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Site M00291

Expedition 313 Scientists2


Transit to Hole M0029A

Preparations for transit to Integrated Ocean Drilling Program (IODP) Hole M0029A commenced at 1455 h on 20 June 2009. This included setting a buoy to mark the location of the casing to be recovered from the seafloor at Hole M0028A. The jack-down procedure began at 1815 h, and the L/B Kayd moved off Hole M0028A at 1825 h, arriving at Hole M0029A at 1915 h. The legs were lowered to the seafloor, and preloading of the platform began at 1945 h. The drilling floor was opened up to operations personnel at 0630 h on 21 June to begin setting up generators, powering up containers, and preparing the drilling floor.

Hole M0029A

During the morning of 21 June 2009, the European Consortium for Ocean Research Drilling (ECORD) Science Operator (ESO) and drilling teams prepared the L/B Kayd for coring operations in Hole M0029A, and by 1030 h, the casing was ready to be run in (Table T1). The first three core runs had no recovery, and it was suspected that the soft sediment could not break through the microsphere bags. The microsphere bags were changed over to softer sample bags, and this, combined with a slight change in lithology, resulted in core recovery in run four. For the rest of the day, continuous coring was completed to 19 m drilling depth below seafloor (DSF), beyond which a switch was made to conducting a 3 m core run every 9 m. Coring continued to progress well for the rest of the day and through the night into 22 June.

After reaching 55 m DSF by 0530 h on 22 June, preparations were made to set the casing deeper into the seabed. The PQ string was pulled and the casing carefully rotated into the ground. To speed the process up, the L/B Kayd's jacking capability was used to assist in setting the casing. Rapid progress was made until the top drive sprung an oil leak and had to be stripped down. After setting had resumed, the casing was successfully positioned within a clay layer at ~11 m DSF. After reaming back down the hole, coring resumed by midnight and continued into Tuesday, 23 June, alternating with periods of reaming and circulating because of caving sands, to 67.31 m DSF by 0850 h.

At 1155 h on 3 June, operations were halted when the PQ string became stuck and a twist-off of the core bit and reamer occurred. After tripping the PQ string and fishing the bit and reaming shell back onto deck, a modified PQ outer core barrel and ALN core barrel was made up. The PQ pipe was run back in at 2230 h.

Early on 24 June, the base of the hole (69.36 m DSF) was reached, and coring, with some open-holing, resumed at 76.47 m DSF. However, at 1150 h, sands with mud polymer patches caused the inner and outer core barrels to stick together, resulting in difficulty in rotating, flushing, and lifting the pipe. For the next 3 h, various attempts were made to release the string. The L/B Kayd was jacked down, taking the casing with it, allowing access to the PQ joint. Once the PQ was disconnected, the HQ was run to the base of the hole. Seawater was pumped down the HQ string, and at 0400 h on Thursday, 25 June, rotation was reestablished. Six rod stands were removed with difficulty and the hole circulated. The PQ string was reamed to the base of the hole, and the hole was advanced by open-hole drilling to 117 m DSF, where two core runs were made. This was followed by further open-hole drilling to 148 m DSF to the seismic reflection thought to be m1.

Open-hole drilling and spot coring continued throughout 26 June, apart from a short time when operations were suspended because of a lightning storm. By midnight, the hole had advanced to 224 m DSF with nine core runs. At 0100 h on 27 June, drilling operations were suspended for 1.5 h because of another lightning storm. After operations recommenced, open-hole drilling and spot coring continued until 1500 h, by which time the base of the hole was at 257 m DSF. The operation then switched to continuous coring.

Initially, recovery was poor in loose sands, and various bit combinations were tried to improve recovery. However, core recovery generally improved on 28 June, although it was still variable. At midnight, the base of the hole had advanced to 312 m DSF. Coring progressed steadily on 29 June, with recovery between 50% and 114%, reaching 352 m DSF by midnight. By midnight on 30 June, the base of the hole had advanced to 395 m DSF.

On 1 July, coring operations were suspended several times because of lightning storms. However, coring then continued from 395 m DSF with excellent core recovery on a steady basis, reaching the target depth of 754.55 m DSF by 1820 h on 11 July. On completion of coring, the rig floor was prepared for the logging program and the hole was conditioned.

During the day, the vertical seismic profile (VSP) equipment, including the air guns, were prepared and tested. Marine mammal observations began 30 min prior to firing of the air guns, which started at 2050 h. The logging program began with through-pipe VSP from the base of the hole. Just after midnight, a storm approached the platform and the lightning safety procedure was implemented. Through-pipe VSP operations were suspended at 0145 h (at ~200 m DSF). The deck was evacuated, and all personnel remained inside the accommodation module until it was safe to return to the deck at ~0400 h. Because of darkness at that time, it was not possible to restart the air gun, as the VSP permit stipulated start-up during daylight hours only. It was decided to abandon the through-pipe VSP operation and switch to through-pipe natural gamma wireline logging from 755 m DSF. The through-pipe logging operation of the entire hole began at 0510 h and was completed successfully by 1215 h, although the winch motor was running very hot.

