Tricone bit and polycrystalline diamond compact bit (namely) of PDC bit, tricone bit design is more difficult to balance, the reason is that the geometry space limitations, rolling roller and a number of design variables. In order to overcome this difficulty, the foreign researchers develop the technology of optimization, makes the balance of rock bit first assessment, and then make its volume and pressure balance. Volume balance is balanced between different rock cuttings removal, while the pressure balance to ensure that each cone of wob, bending torque and bearing pressure is almost the same. As a result, there isn't any a cone or bearing system produces too much stress.
When all of the roller and bearing under the same pressure, cutting structure to reach "pressure balance state. When all roller during drilling pump phase at the same time, the volume of the cutting cutting structure to reach "volume balance state. "Energy balance" bit (EB) refers to it has reached the "pressure balance", and "volume balance".
Energy balance the advantages of cone bit, by balancing the amount of drilling and rock and each rock stress, improving the structure of the roller bit cutting and dynamic state of rock interface. Laboratory and field test show that the energy balance of the drill bit by bottom hole more smooth, and bit minimal impact, so as to improve the cutting ability of the bit. Smooth, Tricone bit low vibration drilling can also help to improve the directional response, reduce the risk of tooth to the fatigue failure and the damage to the sensitive parts of the drill string.
This bit can be set with patented directional tooth and a chisel insert, and loading in the form of perpendicular to the direction of cutting tooth, so that the volume of rock cutting is bigger, and at the same time improve the rate of penetration. In addition, the directional tooth can provide uniform pressure, because this can prevent tooth Angle under high load, thus reducing the phenomenon of broken and broken tooth.
Uniform pressure also shows almost no torque on the cutter, thereby reducing the tooth phenomenon caused by turning off. In addition, although the conical or semicircular insert can't be targeted installation, but still there are ways to make bit cutting structure and bearing system achieve energy balance and force balance condition. Therefore, although not all have directional tooth bit, but they all can benefit from the energy and force balance design technology.
Energy balance design can make the strength of the rock bit with more cutting structure, so as to improve cutting efficiency, bit seal reliability and prolong the service life of the bit. In addition, bit passivation status has improved, so that you can develop a stronger cutting ability of the bit structure, thereby can recommend using IADC code soft bit level. For example, should be using IADC code is 517 standard drill bit, and can be recommended to use IADC447 or 437 bit of energy balance.
In Norway, Canada, Algeria, and some application examples, in the Middle East have proven energy balance cone bit in terms of penetration and mechanical drilling rate, compared with the ordinary drill has the very big enhancement, can save a lot of drilling cost. The drilling instance also proved that balance the performance of the bit advantage - mechanical drilling rate faster, longer Three cone bit service life - not just confined to the PDC bit, with the development of advanced analytical ability, energy balance rock bit can also faster penetration rate and less wear and tear into a longer interval.