Oil Well Drilling Primer

We use exactly that. A hydraulic Accumulator. But it is for another purpose. I'll get to that later.

 

I recieved my well program today. We will begin this well with a 12 1/4" drill bit. We will drill a 12 1/4" hole to 1,500 feet with a 9 ppg mud. Then we will run and cement in place a 9 5/8" casing.
We will run inside that with an 8 3/4" drill bit and drill an 8 3/4" hole to 7,200 feet with a 10ppg to 10.5 ppg mud. We will run and cement a 7" casing.
We will run inside that with a 6 1/8" bit and drill a 6 1/8" hole to a total depth of 9,500 feet with a 14ppg to 14.5 ppg mud. Then we will run and cement a 4 1/2" production casing. We will "Nipple Up" a well head or "Christmas Tree" and release the drilling rig.

 

I have seen that! It is hilarious. My wife freaked out when she saw the Roughnecks working on the floor. She didn't realize how dangerous it is. You have a lot of moving iron and steel around a lot of flesh and blood. The iron wins everytime.

When I started "Roughnecking" in the 70's they used to say that you couldn't call yourself a Roughneck until you lost a finger. I have seen a lot of missing digits and limbs.

If you watch it they will show the part over and over where the mud comes flying out and drowns everyone. Watch the "Driller" "Boo" he does this on purpose. It's called popping a wet one. Usually a "worm" or new driller will do it when they forget to turn the pumps off. The mud is being pumped through the drill string and when you unscrew it it blows everywhere.

This "coon-ass" driller on the show nods to the other hands and you can see them backup.One guy standing next to Mike Rowe doesn't see him and he gets doused good. Watch the drillers left hand, he is holding on to the pump control on the drilling panel and shuts it down as soon as he "pops" the string.

I crack up everytime I see that. Several years ago OU played Georgia Tech in a bowl game. The news was reporting that the two Governers had a freindly wager. If GT won then the Okie Gov. would go down to Georgia and pick peaches for a day. If OU won the Georgia Gov. would come up to OKla. and work on an oil rig. OU won and the news crew was filming the Gov. out roughnecking. The Driller on the rig did the same thing, he popped a wet one on him and just drowned the Georgia Governer, the film crew, and camera man.

It's funny because nobody has a clue what happened. Watch Rowe on Dirty Jobs, he has no idea that they set him up.

 

Another misconception is that we see oil. I have drilled thousands of oil wells and the only time I see oil is if one of the engines is leaking. If oil comes to the surface you have a problem. We usualy don't know if we made a good well until some time after we move off of it.
After the drilling rig leaves a workover rig comes in and does the production work on the well. They run a tool down inside the cased hole and perforate the casing at the target depth. Then there are a variety of different things that may or may not have to be done to get the oil to flow.
I'll detail that process when we get this well drilled. I'll take you through the drilling, completion and production phases. All the way up until the oil is loaded onto a tanker truck and hauled to the refinery.

 

These are some pics I had of different rigs. This is what happens if you let oil and gas get to the surface.

 

This is what happens if you let it get away from you.

 

Thanks E. Hope you all are enjoying this. It's a lot of work.
Not much happening today. Rigging up the little stuff. I've been ordering the tools that we will need.
Have a welder here welding on an extension to the "Conductor" pipe. And BTW it is a 20" diameter pipe and is driven to a depth of 40'. Some are 60' but this one is at 40'. The extension is welded on and the "Tee" section is attached to the "Flow Line". This allows the mud coming back out of the hole to channel up and flow down to the "Shakers and return to the mud tanks.

 

I recieved the drill bit today. It's a 12 1/4" roller cone rock bit. It will drill an average of 100 feet an hour. And will last the entire 1,500 feet of "Surface Hole".
The holes around the bottom of the bit are "Jets". Jets are changeable and are where the mud comes out. You can vary the size of the jets to give you more or less pump pressure, cleaning properties, and bit "Hydraulics".

