On this web page I will be posting daily updates on the progress of our cruise on the R.V. Roger Revelle offshore Western Australia. The object of this project is develop and refine the use of marine EM methods, mostly controlled source EM (CSEM), for mapping hydrocarbon reservoirs.
We are now making good time heading for Darwin, after a hugely successful survey of 144 deployments and recoveries, all with data, and nearly 12 days of CSEM transmitter tow. The only compromise we made was to cut the hydrate line back from 25 deployments to 16. A wonderful job has been done by everyone on the crew and in the science party. We've got data galore and will have fun for years playing with it.Tues 16/06/2009: It is downhill from here. Instrument recoveries throughout the day, with about 20 bagged by the midnight watch change.
Around 2 in the morning a couple of mahi-mahi were hunting flying fish around one of the receivers while we recovered it. Lovely to watch, jumping out of the water to follow the food when it tried to fly away. Mahi often follow our ships when we're cruising slowly - presumably anything out here becomes a habitat pretty quickly.Mon 15/06/2009: Not much to say about a day of successful transmitter towing. Stayed up into the wee hours to make some measurements of the power signal on the cable with and without SUESI transmitting, then left the SUESI recovery and start of receiver recoveries to the trusty midnight shift. Sun 14/06/2009: I got a good night's sleep, and everything was still going well when I got up. Took the day fairly easy and got some laundry done.
Perhaps it is appropriate at this stage to point out that while the struggles tend to be the stuff of narrative (there's not much to say about a day of towing an EM transmitter successfully), we've accomplished a lot so far this cruise. And, of course, the whole thing about research is that you're testing and trying new stuff, and making some things up as you go along. The aim is to come out of this project with a better understanding, and better equipment, than we started with. Several new bits of equipment have worked first time, without the fuss that the Barracudas required, such as the new LEM instrument package and launching system, some new acoustic equipment, new SUESI antenna design, and so on. The data from our regular instruments is as good as ever - we've had a couple of noisy channels so far, but only one channel out of about 300 has failed to collect any data at all. And, of course, all the instruments to date have returned to the surface (albeit some a little too eagerly). We're still only about a day behind in a rather aggressive plan to collect 150 sites of data from nearly 400 km of transmitter tow.
Life is good.Sat 13/06/2009: As anyone who knows me is aware, I'm not a religious person (hardly even superstitious), but it does look as though the gods are trying to slap us down for being too successful. After the premature releases of the two instruments yesterday pushed the SUESI deployment into the wee hours, I patted Kerry on the back and told him that he was up to the task of deploying SUESI without me while I got some needed sleep. Last time I said something like that, a rented winch free-wheeled and put our SUESI 200 prototype and 4 km of deeptow cable on the seafloor, so perhaps I should've known better.
I was quickly roused to help with a minor problem, and roused a little later with the news that SUESI #1 would not transmit current. The suspicion was a broken antenna, but after failing to find any problem there we tested our trusty transmitter, veteran of about 7 flawless cruises including our recent record-breaking run, and it wouldn't transmit even a few hundred milliamps. We have no idea of what could cause such a fault, but in the famous words of consumer manufacturing, there are "no user serviceable parts inside". At least not on a rolling ship and without some specialized lifting gear.
We went back to our previously rejected SUESI #2, and gave it #1's Benthos navigation unit for good measure (since this was the reason we rejected it at the beginning of the cruise), put the antenna back together, and set up for deployment. Winds and seas are picking up, and by the time we had her in the water it was blowing about 25 knots. She came to life just fine when we switched her on. The downlink telemetry is a bit iffy, but all this means is that we have to re-type a few commands every now and then. Apart from that our #2 unit is working perfectly. The navigation, which gave us cause for concern initially, is working as well as ever, and since at the end of the last tow I tweaked the gain on a relay transponder mounted on the tail end of the antenna, we are getting some relays from the tail, which will help us work out what the sideways "set" of the antenna is.
So, after a couple of very long days (about 6 hours sleep in the last 40), I'm ready to hand over to Kerry at midnight and tell him that all is well, and hope that the jealous gods have done with us for the time being.
