CN205173488U - Composite seal mechanism with pressure compensation - Google Patents

Abstract

The utility model provides a composite seal mechanism with pressure compensation, is applicable to full rotation type rotatory steerable drilling instrument in the pit, the go -between is through pack into the left end of seal cover of interference fit, the right -hand member of go -between and the welding of the left end of metal seal bellows together, the welding of the right -hand member of metal seal bellows is at the left end of pressure cylinder liner, pressure cylinder liner high order end is provided with the relief valve, and the right of relief valve is provided with the check valve, the pressure cylinder liner inside with piston interference fit, the piston simultaneously and guiding axle interference fit, the right -hand member face department of piston and the left end welding of spring, the right -hand member welding of spring is in the left end face department of helixseal, the interference fit cover is passed through on the guiding axle to the helixseal, and the helixseal right -hand member passes through the check ring location, the go -between is the sealed drilling fluid and inside lubricating oil that is got into by guiding axle activity space department mainly, and helixseal and piston be the drilling fluid and the inside lubricating oil of sealed clearance entering by spiral seal structure department jointly to the solid particle that fall in drilling fluid is considered by the helixseal, the utility model has the characteristics of high temperature and high pressure, corrosion -resistant, shock -resistant, stand wear and tear, sealing performance height, long -life etc.

Description

A Combined Sealing Mechanism with Pressure Compensation

technical field

The utility model relates to a seal suitable for a full-rotation pointing type rotary steering drilling tool, in particular to a combined sealing mechanism with pressure compensation.

Background technique

The sealing of the steerable drilling tool is mainly to solve the sealing problem between the rotating casing or the non-rotating casing and the mandrel. The seals commonly used in rotary steerable drilling tools mainly include packing seals and lip seals. These two sealing forms are mainly realized by compressing the sealing material to produce large deformation, which is difficult to meet the controllable bend joint rotary steerable drilling tools in different drilling modes. The performance requirements for the sealing structure under harsh working conditions are mainly reflected in the following points:

1. The sealing surface has a swing angle within the design range, so the sealing structure needs to realize the seal while leaving an appropriate swing space for the guide shaft. When adjusting the swing angle, the sealing structure needs to have an automatic compensation function to ensure no leakage.

2. The sealing structure and material can withstand high temperature and high pressure underground, and can resist the impact and vibration generated by the drill bit when breaking rock.

3. The sealing material should be corrosion-resistant, wear-resistant and not easy to age.

4. The sealing structure has high reliability and service life.

Because it is difficult for the packing seal to achieve radial compensation when the sealing surface swings, and it wears faster near the gland; the lip seal is difficult to meet the sealing requirements when the pressure difference on both sides of the sealing surface changes irregularly, and the high temperature underground In the environment of high-pressure and high-abrasive drilling fluid, it is difficult to achieve a sealing effect. Therefore, packing seals and lip seals are difficult to meet the above-mentioned requirements on the sealing structure of rotary steerable drilling tools with controllable bend joints.

Contents of the invention

In order to overcome the defects of the above-mentioned prior art, the purpose of this utility model is to provide a combined sealing mechanism with pressure compensation, which has the characteristics of high temperature and high pressure resistance, corrosion resistance, impact resistance, wear resistance, high sealing performance and long service life Features.

In order to achieve the above object, the technical scheme of the utility model is:

A combined sealing mechanism with pressure compensation, suitable for fully rotary downhole rotary steerable drilling tools, including a connecting ring 3, which is fitted into the left end of the sealing sleeve 5 through interference fit, and the right end of the connecting ring 3 is sealed with the metal The left end of the bellows 4 is welded together, and the right end of the metal sealing bellows 4 is welded to the left end of the pressure cylinder liner 8; the left end of the pressure cylinder liner 8 is provided with a safety valve 6, and the right side of the safety valve 6 is provided with a one-way valve 7, the pressure The interior of the cylinder liner 8 is interference fit with the piston 9, and the piston 9 is also interference fit with the guide shaft 14. The right end of the piston 9 is welded to the left end of the spring 10, and the right end of the spring 10 is welded to the left end of the spiral seal 12. The seal 12 is sleeved on the guide shaft 14 through an interference fit, and the right end of the spiral seal 12 is positioned by a circlip.

