Daily Archives: December 2017

Directional Drilling – Where to Begin

Most people would assume that when drilling for water, oil, natural gas, or other subsurface objects that they are targeted vertically — drilled straight down into the earth. However, this traditional method of drilling has been largely replaced. In the current day, drilling a hole in the ground can consist of complex geometry including builds, turns, and tangents to construct a well. The well can be either geometrically or geologically steered. Geometric steering involves adjusting the position of the wellbore based on a pre-arranged plan and then using complex measurements and surveys to stay on that plan. Geological steering involves orienting the wellbore based on the properties of the lithology being drilled into to “find” the right reservoir rock.

It is important to discuss why directional or horizontal drilling can be not only beneficial but necessary, reasons include:

  • Unreachable deposits: it may be sometimes deemed obligatory to go around obstacles by using directional or horizontal drilling. There could be a variety of barriers that prevent access, such as difficult rock formations, utility lines under the surface, residential areas, or sensitive ecosystems. This allows oil companies to drill away from these obstacles or hazards to make it a more sensible, practical, or environmentally friendly option.
  • Increased operational efficiency: Having the ability to access and drain larger parts of the reservoir from a single pad is a huge advantage of directional drilling. This decreases surface disturbances and also saves money and time with the reduction of well pad setups. Grouped wellheads also allow for fewer rig moves, which in turn saves more time and money.
  • Increased reservoir production: Directional or horizontal drilling can expose the well to the maximum amount of the reservoir or allow the well to cross the largest number of fractures to increase production.
  • Relieve pressure: Directional drilling can help relieve the pressure from out of control wells. Pressure can be relieved from one well by tapping the same well at an angle with another well. These relief wells are drilled at a safe distance away from the blowout but come in to intersect the troubled wellbore.

Directional drilling can cost up to 300% more than vertical drilling, but the potential increases in efficiency along with lowered production cost makes this drilling technique more financially viable.

Ulterra Drilling Minute Video: Directional Drilling Operations

Directional Drilling: A Brief History

Directional drilling dates back to the 1920’s with the advent of techniques for surveying the angle and direction of a drilled well. Prior to this, wells were intended to be constructed vertically but were subsequently found to have deviated quite far from that. The first intentionally deviated wells were drilled in the late 1920’s into the 1930’s by using hardwood, and then steel wedges called whip stocks that were lowered into the hole at a specific angle to force the drill bit in a certain direction. Through the 1940’s and 50’s, various techniques that still exist today were developed, including designing the drilling assembly to bend in a particular way and also jetting (using an oriented large nozzle on the bit to wash away rock in the preferred direction).

In the 1950’s, downhole drilling motors, or mud motors, were developed. These mud motors use fluid flow through the assembly, converting hydraulic energy into mechanical energy to drive the drill bit independently from the rest of the drilling string. A fixed angle could then be put into the assembly which could be oriented and held in the desired direction while the bit still drills ahead. Using a mud motor with the use of a measuring while drilling tool (MWD), a directional driller has the capability to steer the drill bit to the desired zone. The data collected from the MWD tool helps the operator monitor and manage the direction of the bit, obtain records, and generate survey reports. By the time the 1970’s rolled around, mud motors had taken over directional drilling and they firmly remain as the preferred method of directionally drilling a well.

The next major advancement in directional drilling was the creation of rotary steerable (RSS) tools, which allow 3D control and steering of the drill bit without stopping the drill rotation. These tools are directly controlled from the surface using advanced communication techniques, and they either push the bit or point the bit in the required direction in real time. Directional drilling has vastly improved with technological advancements, especially toward a less time-consuming drilling process. These advances have also allowed for greater success and precision in the drilling process. New digital technology has made the collection of data much easier and allowed drilling operations to be better planned beforehand and controlled during the drilling process.

Types of Direction Drilling

When speaking about directional drilling, it is commonly assumed that one is referring to horizontal well drilling, which is a method of deviating the well until it is at, or close to a 90° angle from the vertical in order to drill out sideways and along a specific layer of rock. There are a few other directional drilling methods that will be discussed below.

