced out the bit above the seafloor to spud the hole. Hole U1502B was started at 1255 h, and by midnight we had drilled-in the casing to 294.1 m below the seafloor. Scientists continued to collect, analyze, and write up their data from Hole U1502A and to finalize the Site U1501 reports.