IODP

doi:10.2204/iodp.pr.320T.2009

Operations

Singapore Loyang port call

Once the shipyard and harbor trials testing of the ship's systems were completed, the ship docked at the Loyang Offshore Supply Base in Singapore for final loading and mobilization activities. Besides completing all last-minute loading aboard of supplies and equipment, the ship was bunkered, taking on 2700 metric tons of marine gas oil. Bulk products were also loaded, including 74 metric tons of cement and 103 metric tons of barite. The ship passed her final American Bureau of Shipping (ABS) audit and received her Liberian certification; both were required before the ship was cleared to leave port. The ship departed Singapore on schedule with the last line away Loyang Offshore Supply Base at 0811 h on 25 January 2009 (Fig. F1).

Transit to Guam

With so many remnant ship issues to deal with, plus the routine challenges associated with the first extended sea transit after a lengthy shipyard period, Overseas Drilling Limited (ODL) resources (engineers, rig mechanics, electronics technicians [ETs], and electricians) were focused according to priority. In general, the priority was

  1. Ship's propulsion, power plant, safety, and ABS requirements;

  2. Drilling package readiness (primarily top drive, core winch, subsea television capability, and so on);

  3. Automatic station keeping (ASK) system/positioning beacons, and so on; and

  4. Laboratory stack elevator operation.

Work on air conditioning units and toilets were continually recurring (daily) tasks. Of major importance was the resolution of all International Safety Management (ISM) audit and safety issues identified throughout ship. It was an ABS requirement that these be rectified before arriving in Guam.

The ship continued to transit at full speed to Guam to pick up the assessment team scientists. The ship's speed was impacted by a strong head current of ~1.0 kt, variable headwinds that on some days attained 25 kt sustained with gusts up to 40 kt, and problems early on with the propulsion electrical system. Initial problems were related to inadequate ventilation causing overheating and subsequent failures in the aft thyrig room transformers. Those were overcome once the new heating, ventilation, and air conditioning (HVAC) system was better understood/adjusted and vents to the outside were opened. In addition, the new breakers installed continually tripped when turns on the main screws were increased from 120 rpm to the desired 130 rpm. This caused propulsion motors to kick off-line. The old breakers did not trip as early as the new ones, requiring troubleshooting by the ship's engineers. During the last 2 days of the transit, the problems appeared to be resolved because of the diligent efforts of onboard engineers, ETs, and electricians. Another primary issue was the elevator system, which was inoperable for an entire week. Elevator and HVAC technicians were requested for the Guam port call. Toilet functionality continued to be an issue until personnel learned the idiosyncrasies of the new vacuum system. Drilling package readiness efforts also continued throughout the transit, as well as preparations for laboratory acceptance and the RAT review. The 2638 nmi transit to Guam required 12.3 days at an average speed of 8.9 kt. The first line was ashore pier F-3 in Apra, Guam, at 1830 h on 6 February 2009, ending the transit (Fig. F1).

Guam port call

The JOIDES Resolution spent 2.8 days in Guam, which was nearly 2 days longer than originally planned. During that time seven RAT scientists joined the ship, as well as six additional Lamont-Doherty Earth Observatory (LDEO) loggers (including a wireline compensator vendor representative from Deep Down, Inc.) and three Texas A&M University (TAMU) personnel (including an Asset Management System [AMS; India] vendor representative). TAMU also had three personnel depart the ship. Port call activities included service work on the elevator by a vendor representative and service work on freezers by a local refrigeration company. HVAC work also continued with a vendor representative. Additional vendor work on the elevator and HVAC was scheduled for the port call in Honolulu. A USGC annual inspection was conducted. The ship passed with no deficiencies cited and complimentary comments from the USCG about the ship's condition. The last line away pier F-3 was at 1354 h on 9 February 2009, and the JOIDES Resolution headed for Site 807 located on the Ontong Java Plateau.

Transit to Sites 807 and U1330

The 943 nmi transit to Site 807 (Fig. F1) was completed in 4 days at an average speed of 9.8 kt. Speed was impacted by the strong but highly variable Northern Equatorial Current and erratic headwinds. The RAT scientists spent their initial few days attending briefings on the status of systems aboard the JOIDES Resolution. During the transit the USIO development, technical, and science teams worked on assessment and acceptance testing activities. Transocean personnel continued to troubleshoot and correct remnant shipyard deficiencies, as well as prepared the drilling package and subsea television/sonar systems for operations. The ship arrived on location at Hole 807C (published coordinates: 3°36.42′N, 156°37.49′E) at 1440 h on 13 February 2009.

