RU2411339C1 - Bore bit with sealed oil filled support - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: bore bit with filled oil filled support consists of case of welded sections of brackets, on journals of which there are movably fastened roller cutters with rock breaking teeth and cavities of bearing supports with sealing elements. The packing units are taken off zone of journals base into recesses made on ends of the roller cutters.

EFFECT: increased bearing ability of big friction bearing resulting in increased wear resistance of support and bore bit in whole.

3 cl, 7 dwg

Description

The invention relates to drilling equipment, namely to drill bits with a sealed oil-filled support of cones.

Known cone drill bit with a sealed oil-filled support cone [1], taken as an analogue. The advantage of this bit is the reliable design of the sealing device of the support, providing for the presence of a double seal using two elastomeric rings. These rings, installed one after the other, prevent the abrasive mass of the cuttings from penetrating into the cavity of the support during the entire sufficiently long time the drill bit is working at the bottom of the well.

The disadvantage of this drill bit is that to accommodate the elastomeric rings, it is necessary to take up to 60% or more of the length of a large plain bearing. Reducing the dimensions of the main bearing in the bearing helps to reduce the durability of the support and the bit as a whole.

Known for another roller cone bit with a sealed support [2], taken as a prototype. The advantage of this bit is the reduced dimensions of the sealing device along the axis of the paw axle, allowing more complete use of the space to accommodate a large sliding bearing, in comparison with the analogue. Sealing of the support is ensured in this bit by contact with the end surface of the cone of a steel stepped ring, pressed by an annular corrugated spring coated over the entire surface with elastic material.

The disadvantages of the sealing system of this bit are as follows. The spring, made in the form of a continuous corrugated metal tape, is a fairly rigid element working in compression, with a small amplitude of oscillations in the direction of the cone axis; in addition, with a large number of alternating loads and unloadings with constant axial vibrations of the cone during drilling, the tape quickly loses its elastic properties. In this case, the force of pressing the cantilever part of the steel ring to the end of the cone decreases, and the possibility of getting the abrasive mass of cuttings into the cavity of the support increases. Another disadvantage of the seal is the presence of an open conical space between the rubberized outer surface of the seal on the paw side and the end face of the paw. With possible rotation of the seal around the trunnion during rotation of the cutter, caused by the relatively weak inhibitory properties of the landing surface, the mass of cuttings will be able to penetrate into the cavity of the support between the elastic part of the seal and the surface of the trunnion, reducing the resistance of the support. Another disadvantage of the prototype, although to a lesser extent than that of the analogue, is the reduction in the dimensions of the support - the length of the large sliding bearing in the support due to the need to make a cavity for the placement of the seal.

The technical result of the present invention is to increase the reliability and durability of the drill bit with a sealed oil-filled sliding support. In the first embodiment of the proposed drill bit, this result is achieved by the fact that in the bit, which includes a body of welded sections of the legs, on the trunnions of which the cones with rock-cutting teeth and cavities of bearings with seals in the form of contacting and pressing elements are movably fixed, the pressing element is made in the form of a coated elastic a layer of a spring frame having an annular cylindrical base rigidly mounted on a separate annular protrusion of the end surface of the paw, spaced from the annular surface of the DAC s. The individual elastic conical petals of the spring frame are made in the form of consoles with one end fixed to the base by means of an intermediate curved part so that an angle α> 90 ° is provided between the generatrix of the cylindrical base and the generatrix of the cone of the petals. Between the petals and the end surface of the groove in the cone, a continuous contact ring, ground to the cone, is installed. Between the petals and the end of the paw under the contact ring can additionally be installed resistant elastic ring.

In this proposed version of the bit, the corrugated conical tape of the prototype is replaced by a spring collet frame having an integral cylindrical base on the inside and separate elastic petals separated by radial slots. Each elastic petal is connected to the cylindrical base by a curved transitional part so that the angle α between the generatrix of the cylindrical base and the generatrix of the inner surface of the petals corresponds to a value of α> 90 °. The shape of the frame and individual petals allows you to multiply the amplitude and elastic properties of the seal by making the petals in the form of a console with one rigidly fixed end. The shape of a solid cylindrical base allows not only to firmly fix one end of the petal, but also tightly, with an interference fit, to install the seal on a separate annular protrusion of the end surface of the paw, spaced from the annular surface of the journal. If necessary, to further increase the resistance of the seal against rotation, it can be fixed with glue.