Both the connecting ring 3 and the piston 9 are provided with three identical high-pressure-resistant combined sealing grooves A, the cross-sectional shape of the sealing groove A is trapezoidal, the O-shaped sealing ring 17 is installed in the middle of the sealing groove A, and both sides of the O-shaped sealing ring 17 are installed symmetrically. There are wedge seal ring 15 and backup seal ring 16.

Between the outer surface of the left end of the pressure cylinder liner 8 and the safety valve 6, it is processed into a wedge shape.

The contact distance between the inner circle of the piston 9 and the guide shaft 14 is greater than the contact distance between the piston 9 and the pressure cylinder liner 8 .

The utility model has the following advantages:

(1) The utility model leaves enough space for the guide shaft to freely and flexibly swing around the guide joint, so that the guide shaft can easily reach the maximum inclination angle required by the design, and the sealing mechanism does not produce space constraints on it.

(2) The utility model adopts the combined sealing ring design, and the organic cooperation of the wedge-shaped cross-section metal sealing ring, rectangular sealing ring and O-ring enhances the tolerance of the sealing ring to the high pressure downhole and reduces the damage caused by the pressure difference. The sealing ring fails, which improves the working life of the sealing structure.

(3) The utility model adopts the design method of the pressure compensating mechanism and other sealing elements. The pressure compensating mechanism is composed of a pressure cylinder liner 8, a piston 9, a spring 10, a safety valve 6 and a one-way valve 7. The left end of the pressure cylinder liner is welded with metal sealing bellows, the outer surfaces of both ends of the pressure liner are processed into a wedge shape, and the left end of the pressure liner is equipped with a safety valve and a check valve. The piston is sleeved on the guide shaft, the cross-section of the inner circle of the piston is slightly longer than the cross-section of the outer circle, the inner hole and the outer surface of the piston are provided with grooves, and the arrangement of each sealing ring is the same as that of the connecting ring groove sealing ring. The right end of the piston is welded with a spring, and the right end of the spring is connected to the left end of the spiral seal. Effectively reduce the pressure difference on both sides of the sealing interface, reduce the damage of other sealing elements caused by high pressure difference, and reduce the leakage.

Description of drawings

Figure 1 is a schematic diagram of the combined sealing structure.

Figure 2 is a schematic diagram of the combined structure of the sealing ring.

In the figure: 1 rotating jacket, 2 guiding joint, 3 connecting ring, 4 metal sealing bellows, 5 sealing sleeve, 6 safety valve, 7 one-way valve, 8 pressure cylinder liner, 9 piston, 10 spring, 11 screw seal, 12 Elastic gauze, 13 spring retaining ring, 14 guide shaft, 15 wedge-shaped sealing ring, 16 backup sealing ring, 17O-ring.

detailed description

Below in conjunction with accompanying drawing, the utility model is described in detail.

Referring to Figure 1, a combined sealing mechanism with pressure compensation is suitable for fully rotary downhole rotary steerable drilling tools (controllable bend joints), including a connecting ring 3, which is inserted into the sealing sleeve 5 through interference fit The left end, the right end of the connecting ring 3 and the left end of the metal sealing bellows 4 are welded together, and the right end of the metal sealing bellows 4 is welded to the left end of the pressure cylinder liner 8; The right side of the cylinder is provided with a check valve 7, the inside of the pressure cylinder liner 8 is interference fit with the piston 9, and the piston 9 is interference fit with the guide shaft 14 at the same time, the right end of the piston 9 is welded with the left end of the spring 10, and the right end of the spring 10 is welded At the left end face of the screw seal 12. The spiral seal 12 is sleeved on the guide shaft 14 through an interference fit, and the right end of the spiral seal 12 is positioned by a circlip.

Referring to Fig. 2, there are three identical high-pressure-resistant combined sealing grooves A on the connecting ring 3 and the piston 9, the cross-sectional shape of the sealing groove A is trapezoidal, the O-ring 17 is installed in the middle of the sealing groove A, and the O-ring 17 Both sides are equipped with wedge-shaped sealing ring 15 and backup sealing ring 16 symmetrically. When adjusting the pressure on both sides of the sealing surface, the piston 9 will move back and forth along the guide shaft 14, and the inner and outer circles of the piston 9 are the main pressure bearing surfaces and leakage channels, so high pressure sealing is required.