Had some really very nicely cooked ostrich for dinner. You know you are on a first-class research vessel when you get ostrich.Fri 12/06/2009: Finished the deployments of 23 instruments on phase 3 for our last hydrocarbon-related sounding (if we have time at the end, we are going to tow our small antenna over an area thought to have shallow gas and gas hydrate). The night watch was ripping through the deployments, about one every 20 minutes, so I had arranged for them to go up the line afterwards and collect some navigation data to buy me an hour or two more sleep. Got up at breakfast for the launch of the two LEMs. We were into the first LEM launch when our nifty strayline system announced two instruments had bounced. I noticed that the navigation had been run at a ping repetition rate of 4 seconds, not a good idea when all your instrument release codes are based on about 8 seconds between pings. Renamed David The Navigator as Cruise Scapegoat for the rest of his shift. In theory the release codes should be far enough off 8 to be immune from navigation ranging, but for some reason that's not always the case (I just looked at the logs and found the reason - the LabView navigation interface we use does not actually ping at 4 second intervals, but almost exactly at one of our release timebases, about 4.2 seconds). Anyway, we finished the LEM launch without drama and then went back to pick the instruments up and put them back down. John was pretty pleased that when the instruments are behind the ship, we got over 9 km range out of the straylines. Because of various bits of metal and mast, we only get about 3 km to the front.
Deployed the second LEM after we ran down the line to make sure everything else was still in the water (navigating at a repetition rate of 5 seconds), and started to prepare SUESI for the penultimate deployment.Thur 11/06/2009: Picked up 23 instruments and started re-deployments. Counting deployments on the hydrate experiment last October, Brent's San Andreas cruise in Nov/Jan, and so far this cruise, we are up to 209 consecutive recoveries without loss (before that we had a bad scene in India, but that's another story). Wed 10/06/2009: The day! SUESI comes back after a record-breaking 7 1/2 days of continuous operation at 300 Amps on a new 250 m antenna. All looks good, and the depth gauges on the antenna tail and Vulcan worked this time. This is gonna be a BIG data set. Tues 9/06/2009: Up and down the lines with SUESI stuffing out the current. Monday 8/06/2009: The most exciting thing that happened today was changing the batteries on the Barracudas. Normally we're not that keen on hauling these in (our little 110V capstains are slow and noisy), but everyone was eager to get out on deck in the pleasant warm evening air and haul away after 4 days of watching the grass grow. Two more days and we're done towing phase 2. Sat/Sun 6-7/06/2009: By and large the weekend has been nice and boring, driving up and down lines towing SUESI and the Barracudas (anyone want to start a rock band?), stuffing out 300 amps, pinging on each other, and getting back GPS coordinates by radio. We had made a minor adjustment to how SUESI ranges on the Barracudas when we deployed this second phase, and it is working nicely, giving us locations accurate to about 10 meters on a single ping, which after averaging will bring SUESI's location down to a couple of meters, comparable to what we get on the receivers after doing our acoustic navigation runs.
We did have a little excitement, of the kind we could do without, this afternoon after we turned onto our first downwind run. The weather forecast was for much diminished winds by then, but it was still blowing better part of 20 knots. The trick is that we want to tow SUESI at about 1.5 knots, since the deep-tow wire has several tens of square meters of cross-sectional area and acts as a big sail in the water. If we drive too fast everything kites up behind the ship and we lose a lot of control. The ship drives along the line using what's called dynamic positioning (DP), by which a computer and algorithmic model of the ship drive the two propellors (which can turn in any direction on this ship, including fully backwards) and the bow thruster (ditto) in order to get the ship to do what's asked (drive down our tow line at 1.5 knots). It has been working beautifully so far, but it is a complicated beast indeed, and a recently installed new model to boot. We started the line off OK, but the ship was sorta sideways to the wind, crabbing down the line, and the captain reasonably reckoned that we'd be better off with the wind on our stern (less windage, pushing us down the line less hard), so he turned the ship just so. Well, the DP did not like this. At one point we were doing over 3 knots, and the Barracudas were flying through the water with a wake behind them worthy of a small speedboat. Then we were stalled out and going backwards through the water. This is about the worse thing you can do with a deep-tow out. I can't even bring myself to write about the ugly things that can happen. Poor Jake was in the process of flying SUESI back down to the seafloor with the winch (we haul her in to less than water depth on turns), and suddenly found he was approaching bedrock much faster than he was expecting. He hauled in like mad but still came within 20 meters of bottom. Not a terribly close encounter (we've done 5 meters a couple of times on volcanoes), but still a bit unsettling.
