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From Fossil To Fuel™
From Fossil To Fuel™

Episode 14 · 2 years ago

Episode 13 - Coiled Tubing

ABOUT THIS EPISODE

What is it and when do we use it?

My name is Brennan McDougall and I'm a professional engineer. Or the last decade I've worked in many different facets of the oil and gas industry. While I have a pretty solid technical background in oil to gas, I don't really know a whole lot about the other non technical departments that help run an oiling gas company. Recently I took a course to help develop my business acumen and better understand how the financial side of the business works. What a novel concept to educate the technical people on the business and financial side. I thought it would be a really cool idea to return the favor and educate the non technical people on the technical side. This is how the concept from fossil to fuel was born. Through these twenty four episodes, we will take a journey from how oil and gas was formed millions of years ago how it is refined into the fuel that runs our cars and heats our homes. Come join me on this adventure as we learn how the oiling gas industry operates from fossil to a few coil tubing is a versatile piece of equipment that's used all over the oil and gas industry. It's a staple, but it's primary purpose is for well intervention, which is essentially changing something in or out of the well bore. I'll talk more about other uses for coil tubing as we go through the episode. Coil tubings a long string of metal tube or tubing that is typically anywhere from three quarters of an inch to three and a quarters inch in diameter, which is relatively small compared to what we normally talk about for metal pipe, but it's several thousand meters long. It's wrapped or coiled around a Spool, which...

...is what gives it its name. I should make a note now that, for whatever reason, the oil and gas industry is notorious for interchanging imperial and metric units, and if you haven't noticed by now, I'm notorious, or I'm in the habit of switching back and forth between units. It's a pain in the butt, but it's pretty standard in oil and gas and eventually you just get used to it and you start to do the conversions in your head. So I'll try my best to do the conversion for you where I feel it's necessary. For example, the diameter of coil tubing is in inches, we just talked about, but the length is in meters, kind of like how the diameter of the rims on your cars in inches but the width is in millimeters. Go FIG here. So coil tubing has some similarities to wire line, which we talked about last episode. However, the big advantages are that you can pump things through it because it's pipe, and you can actually push it down whole rather than rely on gravity. So remember that. With wire line it's kind of like rope basically, and you've always I'm assuming you've heard of the concept. You could never push a rope, but coil tubing, because it has some strength to it, you can actually push it down whole and if you need to pull something out, you can pull harder if need be, because the Wireline, even though it is a metal cable, usually metal pipe. You can pull much harder on it if need be before it will actually break. So what's the disadvantage? Well, it's longer to set up and to take down, but primarily it's more expensive. Coil tubing is made to be able to bend and be flexible with the forces created upon it, which is from the injector, and we'll talk about that later in...

...a second. But it is flexible and it's a little bit hard to picture that in your mind's eye when you're thinking about metal pipe that's designed to be strong actually being able to bend, but it is designed to do that. But keep in mind that, as you're continuously bending it back and forth as you go in and out of the well, especially if you're pumping a high pressure fluid through it at the same time, it does have a finite lifespan and the higher the stresses you put on the coil tubing with cycling, which is when I say cycling, I mean moving the coil tubing in and out of the well, though. So the more stresses you put on it with this cycling, the faster it wears out and eventually a new reel of coil tubing will have to be used or purchased, and the cost to replace it is not cheap, which is really why coil tubing can be so expensive. That's really one of the main reasons. So the main parts of Coil Tubing unit that you need to know, and we'll go through most of these individually as we go through the episode here, but the main parts are so the coil tubing itself, the goose neck, the injector the real the power pack, the bottom hole assembly and the well controlled package, which is your vops, your strippers and your lubricator. So even though the tubing is flexible enough to be spooled around a drum so that it can be efficiently transported on a truck, we still need to be careful when running it down the well. Every size of coil tubing has a different allowable bend radius, but if you exceed that radius you can and likely will cause irreversible damage to the coil tubing string, and the only way to fix this is by cutting that damage section out and that, let me tell you, that sucks. So we definitely...

