Basic Overview of Deep Sea Drilling



Chapter 9.  A Little More Overview on Deep Sea Drilling



JOIDES
Resolution Drillship
seen from above

     A regular reader of my blog has posed a few good questions – okay, he is a close friend, Chuck, not a random reader, but his queries are nonetheless to the point.  As he puts it -- I understand your ocean drilling programs called for you to punch holes in the seafloor all over the world, but I never could quite grasp why exactly you were doing it, how or why you pick the specific locations, what you intend to achieve, or what you ultimately found.  He went on to add -- I assume it all had something to do with searching for offshore oil and gas.

     Now, Chuck is a pretty sharp guy and still he missed some of the fundamental points, which tells me I have not done a good job of setting up the overall story.  So I need to revisit some of the basics.

     First, it is important to note that the DSDP and ODP science programs have had NOTHING to do with searching for gas and oil.  The offshore energy business is very motivated ($$$) and quite effective at searching for those valuable reserves offshore with their own equipment, manpower and skills.  They certainly do not need the help of a major international science research program on a bare bones budget to find oil and gas.  But not only was that never the goal of the science drilling programs, it was, in fact, not even possible for those ships to prospect for oil and gas. 

     Here is why – oil and gas reserves, big or small, exist under the ocean floor because ancient subterranean pressure cooker conditions produced the right mix of hydrocarbons millions of years ago.   Then chance kept them from migrating away (the most common circumstance) by placing them under geological “seal or cap structures” – something impermeable (like solid rock or even salt domes) that can trap elusive, energetic molecules for ages.  This rarely (on a global scale) occurs, and thus, oil and gas reserves are doggone hard to locate.  However, when someone does manage to drill thru a suspect geological cap structure and finds the good stuff it is usually there under pressure.   At the moment the seal structure is penetrated a seafloor blowout preventer (BOP) is required to avoid a release of high pressure hydrocarbons up the borehole and into the ocean.  Modern BOPs are enormous (as big as a small house), heavy, complex and expensive.  Neither the Glomar Challenger nor the JOIDES Resolution scientific drillships carried BOPs.  Neither ship had any of the necessary equipment to deploy or operate a seafloor BOP. 

Glomar Challenger

    Therefore, it was imperative that no hole was ever drilled where any over-pressured hydrocarbons could be encountered, accidentally or otherwise.  This was avoided by real time monitoring of dissolved gases in the recovered samples during drilling and coring operations.  But more importantly, avoidance of hydrocarbons was achieved by selecting only drill sites that had zero chance of containing trapped oil or gas reservoirs.  All seafloor sites proposed for drilling were selected after a great deal of seismic profiling performed by specialty ships designed just for that purpose.  This work was done years in advance of any drilling by the drillships.   Any proposed site that reached the level of being on the verge of approval for a science expedition had to go for review before the Site Safety Panel.  The panel’s name has changed over the years but its function and mandate have remained the same – determine if there is any chance whatsoever that the underground geological structure could include a seal or cap structure capable of retaining pressured hydrocarbons.  If the Safety Panel did not reach unanimous agreement that there was nil probability of trapped, pressured hydrocarbons at a candidate site, then the site was rejected totally and forever for scientific drilling.  There was no appeals process for borderline cases. 

     The Safety Panel has always been made up of volunteer petroleum exploration geologists with significant experience in helping the oil and gas industry prospect for reserves.  They knew their business.  In all of the years of conducting this type of open-hole, no-BOP drilling in the deep oceans there has not been even a hint of an oil or gas seafloor blowout.

     A humorous side note – the Safety Panel had to be comprised of very senior, experienced experts who were willing to volunteer significant time to review site data, and then attend meetings to determine yes or no on scores of proposed sites each year.  Volunteers of that ilk tend to get weary of the use of their free time and, thus, they migrate off the Panel all too often leaving the panel chairman the job of recruiting other similar expert volunteers.  At one such recruiting conversation the oil company specialist was given the pitch and said -- Let me be sure I have this right.  You want me to help you NOT find oil and gas under the seafloor, right?  Yes, he was told, that was it in a nutshell.  Well, then, he said, I am your man because I have spent the majority of my career doing just that!

