Drilling commences with a little music from home.

November 9th, 2014

Sunday drilling finally started!  It has been early two weeks since they lost the BHA downhole and have been fishing for scrap metal since.  At 4 a.m. Sunday morning they were able to pick up the last piece of the counterweight at the bottom of the borehole and tripped in the new tri-cone bit.  At approximately 7 p.m. drilling began.  They are taking it very slow to make sure little bits of metal won't mess up the new bit and trying to circulate mud to remove these bits of metal.  I have been assigned a 3 p.m. to 11 p.m. shift making thin sections from the cuttings gathered from the mud.  The collection process is very different than the oil and gas industry.  Mud logging in industry consist of keeping track of the drillers depth which is the depth at which the bit is currently at, and the lag depth which is the depth at which the collected cuttings originated at.  Due to the depth of the borehole and the rate at which the  mud is pumped into the borehole, these depths are different.  While mud logging, we used a software created by Pason that calculated the lag depth based on these parameters.  It tracked the rate of penetration, the driller's depth, and the lag depth.  All of which is very useful in determining where you are subsurface.  In scientific drilling, these are not calculated or tracked except for the drillers depth.  A sieve collects cuttings continuously over 4 meters which is about 12-13 feet.  The cuttings are described as a group over that depth interval and every 6 meters a thin section is made based on the drillers depth.  Currently, the rock has been mostly the same composition,  the problem I see with this is when a change in the lithology does  occur we will not be able to pinpoint that depth.  I asked Tim Little, our team lead, and he said I had a valid point but they hope to see a gradual change in the lithology before that change occurs and another reason they collect continuously is they do not want to loose any cuttings at all.  The differences are interesting and understandable but there seems to be more precise way of knowing and keeping track of these changes.  Maybe they are doing this and I just have not been introduced to the technique. 

    In studying geology, a major part of the undergraduate program is looking at and identifying minerals in thin-section.  Thin-sections are a thin piece of class with an extremely thin piece of rock glued on to it so that you can look through a microscope and see the mineral composition, structures and deformation of the grains on a micro-scale.  I definitely took for granted the hundreds of thin sections I looked at as an undergrad and the work put into creating those.  My assignment here is to make thin sections out of the cuttings collected.  Let me say, this is not an easy task.  The cuttings are collected, washed and dried.  We then take a random sample that represents the overall composition of the sample and create a small "puck" of cuttings in epoxy.  The puck is then glued to the thin-section glass plate and allowed to set for 30 minutes.  After the puck is glued it is taken to a diamond carbide saw and cut relatively thin, but to be useful in thin-section the minerals have to be ground down to a few microns thick so that light can pass through them.  After the thin section is cut we take it to a grinding block similar to a pottery wheel.  This is where it gets quite difficult.  The fly wheel  is basically sandpaper grinding down the thin section a small amount at a time.  The tricky part is putting the thin section on the spinning wheel and holding onto it so it doesn't fly off.   I practiced with scrap thin sections for awhile and only managed to break one.  It isn't natural to put your fingers down on something spinning that fast and you can't even feel the wheel wearing down your finger tips until after the damage is done.  After about an hour of practive with scrap thin sections, I moved on to my first real section.  I had gotten the hang of it for the most part but lost my grip once and the thin section flew off and chipped the corner.  It was bound to happen.  The next step is to move to a finer grained polishing block.  This one is stationary so no where near as difficult.  I polished it off and found that getting an even polish is more difficult than I thought.  Typically when you look at a mineral such as quartz under cross-polarized light in a microscope, the quartz appears black and white as you rotate the disk.  If the mineral is too thick it will have very bright colors as you rotate such as  bright pinks, purples and blues.  This tells you if the thin section has been polished enough.  Well, half of my thin section was perfect and the other half was not.  But if I continued with polishing I risked taking the perfect part completely off of the glass plate.  It is not an easy process, and like I said earlier, for all the undergrad geology students do not take for granted all of the perfectly prepared thin-sections you have to look at for hours in those petrology classes.  Someone had to make each one of those and there is definitely an art to that! 
    After my shift we arrived back at the logistics house for a nice surprise, Ray had arranged for a few musicians to have a house concert for the crew.  Bill Morris and Hyram Twang were sitting in the living room playing acoustic folk music.  They were very talented and something I have been surprised about New Zealand.  They love country music.  This was right up my ally and they played many songs that I knew.  Townes Van Zandt, Guy Clark, Steve Earle and many of their originals.  After they finished playing around 1:30 in the morning we began chatting about their background.  Hyram Twang was originally from California but moved to New Zealand in the 80's to get his PhD in geology from Otago.  Bill Morris is currently attending Otago studying geology and just got back from the states filming a friend on tour there.  He had made a stop in Oklahoma at the Blue Door!  Very cool music venue that I've had the pleasure watching Hayes Carll play  It was a great way to end the night and it took me back home for a few hours.