Diamond drill bits (PDC drill bits) Diamond composite drill bits are known as diamond drill bits. The drill is a one-piece drill, the whole drill has no moving parts, the structure is simple, and it has high strength, high wear resistance and impact resistance. It is one of the three major new drilling technologies in the world in the 1980s. The on-site use proves that when the diamond drill bit is drilled in a soft-medium hard formation, it has the advantages of high speed, long footage, long life, smooth operation, less downhole accidents, and good well quality.
The diamond drill is not only used for a long time, but also can be reused. The diamond drill that is returned to the factory is similar to the diamond drill used at the factory, and it can save a lot of drilling costs.
The quality of the drill bit, the type of drill bit and the suitability of the formation lithology play an important role in accelerating the drilling speed and increasing the footage of a single drill. Drilling an oil and gas well generally requires the use of multiple drills of different sizes. A drill with a larger diameter must be used when drilling the upper strata. Because the stratum drilled by the drill is softer, the single drill has more footage and the use time is shorter. A drill is generally used. Several wells can be reused; drills with smaller diameters should be used when drilling in the lower strata. Because the stratum is hard and there are few footages for a single drill, generally more drills are used. How much a new drill bit goes down into a well depends on the size, type, hardness, and drilling parameters of the drill bit. In general, the larger the drill size, the harder the formation, the less the footage; the smaller the drill size and the softer the formation, the more the footage will be drilled.
1: The balanced design of the force makes the drill have good guidance, and it is suitable for directional drilling with the downhole motor, and has small radial vibration;
2: The reasonable arrangement of patented PDC composite discs with different structures in different positions of the drill bit makes the bit more aggressive and anti-abrasive;
3: Strong offensive design allows the drill bit to obtain high penetration rate;
4: Dynamic flow field simulation technology is applied to hydraulic design to optimize the flow field at the bottom of the well, which helps to increase the chip removal speed and mud prevention.
Because the material of PDC bits is mainly cast tungsten carbide and diamond composites, it has long life and high value.
The Rock Breaking Mechanism of Diamond Bits The rock breaking action of diamond bits is accomplished by diamond particles. To know the rock breaking effect of the drill bit, it is necessary to understand the rock breaking effect of the single diamond. In hard formations, single-grain diamond under rock drilling pressure makes the rock under extremely high stress (about 4200-5700 MPa, and some materials say up to 6300 MPa), which causes the rock to undergo lithological changes from brittle to plastic. Single diamonds are eaten into the formation and the rock is cut under the effect of torque. The depth of cut is substantially equal to the depth of diamond particles. This process is like a plough-type cutting action called a diamond drill bit.
In some brittle rock (such as sandstone, limestone, etc.), the diamond particles on the drill bit under the influence of the biting torque, the volume of the broken rock is much larger than that of the diamond particles. When the pressure is not large, only small grooves can be formed along the direction of diamond movement. When the pressure is increased, the deep groove and the rocks on both sides of the small groove will be broken, exceeding the cross-sectional size of the diamond particles.
In addition to the rock-breaking effect of diamond drills, in addition to lithology and external factors that affect lithology (such as pressure, temperature, formation fluid properties, etc.), the size of the drill press is an important factor. Like roller cone bits, it has three methods: surface crushing, fatigue crushing, and volume crushing. The ideal rock-breaking effect can only be achieved when the diamond particles have enough specific pressure to eat into the rock of the formation and the volumetric fracture of the rock occurs.