Captain gave the DP the old crab angle and everything went back to being OK. Later down the line the bridge was able to ease the ship onto the heading as planned.Fri 5/06/2009: Had a good, long, sleep. Indeed, I overslept my watch, a heinous crime for which Brent was sorely punished earlier in the cruise (he has become the Official Cruise Scapegoat and stars in a video which, if he is lucky, won't ever get posted on the web). Hopefully my colleagues will cut me some slack on account of the hours I've worked past my shift. Wind is still around 20 knots but the turns seem fine, and the ship is able to tow SUESI along the lines both directions, although we ended up crabbing about 40 degrees on one run. We've almost finished the fourth line out of twelve for this part of the project, about 10 hours per line, so we have another three days or so to go. With any luck it will give everyone a bit of a break - watches right now consist of someone minding the winch, one hour on, one hour off, and a second person to provide backup and log voltages, currents, and temperatures.
It is a bit of a tradition at Scripps for chief scientists to send home weekly reports that alway praise the cooking on the ship. The obligation associated with this diminishes the praise somewhat, although the food on Scripps ships is almost always pretty good, and the cooks work long hours to keep everyone eating happily and putting on weight. On a longish cruise the quality of the food plays a big part in morale, and I want to mention here that Jay and Richard do a great job. I have to be careful what I say around the galley - if I mention that the chips would be better with malt vinegar, malt vinegar appears next time fries are on the menu. If I mutter that next cruise we should bring along some real maple syrup for the pancakes, real maple syrup appears at breakfast. They look after us very well. Thanks guys.Thur 4/06/2009: Been remiss about posting the log, on account of a totally crazy sleep pattern. Put SUESI back into the water with a minimum of hassle around 04:00 (nice sunrise), and had her flying 50m above the seafloor by just after breakfast. Would have been a great time to go to bed, but we had a fire and boat drill at 12:15. Got a couple of hours sleep after the drill and was up for dinner and our first turn on this second phase of the survey. We've put out a 2D array of instruments and plan to tow 12 lines, requiring 11 turns, so we don't want to have to beach SUESI and pull the Barracudas in every turn. In the Gulf of Mexico last year we were able to make turns with SUESI out by bringing in some wire (the safe rule of thumb is to have less wire out than water depth, because the deeptow always drops during turns), but the wind has picked up to around 20 knots. The higher winds make things more difficult for the ship to control steering and the resulting "crabbing" causes a significant angle between the wire and the ship, which ultimately means that the wire rubs on the edge of the block (sheave) and winch operators get upset. Also, in the Gulf our Barracudas came to a lot of grief during the turns, as one of them would end up being pulled directly behind the ship (same crabbing/wire angle problem), causing the rope bridle to collapse and the Barracuda to do bad things, like dive undewater and flood, or get their lines crossed. Our attempt to solve this problem involved replacing the ropes with a stiff stainless steel towing frame, which seems to have worked well so far. But you never know until you try...