Operations at Sites 807 and U1330

Thrusters and hydrophones were lowered, and after maneuvering the ship to the exact coordinates of Site 807 (Fig. F2), the ship was switched over to DP control. A new Falmouth Scientific positioning beacon was deployed at 1950 h on 13 February 2009; however, during initial use of the ASK system the electrical supervisors and DP operators discovered that the ship's response did not appear to match the commands given. It was ultimately determined that two thrusters (Numbers 8 and 9) were turning in the wrong direction. This was soon corrected by adjusting the wiring, and the drill crew went to work detorquing the coaxial subsea television cable, picking up drill collars, and spacing out core barrels.

Hole 807C

Final location coordinates: 3°36.3529′N, 156°37.4469′E

Established water depth: 2816.0 meters below rig floor (mbrf)

Total penetration depth: not applicable

Coring system: not applicable (reentry only)

During the pipe trip to the seafloor, the VIT camera was deployed, and after tagging bottom to verify the water depth for determining reentry space out, the ship was maneuvered over the Hole 807C reentry cone. Reentry required a mere 13 min from the time maneuvering was initiated until the bit was in the cone. Unfortunately, the euphoria of the outstanding ASK and subsea television/sonar system performance was short-lived when the bit would not advance further into the casing string. After unsuccessful deliberate attempts to entice the bit further into the casing, it became obvious to the operations and drill crews that the 11-7/16 inch advanced piston corer (APC)/extended core barrel (XCB) bit was too big to fit inside the 11-3/4 inch casing string with an inside diameter of 10.99 inches. This important nuance was completely overlooked by all involved. The drill string was recovered and the bottom-hole assembly (BHA) was visually inspected. To everyone's relief, no damage was identified other than to the used APC/XCB bit. The unforeseen pipe round trip and the inability to marry APC coring with the logging tests in Hole 807C on a single pipe trip necessitated changing the operational approach for the remainder of on-site operations.

Hole U1330A

Final location coordinates: 3°36.3349′N, 156°37.4478′E

Established water depth: 2816.0 mbrf (2805 meters below seal level [mbsl])

Total penetration depth: 553.8 meters below seafloor (mbsf)

Coring system: rotary core barrel (RCB)/RCB center bit

The BHA was changed to a RCB variety and tripped to the seafloor in preparation for drilling a dedicated wireline logging hole. Hole U1330A was spudded at 1355 h on 15 February 2009. This hole was offset 30 m due south of Hole 807C and was drilled to 103.6 mbsf with an RCB wash barrel (1W) in place. A wash barrel has the check valve at the top removed to allow circulation down the inner diameter of the barrel to flush away any material that might get in. It is occasionally used in lieu of a center bit and by definition is designed not to intentionally recover core. Despite this configuration, the core catcher retrieved 7 cm of sediment. This sample was curated as 320T-U1330A-1W-CC. Two RCB cores (2R and 3R) were then cut from a 103.6 to 122.8 mbsf, recovering 84.2% of the formation penetrated. These cores were processed through the laboratories, allowing continued readiness assessment and evaluation of core flow through the laboratories by the RAT (Tables T1, T2).

An RCB center bit was used to deepen the hole to 553.8 mbsf for WHC and logging tools evaluation. A wiper trip was made to condition the hole for logging, the bit was released, the hole displaced with 190 bbl of heavy 10.5 pound per gallon (ppg) mud, and the end of the pipe was placed at 96.7 mbsf. Logging system testing required 48.25 h, with initial testing taking place inside the drill pipe followed by open-hole testing. A total of three logging runs were made using three separate tool strings. The first tool string, consisting of the Hostile Environment Gamma Ray Sonde (HNGS), Hostile Environment Litho-Density Sonde (HLDS), General Purpose Inclinometer Tool (GPIT), and Phasor Dual Induction and Spherically Focused Resistivity Tool (DIT-E), reached to within 1 m of bottom. The second tool string, with the Formation MicroScanner (FMS), reached 524 mbsf or ~30 m off bottom. The third tool string, consisting of the HNGS, HLDS, DIT-E, GPIT, and Magnetic Susceptibility Sonde (MSS), reached 469 mbsf (~85 m off bottom). Preliminary results indicated that although the new Schlumberger WHC was performing at an acceptable level, LDEO and Schlumberger personnel felt that the system ultimately would be capable of exceeding performance levels achieved with the LDEO WHC used previously during IODP Phase 1. Logging activities encompassed general maintenance of the WHC, performance documentation, and analysis of the suite of logging data collected in Hole U1330A.

Logging operations

Hole U1330A was completed to 3369.8 meters drilling depth below rig floor (DRF) (553.8 meters drilling depth below seafloor [DSF]) at 1330 h on 16 February 2009. Conditioning of the hole included several mud sweeps and a complete wiper trip. After the RCB bit was released at the bottom, the hole was swept with 190 bbl of heavy mud (barite) and the pipe was lifted to the logging depth of 96.7 DSF at 0230 on 17 February. This allowed the ~20 m interval (103.6–122.7 m DSF) that was cored in Hole U1330A to be included in the logging program.

