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PDC Cutter:The Key Of Diamond Tip Drill Bit

Blog 1470

Diamond Bit Family And The Rise Of Pdc

When we talk about “diamond drill bits”, the first reaction in our mind is not to refer to one kind of thing, it is actually a big family. There are many ways to do this, but to say that the most popular in the past two years must be PDC Cutter.

PDC Cutter on Rock

At the earliest, we used natural diamond drill bits mostly.

You think, the hardness of natural diamond, there is no doubt that the rock is like tofu in front of it. But the problem is also obvious: the particle size cannot be controlled, and the distribution is random. The key is the price, which is really painful and uneconomical. In those days, it was good to use it.

Later, with the progress of technology, the emergence of artificial diamond drill bits (that is, impregnated diamond drill bits).

This thing is to “seed” small particles of synthetic diamonds evenly into the metal carcass, and then 1 and sinter them. The way it breaks rock is a bit like grinding and cutting, dealing with those particularly hard, abrasive and strong strata, the effect is not bad. It can be said that it solves the cost and availability of natural diamonds to a certain extent.

However, I think it is the PDC bit that really makes the whole drilling industry “live. This thing is the focus of our talk today, the core is its “teeth”-PDC cutting teeth.

PDC Cutter on parts

To put it bluntly, PDC cutting teeth are composite materials sintered by diamond micropowder “holding” with cemented carbide under high temperature and high pressure. It is not only hard against the sky, wear resistance, impact resistance is also strong. We usually weld it to the drill matrix, or directly inlay it. Its main rock breaking method is efficient shearing, directly “cutting” the rock, rather than grinding as before.

In my opinion, PDC cutting teeth can stand out, is definitely a highlight of the design. It combines the extreme hardness of diamond with the “toughness” of cemented carbide.

In this way, the problems of natural diamond, such as size, cost, brittleness, are basically solved. And the most important thing is, the efficiency of drilling is really “rubbing” to rise, which is a real benefit. This is probably brought about by technological innovation, that kind of exciting sense of breakthrough.

drilling rig

Structure, Manufacture And Performance Of Pdc Cutter

Speaking of PDC cutting teeth, I always think it is a rather contradictory combination. You want to ah, diamond so hard, but it needs a “base” to support, to work. Therefore, its excellent performance is really not made out of thin air, but the structure and technology are piled up.

Core structure: diamond layer and cemented carbide substrate

Let’s talk about its “internal organs”.

  • Diamond layer: This is the main character, not without it. Let me tell you, this layer of things is 1 pile of small micron-sized diamond crystals, which are sintered together under high pressure and high temperature by cobalt, the “matchmaker. If you think about it, how did the diamond come from under the ground? It was created by simulating that environment. This layer of diamond is ridiculously hard, wear-resistant (for rock), and has good thermal conductivity. Broken rock, just rely on it.
  • Carbide Substrate: This is the “base”, usually a tungsten carbide-cobalt alloy. To put it bluntly, it is to provide a solid support for the diamond layer. No matter how hard the diamond is, you have to give it a place to work hard before it can chisel the rock. This matrix provides toughness and strength, and is also convenient to connect with the drill body.
  • Interface: between the diamond layer and the substrate. This place is important. Don’t underestimate it. These two “good partners” can be firmly welded together, it is by this “metallurgical combination”.

Manufacturing process: high temperature and high pressure sintering

I always think this process is very interesting. You see, it’s just learning from the diamond formation in the depths of the earth. Put the diamond powder, the binder, and the cemented carbide substrate into the equipment together, and then give it thousands of atmospheres and thousands of degrees Celsius. In that environment, the diamond particles form the kind of “covalent bond”, and the matrix is also “hand in hand” combined. So, although PDC is small, it came out after a “big test.

Burning furnace and PDC Cutter

Performance determinants

I think, what affects PDC performance is probably just a few points:

  • Diamond layer thickness and grain size: it is directly related to how long it can grind, and how many times can carry “blow”. Thick point and larger grain size are good in theory, but the cost also goes up and there must be a balance point.
  • Diamond content and bond type: This determines the overall hardness and strength. If the content is high and the binder is selected right, it will be more “strong”.
  • Cutting tooth geometry: that’s more, what flat, cylindrical, conical, and those serrated, spiral shaped teeth. Let me tell you, this is not designed casually. Every 1 shape is designed for specific rock breaking efficiency, or to “self-grind” sharpness, or to reduce chipping. Behind this are countless experiments and optimizations.
  • Thermal stability: this is really terrible. When drilling, friction heats up, and the temperature is very high. If PDC cannot withstand high temperatures, the diamond layer may degrade and become graphite, which is discarded. Therefore, the thermally stable PDC(TSP) produced now removes cobalt from the binder in order to enable it to work “hard” at high temperatures.
  • These factors, like a system, affect the whole body.

