The Birth of Brandi's Twins [COTW 8/8/11]

[Mr Twisty]

Ok... try this on for size...

pull the bit out... replace it with some sort of hydraulic jet (like a water hose sprayer)... run it back down and blast the piss out of the bottom of the hole at an angle, enough to offset the bottom. Then when the bit is run back down, it's going into a bit of a bind, causing it to try to follow the new path that was jetted into the bottom.

.... So... what if we accidentally stumble onto a better mouse-trap here... you gonna share in the profits, Mr Halliburton?

[Happy Pappy]

Ball Bearings ..... It's all done with Ball Bearings these days......

[CamaroSkooter]

Transformers.

[mlee]

You guys are good... I see some patents coming.

Here are two directional wellbores from the same top hole. TVD or Total Vertical Depth is only 3000' but the wellbore is 11,000' long.

[carbon8]

You use a directional motor to drill directional wells. The motor has a bend on the bottom 4 feet anywhere from 1-3 deg. The bit also spins from the gallon per minute pumped threw the string. You can rotate the bit only by pumping mud threw it. This is how you get your curve in the hole. You just point the bend where you want it to go. ( it's way more complicated then this). And if you want it to go straight in the direction that you have started it going you rotate the bit and the string at the same time.
The way they know where the bend is facing is called a WMD tool. It's works off of a magnetic tool face. They take surveys every 30 feet and plot it on a map. This is how they know where they are every time. It is all much more complicated then this but I tried to put it short and sweet.

[mlee]

Bent sub and downhole motor...


Edit: I see you edited and explained...

[carbon8]

This shows the difference between just sliding with a directional motor and rotating with a directional motor.

[Mr Twisty]

I think I got it.... But you'll need 2 miles of rope, ball bearings and a midget.

[mlee]

Originally Posted by Mr Twisty

I think I got it.... But you'll need 2 miles of rope, ball bearings and a midget.

So we have PQ... Check...

[SSE 4 2SS]

As was mentioned by mlee who works in a monitoring center for drilling operations world wide, and by Carbon8, who is a tool pusher on land rigs... There is one way of doing it, called sliding in our terminology... you do not rotate the pipe so much as you use a mud motor right above the drill bit... it you want to go a specific direction, you turn the pipe just enough to face the bend in the direction you want to go... Then alternating brake and release action on the drillers handle allows it to slide in the direction you want it to go...

That's a bit older school for us...

As Skooter alluded to... and was quite close... We use a directional head...Baker Hughes, Schlumberger and several other companies build these. I happen to know where two of them are buried side by side in the Mediterranian... You can't drill a horizontal section 5900 ft and then stop rotation and slow the pumps to a back fill rate only and pull it 5900 feet back out of the hole... You will bulldoze the cuttings with the tool and very soon after pack it off to a point where the pipe parts...

There is a gimbaled head on the BHA, Bottom Hole Assembly, that recieves signals via either pressure or accoustic signals sent via the mud being pumped down the drill pipe... These signals tell the head which direction to gimbal the bit and the rest of the assembly follows along...

We have actually drilled sections uphill at times, not entirely on purpose... The guidance is the responsibility of the directional driller, a high priced underworked hand that couldn't hack it as a tool pusher... Kudo's to you carbon8... Tool Pusher...

[Mr Twisty]

Ok... so how do you keep the rig at a fixed point in space?

[CamaroSkooter]

Aliens.

[SSE 4 2SS]

Originally Posted by Mr Twisty

Ok... so how do you keep the rig at a fixed point in space?

That would depend on the type of rig it is... Land rigs, ask carbon8... I think they set tyhe brakes on the trucks...

Offshore rigs...

Jacketed rigs... these are permenantly attached to the sea floor rigs. The legs they stand on are driven into the sea floor and the rig is installed on top...

Jack-up rigs.. These are rigs that are floated into an area, and the legs are spudded in, driven into the sea floor via bubbling the can, big feet on the bottom of the rigs, and then the rig is jacked up to a working height...

Semi-Submersible... Like the rigs I work on are floating rigs...

Moored or Anchored... Like the rig I am currently on, we are towed into location and then an anchor boat pulls our anchors out and sets them. We then pull tension and exactly locate the rig where the oil company wants it...

Some of these rigs are self propelled, but only for travel from one location to another, then an anchor boat helps them get the ancshors out...

Then we get to the bad boys...

DP rigs... DP is Dynamic positioning... These rigs are self propelled and basically hover over the drilling location under their own power. These rigs will have an entire Marine Crew Contingent from the Captain to the Chief Engineer on down... Chief Mate, Bosun's Mate etc...

These are the newest and generally the biggest rigs working the oil fields... Typically they are used in deeper waters where it isn't so practical to use anchor moorings, and due to their size, they are capable of handling the greater weights of deep water runs of riser and the bigger BOP stacks... Some of these rigs have stacks weighing close to if not over 1,000,000 lbs...

[carbon8]

As far as land rigs go we just move them from one location to another piece by piece. All my rigs (as I am a drilling superintendent over 5 rigs now) are to big to be mounted on trucks. My rigs range in size from 500,000lb Derricks to 1,000,000lb derricks which can drill wells up to 20,000 feet deep.