RU2276247C1 - Drilling bit with air-tight bearings for drilling wells with well bottom flushing with air - Google Patents

Abstract

FIELD: drilling equipment, particularly drilling bits.

SUBSTANCE: cooling is performed by providing direct air flows circulation in gaps between drilling bit leg, axle and rolling members along with air flows discharge through central channel made in the axle. Air flow parts are supplied into unloaded roller bearing zones and in grooves of thrust journal and are directed through one or several orifices of unloaded major race, which are communicated with channels extending through axle and in leg body. The air flow parts bypass seal and orifice for locking finger receiving. Outlet orifices to feed air flows from bearing assembly cavity to hole annuity are created in rounded leg back surfaces so that cooling air jets are directed in gap between leg back and well wall or the outlet orifices are formed in side leg surfaces so that the jets are directed into hole annuity by-passing well wall to create injection effect during well bottom cleaning of cut rock.

EFFECT: provision of direct cooling agent contact with bearing assembly races and rolling members.

4 cl, 8 dwg

Description

The invention relates to the field of drilling equipment and is used when drilling wells with blowing the bottom of the air.

Known drill bit [1], containing a housing with purge channels, rock cutting bodies in the form of roller cutters with milled teeth or carbide teeth. The cones are movably fixed on the pins of the paws of the chisel sections. Roller cones are sealed and oil-filled. In the upper part of the bit body, a lubricant consumption compensation unit is provided during operation on the face with a system of channels connecting the cavity of the lubricant consumption compensation unit with the cavity of the sealed support.

A disadvantage of the analogue is that the air circulating in the bottom face cleaning system, partially entering the system of support cooling channels, does not directly contact the bearing surfaces and rolling bodies. The cooling of the cavity of the supports and rolling elements is possible only through the wall thickness and the oil layer in the support, which has a very low heat transfer coefficient, and therefore is ineffective.

A drill bit [2] is adopted as a prototype, in which compressed air is used for more intensive heat removal, which also partially enters the cavity inside the journal and does not enter the sealed oil-filled support cavity. The specified bit is also not effective enough to provide cooling of the loaded zones and rolling elements. Despite the fact that this bit provides for a significant approximation of the air flow to the inner wall of the pin, its direct contact with loaded surfaces and rolling bodies also does not occur.

As in the design of the bit, taken as an analogue, in the prototype, the cooling of the cavity of the supports and rolling elements occurs only through the wall in the paw axle and a layer of grease.

The aim of this invention is to provide a reliable and efficient cooling system for the support of drill bits.

This goal is achieved by the fact that in a drill bit with sealing supports for drilling wells with blowing the bottom of the air, containing a body with a nipple and blowing channels to clean the bottom of the cuttings, as well as to cool the supports, rock cutting bodies in the form of cones with teeth mounted on made with the channels of the paw pins by means of rolling bearings, a step lock finger located in the pin hole, while cooling inside the sealed cavity of the support is carried out using direct compasses air flows in the gaps between the paw, axle and rolling elements with their entry through the central channel in the axle and outlets from it into the unloaded zones of roller bearings, as well as into the grooves of the thrust foot with the outlet of flows through one or more holes on the unloaded surface of a large roller track connected to the channels passing inside the trunnion and the body of the paw, bypassing the seal and the hole for the locking finger.

The outlet openings for exhausting from the cavity of the support of air flows into the annulus are located directly on the radius surface of the back of the paw with the direction of the jets of cooling air in the gap between the back of the paw and the wall of the well or on the side surfaces of the paws with the direction of the jets into the annulus, bypassing the wall of the well with the creation of an ejection effect when cleaning the face from cuttings.

Outlets for the removal of airflow from the support cavity can also be located in combination with the direction of the jets into the annulus at an angle to the borehole wall, as well as bypassing the borehole wall.

Figure 1 shows a General view with a longitudinal section of a section of a drill bit for drilling wells with blowing the bottom of the air and sealing the supports. Figure 2 and 3 shows the cross section of the paw of the bit with options for the direction of the outlet on the surface of the paw towards the side of the well wall and bypassing the wall of the well. Figures 4 and 5 show cross sections of a pin pivot pin on a large and small running roller track. 6 and 7 show the same sections with rolling bodies and treadmills in cone. On Fig shows a bit and a view of the back of the paw with options for the directions of the outlet on its surface towards the side of the well and bypassing the wall of the well.

The invention consists in the following. In the body 1 of the bit (figure 1) there is a system of channels for supplying compressed air from the cavity 3 inside the nipple through the nozzle 4 directly to the bottom of the well to clean it from cuttings. The paws 5, during welding of which the housing 1 is formed, are equipped with trunnions 6 with bearing tracks 7, 8 and 9, rolling elements 10, 11, 12. Rollers 13, movably mounted on the trunnions 6, have reciprocal bearing tracks corresponding to tracks 7, 8 and 9, made on the pins 6 paws 5.