 

This is what happens if you run one too long. You have to know the signs of a dull bit and pull it out of the hole before it gets this bad. These kind of bits coming out of the hole have cost several Drillers their job!!

 

How hard are the teeth and buttons on that?

Another side light:

FWIW, this looks like a very small version of a TBM boring head.

Once started, the loading of the bit is monitored, and as it bores thru different rock layers, the load on the drill string changes, and the wear varies. On the raise bores I've done, the idea was to maintain a constant load regardless of speed of advance. One way to gage the wear is progress thru the strata. As the advance slows, the wear is showing up. The main idea is to avoid pulling the string until just before the bit goes to hell, that is, so they can be rebuilt. (Much cheaper than buying a new one; they are pricey, an important cost of making deep holes.) On the TBMs, we could back off a touch from the face and actually have a look at the teeth and rollers. We programmed changing one third of them out every so many hours of boring.

One thing that is not so obvious is that the toothed wheels rotate as the drill stem turns, they ain' no drive shaft in this baby.

I don't know if you can vary the force on the drill string going down, but we did on the raise bores, and of course the loading on the TBM head is tightly controlled. Seems like you would have to be able to compensate for the weight of the string somehow.

FWIW, the raise bores did not use mud, and likewise the TBM heads. Plain water for dust control, if there is no inleakage from the strata. Not needed in raise boring, as the the muck drops to the bottom of the hole and is taken out from the tunnels, and the TBMs are self mucking. "Muck" is a term from the old days when drill and shoot was used for tunnelling and the water inleakage made mud. Today, muck is shot rock, TBM grindings, whatever the machinery and blasting leaves behind.

 

You are right on the money G. It is basically the same thing. We lower the drill string to put more weight on the bit. I am getting ready to post some pics of the drill string. We add weight and increase or decrease the rotary speed to find a "Sweet spot" where we can drill the most hole. The amount of weight is determined by the size of the bit. The rule of thumb is #5000 per square inch of bit. So a 12 1/4" bit can be run with a maximum of 61,250 pounds of pressure on it. I will pick up a very heavy, thick walled, pipe called a collar. 8" diameter, 30' long, #165 per foot. I will drill down and screw together enough "Bottom Hole Assembly" to give me all the weight I need. My BHA is going to be a drill bit, two 8" drill collars,a stabilizer sub, one more 8" DC, then I will change over to a smaller DC, six 6 1/4" DC's(#85 pound per foot), then twenty 4 1/2" Heavy weight drill pipe (#41 lb/ft) for a total BHA weight of about 55,000 pounds.

FYI, I was reviewing my well program today. I have been assigned 18 days to drill this well and an AFE (Approved Field Expenditure) or budget of $2.5 million. That is for the entire process. I will spend about $1.5 million on the drilling portion. The rest is for completion and production.

 

The bit is screwed onto a "Drill Collar". A drill collar is a heavy pipe used to give weight to drill with.

 

Then as they are drilled down smaller pipe is screwed onto that. Until you get to the "Drill Pipe". Ours are 4 1/2" diameter, 13.3 lb/ft, 31' long, joints. We will eventualy screw together over one mile of them.

 

How do you keep the string from bending under load? Not a problem with raise boring, the string is under tension, so lighter pipe is used. We pulled 350K lbs on the heads, 4' diameter.

 

The majority of the weight is in the "Bottom Hole Assembly". The collars and heavy weight pipe. We never put all of your BHA weight on the bit. That way your drill pipe are always in tension.
They're are occasions when the drill pipe breaks or comes unscrewed and falls down the hole. If it happens when your are "Tripping" in or out of the hole and the string is high up in the hole it makes a real mess. The drill pipe "Corkscrews" and is bent all to crap.
There are a lot of indicatore to tell you when the bit is getting dull. More torque required to turn it, a bouncing or hopping, drill string, erratic penetration rate. And it is a balancing act to get all you can out of it, but don't leave it in the hole so long that it is damaged.