Chapter 5. Drilling Near Antarctica
I have been involved in several drilling and coring projects involving Antarctica and got to go there for the better part of 11 weeks in the winter (southern hemisphere summer) of 1986 and 1987. So, if this blog is about scientific ocean drilling, how does that relate to drilling in Antarctica – it is a continent, isn’t it? Yes it is; a huge and somewhat unexplored continent from a geological point of view.
Drilling for exploration in the seas around Antarctica, or on the continent itself, has a limited history. The main problem is just getting a large drill rig to the place as well as supporting it with a crew and supplies. The weather is the main impediment. Also, Antarctica is remote and not very user-friendly for such things. In terms of severity of conditions, you can compare it to drilling on the North Slope of Alaska for oil and gas, but there are big differences. The North Slope is much closer to civilization and infrastructure than Antarctica. There is known to be petroleum there under the permafrost, hence a serious motivation exists for oil and gas companies to commit large sums of capital to building up drilling resources. And the oil recovered there can be pumped immediately into the Alaskan pipeline and on its way to market and profit. None of this applies to Antarctica. Even getting approval to drill for commercial purposes there would entail international legal complications that would make it untenable, if not impossible at the present time. There is every indication that oil reserves do exist under the Antarctic ice (both on shore and off) and they will someday be exploited. But to my knowledge it has not happened yet. I believe international treaties currently prohibit any Antarctic oil drilling until 2041, see Ref. [1].
But drilling for geological research under the sea ice around the continent has long been one of the holy grail objectives of marine geologists. Geologically Antarctica has a fascinating history. It was part of the super-continent, Gondwanaland , until tectonic forces caused it to break away and “drift” (over the mantle, not over the waves) to its present day location straddling the south pole, separating from a brief marriage with Australia along the way. Core samples taken offshore in the Weddell Sea on our voyage revealed ancient spores from certain trees and ferns, providing a clue to the warm tropical climate that would have been required for those plants to prosper 70-100 million years ago. Other paleomagnetic and paleontological evidence has confirmed that the continent once occupied an equatorial address. The theory behind Antarctica’s continental drift history was well established but before any of it could be verified (by actual core sampling, known as ground-truthing) some large deepwater drilling rig had to go to the waters off Antarctica to core and recover some significant samples. See New York Times article from the time, Ref. [5].
The Glomar Challenger took a good crack at the problem in 1972-73 on one expedition drilling in the Ross Sea and around Wilkes Land south of Australia. Unfortunately that season turned out to be a heavy ice year when conditions would not allow a non-icebreaker vessel to get very close to the actual continental boundaries. Everyone remembers the Titanic and its encounter with a piece of an iceberg – nobody would consider allowing a non-ice-strengthened drillship to suffer a similar fate.
In December of 1986 I was part of an ODP expedition onboard the JOIDES Resolution to the Weddell Sea, offshore Antarctica, just south of the tip of South America, where the next attempt would be made at conducting serious subsea drilling and coring operations in the waters off Antarctica. We hoped to get closer to the continent than ever before in history where we would drill as many sites as possible giving due consideration to safe conditions when surrounded by sea ice and icebergs. We were lucky; that season turned out to be a favorable ice year in which the annual pull-back of the sea ice got closer to the continent than in most earlier years. I was introduced to the phenomenon of the “polynya”, a borrowed Russian word for hole in permanent pack ice. Antarctic polynya events are seasonal, unpredictable, and rarely extensive during any given austral summer. We were fortunate to be treated to one of the biggest polynya “seasons” ever recorded in the Weddell Sea just at the time we were scheduled to be there. The opening of the pack ice allowed the Resolution and our escort vessel, the Maersk Master, to get to offshore sites normally inaccessible to any ships except icebreakers, which are not drillships. Note: there have been a few ice-capable smaller vessels outfitted to conduct a limited amount of offshore science research drilling in the presence of oceanic pack ice, but their impact on the marine geology world has been limited and was still years away in 1987.
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| ACEX Arctic Drilling -- (near to far) Converted workboat with small drill rig, Norwegian icebreaker, Oden, and Russian nuclear icebreaker, Sovetskiy Soyuz |
A note about offshore ice. Go in a ship anywhere near Antarctica and you learn a lot about ice in the ocean. First, there are two completely different and distinct kinds – icebergs and sea ice or pack ice. Sea ice is surface seawater that freezes over every winter. Some of it gets so thick that it does not melt during the austral summer, gets pushed into more dense packs and eventually becomes designated as pack ice. It is perpetually found around the shores of the Antarctic continent. Ice breakers can force their way through it if the conditions are right. Some pack ice is forever trapped against the land, some floats free and is blown around by the southern ocean winds. It breaks up and days later re-congregates. Pack ice is generally not life-threatening to a modern ship, although there are plenty of historical incidents of ships unexpectedly stuck in pack ice that become trapped long enough for the gathering ice to crush the hulls. This problem was a lot more frightening in the days of sailing ships with wooden hulls. Look up the history of Ernest Shackelton’s explorations and loss of his specially strengthened wooden sailing ship, Endurance, which was trapped and sunk in pack ice in the Weddell Sea in 1915. Mandatory reading for anyone going to Antarctica.