On the cone side, the seal is provided by a contact steel ring, and on the opposite side, by a cavity and a mounting collar for installing and fixing the contact ring on a spring collet frame. Mounting on the collet frame can be ensured during coating of the frame with an elastic material, for example, rubber coating.

To eliminate the main drawback of the analogue and the prototype, which consists in the need to drastically reduce the dimensions of the main bearing of the sliding bearing of the support to accommodate the seal, 100% of the contact surface of the journal and the inner surface of the roller cone are completely freed from the placement of the sealing ring.

This is achieved by the fact that on the end surface of the paw, separately from the base of the pin, a continuous annular protrusion is made, the axis of which coincides with the axis of the pin. This annular protrusion is designed to install and secure the sealing assembly, in the prototype, mounted directly on the paw axle.

In response to the annular protrusion on the end surface of the paw on the end surface of the cone, a recess is made for the specified protrusion and a sealing ring fixed to it. The annular recess in the form of a niche in the end of the cone is intended, in addition to placement, also to protect against abrasion of the specified protrusion of the paws with the seal assembly.

The distance from the internal cavity of the recess to the contact surface of the cone with the trunnion (cone wall thickness) is selected constructively, based on the strength properties of the material and the forces perceived by the cone bit when drilling.

In the second embodiment of the proposed bit, the technical result - improving the reliability and durability of the support - is achieved in the same way as in the first embodiment, due to the full, 100% use of the surface of the paw axle as a support element, by removing the seal assembly from the surface of the axle to the end face cones.

In this embodiment, instead of a collet seal, a steel-to-steel mechanical seal is used, in which constant compression and wear compensation from abrasion of steel rings are compensated by the elastic properties of the compression rings.

In the third embodiment of the invention, an increase in the reliability and durability of the support is ensured, as in the two previous versions, due to the 100% use in the work of the support of the contact surface of the pin of the leg and cone. In this embodiment, an elastomeric ring is used as a sealing element between the protrusion on the end surface of the paw and the cone.

From the above three options of the proposed bit with a sealed oil-filled support, it should be understood that the main feature of the invention is the transfer of the sealing assembly, located in the analogue and prototype directly on the paw pin, into the cavity made on the end of the cutter, in order to maximize the use of dimensions and bearing capacity of the main plain bearing. In this case, the options or schemes of the transferred seal itself may be other than the 3 above options.

The list of figures drawings. Figure 1 presents a section section of a bit-analogue. Figure 2 shows a longitudinal sectional view of a section with a first embodiment of the sealing unit of the proposed bit, figure 3 is a callout of the sealing site of the support of the bit in an enlarged scale. Figure 4 presents the second variant of the proposed bit with a node sealing the support, figure 5 is a callout of the second version of the node sealing the support on an enlarged scale. In Fig.6 shows a third variant of the site of sealing the support of the proposed bit, Fig.7 is a callout of this version of the site of sealing the support of the bit on an enlarged scale.

In figure 1 are indicated: pos.1 - paw of the bit; Pos.2 - pin paws; pos.3 - the first seal; pos.4 - the second seal; pos.5 - deposited working surface of a large (main) sliding bearing, which receives the main part of the axial load on the bit when it is working on the bottom of the well; pos.6 - a pair of paired seal; Pos. 7 - cone.

As can be seen from figure 1, the twin seal assembly occupies more than 60% of the length of the generatrix of the sliding bearing. The use of the full length of the plain bearing on the pin, including the length of the generatrix for the seal, would dramatically, by more than 60%, increase the bearing capacity of the bearing, and thus reduce the specific load on the bearings during drilling and, thereby, increase the resistance of the support and bit as a whole .