...do not want to do that. So this is why the coil tubing is run over the Gooseneck, and the Gooseneck, like a lot of things in oil and gas, gets its name because of what it looks like. So it's a basically like a gentle curved guided arch that the coil tubing. If you can picture in your head, there's a spool on the back of a truck. So the coil tubing, as it's coming off the Spool, goes up into the air around this, kind of like a upside down see like the letter c. So it's imagine like a curved arch in the shape of a letter C. So goes up and then over this arch and then back down into the well or, if we're coming out of the well, back onto the real and so this goose neck or this curved arch is designed so that you don't exceed the bend radius so that you don't actually snap the coil tubing when you're running it in or out of the well. And Really, depending on what type of coil will you're using or what type of coiled unit that you're using, the gooseneck setup was going to be a little bit different, but generally speaking that's what it's used for. So most wells that coil tubing is run into are producing wells, meaning that there's oil and gas creating pressure, or I guess we'll call it positive pressure, on the well head, which means if you want to get coil tubing into those wells, you need to mechanically push the coil tubing into the well and have a way to hold it there so that the pressure on the wellhead because remember, the pressure coming up and you want the coil tubing to go down. So you need something to hold it there so the pressure that's coming up doesn't cause the coil...

...tubing to be spit back out like a big long spaghetti noodle. The coil tubing uses something called an injector to push the tubing into and pull the coil tubing out of the well. So the injector is able to grip the coil tubing and as it grips it, that's what enables it to push it into the well. The the grips and the injector. If I can help you visualize this in your head, it kind of looks a little bit like miniature tracks from a tank, like a military tank, that rotate and as these tracks rotate they grip the coil tubing and push it in, similarly to how the tracks on a military tank rotate and grip the earth and push the tank forward. They also allow you to control the rate at which you push in and pull out of the well the bottom of the coil tubing. So remember the coil tubing itself is just metal pipe. So the bottom of it there's nothing on it. It's just the end of the pipe. But of course we're not just most of the times we're not just going to run pipe into the well. We have something that we want to do, and so all of the equipment or tools that we have attached to the bottom of the coil tubing is called the Bha or the bottom hole assembly, and so you've probably heard this term a couple of times now throughout these different episodes, and it's still the same as kind of that generic term that refers to all the tools attached to the end of you know, your drill string or your coil tubing string or your wire line string, whatever it is. It's the generic, generic term for all of the stuff at the bottom. So it could be...

...a nozzle, that could be a mill. We can run perforating guns, similar to what we did with Wireline, or could be something else. So the ability, or really the versatility of coil tubing is what makes it so useful. You can clean out debris in the well with a nozzle, which is kind of like cleaning the side of your house with a pressure Washer. You can drill a well board with it, you can drill up FRAC plugs or other pieces of equipment with it. The coil tubing itself doesn't spin the drill, but you can use a motor or something like it that causes the drill to spin by pumping fluid through it. You can run equipment or retrieve equipment with it, and retrieving equipment is generally known as fishing, although usually when we're fishing we're retrieving equipment or things downhold that we didn't want down there in the first place. So fishing is generally not a good thing. But we'll talk about this more specifically an episode fifteen. You can perforate with your coil tubing. You can pump chemicals down it, you can even FRAC with it. When we talk about service rigs in episode twenty one, you'll see that the service rig has to connect joints of pipe together to go deeper in a well. But because coil tubing is one long piece of Metal Tube, you actually don't have to make these connections because it's one piece, so you don't have to stop as you're running in the hole. So big advantage there. Some people will even leave it permanently in the well and flow through it as opposed to tubing like we talked about in previous episodes, like permanent production tubing. There are many different uses of coil tubing and the huge benefit is that you can do it all while the well is still flowing. The main...

...component of the well controlled package that we talked about is the BOP or the blow up preventer. So if you're ever able to run into a situation where oil and gas is coming out of the well at an uncontrollable rate, you have to have a way to shut it in to stop the flow, kind of like having a main water shut off valve in your house. And Remember we talked about bops when we were going through the whole drilling sections. It's the same concept here, except the Bope's are just a lot smaller because the pipe or the tubing is smaller. So if your kitchen sink is leaking badly and you can't shut off the tap, you can always go down and shut off the main water valve which will allow you to fix whatever is wrong. So the real of the coil tubing unit will have a valve, it's called the real valve, which is kind of like your kitchen sink tap, which allows you to turn it off and on. But the BOP, the blow up preventer, is kind of like the main water valve. So Coil Tubing BOPs have four main components. Just the same as what we talked about with drilling, so pipe rams, tubing rams, sheer rams and blind ramps. I'm not going to go through details on these. I'll give you a quick recap, but if you want more details you can go back to episode. For so the rams are powered by hydraulic pressure. Enter size specifically for the size of coil tubing, meaning the diameter being used. The sheer rams, as you'll recall, are basically the holy crap rams and are only used in emergency situations because they actually seal by cutting through the pipe like scissors. So it's never a good situation if you have to use the shear rams. Never a good situation. So let's do a little bit of a recap here. We talked about some common situations where you could and likely would use coil tubing.