     Okay, so the non-connection to oil and gas prospecting has been established and explained (I hope).  That leaves us with the other fundamental questions – what, where, why and to what gain are/were the research drilling programs all about?  The answer in its simplest form – the goal was and is fundamental geological research.  All fields of science (pick any one you like) require research to establish the basics; you can’t understand biology without studying and comprehending cells, for example; chemistry requires understanding the periodic table of elements; effective medicine must be preceded by comprehensive understanding of the human body, etc.  

     Same thing with geology – it is the study of the earth as a dynamic entity.  There is the core, mantle and crust.  Continents move around on the mantle; ocean basins are crustal but very different than continents; mountains are created, grow and then decline; sea levels increase and then fall.   How and why does all of this happen?  Basic geological research is aimed at these general questions at first.  Then thousands of other questions lead to answers that add a piece of the jigsaw puzzle of new information here and there.  Because 75% of the world is covered by water marine geology has a special role – studying the geology that occurs only under the oceans (and some very large lakes).

     A lot has been accomplished since marine geology was born sometime in the late 1800s.  Measuring the depth of the oceans, and dredging up random samples of sediments were the beginning.  After those meager scraps of information were procured things got more complicated.  Dredging from the seafloor, visual observations of the seafloor by divers and perhaps cameras were added.  Gravity corers were introduced that could take seafloor samples using smaller research vessels.  Echo sounding to determine water depth in the oceans evolved into seismic profiling of the terrain beneath the seafloor.  The ultimate of seismic studies is possible when a large earthquake occurs -- its echoes can be detected on the opposite side of the globe providing earth scientists with reams of new information about the internal structure of the planet.  Then came drilling and sampling under the oceans to complete the research methodology picture.  And in recent years there are some incredible examples of satellite oceanic measurements that also add their bits of data to the marine geology puzzle – satellites can measure the precise average sea level at any point in the oceans, which is affected by gravity differences relative to water depth; over seafloor mountain ranges there is a tiny dip in average sea level, over trenches the sea surface has a small hump that follows the trench line.

     At first (1930s and 1940s) offshore drilling and sampling were elementary and a lot of that was aimed at prospecting for energy resources by industrial interests.  But even to this day oil and gas reserves have never been recovered at water depths greater than 10,000 feet – and most of the areas covered by the world’s oceans are deeper than that.  So that explains the push for deepwater drilling for the sake of pure science research.  Before the advent of the science drillships it was the great unreachable unknown (see my blog Chapter 3 – Where It All Began).

     That is some background, very briefly, explaining the what and a bit of the why.  Fast forward to 1968, the beginning of the Deep Sea Drilling Project, and the conversion of the Glomar Challenger to be the first full time scientific drillship.



Rig floor and bow area of
 the Glomar Challenger

For the international marine geology field this was BIG news.  Naturally any senior marine geologist wanted in on the show.  Many, many intriguing and important questions could then be addressed with cleverly planned drilling and sampling at great depths (up to almost 30,000 feet combined water depth and seafloor penetration).  Was continental drift real or just a hair-brained theory?  Had the Mediterranean really dried up multiple times in recent history due to closure of the Gibraltar Strait?  Had sea level really risen and fallen dramatically over time?  Could evidence be found of what killed off the dinosaurs (and 90+% of all existing organisms at the time)?  What was the record of earth’s magnetic field reversals?  What were those crazy methane hydrates found in sediments and sometimes accidentally brought to the surface in trawl nets?  These and hundreds of other geologic questions could potentially be put on the agenda for real hands-on research with strategic use of a dedicated drillship capable of bringing back good core samples and other deep ocean downhole measurements.

     But there was only one scientific drillship faced with enormous international interest and demand.  To handle this problem a set of committees was established with members including prestigious geologists from all over the world.  (Countries that contributed funding naturally went to the head of the line).  A framework of operations was set forth – the Challenger would conduct six voyages (legs, later called expeditions) per year, roughly two months in duration, with some scheduling flexibility built in to allow the ship to move around the world.  Each Leg would be a self-contained research exercise with a preselected complement of scientists.  Drilling was aimed at heavily reviewed, pre-selected sites chosen to have the greatest chance of recovering subterranean samples that would help explain some facet of the goals of the specific research.  Proposals for specific voyages were solicited, received, reviewed, nurtured to maturity and ranked.  The small percentage of winning proposals became operational plans for specific Legs and were put on the drillship schedule years in advance.
  


