CN116201499A - Sucker rod dynamic sealing device - Google Patents

Abstract

The utility model relates to the technical field of underground tools for oil and gas field development, in particular to a dynamic sealing device of a sucker rod, which comprises an upper joint, an upper centralizing sleeve, a central cylinder, a lower centralizing sleeve and a lower joint which are sequentially arranged from top to bottom, wherein a plurality of sealing assemblies for sealing a continuous oil pipe are arranged in the central cylinder, and a plurality of centralizing assemblies for centralizing the continuous oil pipe are arranged on the inner wall of the upper centralizing sleeve and the inner wall of the lower centralizing sleeve; the sealing assembly comprises a rubber cylinder with a triangular section, the inner wall of the rubber cylinder is a tip, and guard rings are symmetrically arranged on two sides of the rubber cylinder; the centering component comprises a pressing ring and snap rings symmetrically arranged on two sides of the pressing ring, and the cross section of the pressing ring is in the shape of a middle bulge. The utility model ensures that the centralizing component can effectively centralize the continuous oil pipe, and also ensures that the triangular sealing ring has good sealing performance. And the device can be suitable for a high-temperature environment of 150 ℃ and a high-pressure environment of 70MPa, and has long service life.

Description

A sucker rod dynamic sealing device

technical field

The invention relates to the technical field of downhole tools for oil and gas field development, in particular to a sucker rod dynamic sealing device.

Background technique

At present, coiled tubing operation technology is more and more applied in the production process of oil and gas wells. The completion of coiled tubing effectively avoids the leakage problem caused by corrosion of threaded joints. At the same time, it is easy to install and has a high degree of automation. Shorten the operation time to a great extent and reduce the operation cost. However, during the process of coiled tubing running into the well, the sealing ring of the coiled tubing dynamic sealing device is prone to overturning and falling off, resulting in seal failure, and the requirements for the smoothness of the sealing surface are high, and later insertion cannot be realized.

Patent CN107989569B discloses a dynamic sealing device for coiled tubing. Its technical solution is: the lower sealing oil scraping structure and the upper righting structure are connected by a limit support plate and connecting bolts. The inner cavity of the limit support plate is a sealed cylinder. The sealing base sleeve, sealing rubber core and easy-to-change rubber pad are added to the inner cavity of the sealing cylinder. The sealing rubber core is installed in the inner cavity of the sealing base sleeve, and then the limit support plate is opened or closed, and the sealing base sleeve, Sealed rubber core or easy-change rubber pads for replacement. The beneficial effects are: by adding multiple sets of positioning and straightening steel balls, the coiled tubing can be straightened and the friction can be reduced; by installing the sealing base sleeve, sealing rubber core and easy-change rubber pad in the sealing cylinder, not only It can realize the dynamic sealing of the coiled tubing, and it is convenient to replace the corresponding seals, and the oil scraping device is added to improve the effect of the dynamic sealing, prolong the service life of the coiled tubing, and avoid leakage accidents at the wellhead. However, the sealing device has a relatively large frictional force on the coiled tubing, and it is difficult to insert the coiled tubing.

Patent CN213743337U also discloses a coiled tubing dynamic sealing device. The long rubber sleeve is sleeved on the outer wall of the coiled tubing, and there is an annular space between the outer wall of the long rubber sleeve and the inner wall of the outer cylinder; the upper end of the annular space can be connected to liquid, and the lower end is Airtight, the inflowing liquid is in a static state due to the closed lower end; when the triangular seal fails, the inner wall of the long rubber tube contacts the high-speed flowing liquid, forming a pressure difference with the static liquid in the annular space, and then pushing the long rubber tube radially inward, Hold the outer wall of the coiled tubing. The utility model manufactures the pressure difference between the inner wall and the outer wall of the long rubber tube, and the long rubber tube can retract and hold the continuous oil pipe tightly when the primary rubber tube seal fails to form a second seal, effectively ensuring its normal operation. But after holding the coiled tubing tightly, it is difficult to pull out the tubing, and the follow-up operation is difficult.

Therefore, there is an urgent need to provide a sucker rod dynamic sealing device, which is easy to operate and has good sealing performance.

Contents of the invention

In order to solve the above problems, the present invention provides a sucker rod dynamic sealing device.

To achieve the above object, the technical scheme of the present invention is as follows:

A sucker rod dynamic sealing device, comprising an upper joint, an upper centering sleeve, a central cylinder, a lower centralizing sleeve and a lower joint arranged sequentially from top to bottom, and several seals for sealing coiled tubing are arranged in the central cylinder Assemblies, the inner wall of the upper centralizing sleeve and the inner wall of the lower centralizing sleeve are provided with several centralizing components for centralizing the coiled tubing;

The sealing assembly includes a rubber tube with a triangular cross-section, the inner wall of the rubber tube is a sharp point, and protective rings are arranged symmetrically on both sides of the rubber tube, and the protective rings on both sides cooperate with the rubber tube to form a cylindrical shape; the inner diameter of the barrel is smaller than the inner diameter of the grommet;

The righting assembly includes a pressure ring and buckles arranged symmetrically on both sides of the pressure ring, the cross section of the pressure ring is in the shape of a middle bulge, and the pressure ring cooperates with the two buckles to form a cylindrical shape;

The inner diameter of the rubber cartridge is 0.3mm-1mm smaller than the outer diameter of the coiled tubing; the inner diameter of the pressure ring is 0.1mm-0.5mm larger than the outer diameter of the coiled tubing.