Pack ice is moved primarily by winds because the draft is only a matter of feet. Icebergs are moved mainly by currents because they have deep drafts, up to 800 feet. It is not uncommon to see icebergs plow straight through a region covered with pack ice when winds and currents operate in different directions.
Pack ice is moved primarily by winds because the draft is only a matter of feet. Icebergs are moved mainly by currents because they have deep drafts, up to 800 feet. It is not uncommon to see icebergs plow straight through a region covered with pack ice when winds and currents operate in different directions.
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| A Classic Tabular Iceberg -- No telling how far it extends out of frame to the right |
Tabular bergs are big and flat (generally about 200+ feet of ice above the waterline) and level on the ocean. They eventually deteriorate due to melting, storm damage, colliding, and running aground so that in time they break completely apart or big chunks break off. The chunks are generally not stable floating flat so they tilt to find a floating equilibrium attitude.
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| D/V JOIDES Resolution and small "mountain-shaped" iceberg |
Successful and safe navigation around Antarctic ice involves avoiding pack ice that a non-icebreaker cannot handle, avoiding collision while moving with large bergs or bergy bits, and trying to avoid rubbing against too many growlers. We found that it was a fairly easy chore to avoid ice disaster as long as everybody was vigilant and exercised good anticipation of ice plus ship movements. The bergs bigger than small bergy bits show up very clearly on modern radar at a range allowing plenty of time for the moving ship to sail carefully around. Smaller bergy bits and growlers had to be visually spotted by lookouts in order to avoid them, but our ship could handle some minor collisions with them without fear of significant damage. At night the lookouts’ job was more difficult so the solution was to either avoid sailing thru ice-infested waters after dark, or go slowly with the lookouts using a searchlight to spot dangerous ice. The good news is that when you are that far south in the austral summer the sun literally never sets. It does get darker around midnight but that twilight darkness is only a minor problem for navigation.
When we were underway in ice-clogged areas our ice lookouts were some of our rig floor roustabouts, who were all Filipino in those days. The ship’s doctor worried about their health since the lookout station was a platform literally hanging out in front of the bow where there was almost no wind shelter and it got bitterly cold. He commented about what a poor plan it was to have tropical natives assigned to such cold weather duty and predicted wryly that if we ever had need for lookouts on some equatorial cruise we would probably go out and hire Eskimos for the job.
We also had to avoid ice when we were station-keeping over a drill site and unable to move quickly because we had 1000s of feet of drill pipe suspended from the ship into the hole in the seafloor. That was a much more serious problem. It was not life- or ship-threatening because icebergs moving toward us on a collision course would not do so rapidly. (It was like the world’s slowest game of Space Invaders.) But it required careful management -- we could certainly not tolerate constant interruptions to sidestep advancing bergs if we expected to get any drilling accomplished. To help with this part of the operation we chartered the Maersk Master ocean-going workboat to accompany us as an ice management vessel. The MM would scout out planned drill sites before we arrived to check for quantity of ice in the vicinity, when the drillship was working at a site they would scout up-current and up-wind to see what ice was approaching the vessel, and they would try, at least, to deflect approaching bergs that might otherwise collide with the ship when the drillship could not be quuickly moved out of the way.
Nobody was completely sure how that berg-deflection plan would work out but we came prepared. One trick we planned was to include a long polypropylene rope on a winch drum with floats onboard the MM that could be used to “lasso” a medium size or smaller berg and tow it aside. Would this actually work? The technique had some prior trials with icebergs in the waters around Greenland with some success. Everyone was convinced it would work on bergs up to a certain size but what would be the limit? We had a couple successes in the iceberg-towing operations but mainly it was futile. The smaller bergs resisted getting the floating rope securely around them (because of their shapes the rope would slip completey under the berg, or cause the berg to topple and allow the rope to pass over the top). And those bergs could generally be moved more easily by having the MM simply push on them tugboat style. Larger bergs proved to be more than a match for the 20,000 horsepower of the MM and we eventually had to give way to a number of big ones when they stubbornly continued on courses too close to the drillship for comfort.