Pdc Cutter: The Key Of Diamond Drill Bits

From my personal experience, the PDC cutter is simply the heart of the diamond drill, it is the whole drill live. To put it bluntly, how PDC cutting teeth play directly determines whether our drill is good or not, whether it is efficient or not, and how long it can last.

PDC cutter at oil field drilling site

The reason why PDC cutting teeth are the key to diamond drill bits is that it directly determines the following core performance of the drill bit:

  • Rock Breaking Efficiency (ROP): As you know, PDC cutters are powerful in the way they cut. It is not the kind of silly grinding ah, smashing ah, but with its sharp edge to shear, scraping rock. This efficiency, I tell you, is more than a little higher than that of traditional drill bits. When designing, our engineers directly raised the drilling speed by optimizing the geometry and arrangement of PDC cutting teeth. This thing, well done, the drill speed is going up.
  • Drill life: This life is what we are most concerned about. PDC cutting teeth of the diamond layer, that hardness and wear resistance, simply! In a terrible place like underground, with high temperature and high pressure, the rock is abrasive and strong, it can withstand it, and it will not fall off the chain after working for a long time. In this way, the life of the drill bit will be longer, we will have a lot less trouble of tripping, and the cost will naturally come down. Save money, who doesn’t like it?
  • Adaptability and Flexibility:
    • Customized design: I have always thought this is quite awesome. PDC cutting teeth have various models, sizes and shapes. We can flexibly select and combine them according to different formation conditions, such as rock hardness, abrasiveness and porosity. For example, if we encounter a soft formation, we will use large-size cutting teeth to drill faster; if it is a hard formation, we will use a small size, high density, more wear-resistant and more stable. It’s like our toolbox, always find the right tool.
    • Innovative arrangement: engineers are not vegetarian. We will tamp the number, spacing, inclination angle and cutting depth of PDC cutting teeth on the blade. Don’t underestimate these, they can directly affect the torque, stability, vibration resistance, and even the cleaning effect of the drill. It’s like playing chess, every step has to be calculated carefully to achieve the best results.
  • Impact resistance: The downhole conditions are complex and changeable, and it is common to encounter hard interlayers or irregular formations. At this time, the impact resistance of PDC cutting teeth is particularly important. Good design can effectively disperse the impact force and reduce the risk of cutting teeth chipping or falling off. If you think about it, if the cutting tooth falls off at the critical time, it will be in trouble. Therefore, the impact resistance must be excellent.
  • Hydraulic structure optimization: The unique rock-breaking method of PDC cutters gives our engineers a lot of room to optimize the hydraulic structure of the drill bit. The most direct benefit is that it can more effectively remove the cuttings at the bottom of the well and cool the cutting teeth. The bottom of the well is clean, the cutting teeth are cool, and the drilling efficiency and the life of the drill bit will naturally go up. This is a whole system, PDC cutting teeth are the core, driving the performance of the entire drill.

Future Prospects Of Pdc Cutter

PDC cutting teeth to today, has been very mature, but to say that it has stagnated, it is absolutely impossible. Personally, I think that the future direction of innovation will probably revolve around these points:

First of all, the material upgrade is certain. Although the diamond composite materials used now are severe, they are still a little overwhelmed under some extreme conditions, such as high temperature or strong impact. Therefore, the development of new materials with better thermal stability, stronger impact resistance and slower wear is definitely a major direction in the future. You said, if you can really come up with a 1 kind of “super PDC”, then drilling efficiency will not have to go to a higher level?

Then, intelligent manufacturing. These days, everything is smart. The design and manufacture of PDC cutting teeth, in fact, there is a lot to do.

Do you think, now we design geometric shapes, often by experience and simulation. However, if AI and ML can be introduced, the algorithm can optimize the geometric design of cutting teeth, and even automatically adjust the manufacturing process according to different formation conditions, the efficiency and accuracy will definitely be much higher than now. At that time, our engineers may be more to “set up” AI, rather than one knife to draw pictures.

Again, functional integration. This point, I think, is a bit interesting. At present, PDC cutting tooth is a pure “cutting tool”, but if the sensor can be directly integrated into the cutting tooth to monitor the cutting state, temperature and even the health of the drill in real time, it will be of great guiding significance to our field operation.

It is like installing an “eye” and “nerve” for the cutting tooth, which can tell us at any time how it “feels” and whether it is about to “get sick. This real-time feedback can greatly improve the safety of the operation and better protect the drill bit.

Finally, multi-functional integration. Now we often choose different types of drill bits according to the formation conditions. However, if a 1 multi-functional PDC bit can be developed that combines the advantages of existing PDC cutting teeth and can adapt to a wider range of formation conditions, it will undoubtedly simplify many field operations and reduce inventory costs.

For example, can you integrate some other functions on the PDC cutting teeth so that it can perform well in both soft and hard formations? This may require some cross-border design thinking, but I think the potential is huge.

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