The turn went well. I stayed up until a little after midnight to try to get back onto my watch schedule. I even played a few games of cards with the trusty colleagues. I was introduced to "Bang", a sort of card game version of the spaghetti western and much favored on these cruises by the younger trusty colleagues. This I liked, because it requires little skill and I was on the winning side of both games. I did less well at a few rounds of Euchre against Karen and Rachel, which was entirely unreasonable, since I've been playing Whist games since birth, including competitive bridge (at a later age), and my partner (Matt, the res tech) clearly had skills in this endeavor. Rachel and Karen, on the other hand, seemed to largely clueless, Karen taking the final trick with a nine of diamonds (not trumps) after declaring with a near pass-in hand. Still, they won repeatedly. It may be a good act - in which case I shall have to be careful if they suggest playing for money.Wed 3/06/2009: A nice boring day of navigation of receiver positions and catching some sleep. As usual, the estimate for me being around for the launching of SUESI was about 02:00. Tues 2/06/2009: As of about 8:00 pm we had re-deployed all our receivers except one. I had actually planned on one being "lost" on the first phase of the project, so I was happy to set aside an instrument that had an intermittent problem with the data logger. We then started putting in the two LEM instruments, which meant that I ended up staying up until early morning. Mon 1/06/2009: No gnarly problems last night, and another largely routine day of deployments and recoveries. We are only a few instruments away from recovering all of the first 52 sites. Data continues to look nice. There was a stowaway on the second LEM (see photo on main web page). The excitement for today was a deluge of rain during the last recovery of the day shift - no wind, not cold, but heavy, serious rain. Sun 31/05/2009: A remarkably routine and uneventful day. I should note that the weather has been nice since we arrived on site. We continued to pick up instruments and by 3:00 pm had 26 on deck ready to start deploying again. The plan is to move the 50 receivers in two groups, in order to allow enough space on deck to leave the magnetometers (the blue tubes in the photos) on the instrument frames. It also breaks up the work a bit. By midnight we had about half of them redeployed ready for the next phase of the operation (a 3D survey in the "ears" of the rabbit).
Think I'll go to bed before any gnarly problems show up.Sat 30/05/2009: Has anyone noticed that all the really gnarly problems show up around midnight? And John and I end up working until 2:00 am fixing them?
We got SUESI into the water as planned at around 1:00am, and put out the barracudas. John and I had stayed around to help Kerry fire SUESI up (sorry - poor choice of words - switch SUESI on). We did our thing and... no current. Well, 10 amps, but that's not much in this business (we were expecting 300). Most likely we had lost an electrode, and most likely it was the far electrode. We had made the run between lines at 4 knots, which was perhaps a little too fast, and the movement of the vulcan being towed behind the antenna may have worked the electrode loose. So, we hauled in the barracudas (again), and brought SUESI on deck. Then a bit of good news - the near electrode was missing. This beats bringing in 250 m of long antenna, and we had the near trode replaced fairly quickly. By now it was about 4:00 am, and John had given Kerry a cheat sheet on bringing SUESI alive, so I wished him luck and went to bed.
I slept for the whole line. Kerry had no trouble bringing SUESI up, and when I got up after lunch SUESI was coming in and Kerry was very happy with the barracuda navigation (see his screen shot on the web page). We secured SUESI and started to pick up receiver instruments, and as of midnight had six instruments on the surface, and the data are looking good.Thur/Fri 28-29/05/2009: We've been without internet for a day because last night we turned onto our tow line going NE, which is the bad heading for the antenna.
The "all is looking good" from Wednesday's entry turned out to be mostly, but not completely, accurate. The old SUESI fixed the problem with the BENTHOS unit working intermittently, but we still had a problem receiving replies from the towed Barracuda transponders. We established that everything was fine when SUESI was not transmitting current, but things went bad when the current was switched on. The BENTHOS was triggering all the time, so SUESI was clearly making either electromagnetic or acoustic noise. So, when we got to the end of the line and needed to make a turn to run the line again from the other direction, we beached SUESI on deck and I rigged a mount for the BENTHOS transducer head high up on the tail fin with rubber vibration isolation. (How do we do things like this on a ship? That's a good part of the fun.) We put SUESI back in the water around 9:30 pm to run the line a second time. Things looked good for a while, but then went bad again. This was discouraging to say the least - we had pinned all our hopes on this navigation system, and now we seemed to have run out of things to do. A very low moment, indeed, but one has to keep bashing on the problem. John and I noticed that the second BENTHOS channel set to a different frequency was not triggering on noise. So we set the first channel to 12.5kHz (the Barracudas reply at 12.0kHz), and the noise problem went away. Maybe we had a fix, but why? Half a kilohertz should not make much difference. Then I had one of those moments that we live for - I divided 800Hz (the ripple frequency after the 400Hz power we send down the deep-tow cable is rectified) into 12.0kHz and got 15. Exactly 15. (It took me two goes with a calculator; I was getting tired again.) Our acoustic operating frequency was right on a harmonic of SUESI's hum frequency (it still could be either acoustic or EM - the ripple is about 100 amps, which tends to rattle things around). OK, promising, but we needed a test. Sixteen kilohertz is a harmonic too. We set SUESI's BENTHOS to listen on 16.0kHz, and lo and behold we got lots of triggers. We not only had a fix, but we now knew why. With glee and anticipation we hauled in a Barracuda and changed its acoustic unit to reply on 12.5kHz. We put it back out and presto! We got good ranges from SUESI. We did the same for the other one and got good ranges from it too.