Nobody was completely sure how that berg-deflection plan would work out but we came prepared. One trick we planned was to include a long polypropylene rope on a winch drum with floats onboard the MM that could be used to “lasso” a medium size or smaller berg and tow it aside. Would this actually work? The technique had some prior trials with icebergs in the waters around Greenland with some success. Everyone was convinced it would work on bergs up to a certain size but what would be the limit? We had a couple successes in the iceberg-towing operations but mainly it was futile. The smaller bergs resisted getting the floating rope securely around them (because of their shapes the rope would slip completey under the berg, or cause the berg to topple and allow the rope to pass over the top). And those bergs could generally be moved more easily by having the MM simply push on them tugboat style. Larger bergs proved to be more than a match for the 20,000 horsepower of the MM and we eventually had to give way to a number of big ones when they stubbornly continued on courses too close to the drillship for comfort.
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| Maersk Master Workboat -- preparing to "tow" a large iceberg |
There have been other research drilling projects conducted on the Antarctic continent and the adjacent seas or glacial ice shelves still attached to the land. The ice shelf drilling has been conducted by the ANDRILL group headquartered in New Zealand who have successfully sampled the seafloor under permanent, fixed shelf ice and will soon penetrate the seafloor under fast-moving glacial ice that creeps away from land at several meters per day. Drilling from atop fast-moving ice to a fixed spot on the seafloor is a pretty good trick, if you think about it. See Ref [3].
A Russian-American-British research team have capped off nearly two decades of drilling thru the Antarctic continental ice with a remarkable breakthrough – reaching the waters of Lake Vostok, buried for 15-25 millions of years under more than 12,000-ft of never moving ice. This drilling differs from the ANDRILL and ODP subsea drilling efforts in that the Vostok drilling was through all ice; part drilling, part melting to produce a borehole. ANDRILL and ODP as well as ACEX Arctic drilling, mentioned above, entail actual rotary drilling and sampling in seafloor sediments and rocks.
A Russian-American-British research team have capped off nearly two decades of drilling thru the Antarctic continental ice with a remarkable breakthrough – reaching the waters of Lake Vostok, buried for 15-25 millions of years under more than 12,000-ft of never moving ice. This drilling differs from the ANDRILL and ODP subsea drilling efforts in that the Vostok drilling was through all ice; part drilling, part melting to produce a borehole. ANDRILL and ODP as well as ACEX Arctic drilling, mentioned above, entail actual rotary drilling and sampling in seafloor sediments and rocks.
For some additional reading see,
[1] Article about future concerns about oil drilling in Antarctica
[2] IODP Expedition 302, Arctic Coring Expedition (ACEX): A First Look at the Cenozoic Paleoceanography of the
Central Arctic Ocean http://ic.ucsc.edu/~acr/BeringResources/Articles%20of%20interest/Central%20Artic/Backman_%20Moran%20and%20McInroy%20et%20al%202005.pdf
[3] Details ANDRILL scientific drilling through the ice shelves to the seafloor
[4] Details of drilling through continental ice to Lake Vostok
[5] NY Times article about Leg 113 – Antarctica, by Walter Sullivan, NY Times science writer.
Anecdote: “You Find Some of the Darndest Things in the Ocean – The FAD and the Tree”
These are two stories loosely connected according to the title of this anecdote.
The FAD. I got his story from Glen Foss, one of my long-time colleagues at both DSDP and ODP. That is Glen in the picture – the one with the beard and the quizzical look on his face examining something that looks suspiciously like the stub end of a broken piece of drill pipe. The fact that it is being examined at the vertical while still over the rotary table suggests it just came out of the ocean having lost everything in the drillstring below. A bad and unlucky day in the drilling business. On a land rig, or offshore oil rig, the broken drillstring in the hole would not be lost. It would be “fished” out and recovered, although sometimes with considerable difficulty. Not so when a floating drilling vessel drops drillpipe when drilling in open hole. In that case the lost pipe falls to the seafloor, probably in a pile resembling spaghetti, never to be seen or recovered.
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| Scene on the rig floor of Glomar Challenger |
So back to the FAD story with details from Glen who was directing operations on that unusual voyage. The Resolution was setting up to begin drilling at a site in the Sulu Sea, between the Philippines and Borneo. The ship took up position and dropped an acoustic positioning beacon to the seafloor (which would enable the ship to maintain station at that exact location in the open ocean for as many days as was required to complete the drilling and coring). At the time the crew noticed a piece of flotsam (floating junk) some distance away but paid it no attention. The drillstring was lowered into the approximately 5000m of water trying to tag the seafloor and begin the actual work of drilling and coring.
The running-in of the drillstring did not proceed quite normally and some odd resistance was felt. The ship was repositioned a few hundred feet in hopes of finding a less difficult place to begin the actual hole in the seafloor, even though there should not have been any problems at all. At this point in the proceedings Glen recalls that he absently noted the floating object had moved closer to the ship rather than floating away as expected. Hmmm. Within a few hours the crew found out why.
