Change of Plans again, or Whoops We Broke Something!

Thursday, January 21st, 2010

Boy, what a difference 2 days can make.  Today is the first time I have regretted updating this blog every 2 days.  So this entry is a bit longer then I usually would post.

One of the Co-Chiefs, Dr. Carlota Escutia put it simply, “This is what happens when you drill where nobody has drilled before”.

Over the last 2 days, we have had to move to a backup site because of icebergs, broken 2 coring barrels, nearly got a drill bit stuck, gave up on our coring location, pulled out and are now moving almost 80 miles away.

It has been an adventure!

Just to give you an idea, here is a picture of the drillers installing one of the pieces that actually broke.

We broke two of these!  They are solid metal!  One of which we bent so badly we could not pull it up!  After we broke these, we ended up using one of these bits to drill.

And it nearly got stuck, because the hole started to collapse around it, making it very difficult to pull out.  If we had drilled any deeper, we would not have been able to get it out!

The bad part is the time lost.  When you drill in the ocean, you have to lower the drillbit to the bottom of the sea.  You do this using something called the drillstring.  The drillstring is made of a bunch of pieces of drillpipe called stands, and each stand is 30 meters long (about 90 feet), and you use as many as you need to get to the bottom. 

Each stand takes about 5 or 6 minutes to install, then lower.  If you are in shallow water, this might take an hour or two.  But if you remember the last blog, we were in 3500 meters of water (about 11500 feet, or more then 8 Sears Towers down!).  If each stand is 30 meters, then we need about 115 stands to reach the sea floor!

If each stand takes 5 or 6 minutes, then we need between 575 and 690 minutes to reach the sea floor.  That is between 9 and a half, and 11 and a half hours!  Each way!  So when we had to pull out to fix the stuck drillbit, that was almost a day of just pulling the drill string up, and then lowering it back down!

As I post this, we are just coming on station at the new drilling site.  The water depth here is about 4000 meters, or 13100 feet, or another Sears Tower deeper!  So it is going to take between 11 and 15 hours to lower the drillstring to the bottom!  To put it another way, it is about my bedtime right now.  I will go to sleep, wake up, and probably even have lunch before the drillstring reaches the bottom of the sea!

Drilling in deep water takes a while!

But enough about our problems, let us get back to Lambchops tour.  When Lambchop left off, she was talking about the measurements the MST takes.  She just talked about GRAPE, but fortunately she did not eat it, because we need it to work!  But the next sensor on the MST is called “Magnetic Susceptibility”, which looks like.

Lambchop usually calls this MS, because it is much easier to say!  MS measures how the sediments respond to a magnetic field.  This actually tells Lambchop a lot about where the sediments came from, because sediments that started on land has small magnetic grains in them, which the MS can pick up on, while sediments made of the shells of little creatures that tend to live in the ocean do not have any of these magnetic grains.  So MS allows Lambchop to tell something about where the sediments came from, even without looking at them!

Of course, this is not the last MST measurement taken, and while MS is very useful for telling something about where the sediments come from, after Lambchop is done with all of her measurements for Physical Properties, she will split the core, so she can look at it directly.  So make sure you stay tuned.