Such a means is contained in the new drill-bit bearing-support design that provides drilling at sharply increased loads and using increased rotational speed levels.
The offered design of the slider bearing support (viz. the figure) allows to increase its bearing surface by the factor of two, and double the drill bit load-carrying capacity respectively. This is achieved by excluding a retaining roller bearing from the support and, respectively, increasing the width of slider bearing 1, on the one hand, and by increasing the sliding diameter at the contact with roller bit 2, on the other hand. The latter also ensures a considerable increase in the thrust flat surface of the slider bearing at its contact with the roller bit. The roller bit retainer on the journal is formed by sleeve 3 which is connected to the roller bit and contacts the conforming flat surface of the slider bearing. The end cylindrical portion of the slider bearing additionally increases the load-carrying capacity, and also the support base. As it is clear, slider bearing 1 integrates the functions of retaining, peripheral, thrust and end bearings.
A specific shortcoming of the drill bits with a conventional design of slider bearings appears to be, as it is generally known, limited rotational speed which is connected with increased friction factor values, as compared to roller bearings, and the low heat resistance of elastomer components used for hermetic sealing of the bearing cavity where heat is generated. This results in the requirement to limit mechanical drilling speed, and, in the case of sealing the bearing cavity with a radial elastomer seal, the latter undergoes fast wear – and, therefore, a limited range of penetration per drill bit in meters.
In the offered design, the indicated limitations are radically removed – by excluding elastomer components and, therefore, by safely increasing heat generation, from the point of view of increasing loads and speed. In the face bearing, as used here, the functions of a shock-absorber for the axial movement of the roller bit along the journal, and for pressing up face rings 4 and 5, are executed by resilient metallic diaphragm 6.
The drill bits with the offered support have an obvious advantage of their feasibility in improving mechanical drilling speed, bit service life, trip drilling rate, and in decreasing both drill bit and energy consumption, and drilling costs.
The offered design of a slider bearing comprises the following additional advantages:
a) possibility of using up-to-date materials and technologies, ensuring an increase in the load-carrying capacity and wear resistance of bearing support surfaces, and a decrease in friction factor values;
b) decrease in labor input and cost value for the manufacture in case of using up-to-date heat-resistant elastomers and sealing the bearing cavity with an ordinary radial elastomer ring;
c) multi-purpose duty of the offered bearing support as applied to any sort of equipment, this advantage meaning that technological manufacture lines may be readily simplified, and the manufacture itself may become cheaper;
d) multi-purpose duty and efficiency of the offered design of drill bit bearing support as applied to practically any conditions and operation modes of drilling;
e) applicability of the drill bits with the offered bearing support design to drilling thermal wells, including super-deep wells.
There is no doubt about vested interest of drilling operators in the offered innovation. However, on the part of drill bit building companies, the offer of this innovation finds no response. It remains to suggest that this attitude is connected with the perspective of drill-bit consumption decrease and, consequently, sales volume decrease. Furthermore, the manufacture of new products would require certain changes in the technology and organization of the existing production. In this connection, it is to be noted that the manufacture of new products would be the most profitable business at a newly set-up drill-bit enterprise. In this issue some consensus should be found between drill-bit consumers and manufacturers.
The author offers to any juridical or natural person the concession of rights by the invention applicant (later on – patent holder) with ensuing therefore a leading position in the drill-bit making a profit from the sales of the pertinent licenses.
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