The outer surface of the left end of the pressure cylinder liner 8 and the safety valve 6 are processed into a wedge shape to prevent the pressure cylinder liner 8 and the sealing sleeve 5 from being collided and squeezed when the metal sealing bellows is bent and deformed.

The contact distance between the inner circle of the piston 9 and the guide shaft 14 is greater than the contact distance between the piston 9 and the pressure cylinder liner 8; in order to increase the follow-up compensation of the piston 9 when the guide shaft 14 frequently swings.

The working principle of the utility model: when the controllable bend joint is drilling vertically, the guide shaft 14 is on the same axis as the rotating jacket, and the high-pressure resistant sealing structure at the connecting ring 3 plays the main sealing role with the piston 9 and the screw seal. The connecting ring 3 mainly seals the drilling fluid and internal lubricating oil entering from the movable space of the guide shaft 14, the screw seal 12 and the piston 9 jointly seal the drilling fluid and internal lubricating oil entering from the gap at the structure of the screw seal 12, and the screw seal 12 Seal 12 filters out solid particles in the drilling fluid.

During steerable drilling, the flexible deformation of the metal sealing bellows 4 makes the sealing structure oscillate with the guide shaft, thereby ensuring the stability of the connecting ring 3 and the pressure balance mechanism, and reducing the floating of the sealing ring. Elasticity requirements reduce the friction and wear damage and improve the overall performance. In addition, the axial deformation of the spring 10 and the metal sealing bellows 4 also play a certain role in shock absorption and buffering, which is also very beneficial for maintaining the relative stability of the high-pressure sealing surface . The elastic gauze 12 has good follow-up compensation, which can timely make up the gap produced by the guide shaft when it deflects, and effectively filter the solid particles in the drilling fluid to prevent the deposition of solid particles from hindering the swing of the guide shaft.

During the whole process of directional drilling, the pressure compensation mechanism makes corresponding changes to the downhole drilling fluid pressure from time to time, and the pressure difference on both sides of the sealing structure is adjusted by the movement of the piston 9 to keep within the design requirements, which improves the life and performance of the sealing structure.

Claims (4)

1. A combined sealing mechanism with pressure compensation, suitable for fully rotary downhole rotary steerable drilling tools, characterized in that it includes a connecting ring (3), and the connecting ring (3) is loaded into the sealing sleeve (5) through interference fit ), the right end of the connecting ring (3) is welded together with the left end of the metal sealing bellows (4), and the right end of the metal sealing bellows (4) is welded to the left end of the pressure cylinder liner (8); the pressure cylinder liner (8 ) is provided with a safety valve (6) on the leftmost end, and a check valve (7) is provided on the right side of the safety valve (6). The shaft (14) is interference fit, the right end of the piston (9) is welded to the left end of the spring (10), the right end of the spring (10) is welded to the left end of the screw seal (12), and the screw seal (12) passes through Ying fit is sleeved on the guide shaft (14), and the right end of the screw seal (12) is positioned by the spring retaining ring. 2. A combined sealing mechanism with pressure compensation according to claim 1, characterized in that the connecting ring (3) and the piston (9) are provided with three identical high-pressure resistant combined sealing grooves (A), The cross-sectional shape of the sealing groove (A) is trapezoidal, and the O-shaped sealing ring (17) is installed in the middle of the sealing groove (A), and both sides of the O-shaped sealing ring (17) are symmetrically equipped with wedge-shaped sealing rings (15) and backup sealing rings ( 16). 3. A combined sealing mechanism with pressure compensation according to claim 1, characterized in that the space between the outer surface of the left end of the pressure cylinder liner (8) and the safety valve (6) is processed into a wedge shape. 4. A combined sealing mechanism with pressure compensation according to claim 1, characterized in that the contact distance between the inner surface of the piston (9) and the guide shaft (14) is greater than that between the piston (9) and the pressure cylinder liner ( 8) The contact distance.