By now it was midnight and Kerry was up to take his shift. He had written a nifty Matlab program to take the BENTHOS data being streamed up from SUESI, ship's position, wire out, and water sound velocity to calculate where SUESI was and plot it all up in real time. He fired up his program and watched the fixes come in where we expected them to be. Success at last. I went to bed.
I got up before lunch today (Friday) and everything was humming along just fine, so I started on some paperwork and generally took things slowly for a change. Got a migraine at dinner time. Not really suprising - you gotta pay for all that stress somehow. With any luck things will be easier from now on. We got to the end of the line around 9:30 pm and we beached SUESI for a turn onto the cross-line. She'll be back in the water in about an hour at 1:00 am tomorrow.Wed 27/05/2009: Launched SUESI after breakfast. This is actually the unit that failed in the Gulf of Mexico in October, and we later found out that a hairline crack in an underwater connector had let a little water into the pressure case. We've fixed this and want to get some run time on our second transmitter.
Everything seemed to be going very well, and by about 10:00 am we had SUESI flying 50m above the seafloor and stuffing out more than 300 amps. However, the BENTHOS acoustic ranging unit mounted on SUESI was working intermittently and generally poorly. This unit is part of our navigation system for SUESI - it ranges on two transponders being towed behind the ship and fitted with GPS receivers which radio positions back to the lab every few seconds. This is our infamous barracuda system that readers of my Gulf of Mexico blog will know all about. We struggled mightily to get this working in the Gulf and thought we had it all worked out by the end, and planned to have this as our primary navigation solution for this trip. Thus, even though the rest of SUESI was working fine, we decided to swap it out with the #1 unit that we had successfully used in the Gulf. This meant turning around with 500 m of antenna and vulcan behind the ship and steaming slowly back to the start of our tow line, an operation which took unil 9:00 pm.
We got everything back down to flying height by about 10:30, and all is looking good.Tues 26/05/2009: Trusty colleagues were doing acoustic navigation of our receiver array while I prepped SUESI and our two vulcans (receivers towed behind the transmitter antenna - looks a bit like a small aeroplane). By dinner the acoustic nav was done and we put the vulcans in the water for a test, but when we recovered them we discovered that the widgets that log depth, pitch, roll, and heading had not worked. John and I spent another late night debugging these, and it turned out we had two problems, one software (not our fault), and one hardware (our mistake in some wiring). We went back to collecting more nav data to give John and me a few hours sleep before launching SUESI in the morning. Mon 25/05/2009: By early morning all the receivers were deployed, and we started to deploy the LEMs. These are lowered close to the seafloor and then released about 5-10m from the bottom. We had built a new launching system to do this and it worked pretty well. By noon we had both LEMs deployed as well as a prototype receiver built by Quasar Federal Systems. By dinner we had deployed the other Quasar instrument and a refurbished Koala (the one that bounced on Saturday night), and had swapped the deeptow cable from the LEM launcher over to SUESI (our EM transmitter). 54 instruments in the water! After dinner we started acoustic navigation of all the instruments so we'll know where they are on the seafloor to within a couple of meters. This will take about a day, but I've been up since about 5:00am, am ready for a break, and this is a job that can be handled by my trusty colleagues.
Yesterday Jake offered me a bottle of wine if I could make the seas glassy today, and I complied, but he hasn't given me any wine yet.Sun 24/05/2009: A full day of deploying receiver instruments, 38 in all. I slept in until lunchtime to recover from last night and then started to prepare two LEM systems for deployment tomorrow. These instruments have a long cable for an antenna (I've deployed up to 3km long, but this time they are 200m), increasing the signal to noise ratio over the standard receivers with fixed 10m arms. We also divide the antenna into two 100m dipoles to measure field gradients very accurately. If there is a deep resistive body (e.g. an oil or gas field), then the field gradients are smaller than without. We've used LEMs at Scripps for over 25 years, but this will be the first time we've deployed them over a hydrocarbon reservoir, and the first time in gradient mode other than for a test off San Diego.