  • Horizontal Drilling: The trajectory of a wellbore starts vertically then steers horizontally at depth for thousands of feet. This allows increased contact between the well and the reservoir to increase productivity. It also provides access to reservoirs that are too thin to be accessed by vertical drilling.
  • Multilateral Drilling: A single wellbore creates a trunk and then many branches stem from it, increasing production from a single drilling site. This drilling technique increases the contact area and allows for many branches to produce from the same well. These can be horizontal, curved slightly to one side, or turned sharply to form a J-type well. Multilateral drilling can occur in either new or existing oil and gas wells and typically includes two laterals. The main benefit of using this drilling approach is the increased efficiency and reduced cost of tapping multiple reservoir locations from a single point.
  • Extended Reach Drilling (ERD): To figure out if the well is considered an ERW, calculate the ratio of horizontal departure to vertical depth. If the depth ratio is greater than 2, the well is considered an Extended Reach Well (ERW). An ERW can be relatively long and deep, short and shallow, or something in between. The benefit of ERD is the increase in efficiency by exposing the open hole to long sections of the reservoir rock, or by crossing through multiple reservoirs in one long wellbore. It is expensive and risky but it is sometimes the best option available. With advances in technology, these wells are getting longer and longer as we get better at overcoming the challenges of managing downhole pressure, managing and controlling the mechanical loads on the drill string, and hole cleaning.
  • Coiled Tubing Drilling (CTD): Coiled tubing refers to a specific type of small diameter, long, continuous metal pipe rolled on to a giant reel (the coil) that can be used as a drilling assembly to reenter and extend a previously drilled hole, drill out from it in a different direction, or perform remedial work to get the well flowing efficiently again. Although drilling using a small flexible pipe has its own challenges, particularly when it comes to directional control, it can be done relatively inexpensively and fast.
  • Through Tubing Rotary Drilling: This is an expensive way to create a shorter length sidetrack of an existing well. This can be done after a well has already been constructed and used, but requires more reservoir to increase production. This is a great method to revitalize old reservoirs that were previously tapped using vertical holes that could also benefit from the horizontal exposure of the reservoir. A hole is cut in the steel pipe that lines the wellbore and then a steel whip stock is set in place and used to push the drilling assembly sideways out of the side of the well. This technique is also used to explore deep layers of rock below the target reservoir, before casing it off and using the same wellbore to access the main target.

Path of a Drill Bit

Directional wells carry various economic and safety benefits. Economically speaking, directional drilling increases the access to a reservoir, increases hydrocarbon recovery, increases the well count number from one location, and reduces rig move costs. Although directional drilling could be as much as three times more expensive than vertical wells, the higher production rates and efficiencies offset the expensive process. The combination of fracking with cutting-edge technologies and horizontal drilling has caused a huge surge in the oil and natural gas production in the United States, particularly in major oil and gas regions such as the Permian Basin, Eagle Ford Shale, and the Bakken Shale.

Directional wells should be meticulously planned in advance and flawlessly executed in order to manage the additional costs. A directional plan is created prior to drilling commences, which outlines the position of the well precisely under the surface of the earth. It typically contains specific targets in 3D space that the drilling assembly must hit in order to contact the reservoir at the optimum point, as well as specific changes in angle required to hit those targets. The directional plan is optimized to try and reduce drastic changes in angle, called DogLeg Severity or DLS, and to minimize the complexity of the well.

The directional plan also includes careful selection of the directional tools, mud motors, and the rotary steerable system that will be required in order to hit the directional targets in the best way possible. To help these tools guide the well path to the optimum position, careful selection of the drill bit is required to ensure that it is compatible with the tools, the formation being drilled, and the directional change requirement, or Build Up Rate (BUR).

By selecting a drill bit that achieves the best compatibility possible with the directional tools, the tool can better guide the well path to the optimum position for the formation being drilled and any directional change requirements or build up rates (BUR) that may be encountered.

Ulterra specializes in creating custom drill bit designs which are compatible with all aspects of the application and the directional drilling requirements. Our knowledge and expertise of directional drilling applications mean that we can offer bespoke solutions that convert to high rates of success in this high-cost environment, where success is the only option!

Please browse all the other educational Drilling Minute Videos and email marketinginfo@ulterra.com with any comments, questions, or concerns.