The next stage was to pull the pipe back to 600 m DSF and open-hole log the bottom section of the hole. However, the drill pipe was stuck and required significant effort to free it. Alternating pulling pipe with reaming and flushing continued for most of the day without significant improvement in the condition of the hole. As by this time the pipe had been pulled back above the 600 m DSF level, the decision was made to continue the hole conditioning operation while pulling up to the next logging step at 484 m DSF and from there try to log the bottom two sections of the hole. This depth was reached at 2245 h on 12 July.

Logging with the resistivity sonde began at 2350 h and was completed at 0300 h on 13 July, despite an intermittent electro/mechanical fault on the winch. The hole was conditioned, and the sonic sonde was lowered. At 624 m DSF, as the sonde was logging, the power supply to the winch tripped several times, and eventually both the winch motor and control box burned out. The sonde was manually recovered to deck by pulling 600 m of wire up the drill pipe and was back on deck at 0905 h. The winch was removed from the drill floor and replaced with the back-up logging winch that had been used for VSP operations. Logging recommenced at 1110 h, first with the sonic and then with the magnetic susceptibility sonde. Between each logging run, the drill hole was conditioned by circulating mud and rotating the pipes.

At 1925 h, the acoustic imaging sonde was connected to the winch cable on deck. No signal was detected, indicating a faulty tool, cable, or connector. Fault-finding efforts continued until 0100 h on 14 July, with several faults being repaired and the tool replaced. On deployment of the tool at 0100 h, a further fault developed with the winch. Then, fatally, all contact was lost with the tool at 0235 h. The generator was also causing concern but kept functioning. The tool was retrieved by 0515 h, and fault finding restarted. An earth-leakage fault in the winch cable at the tool-connector end was finally identified. A section of cable was removed, and the end of the cable was reterminated. Once fixed and tested, the log run was successful, finishing at 1800 h.

Before tripping pipe up to the top of the next logging interval, the opportunity was taken to complete the through-pipe VSP that had been aborted on 12 July. Marine mammal observations started at 1700 h, and the top section of the hole (0–200 m DSF) was logged successfully, finishing at 2100 h. Once complete, the drill pipe was tripped back to the top of the next logging interval at 335 m DSF. It was noted that the drill pipes were very tight for the first five double stands.

On 14 July, the supply boat Sorensen Miller conducted a postdrill survey around Hole M0028A with side-scan sonar and magnetometer, prior to recovery of the casing at a later date.

On 15 July, tripping of the pipe was completed by 0150 h. The natural gamma sonde was lowered down the hole but was unable to progress very far. It punched through an upper bridge but could not penetrate deeper than 352 m DSF because of a second bridge. Logging was therefore conducted between 335 and 352 m DSF. A reaming operation started at 0825 h and was completed at 1845 h, having encountered a third bridge at 495 m DSF. Following this, the resistivity sonde was lowered down the hole at 1900 h. It was unable to penetrate the bridge at 352 m DSF despite reaming. Further reaming and probing indicated open-hole conditions below 357 m DSF. The decision was taken to ream down beneath both bridges and log the lower part of the scheduled logging interval. However, upon reaming to this depth, the probe revealed that a new bridge had formed at 400 m DSF. Further reaming continued to remove this bridge.

Logging with the resistivity, sonic, and magnetic susceptibility sondes continued until 1205 h on Thursday, 16 July. However, after connecting the acoustic imager sonde to the winch, an electrical problem in either the winch cable or connectors halted operations. Despite tripping pipe back to 352 m DSF to enable time for the repairs to be made, it became obvious that it would not be possible to complete repairs and finish the logging schedule within the remaining time because of transit time and the need to enter Atlantic City, New Jersey (USA), on a high tide. Therefore, at 1425 h on 16 July, the decision was made to stop operations, trip all drill pipe and casing, and prepare the containers for transit back to Atlantic City.

Transit to Atlantic City, New Jersey

The L/B Kayd began preparations to depart from Hole M0029A at 0100 h on 17 July 2009, which involved removing all power to the ESO containers, securing the drill floor and equipment, and moving all personnel into the accommodation block. Jacking-down of the platform began at 0200 h, and transit to Atlantic City commenced at 0315 h, with the vessel arriving alongside the Coast Guard Station quayside at 1545 h.

Demobilization of the ESO containers and equipment continued on 17 and 18 July, with the containers being lifted onto the quayside on 18 July. On 19 July, all containers were collected for shipping back to Europe, with the wireline tools being collected on Monday, 20 July. All ESO staff departed on 20 July.

1Expedition 313 Scientists, 2010. Site M0029. In Mountain, G., Proust, J.-N., McInroy, D., Cotterill, C., and the Expedition 313 Scientists, Proc. IODP, 313: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.313.105.2010

2Expedition 313 Scientists' addresses.

Publication: 4 December 2010
MS 313-105