If you're ever circulating any fluid in and out of your well or if you just want to pump something down, whether it's chemicals or cement, we can drill with it. So whether there's debris or equipment that you didn't want in the well, you can drill it out with coil tubing. perforating. So again typically something that we do with wireline just because it's cheaper. But you can do it where coil tubing as well. It's called TCP or tubing conveyed perforating. Fishing, of course, is a common activity where you would use coil tubing, and so that, as a reminder, is never a good thing. But it's the act of retrieving something that's further down the well. We can do camera runs, so if you want to see something that's down the whole or have a glimpse at whatever is going on down there, if you're having any issues, you can run a camera type device. On Coil Tubing, some people will actually FRAC through the coil tubing, so you're pumping your FRAC fluid down through the inside of the coil string and you can actually produce through coil tubing strings that are effectively left permanently in the well. There's all kinds of different uses for coil tubing. I guess we should probably do a bit of a recap here too on the visual. We talked before about all the different parts, so I'll see if I can combine it all together here in one quick final visual for you, just because we didn't talk about all the pieces exactly. But so what we started off with. Earlier in the episode, we talked about how the main parts are the tubing, the Gooseneck, the injector, the real the power pack, the Bha and...

...the well control package. So if I can paint a bit of a visual for you, when you're using your coil tubing unit, the coil tubing itself is going to be wrapped around the reel, kind of like you would wrap that piece of cord around a cylinder. Same, same kind of visual, just really big the to put it in perspective, I would say the average coil tubing real so the real with the tubing itself would probably be somewhere around the size of maybe a couple of large trucks put together, or say half of a semi truck. So it's fairly big and it weighs a ton. So the tubings wrapped around the reel. As you want to run the coil tubing into the well, the coil tubing gets or comes off of the reel, it goes up into the air, it goes around the goose neck, which is the gentle curve, and into the well. And what's pulling the coil tubing up and therefore pushing it down into the well is the injector. So the injector is a piece of equipment that has those like kind of tank tracks, and the tank tracks, as they rotate around, grip the pipe. So their metal, it's metal on metal as well. They grip the pipe and as the rotating they grip and physically push the coil tubing into the well. So all of this gets its power or force from the power pack. No surprise there. And remember that at the bottom bottom of the coil tubing string is the Bha or the bottom hole assembly, and that's all the tools that you're using. So it could be your nozzle assembly, it could...

...be your mill assembly, it could be if you're fracking through it. There might be a little piece of equipment at the very end that you would frac through. So as you're going into the well, remember the injectors pushing everything in. It's going to be pushing it through your bopeas, and so the Bope's, remember that's kind of like your main water shut off. That's your last line of defense if anything were to ever to go wrong. And so bopeas blowout preventers have different types of rams in them that are going to be used to help shut off any oil and gas flow that would be coming up the well that is uncontrolled. You're going to have strippers and a lubric theater, which we talked about the lubricator in the wireline episode. Same exact same kind of concept, except it's just designed for coil tubing and strippers is basically just stripping the pipe of any fluid as it's going in or coming out of the well. So the fluid will actually be they'll be some fluid attached to the side or the walls of the coil tubing so the strippers will actually help strip that off as you're coming out of the wall. So at a high level, that's really the coil tubing unit in a nutshell, but it is an important one to note because it is such an integral part of the entire industry. Hey, guys, if you like today's episode, make sure you subscribe to the podcast. Unlike most podcasts that release an episode every week or two, I did all twenty four at once, Netflix style, so you...

...can listen to them all right now if you just hit subscribe. If you like today's episode, make sure you leave me a comment or thumbs up, or you can email me at from fossil to fuel at GMAILCOM or look me up on Linkedin. I'm Brendan McDougall.

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