PDC Bits

PDC History and Benefits

It was in 1908 that Howard Hughes invented the two-cone drill bit. Again in 1933, Hughes furthered his two-cone invention by inventing the tri-cone drill bit. The two-cone and the tricone revolutionized the oil drilling business at that time. Tricones have come a long way since 1933. The technology, materials, and efficiency have all improved. The drill rigs have also improved along with various other aspects of the drilling industry. The tricone is no longer exclusive to the oil and gas but instead is utilized in all drilling industries including but not limited to water well, geothermal, HDD, construction, foundation, and mining to name a few.

In 1976 the drilling industry was again revolutionized with the introduction of the PDC (polycrystalline diamond compact) bits. When they were first developed, PDC bits were extremely expensive and only the biggest players in the oil and gas industry could afford to use them. As time has passed and the technology has gotten better and more affordable, PDC bits are now utilized in all drilling industries just as the tricone is. However, there is still a hesitation among many drillers to try something new. I am going to try to explain the ins and outs of PDC bits and why they may work for you.

It doesn’t matter what drilling industry it is, many drillers are hesitant to try something new simply because they know what has worked for them in the past and if it is still working, why would they make a change. We are all creatures of habit. Most of us do not like change even if the change could be for the better. PDC bits are the drilling industry’s change that many do not wish to make. Here are a few reasons that drillers should consider making the change to PDC bits.

1. Cost Effective

PDC bits can be very cost effective. Unlike tricones, there are no moving parts on a PDC bit to wear out. The synthetic diamond facing can chip, but that PDC cutter can be extracted and new one can be put in its place. Rebuilding a PDC bit is normally around one half the price of buying a new bit. Whereas once the bearings on a tricone bit are damaged, the tricone is of no use and cannot be repaired. Unlike hammers and hammer bits, a large air compressor is not needed. Air compressors can be expensive to rent/buy and they use a lot of fuel to drill with. While air can be used to drill with PDC bits, it is not necessary.

2. Rate of Penetration

PDC bits, in the correct formations, have an incredible rate of penetration. Formations that PDC bits do well in include but are not limited to shale, limestone, sandstone, and clay. PDC bits can be anywhere to 3-5 times faster than tricones. I have experience with drillers that were getting 60-minute rods with a tricone to 15-minute rods with a PDC bit in rock around 30,000 PSI. There are many drillers that have also switched from using a hammer to PDC bits because PDC bits can out drill a hammer in rock that is less than 35,000 PSI.

3. Rig Capability

Many drillers are working with rigs that do not have the capability to run tricones correctly based on what the manufacturers call for. Tricones tend to call for more weight than what many rigs are capable of putting on the bit. Without the correct weight on bit, the tricone is often over rotated to attempt to compensate which can cause premature bearing failure. PDC bits, on the other hand, take around half as much weight as tricones to run correctly. However, PDC bits need a minimum of 50 RPMs to work correctly and ideally, they are turned at around 100 RPMs minimum. PDC bits like less weight and more RPMs. This particularly works well in the HDD industry where most smaller rigs do not have enough weight capability and tend to rotate too fast. PDC bits also tend to run much smoother than hammers and tricones. A smoother running bit is much easier on the rig itself.

4. Cost Savings

In short, PDC bits save money. Because PDC bits drill so much faster, there is a lot of time saved. Time saved allows for the driller to complete more jobs in a shorter period of time. On a small job, it is hours and days saved. On a larger job, it is weeks and months saved. Benefits of completing the job faster would include saving on man hours and fuel, meeting and/or exceeding deadlines, and using fewer bits and consumables.

Overall, there are many benefits to drilling with PDC bits. I have highlighted some of the main benefits, but there are many more. Just like everything else, the drilling industry is always changing. Change in technology and drilling can be a great thing. PDC bits could be the change that makes the difference for you.