Ulterra PDC Bit and MORE Global Water Provision Story Part 2

We love the second chapter of this story and are proud to have played a part in MORE’s efforts to address the global water crisis. This story first appeared on the https://more-water.org site. It’s a great read from the perspective of an Ulterra PDC bit.


“Petey Goes Deep”

When we last heard from Petey, the PDC drill bit – and, no doubt, the sole drill bit blogger on the planet –  he had just arrived, by plane, into the Kenyan coastal resort town of Diani Beach, at the home of my American missionary friends, Chris and Lisa Moore.  While he was thrilled with the beauty of his new surroundings, what he didn’t know was that this was not his final stop – and certainly not his destination.  C’mon, he’s a drill bit, for crying out loud.  Their not supposed to have it soft.  Let’s catch up with him here:

So it didn’t take me long to get used to these new digs.  I was lounging around, while wondering what Bobu had in store for me. But I sure wasn’t stressing about it, I can tell you that.  One morning, just when I was planning to settle in, Bobu rolls me out of my new digs and sticks me in the back of a shiny blue pickup truck.  Then he takes off on some really bumpy dirt roads to – “I have no idea where”.  “Of course not,” I tell myself, “your a drill bit, remember?”  “Everything with you and Bobu is on a need to know basis.”  I’m sure that I’ll figure it out when we get there.  Along the way we stop and meet up with some more of his friends, who all seem happy to see Bobu.  There is lots of laughter and hugging and more of that gibberish that I simply cannot understand.  And Bobu’s joined in with it.  Great!

They fill the back of this pickup with lots of stuff and then connect this cute little drilling machine to the back of the truck.  “Surely”, I assume, “they’re not going to use me on THAT little drill, I hope!”  “Or are they?”  “Ha!”  “If that’s true, I gotta see this!”  We all take off for ‘who knows where’, with Bobu driving again.  Some of the guys pack into the back with me.  The rest ride up front, with Bobu.

Sure enough, after a not-so-long, but bumpy, dusty ride, we stop and all the men jump out and start unloading all the stuff from the back of the pickup, me included.  “Hey, watch how you handle me!”  “I’m a star, you know!”  Apparently they don’t.  Next thing they unhook their little drilling machine and roll it into a corner of this field.  After a lot of jabbering and animated discussion (yeah, I know about that.  I grew up on oil rigs, remember?), they come for me.  “Here we go,” I thought, “this outa be good!”   Sure enough, they connect me to a (really short) piece of drill pipe.  “Hey, I’m used to being at the end of three 30+ feet of connected drill pipes – like 100 feet, ya know!”  “Bobu, are you going to let them do this to me?”  Doesn’t seem to dissuade them from their follies, I see.  Come to think of it, he’s the one that brought me here.  I guess this is what he had in mind.  Fat chance they will get any oil out of this hole.  I’ll just go along with it.  This could actually be quite comical – and fun, who knows?

But what is this?  They didn’t install my nozzles.  They connected the drill pipe to the drilling machine and just began drilling me into the ground, with no water, no mud.  “What’s with that?”  I screamed.  But nobody heard me, evidently.  Oh yeah, I’m a drill bit.  Sometimes I forget that.  Needless to say I was just getting plugged with the topsoil layer.  And the drilling, if you want to call it that, wasn’t going very fast at all.  Finally they started pouring some water into the hole and that helped a little.  But it was obvious, these guys didn’t know anything about drilling oil wells.

After drilling only a few feet, they stopped and brought me back to the surface.  Then they all got together and pushed and tugged and moved the drilling machine. Yeah, by hand!  That’s how light it was.  But they only moved it about 10 feet.  Once the drill was anchored, they went through the same process of using me – a world class rock bit – to drill a couple feet through mud.  How peculiar.  I was actually getting embarrassed for Bobu.  As their apparent leader, it would help if he knew something  about drilling, don’t ya think?  Eventually the second shallow hole was complete – and I was, once again, laden in mud, my water cavities stuffed full of the heavy stuff.  When they raised me back to the surface and removed me from the drilling machine, at least they took the time to wash me.  They did a good job, too.  It felt good to be clean again.  Then they put me back in my box and left me for a couple days.

