Work: Well Installations
In March 2007- my work schedule changed from 80% office/20% field work to about 60% field/40% office work. Installing groundwater monitoring, extraction and soil vapor extracting wells has been one of the activities I do in the field. Well installs can vary from taking just a few hours to a few weeks and rang in cost from several thousand dollars to nearly a million. My job during the installs is to oversee all subcontractors and making sure the well is installed correctly and that no one gets hurt or killed.
So below are some pictures from 3 well installs completed over the last 6 months.
A well install done back in May 2007 in Torrance, Ca. Its early morning and the drillers have just arrived onsite and the support truck is driving to the proposed well location. The support truck carries all the extra equipment such as drums, drill bits/stems and tows the forklift and generator. Crenshaw Blvd and the Ball Manufacturing plant are in the background.
The HSA drill rig. HSA = hollow stem auger - which is a method used for drilling. This particular well went down to 100 feet below ground surface (bgs, and we hit ground water at 70. If anyone is really really interested in how this method works check this link out http://www.geology.sdsu.edu/classes/geol552/hollowstem.htm
Closer view of the support truck. You can see the auger flights (they look like giant screws) stacked up towards the back.
In the background is the Dow Chemical Plant.
While drilling is going on - the drillers bring me a sample every five feet(approximately three feet long ) which they collect in a in a steel sleeve while drilling down. These steel sleeves or rods (located in the center of the hollow auger flights) collect soil as the auger advances deeper.
The view inside of this rod. Most of West Torrance is located on top of ancient sand dunes and ocean floor. This sample - taken at 30 feet bgs - yielded "beach" sands and shell fragments (the white stuff).At this depth - these shells could be several thousands of years old.
This was my birthday well install - as in this is what I did on my birthday. This was a vapor well install and only went down to 35 feet bgs. It was also drilled using a HSA rig. In this photo, the drillers are removing a PVC pipe left over from a pilot study (Pneumatic fracturing) done in the same location . This was located at our Carson site. You can see the BP refinery in the background.
A vapor well, unlike a water well, is used to extract soil gas from the soil where is it is then pumped through a system for treatment.
Drillers setting an auger flight in place. This rig was much smaller than the one shown above. Not as much power is needed to go shallower depths.
This soil has been contaminated with chemicals known as volatile organic compounds - which means these chemicals volatilize at low temperatures.
Both of the well installs shown above were done using HSA, took less than a day to complete and cost under $10,000 each to install. This well install in Carson took two weeks and cost over $250,000. This well install was also conducted at the Carson Site, but a Mud Rotary method was used.. In this picture you can see part of the rig behind the soil bins. My boss (white hard hat, blue shirt ) is chatting with the Driller by the hopper.
A photo of the mud rotary rig next to the shaker.
Mud rotary drilling uses bentonite slurry (a type of clay mixed with water) to cool the drill bit and keep the borehole from caving.
The mud is pumped out of a mud tank at the ground surface, down the drill rods, out through the bit, up the circular ring of the hole between the drill rods and borehole, and back into the mud tank.
The circulation of drilling mud removes the cuttings generated during the drilling process from the borehole and carries them to the surface where they are allowed to settle out in the mud tank.
Unfortunately, during the two weeks I was out there, I didn't take a picture of the drill bit. But this is a picture of the drillers inserting more piping as the drilladvances deeper into the ground. This particular well went down to 300 feet.
A close up of the rod. The hoses on the left hold the bentonite (mud) slurry. These hoses pump the mud down the rods, down to the drill bit.
The mud pan and the rods moving further down to the ground. The mud inside the pan is the mud which has already traveled outsire the rods, over the drill bit and back up through the boring. It keeps the the drill bit cool, the hole open and carrying the drill cuttings (or the dirt generated from drilling).
The mud then flows to the other end of the pan where it is then sucked into the shaker.
The shaker ( the little yellow thing to the right) separates the mud from the soil via centifuge.
The soil cuttings after being separated from the mud. The mud is cycled back through the system. The soil scientist/geologist's job is to log the soil as it comes off the hopper in order to determine where the drill bit is located - in an aquifer or an aquitard. At this site, the contamination spread to four aquifers down ( down to 300 feet). An aquitard (made up of fine silts and clays aka an impermeable layer) divides the aquifer (which consists of sands).
An example of aquifer sands with a bit of mud.
An example of an aquitard.
When we reach an aquitard, we then set the conducter casing. The conducter casing seals off the aquifer. This particular well is being installed to monitor the 4th (and deepest) aquifer. The conducter casing prevents water/contamination from the shallower aquifers from contaminating the deeper aquifers. These conducter casings are for the shallowest (A) aquifer, thus they are the largest.
These are the B aquifer conducter casings. Each subsequent conducter casing must fit inside the last, so they get smaller as you go deeper.
A shot of the drillers setting the A conductor casing. It is crucial that it goes in straight.
As they put the conducter casings in- the head driller welds them together - this takes about 6 hours to complete.
After they insert the casings into the ground, concrete is pumped in to hold them in place. Notice the position of the rig.
My boss, joking with two of the drillers.
It takes a lot of water to install a well. My boss assists our new geologist with hooking up the hoses to a the water source over the fence.
A huge tumble weed!
One day - towards the end of the install - a small cyclone/large dirt devel came through. As you can seen from the photo- it was rather large.
My boss and I had a little moble office set up with our laptops with an awning. The cyclone picked up the awning, carried it several feet and the slammed it down on the ground, smashing it. All of the metal supports were bent. Strangely enough, the cyclone did not disturb any of our papers or other equipment on the tables.
The cyclone traveled across the site, it knocked over all the empty sparkletts bottles and
and moved "Porky", out 250 gallon poly tank approximately 20 feet. I circled where the storage location of the tank. There were no drag marks. The cyclone pickup the tank and then dropped it. Over the next several weeks, we keep on finding sparkletts bottles all over the site, some as far as 100 yards away from where they are usualy kept!!