The drillstring had become hopelessly fouled with miles of polypropylene rope. It was wound around the drillpipe and clearly attached to the mysterious floating object, which turned out to be an FAD (Fish Attracting Device), in this case a raft-like object made of oil drums, wood, and palm fronds. Amazingly it had been anchored to the seafloor with roughly 7000m (!) of the plastic rope. Any reasonable, experienced sailor would have said nothing like that raft could possibly be anchored in such a depth. But it certainly had been, and very soon the problem got worse.
The drillstring had become hopelessly fouled with miles of polypropylene rope. It was wound around the drillpipe and clearly attached to the mysterious floating object, which turned out to be an FAD (Fish Attracting Device), in this case a raft-like object made of oil drums, wood, and palm fronds. Amazingly it had been anchored to the seafloor with roughly 7000m (!) of the plastic rope. Any reasonable, experienced sailor would have said nothing like that raft could possibly be anchored in such a depth. But it certainly had been, and very soon the problem got worse.
The drill crew had no choice but to cut loose the FAD raft, slowly recover most of the drillstring, and pull in and chop up a mountain of poly rope. Thinking all was well the Resolution crew went back to work until a local fishing boat appeared over the horizon and approached the ship. Sitting on its deck was the now-familiar FAD float. The not-so-happy fishermen requested to come aboard and wanted reparations for their lost materials. They were eventually paid in full for their losses by the Ocean Drilling Program -- this despite the fact that the Captain was fuming that anything anchored in the open ocean and unlighted was an illegal hazard to navigation. The amount of money involved was not enough to make a fuss over and I guess you can never buy too much goodwill.
The Tree in the Ocean. One of the pleasures for me of going to sea is to enjoy the actual voyage itself. I loved to go over the navigational charts on the bridge and monitor our position as we sailed through some pretty remote and even exotic places in the world. I have always loved maps this way – flashback to many happy backpacking trips into the mountain wildernesses of the West using a topo map and compass to find hidden gems of places well off the established trials. If you’ve never seen modern navigational charts you’d be surprised how detailed and accurate they are in this age. These charts trace their roots back to man’s earliest voyages on the oceans – they represent a very evolved and useful, if not to say vital, seafaring art form.
On one expedition somewhere around the Philippines, Guam, or south of the Japanese islands (I no longer remember exactly where) we were crossing a long expanse of open ocean, which usually means the nav chart is less interesting than when you are nearer to land. But on this day a couple of us spotted a very odd notation in the open ocean close to our planned route. It was a symbol of a large tree, like an oak or elm in full spread of branches and leaves. No land around, just the tree symbol. And it was labeled, not too surprisingly, and without further clarification, “Tree”. We corralled the Captain and showed him the symbol and asked, what the heck is that? He didn’t know either, but noted that the water depth went suddenly from thousands of feet to just a handful of feet in the immediate vicinity of the tree. No island shown, but some shallow water, probably the remains of a seamount or guyot (a small mesa under the ocean.) or maybe a submerged atoll. The captain was now intrigued as well and pointed out that the Tree was very close to our planned route and had water deep enough within a mile that we could safely sail by close enough to get a good look through binoculars.
Now, I’ve observed plenty of felled trees floating on their sides in the ocean, and seen some odd notations on navigation charts for buoys and rocks and lighthouses, and so on, but this Tree was something new – it could not possibly be just a “tree” sticking up in the open ocean. But it turned out indeed to be just that. Don’t ask me what kind of tree, or how it could prosper rooted under the waves in several feet of seawater miles and miles from any dry land. (We sailed by before I managed to take a picture). Not only was it a big, healthy looking tree standing perhaps 30-40 feet out of the water, but it hosted a tiny village of fragile-looking huts built up on stilts and all more or less attached to the tree and each other. Most of the building materials appeared to be driftwood. Clearly a tiny village of people lived there, (maybe the village was officially named, "Tree".) We could make out one or two small boats with outboard motors tied up to the huts and connecting elevated walkways. We never did see any people, but guessed they were either off fishing, hiding, or a bit weary of sightseers dropping by unannounced to rubber neck in their neighborhood.
I do wish I had more detail about this bizarre tree-village. So I’d like to throw the question open to the readers of this blog. Does anyone know of this amazing place? Where it is exactly? Who lives there? And are they still living in those huts despite the obvious problems of surviving storms and getting basic supplies to and from the nearest land? I should note that in most parts of the open ocean there is very little tide so at least that was probably not one of the villagers’ big problems of survival. If you know something about this tree-village in the open ocean of the western Pacific please post a comment at the end of this blog page, or email me at dphuey48@gmail.com
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