The next time that Bobu brought me back out, He did insert my nozzles.  Huh, maybe he does know what he’s doing.  Then they attached me to another of those cute little drill pipes, and inserted me onto the drill machine.  Just before I dropped below the surface, I saw those two shallow holes that they used me to drill a couple days before.  But now they were filled with concrete, it appeared, and a steel hook was sticking above the top of the concrete.  To that they had attached straps, which were wrapped around the drill machine’s outriggers.  “Oh, I get it now,” I thought.  These are used to anchor the light-weight drill machine – so that it could exert more force on the drill pipes – and on me.  Why, that’s rather ingenious.  Maybe these guys are smarter than I thought!

As I descended, I could see that they had actually drilled pretty deep.  Well, not thousands of feet, like I’m used to on those big Texas drill rigs.  But over a hundred feet, I bet.  That seemed pretty good for this little drilling machine.  As I continued down the hole, I could see that there were layers of various types of soil, and some occasional rock.  There were a number of layers with water coming out of them.  That happens a lot in oil drilling.  Most of the water is just a nuisance, I remember them saying once, when I emerged from a deep hole.  But these guys don’t seem to mind. That’s all they were talking about, later, when they brought me back out of the hole.  I wonder whats with that?

The drilling was so much slower than I’m used to on a mammoth oil rig.  But it was steady.  And it was probably all that this little drill rig could muster, as it didn’t seem very heavy.  But it sure was working hard.  Everyone was.  And they all seemed to like what they were doing and talked real nice to one another.  I was starting to feel better and better about this.  It was not hard work, really.  I just was not sure if this machine could ever drill me deep enough to hit oil.  I started to feel bad for them, because I didn’t want to see them disappointed.

The next morning they started the process all over again.  Connected me to the drill machine, which slowly lowered me down the hole, one small drill pipe section at a time.  And then it happened, something I never had experienced before.  About half way down the hole, or so, I plunged into water.  I wasn’t drilling yet, because they had not turned the mud pump on.  But I was submerging ever deeper into cool water.  Then when I got to the bottom of the hole, where we had stopped the night before, they turned on the mud and I started drilling again.  We drilled all day again, stopping from time to time. But not ever for very long.  It was still slow.  But it was steady.  Some of the rock that I was drilling through was really quite hard, I could tell.  But it was no match for my razor-sharp PDC -teeth.  Slowly, but surely, I was chewing right through it.

Each time that they brought me back to the surface, I noticed that there were a lot of people watching.  Women and children, as well as men and young boys.  They always seemed excited to see me.  I was experiencing something new.  I never had drawn a crowd of onlookers before.  On the oil rigs it was always just a few rig workers, who never said much.  Just gave orders to one another.  But these people were different.  They really seemed to like me, as they would point and jabber quickly, whenever I emerged from the hole – even if I was covered in a layer of crushed rock particles.  When Bobu or one of the workers would wash me off, several of the onlookers would come close to watch.  Some even came over and ran their fingers over my teeth and many curves and grooves.  They seemed fascinated with me, even as I was with them.  I could not tell what they were saying, but they would talk excitedly to one another.  I must say that I was enjoying my return to center stage.

That night I started thinking more about the water in the well – how cool it felt – and how unusual.  Then I remembered hearing some of the stories that several of the drill bits that went through the “spa treatment” with me back at the Ulterra shop.  Some of them said that they didn’t drill oil wells, but water wells.  How peculiar, I thought.  Whats the purpose?  Its the oil that everyone is fighting over, right?  Not water. Water’s cheap.  And besides, it just gets in the way and becomes a nuisance, right?   But I could see that this was all starting to make more sense – in a weird sort-of way.  What if it’s the water that these people are all milling around and talking excitedly about?  Maybe there is no oil here – only water.  So, maybe now I’m a water well drill bit?  Like some of those bits back at the spa.  I’ll have to think about that some more.  But hey, if it makes them this excited – and helps me retain my “rock star image”, then I could live with that.  Live with it, huh! – I answered myself – I could downright revel in it. “Hey everybody, I’m a water well-drilling rock star!”  Ya know what?  I like that.  If these people want water – then I want to help them get it.  That night I went to sleep feeling really good about my new role.

And that’s how Petey came to be in Africa, drilling water wells.  I can report to you that he really does like his new job – and the people he serves.  He is doing an awesome job and truly is – a “rock star drill bit!”