Designations in figure 2 and 3 (and partially in figure 4, 5, 6, 7) - pos. 8 - weapons elements, pos. 9 - paw axle, pos. 10 - roller cutter, pos. 11 - lock finger, pos. .12 - well wall, pos.13 - continuous annular protrusion, pos.14 - niche in the end of the cone, pos.15 - additional cone wall in contact with the increased length of the sliding bearing, pos.16 - elongated floating sleeve of the sliding bearing, pos. 17 - deposited layer of hard alloy on the loaded surface of a large sliding bearing on the paw axle, pos. 18 - collet seal frame, pos. 19 - elastic coating digging a collet seal, pos. 20 - steel sealing ring mounted on the frame, pos. 21 - elastic sealing ring, additionally pressing steel ring 20, pos. 22 - groove for deepening the collet seal, if necessary, reduce the depth of the groove 14 relative to the end of the leg 23 trunnion 9, pos.23 - end surface of the paw at the base of the trunnion.

Additional notation in FIGS. 4 and 5: item 24 - steel wear-resistant ring, pressed into a niche 14 at the end of the cone; pos.25 - inner wear-resistant ring, providing contact seal "steel on steel"; pos.26 - end elastomeric ring, providing continuous pressing of the steel ring 25 to the ring 24; pos.27 - elastic sealing ring, centering the position of the ring 25; POS.28 - a shaped groove on the protrusion 13, fixing the position of the ring 27 during operation of the bit on the bottom of the well.

Designations in Fig.6 and 7: pos.29 - undercut in the niche 14 for fixing the sealing elastic ring 30; pos.31 - labyrinth seal.

When assembling the sections of the bit according to the first embodiment (figure 2), the collet frame 18 with an elastic coating and a steel contact ring 20 is tightly mounted until it stops on a continuous annular protrusion 13. If necessary, installation is possible with glue. Then, the cone is mounted on the pin of the paw with the assembled support elements and closed by the balls of the lock bearing, which are fixed, in turn, by the locking finger 11. During installation of the cone, the gaps between it and the continuous contact ring 20 are selected, an additional elastic ring 21 is compressed.

When assembling the sections of the bit according to the second embodiment (Fig. 4), the ring 24 is pressed into a niche 14. An end sealing elastomeric ring 26 and a radial ring 27 are installed in the recess 22 on the end of the paw, then the steel ring 25. During the installation of the cutter 10, the end of the steel ring 25 deepens into the elastomeric ring 26 and the gaps between the rings 24 and 25 are selected. The cutter is fixed on the paw axle with the lock bearing balls and the lock finger 11.

When assembling the sections of the bit according to the third embodiment (Fig. 6), the elastic sealing ring 30 is placed in the undercut 29 in the recess 14, then the cone 10 is mounted on the pin and fixed by the lock bearing balls and the locking finger 11. This sealing option of the bit support additionally allows the use of a labyrinth seal 31.

All three options of the drill bit with a sealing seal, extended outside the paw axle, allow drastically (up to 60% or more) to increase the length of the generatrix and the dimensions of the bearing sliding bearing and, thereby, increase the durability of the drill bit.

The results of field tests of samples of the proposed drill bits confirm their significant advantages over existing similar structures.

Information sources

1. US patent No. 6533051 of 03/18/2003, “Drill bit with double seal” (analog).

2. US patent No. 3370895 from 02.27.1968, "Sealing seal for drill bits" (prototype).

Claims (3)

1. A drill bit with a sealed oil-filled support, comprising a body of welded sections of paws, the trunnions of which are mounted on the cones with rock cutting bodies and cavities of bearing bearings with sealing elements, characterized in that the sealing sealing units are removed from the base zone of the paw trunks in niches at the ends of cones. 2. The drill bit according to claim 1, characterized in that in the sealing sealing nodes the contact between the rubbing roller and the paw is provided according to the steel-to-steel scheme with wear compensation due to the expansion of collet pressing rings coated with an elastic layer or due to elastic properties o-rings, or through a combination of both. 3. The drill bit according to claim 1, characterized in that in the sealing sealing nodes the contact between the rubbing roller and the paw is provided according to the “elastomeric ring in steel” scheme with compensation for wear due to the elastic properties of the ring.

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