Examples of microfossils
found in ocean sediments

     For example, if global climate change were to be studied sites might be selected with potential to reveal the fates of buried ancient reefs that might have died off due to sudden warming or cooling of the climate.  To study seafloor groundwater activity, the scientists might select sites known to have elevated temperatures caused by near-surface geothermal activity of unknown origin.  To study global mass extinction events sites would be selected likely to have high sedimentation rates where a treasure trove of marine microfossils could be expected.  See some examples of oceanic (pelagic) microfossils at left.  Each was once the skeleton of a tiny living creature.  There are tens of thousands of known varieties.  Only the largest can be seen with the naked eye.

     Then it got more complicated.  Once more was learned by the marine geology science community, more complex questions could be derived.  For example, a particularly confusing bit if tectonic plate structure could be targeted for one Leg where drilling through the sediments to basement rock would shed light on theorized plate movements explained up until then by seismic studies alone.  Once the book of knowledge is opened there is no The End in sight.  The marine geology textbooks of today (and tomorrow) had to have facts based on something.  And a whole lot of that something was the information gleaned one core sample at a time from the never-ending voyages of the scientific drillships plus the dedicated, almost zealous attention of the best geological minds of about 2-1/2 generations, and counting.

     And lastly, what have they found?  We would need to look at a modern marine geology textbook to even scrape the top of that question.  And an expert beyond by level would be required to explain most of it.  But since I am the chronicler here (it is my blog after all) I will hit a few of the high points, much more as example than as summary.

• The highly controversial theory/hypothesis of continental drift was positively confirmed by deep sea drilling before the 1960’s ended.  Scientists are still struggling to absolutely explain how that can happen, but it is now indisputable that South America was once joined to Africa and the Indian subcontinent did go on a wild joy ride north across what is now the Indian Ocean until it crashed into Asia and has been trying to make progress ever since by forcing up the entire Himalayan mountain range, to cite a couple examples.
• And, while we are on that subject, the submarine fans of deposited sediments from the Himalayas brought out to sea by the Ganges and Indus riser systems are so voluminous that they suggest that there would be a range of mountains 3 or 4 times as large as the present day Himalayas if not for the constant wearing down grain by grain that gets carried away and deposited at sea.
• And, yes, the Mediterranean did dry up completely more than once due to closure of the Strait of Gibraltar.  The first time has been dated to about 5.9 million years ago.
• Yes, the dinosaurs and almost all of the other living creatures on earth at the time were made extinct about 65 million years ago because of a comet that smacked into the Yucatan peninsula coastline at the Bay of Campeche, triggering a “nuclear winter” that lasted many years.
• The North Pole has continued to wander from its previously-presumed fixed location, and still does so.  And this is independent of continental drift that just confuses the geologic clues.
• The oldest seafloor is only about 230 million years old even though the earth itself is a little over 4 billion years old, or only about 5% of the total.  How can this be?  The seafloors are continuously created at undersea mountain ranges which act as seafloor spreading centers.  “Zero age crust” is created (even as we speak) when basaltic mantle material oozes out along the ridge crests and then moves off in both directions (very slowly – covering a distance about equal to your height in your lifetime).  This starts the great “conveyor belts” of new seafloor material that becomes new crust and move across the top of the mantle in great tectonic plate migrations, gathering sediment along the way, getting therefore heavier, sinking further into the mantle, and finally bumping into another plate or a continent.  At that point the moving seafloor plate generally subducts, or plunges under the continental plate and disappears back into the mantle.  The great seafloor trenches are created at the subduction regions.

Chunks of solid form methane
hydrate ignited to burn off the methane

•  Methane hydrate deposits naturally occur in the ocean sediments in an impressive number of places worldwide.  How much of these deposits exist worldwide is a subject to wide ranging speculation based on wholly insufficient data.  what is known, however, is that they represent

  

an untapped energy resource that may outstrip anything mankind ever derived from oil, coal or gas combined.   Or maybe not that much – nobody really knows yet, but the potential is awe-inspiring.  Methane hydrates look like lumps of dry ice but convert to pure methane and water if you simply expose them to room temperature heat and ordinary sea level pressure.  At that point the pure methane can be burned with products of combustion as clean as or cleaner than burning natural gas.  Think about it.  Want to invest now in this potential gold mine of all time?