At the end of axle 6, a persistent heel 14 with channels 15 is installed for passage in the heel of cooling air flowing through channels 2 and 16 with exit 17 and 18 to the treadmills. The channels 17 and 18 in the preferred embodiment, displayed on the unloaded sectors (figure 1, 2, 3, 4, 5, 6, 7), outside the lower loaded part.

Studies of the nature of the loading and wear of the elements of rolling bearings showed that during operation, the load from the reaction of the face is perceived on the treadmills of the paw axle with sectors with a central angle not exceeding 120 °. Therefore, the channels 17 and 18 are made taking into account this circumstance, so that the load on the treadmills under the rollers in the exit areas of the holes is minimal or absent altogether - in accordance with the loading diagrams "a" and "b" (Figs. 4, 5). For the same reasons, openings 19, 20 are made in the unloaded zone with exits to the surface of the legs 21 and 22 for draining the cooling agent from the cavity of the support through the body of the leg of the leg to the surface of the back of the leg (Figs. 7).

The options for the exit of these holes on the back of the legs can be different. For example, as shown at position 21, on the radial surface of the back facing toward the wall of the well, or, as shown at position 22, on the side surface of the paw (Fig. 8). The latter option is more preferable from the point of view of preventing the possibility of mashing and blocking the outlet with the cuttings. This embodiment of the channel contributes not only to reducing the possibility of clogging it with drilled particles of the rock, but also increasing the ejection effect, which contributes to the intensity of cleaning the bottom of the cuttings. Position 25 denotes a sealing ring that protects against particles of cuttings in the cavity of the support during drilling. The cross section of the o-ring may be of various shapes (for example, O-shaped, as shown in figure 1). Position 26 (figure 1) indicates a filter designed to protect against ingress of cuttings in the support. Its design can be different (slotted, mesh, etc.). It is desirable that the cross-sectional areas of the holes inside the pin of the paw and at the exit of the paw are approximately the same and do not interfere with the passage of cooling air.

The work of the drill bit is as follows. Under the influence of axial load and torque created by the drilling rig, the bit begins to rotate around its axis, and cones with rock-cutting teeth begin to rotate around their axes as well, which contributes to the destruction of the rock. In order to remove drill cuttings from the bottom and ensure cooling of the bit supports, compressed air is supplied from the compressor through the pipe space to the bit, and then along the annular space between the pipe and well walls along with the cuttings, it is supplied to the surface (to the wellhead). 60-70% of the total air flow is supplied through the nozzle 4 to the face, and 30-40% of the flow is supplied through channels 2, through the hole 15 in the fifth, the central axial channel 16 and channels 17 and 18 directly to the roller treadmills, intensively cools them and rolling elements, helping to increase their performance. The channel system and the directions of the cooling flows are shown in figures 1, 2, 3, 4, 5 and 8 by arrows.

The advantage of the proposed drill bit is the sealing of the support, which protects against ingress of abrasive particles of drill cut, which is inevitable for any type of open, unsealed support, direct and effective contact of the coolant flow with the treadmills and rolling elements of the support, and the flow exit into the annulus, which contributes to ejection effect during the lifting and removal from the face of particles of destroyed rock.

High reliability in operation allows you to achieve the desired result - to sharply increase the durability of the bit by increasing the stability of the support, to increase penetration and mechanical drilling speed.

The possibility of carrying out the invention is confirmed by successful bench and field trials of prototypes of drill bits according to the invention.

Information sources

1. Copyright certificate No. 1406331, cl. E 21 B 10/18, publ. 08.30.88 g. (Analog).

2. Copyright certificate No. 1423722, cl. E 21 B 10/22, publ. September 15, 88 (prototype).

Claims (4)

1. A drill bit with a sealing of supports for drilling wells with blowing the bottom of the air, containing a body with a nipple and blowing channels for cleaning the bottom of the cuttings, as well as for cooling the supports, rock cutting bodies in the form of roller cutters with teeth mounted on the pins axles by means of rolling bearings, a step lock finger located in the pin hole, characterized in that the cooling inside the sealed cavity of the support is carried out by means of direct circulation of air flows in the gaps between the paw, axle and rolling elements with their introduction through the central channel in the axle and withdrawal from it into the unloaded zones of the roller bearings, as well as into the grooves of the thrust heel, with the flow through one or more holes on the unloaded surface of a large roller track connected with channels passing inside the pin and the body of the paw, bypassing the seal and the hole for the locking finger. 2. The drill bit according to claim 1, characterized in that the outlet for exhaust from the cavity supports the air flow into the annulus is located directly on the radial surface of the back of the legs with the direction of the jets of cooling air into the gap between the back of the legs and the wall of the well. 3. The drill bit according to claim 1, characterized in that the outlet for exhaust from the cavity supports the air flow located on the side surfaces of the paws with the direction of the jets into the annulus, bypassing the wall of the well, with the creation of an ejection effect when cleaning the bottom of the cuttings. 4. A drill bit according to any one of claims 1 to 3, characterized in that the outlet openings for exhausting from the cavity of the air flow support are located in combination with the direction of the jets into the annulus at an angle to the well wall, and also bypassing the well wall.

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