Turned in a little early (10:00pm) in order to be ready for LEM launches tomorrow, with only 8 receivers left on deck to deploy.Sat 23/05/2009: Woke this morning to greetings of "happy birthday" and a poster-sized card featuring assorted pictures of me doing assorted things (bumming rides on corporate jets, burying magnetometers, checking out instruments, gutting fish, etc.). I had completely forgotten the event myself, having other things on my mind, so it made for a pleasant surprise. The cooks made a cake and broke out a case of Bundergerg Ginger Beer (the strongest thing you are likely to get on a dry ship). All very jolly.
We arrived on station just before dinner and started to deploy instruments. We were about to launch the sixth when our clever strayline system announced that instrument Koala was on the surface 4 km away. We finished our current deployment and went back to pick it up. The nightime unrehearsed recovery in moderate seas was not quite a textbook example and the instrument was damaged, although probably repairably. John and I spent several hours trying to work out why the instrument had fired both its releases, and finally discovered a fault in the assembly of the acoustics (bad ground contact to a shield). We figured this was the case for the entire last batch of acoustic releases (it was), so we stayed up until the wee hours going through them all and making a fix. We were both pretty zonked by 2.00 am, but it was the right thing to do. We used some of these same releases last October on our Gulf of Mexico hydrate cruise with no problems, so we're optimistic this won't happen again.
Our first line of instruments is along just the right heading for the ship's mast to shield our antenna from the satellite we use for internet, so internet is down a lot of the time (in case you're wondering why we are not more responsive to email, chat, etc.).Fri 22/05/2009: Winds and seas gradually calmed down during the day and by evening the ride was more like what we were expecting. Finished setting up the labs and started to string electrodes in the arms of the receiver instruments -- everyone's least favourite job. We also began powering up loggers ready for deployment (looks like arrival on station tomorrow evening). With 50 instruments this will take a couple of days to finish. So far, everything is looking good. Thur 21/05/2009: The "gentle rocking" turned into "moderately severe pounding" sometime in the night, and the Southwest got its first rain for the season. Three people were too sick to participate in the fire and boat drill at 10:15, and a few more went down after sitting around in life vests. Felt none too good myself at that point, but better after a bit of fresh air and lunch. Winds peaked at around noon, blowing 40 knots and gusting to 50. Suspended our ambitions to start preparing instruments -- we have three days transit (more at this speed), and expect to drive out of the weather as we head north away from of the latitudes of the westerly winds. Wed 20/05/2009: Ship is looking pretty good by now, with just about all of the gear tied down. This is just as well, since in the morning we had about 80 people from the local chapter of the Australian Society of Exploration Geophysicists through the ship for a show and tell. This went really well and seemed to be appreciated by all. In true Australian style the tour finished with most people going to a brewery for lunch, allowing some final modest drinking before sailing.
Kerry bought a didgeridoo.
We set sail at 16:00 under sunny skies but with a stiff breeze. Still no rain, but it is clearly trying as the first fronts of the season blow through. There is a bit of a sea running, but the Revelle is pretty stable and the effect is of a gentle rocking for our first night at sea (on this trip).Tue 19/05/2009: Working on tying everything down. I spent some time terminating the deeptow cable so we could test our transmitter (SUESI: Scripps Undersea Electromagnetic Source Instrument) before leaving the dock, since it is such a critical piece of the operation. After a couple of false starts (the usual silly stuff, like finding that the winch wires were not connected to the slip rings, or that the 400 Hz GPS signal was not plugged in) SUESI woke up and talked to us after we applied power. This is really good.
More drinking in the evening and still no rain.Mon 18/05/2009: Started loading the ship. The local stevedores had all five containers (three 40' and two 20') unstuffed before lunchtime. Impressive. We'd been warned that loading might go slowly, but not with these fellows running the forklifts. It took the rest of the day for us to crane everything aboard. Rain forcast for this evening, but didn't show.
John bought a guitar.
A bit of drinking went on at night in anticipation of 35 days aboard a dry ship.