A critical component of logging operations during this expedition was testing of the WHC, both in the drill pipe in the water column and below the seafloor, as well as in open hole. Acceleration data were collected on the ship (using the MRU) and downhole (using the GPIT). The heave compensation system was tested at static stations (300, 600, 1200, 2800, and 3000 meters wireline log depth below rig floor [WRF]) and during dynamic logging runs of all three tool strings.

The first logging tool string composed of the HNGS, HLDS, GPIT, and DIT-E was built and lowered into the hole at 0415 h on 17 February. The first pass started at 3369 m WRF (542 meters wireline log depth below seafloor [WSF]) and continued to 3275 m WRF (448 m WSF). During this pass, the winch experienced some difficulty in pulling, leading to some concern about the caliper. The second pass logged the entire hole from 3369 m WRF (542 m WSF) to the mudline (2815 m WRF, 0 m WSF). Because of concern for the caliper, this pass was logged at 1800 ft/h, with the caliper closed for the deepest ~50 m of the section. At the completion of this run, the tool string was brought back on deck and it was confirmed that the caliper was undamaged.

The FMS tool string (HNGS/GPIT/FMS) was then rigged up and lowered into the hole. The FMS tool experienced some bridging at ~3343 m WRF (~25 m of hole fill from the base) and did not descend all the way to total depth. The first pass was run from 3342 mbrf (515 m WSF) to 2938 m WRF (111 m WSF). The second pass started at 3331 m WRF (504 m WSF) and ended at 2938 m WRF (111 m WSF) when the tool arms were closed. Both runs were made with a logging speed of 1800 ft/h.

The final logging run utilized the new MSS accompanied by the HNGS/HLDS/GPIT/MSS tool string. The tool string was rigged up and lowered into the hole, and three passes were made, logging at 1800 ft/h except over three intervals (3280–3250, 3220–3190, and 3150–3120 m WRF), which were logged at 900 ft/h. The first pass was logged from 3284 to 3080 m WRF with the HLDS caliper open. The second pass, from 3286 to 3097 m WRF, was logged with the caliper closed in order to test the influence of the caliper in assisting the MSS bowsprings as they push the tool against the borehole wall. A bridge was met at ~3280 m WRF on the way down for the final pass, indicating deteriorating hole conditions. The third and final pass, from 3280 to 2888 m WRF, was logged with the caliper open all the way into the pipe.

Hole U1330B

Final location coordinates: 3°36.3213′N, 156°37.4467′E

Established water depth: 2814.8 mbrf (2802.2 mbsl)

Total penetration depth: 92.2 mbsf

With time running out, the drill string was tripped back to bottom with an APC/XCB BHA and Hole U1330B was spudded at 1945 h on 19 February 2009. This hole was continuously APC cored to 92.2 mbsf. Ten APC cores were recovered with an overall average recovery of 94.6% (Table T2). The relatively low recovery for APC coring resulted from Core 320T-U1330B-4H losing 76% of its material when the flapper core catcher stuck in the open position. The other nine cores achieved more respectable recovery rates of 101.1% to 105.4%. The new FlexIt core orientation tool (replacement for the Tensor tool) was successfully deployed on all 10 APC cores. The APC temperature tool (APCT-3) was successfully deployed on Cores 320T-U1330B-5H, 7H, and 9H at depths of 44.7, 63.7, and 82.7 mbsf, respectively. The drill string acceleration (DSA) tool was deployed for Cores 320T-U1330B-5H through 8H (35.2–73.2 mbsf), recovering just under 6 h of motion data. These data coupled with LDEO Motion Reference Unit (MRU) data from the WHC should allow later evaluation of passive heave compensator (PHC) performance. All rig floor drilling equipment and all downhole tools/coring systems performed well and are considered operational for science operations. The upgraded Falmouth Scientific positioning beacon also performed well, including the wide-angle transducer (shallow water) version mounted on the subsea television frame. The beacon was successfully recovered at the conclusion of drilling operations. The drill string was recovered, the drilling assembly laid out, and the rig floor secured for transit. Per schedule, the vessel departed Site U1330 bound for Honolulu at 1645 h on 20 February 2009.

Transit to Honolulu

The transit to Honolulu was marked by periods of excellent speed (≥11.5 kt) intermixed with periods where slower speeds (~6 kt) prevailed. Variations in speed were due to a highly variable Northern Equatorial Pacific Current and associated countercurrents, as well as variable winds taken on or just off the bow. In general the transit was marked by extended periods of overcast skies, cloudy/overcast days, and either rain or intermittent drizzles. Effort continued in commissioning laboratory equipment and software applications, as well as support of the RAT scientists as they continued with their SODV and vessel readiness assessment tasks and reports. The 2901 nmi transit to Honolulu, Hawaii, required 13 days at an average speed of 8.9 kt. The first line was ashore Pier 29, Honolulu, at 1042 h on 5 March 2009, ending the transit and officially ending Expedition 320T.