• Global warming (and cooling) has happened over and over again in geologic history, with corresponding increases and decreases in average sea level.  And there is NO record of any such occurrence in the geologic record that matches the dramatic parameters of the global warming we have been experiencing since the beginning of the industrial revolution.  Ice core samples have been taken from deep in the ice caps of Antarctica, Greenland and even Peruvian glaciers dating back about 200,000 years in Greenland and up to 420,000 years in Antarctica.  Tiny gas bubbles trapped in the ice contain atmospheric air as it was composed at the time the ice formed.  Data for dates up to 5000 years ago can even be inferred from tree
  ring growth rates in Bristlecone Pine trees (left) found in the White Mountains on the California-Nevada border.  There is a laboratory in the National Forest there dedicated to
  

  

  Very old tree in the Ancient
  Bristlecone Pine National Forest

  study of the ancient trees, the oldest living things on the earth.       All of these ancient atmosphere data indicate that the overall percentage of CO2 (a greenhouse gas) in the earth’s atmosphere has spiked during this current warming cycle to a greater level than anything ever known, especially so since the start of the industrial age.  The implication is inescapable that activities of man have contributed to the speed up and magnitude of the latest natural global warming cycle.

• The earth’s magnetic field has, without question, fully reversed (north and south poles exchanging places) dozens of times over the last 230 million years as verified in the seafloor sediment record.  The record is completely consistent worldwide.  The reversals were instantaneous by geological time scale resolution but that only means the sediment record can’t resolve the reversal phenomenon into a time frame less than 500-1000 years.  Nobody really knows why reversals occur or when to expect another one.  Or what happens during and immediately after a reversal.  (Migratory birds navigate at least partially by using their ability to sense the earth’s magnetic field.  What happens to them when reversals occur?)  The reversals do not happen at regular intervals and are not associated with global mass extinction events.  So maybe they are not dangerous for life on earth.  They have not occurred with any predictable regularity but, on average, we are about 20,000 years overdue for the next one.  Hmmm.

     The final observation here is an answer to the questions – why is all of this important, why is it worth the time, money and effort?  To judge if this work has an acceptable level of importance you have to accept the intrinsic value of basic scientific research.  This includes faith that some payoffs may eventually come in the future.  At the first discovery of cells did anybody envision that new knowledge leading ultimately to researchers finding a cure for polio or cancer?  When electricity was first the subject of experiments in some rudimentary lab did the people then envision cell phones or computers?  It is not fundamentally different with basic geological research.  Can studying samples of subducting plates lead someday to the ability to predict earthquakes before they happen?  Maybe.  It sure would be handy for folks like the Japanese who live on a string of volcanic islands.  Some marine geology research has more immediate probable payoffs.  Characterization of methane hydrates and global climate change studies are obvious examples.  Studies of microfossil distributions, oceanic circulation or hydrothermal vent regions are a bit more obscure.  But there is no gate-keeper judge on what basic research is more important than others.  In the end the underlying theme is – we should try to understand it all.

     That is a brief synopsis of the goals, methods and benefits of scientific ocean drilling.  As you can imagine books can and have been written on the subject.  A simple little blog like this cannot hope to explain much but any start that gets someone to read (and maybe read on) is worth the effort.  Below are some websites with more interesting information for those who care to learn more.

Core Discoveries Newsletter from NSF, with lots of details about every present-day aspect of US Scientific Ocean Drilling, Spring 2013 online version

http://iodp-usssp.org/wp-content/uploads/CoreDiscoveries_Spring2013_FINAL.pdf

Ice Coring to determine historical CO2 levels in atmosphere

http://news.wsu.edu/articles/36605/1/New-ice-cores-reveal-more-about-past-climate-change

http://www.daycreek.com/dc/images/1999.pdf

 Bristlecone Pine climate data

http://www.scientificamerican.com/article.cfm?id=great-basin-bristlecone-pine-growth-rate-tree-line

Anecdote:  “A Good Bar Fight Story”

      No recitation of sea stories is complete without a bar fight story and I have a good one.  I know it is going to sound like some scene out of a movie, but, honestly, it really happened, I was there.  Our science and technician crew were celebrating another successful offshore exploration into the unknown at our final port of call, Singapore.  About 10-12 of us were enjoying our liquid refreshments at the bar of the famous Raffles Hotel.  Great place.  Looks just like you’d expect if you saw it in some old Humphrey Bogart movie.  Raffles, like much of Singapore is quite refined, polished and sedate.  Probably not the right place for a bunch of rowdy folks just coming off two months at sea and looking to blow off some steam.  We came to this realization when the young lady standing on the table singing the Aggie War Hymn was politely asked to leave the premises – and take your rowdy half-drunk friends with you.

