Expedition 395: North Atlantic Mantle Convection and Climate

Technician: Mark Higley

Scientists: Katharina Hochmuth and David McNamara

Summary

Expedition 395 recovered mostly sediment due to the lack of severing tools (explosives) for most of the expedition which, as a safety precaution, prevented drilling into hard rock. The severing tools were eventually delivered to the JR 2 weeks before the EOX via the icelandic coastguard while the JR was waiting on weather at the last hole (U1564F). Wireline logging was attempted at U1602E but only a downlog was collected due to stuck tools. No VSI was attempted due to presence of abundant protected species however the issue with one of the gun solenoids not firing was resolved. The niskin bottle and CTD were deployed at U1564F for both the casing drill in and the re-entry. The APCT3 was used at all sites with the exception of U1562 and the data was generally very good.

Wireling Logging

VSI

The previous expedition (X399) reported that one of the VSI guns could be triggered using the box at the fantail but not in the telemetry lab indicating some sort of break in the line between the telemetry lab and the fantail box.  This expedition encountered the same issue. As a work around, the cables were re-wired at both the fantail tail box and the box in the telemtry lab on the wall so that the cables that were being used for the time break switches are now used for the solenoids. This should not pose any problems since we have the hydrophone which performs the same function as the time breaks and is more reliable (per SLB engineer). Because the cables were swapped on both ends, the boxes are hooked up the exact same as before (i.e. connect the time break fly lead to the time break connector on the box, and the solenoid fly lead to the solenoid  connector). See write up below from the SLB engineer with more details:

• Tested existing configuration and found that Gun Solenoid #1 was NOT firing; swapped ports on the Schlumberger end to confirm that this was not due to settings or a fault with the WSI shooting box

• Connected a “shunt” (i.e. dummy plug with the two lines shorted together) to the Solenoid #1 port at the fantail end while checking the resistance reading on the telemetry office end to confirm if the problem was a short, an open, or not related to the cable.  This showed that the resistance on the Solenoid 1 lines (which were lines #1 and #2 in the cable that runs below the pipe racker, which I shall refer to as the “link cable”) was around 190k with the line open and around 90k with the shunt in place.  This was an ambiguous result, so it leads us to believe that the insulation between those two lines may be breaking down at higher current. 

• Conducted the shunt test on the Time Break #1 sensor lines and found that they behaved as expected:  the meter showed an open line with the shunt disconnected, and 5.4 ohms (short) with the shunt in place, thus proving that the lines (#3 and #4 in the link cable) would be suitable for use as gun solenoid lines.

• Tested resistance on Solenoid #2 port with nothing connected to the fantail end and only a multimeter on the telemetry end and found that resistance between the two wires associated with that solenoid was approximately 1 megaohm, which is less than nominal, but still operational.

• Decided to swap the lines used for the #1 gun solenoid with the ones used for the #1 time break sensor, as TB sensors are typically not used for anything anyway, provided there is a hydrophone available to use as the primary “surface sensor” during the seismic survey.  The nitty-gritty of this is that within the link cable, wires #1 & #2 were allocated to the solenoid while #3 & #4 served the TB1 sensor.  We opened the interface box on the fantail and physically swapped the wiring at the terminal block so that the solenoid header now connects to the good lines 3 & 4 rather than the faulty lines 1 & 2.  We then made the same swap inside the interface box in the telemetry lab so that the Gun #1 Solenoid input would be routed to lines 3 & 4 while 1 & 2 would carry the signal from TB1.

• Tested the system again using a test solenoid on the fantail and a manual firing pulse from the Schlumberger WSI interface module (shooting box) and found that, as expected, both guns were firing reliably.  There is no good way to test a time break sensor at surface, but since it was a redundant and thus unused measurement anyway, if it turns out to be faulty now that the lines have been swapped, we’ll simply ignore it like we always have anyway.

• In terms of how things are physically connected, there is no change to the front panel port layouts; all changes were made “behind the scenes” on both ends, so when it comes time to connect the guns, they will still be connected just as they always have been, in accordance with the labels on the front of the panel – the signal re-route occurs between the fantail interface box and the telemetry lab interface box, but all external connections remains just as they always have been.