     Not a problem, we knew of other good places to go.  One night club, in particular, was well known and catered to tipsy foreigners intent on not calling it a night at that hour (it might have been 1 am but my memory cells have suffered some abuse since then so I can’t be responsible for exact details here).  We repaired to the huge bar via several taxis and found it positively hopping with people and loud music.  It was a huge place as clubs go, two stories and full of everything a lonely sailor on leave could possibly want.  Again, the name is fuzzy in the old memory banks, Paradise Inn or something along those lines.  The cab driver knew exactly where to take us almost without us having to specify.

     We went in and situated ourselves at a couple tables on the second floor, which was less crowded – meaning that it was actually possible to wiggle your body through the masses of drinkers and dancers to the bar itself whenever you wanted to order a fresh beverage.  I had started drinking ginger ale at that point because I sort of knew my limits (but don’t tell anybody).  One of our scientists (I will call him Ethan to save his reputation, although that was not his name, of course) was thoroughly lit but still functional.  He was also one of those happy drunks who just gets more pleasant and funny as he drinks.

     Ethan made his way to the bar and wiggled in next to a group of Australian Special Forces guys who were there for much the same reason as us.  Nobody quite knows what happened next but Ethan evidently, quite innocently, did something that really ticked off the Aussie solider at his elbow.  Maybe he said something not as funny as intended, maybe he bumped into the guy, maybe he just made eye contact and the moody Aussie was itching for an excuse to start a fight.  In any case the soldier jumped up and punched the living daylights out of Ethan, who dropped like a stone and started bleeding on the floor.  The Aussie was not quite happy with that result so he tried to finish poor Ethan off but had a bit of trouble doing so because the crowd was packed in and Ethan was busy crawling through people and table legs to get away, at least until the bleeding and initial shock wore off. 

     Quickly his mates (us) noticed the ruckus and jumped to his rescue.  Well sort of, it was shaping up to be a  brawl between a half dozen mostly drunk, out of shape, generally pacifist scientists and lab techs against a human wall of young, fit, trained killers.  This is not good, I remember thinking.  At that moment the senior Aussie in uniform did something very sensible and welcome.  He jumped between the two skirmish lines and shouted – one on one, mates, let the boys go at it one on one.  I recall hearing one of our computer techs shouting back – what do you mean one on one?  It is one on zero, Ethan is not fighting, he’s crawling and looking for a place to hide.  Perfectly correct observation, I thought.

     And then the movie part occurred.  One of our number, a very well-proportioned scientist from Michigan (name withheld, I’ll call him Brad) came out of the men’s room, saw the situation and decided he needed to rush to our defense.  This is not as silly as it sounds because this particular man played football at Michigan and was drafted by the NFL Miami Dolphins.  He never played for the Dolphins due to some injury problems during his first training camp, but he was nevertheless the biggest, fasted and strongest of us all, by far.  He rushed up to the group, pushing bystanders aside, and approached the Aussies from their rear.  One Aussie turned in time to see Brad coming, sensed danger, and started to throw a punch, which he never finished because Brad caught him on the jaw with a picture perfect haymaker and the Aussie went down in a heap.

     Oh my God, I thought, this has gone nuclear, we’ll all be lucky to avoid a Singapore hospital or jail, or both.  And then the wise senior Aussie did another wonderful thing.  He jumped between Brad and the furious Aussie men of war and shouted – Good on you, mate.  One apiece.  Even Steven.  Let’s drink to that!  And that is what we did.  It was a hoot. 

     The end of the story is that we still had to fix up Ethan and very shortly someone had called the Singapore police.  Singapore has a well-earned reputation for being a tough law and order city-state and we did not want to mess with their police or legal systems.  So we went into high gear to find Ethan and get him out of there.  Ethan is sort of cute (women tell me) and even drunk and bleeding he caught the sympathies of a couple hookers with hearts of gold who had spirited him away to another room where they could protect him and clean him up a bit.  A couple of us reclaimed him, got him downstairs and into a cab and drove away just as the police were noisily arriving.  Ethan appeared at the hotel the next day for breakfast with a classic black eye but otherwise none the worse.  And with a pretty good story to tell for the rest of his life. 

     Epilogue:  I followed Ethan's career from then on and it is interesting to note that among other things he went on to be the director of a major museum featuring oceanographic displays.  They had a nice photo of him in the lobby - without the black eye.