• In terms of longevity, the take-away is that the insulation between the lines in the link cable running from the telemetry lab interface box to the fantail interface box (routed under the pipe racker) is very likely beginning to break down due to age.  The latest workaround puts the critical signals on lines that are still good, and it is likely that it will continue to function for the remainder of the IODP program (i.e. through Sept. 2024) and perhaps afterward, but if there is any need for those lines post-IODP, it may be prudent to replace the link cable at some point before it fails entirely.

• Bottom Line:  Both guns are now firing normally; just connect them as labelled (no changes made on the front end) and the system should work normally.  Time Break #1 may or may not work, as we essentially moved the fault from the solenoid to the TB sensor, but since it isn’t normally used for anything anyway, that should have no impact on operations at all.

VIT

• The VIT was used at hole U1564F to drill in 550 meters of 10 3/4" casing. The VIT was deployed for both the drill in and the re-entry. The niskin bottles and CTD were deployed both times.

• The beacon release was not changing tone when it was triggered. Typically, when the signal is sent to the beacon release to activate it, the tone changes confirming that the beacon release has received the signal. No change in tone was being noticed when the signal was sent despite the beason receiving the signal (as confirmed by the fact that the niskin bottles closed). Becasue of this, the beacon release was replaced which fixed the issue.

• A new niskin bottle trigger cord guide was 3D printed because the old one cracked where it is bolted to the beacon release. The bolt holes were made slightly larger to better accomodate the mounting bolts. The .stl and .sldprt files are on the confluence 3D printer page.

• New camera in the glass dome (closest to the CTD and Niskin bottles) is not set up to be displayed on any of the monitors. Currently, the only place it can be seen is in the DP office. This made it difficult to see the weighted indicator lines for the niskin bottles. Additionally, this camera has the capability to rotate, tilt, and zoom but none if this functionality is currently set up.

Niskin Bottles

The duel niskin bottle setup (4L +1L) was used to collect 5 liter samples of water for neodymium analysis at U1564E. The bottles were deployed for both the casing drill in as well as the re-entry. The scientist only need 5L of sea water but the bottles were deployed for both VIT runs in case the bottles malfunctioned during the re-entry there would be a backup. The intent was to use the sample collected during re-entry as the primary sample.

On the first VIT run, the weighted indicator line became caught in the bottom cap when it closed preventing a good seal. Because of this, the full volume was not collected as the water ran out of the bottle as it came to the moon pool door. On subsequent runs, the weighted indicator line was left off of the 5L bottle and only used on the 1L bottle. Additionally, the place where the weighted indicator line for the 1L bottle was moved

CTD

The CTD was deployed for both the casing drill in as well as the re-entry. The CTD was also deployed for the re-entry following a bit change.

Formation Temperature: APCT-3

Computers:

• The port logging computer (tag#91213) was having a strange behavior were new directory folders could not be created. This happened on the local harddrive, the network drives, external drives, it didnt matter. None of the usual methods would work (right click, ctrl+shft+n, ribbon bar. Folders could be created through the command line but that was getting cumbersome.  The MCS's tried to fix the issue but the only way they could fix it was by re-creating the DAQ account. After the DAQ account was re-created, new folders could be created again. Python did not transfer to the new DAQ profile so python 3.10 was reinstalled.

• QGIS was installed on the port logging computer (tag#91213) to help facilitate creating surfaces for display in navipac. Bathymetry data was downloaded from GEBCO in an ESRI ascii grid format. This needed to be reprojected from lat/long into UTM x/y coordinates then exported using the GDAL2xyz tool into an xyz file. This could then be loaded into petrel or navipac.

Shipping:

Items received:

• CTD pressure sensor  306525 and Temp/Conductivity sensor 450466 arrived back on the ship after being calibrated on shore. Calibration documents are saved on the server at T:\IODP_Share\Logging\CTD\calibration docs, the tracking sheet on confluence (CTD Calibration Dates) has been updated, and the hard copies are in an envelope in the CTD case.

Items shipped:

• APCT3 Electronics support frame s/n 1858041C (temperature probe damaged)

• APCT3 cutting shoe s/n 1117 (has temperature probe stuck in it)

• ETBS, 2 MTT's (2 bottom sensors, 1 inline sensor), MTFM