Further, the sealing assembly also includes a spacer ring, the spacer ring is arranged between the rubber tube and the central tube; the spacer ring is L-shaped, and the rubber tube and the retaining ring are embedded in the In the spacer, the rubber cartridge, the guard ring and the spacer just form a cylindrical structure.

Furthermore, a first groove is provided on the outer wall of the spacer ring, and a first sealing ring is arranged in the first groove.

Furthermore, spacer ring grooves are symmetrically arranged on both sides of the central cylinder, and the spacer rings are embedded in the spacer ring grooves, and the spacer rings are arranged in an L-shaped upward direction in the above spacer ring grooves , the spacer rings are arranged in an L-shaped downward direction in the spacer ring groove below.

Further, the lower part of the upper joint is embedded in the upper centering sleeve, the upper joint and the upper centering sleeve are connected by shear nails, and the upper joint is embedded in the outer wall of the upper centering sleeve A second groove is arranged on the top, and a second sealing ring is arranged in the second groove.

Further, the upper part of the lower joint is embedded in the lower centralizing sleeve, the lower joint and the lower centralizing sleeve are connected by shear nails, and the lower joint is embedded in the outer wall of the lower centralizing sleeve A third groove is arranged on the top, and a third sealing ring is arranged in the third groove.

Further, the lower side of the upper righting sleeve is embedded in the upper end of the central cylinder, and the upper central sleeve is connected to the central cylinder through shear nails; the upper part of the lower centralizing sleeve is embedded in the central cylinder The lower end of the lower centering sleeve is connected with the central cylinder through shear nails.

Further, a first centering groove is arranged above the upper centering sleeve, and the centering assembly is arranged in the first centering groove; a second centering groove is arranged under the lower centering sleeve, and the first The centralizing component is arranged in the two centralizing grooves.

Further, both the pressure ring and the buckle are made of PEEK material.

Further, the number of the sealing components is 12 groups, and 6 groups are arranged on both sides of the central cylinder; the number of the righting components is 8 groups, and each of the upper righting sleeve and the lower righting sleeve is set 4 groups.

Compared with prior art, the beneficial effect of the present invention is:

1. The present invention ensures that the centralizing component can effectively straighten the coiled tubing by setting the triangular seal and the bulging type centralizing component, and defining the relationship between the inner diameter of the triangular sealing ring, the inner diameter of the centralizing pressure ring and the outer diameter of the coiled tubing, And it can also make the triangular sealing ring have good sealing performance. And the triangular sealing rubber tube reduces the contact area between the rubber tube and the coiled tubing, which can provide better sealing performance and reduce the frictional resistance of the coiled tubing, and because the tip of the triangular sealing rubber tube faces the coiled tubing, therefore, for The size requirements of the inner wall of the rubber tube are relaxed, which increases the process design space of the inner wall of the rubber tube.

2. In the present invention, the righting component is set as a pressure ring in the middle and buckles on both sides. The pressure ring is a bulging structure, and the bulging pressure ring ensures that the pressure ring has a higher strength and has a good supporting effect; In addition, the pressure ring and the retaining rings on both sides are in arc-shaped contact, and the contact between the two is equivalent to a spherical bearing, which can adapt to the angle change of the sucker rod and play the role of fine-tuning the angle, which is beneficial to the straightening of the sucker rod.

3. The present invention is easy to install, has no locking phenomenon, and can be adapted to a high-temperature environment of 150°C and a high-pressure environment of 70MPa, and has a long service life.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a structural schematic diagram of the sealing assembly described in the present invention.

Fig. 3 is a structural schematic diagram of the righting assembly described in the present invention.

Fig. 4 is a pressure data diagram of the present invention at normal temperature.

Fig. 5 is a pressure data diagram of the present invention after wearing for 150 meters at normal temperature.

Fig. 6 is a pressure data diagram of the present invention after wearing for 150 meters at 150°C.

Explanation of reference signs:

1-upper joint; 2-upper centering sleeve; 3-central tube; 4-spacer ring; 5-lower joint; 6-buckle; 7-pressure ring; 8-retaining ring; Nail; 11-the second sealing ring; 12-the first sealing ring; 13-the lower centralizing sleeve; 14-the third sealing ring.

Detailed ways

The technical scheme of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. Embodiments all belong to the protection scope of the present invention. It should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal" etc. are based on the orientation or position shown in the drawings The positional relationship is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

As shown in Figures 1-3, the present invention provides a sucker rod dynamic sealing device, which includes an upper joint 1, an upper centering sleeve 2, a center tube 3, a lower centering sleeve 13 and a lower joint arranged in sequence from top to bottom 5. A plurality of sealing components for sealing the coiled tubing are arranged in the central cylinder 3, and a plurality of centralizing components for correcting the coiled tubing are arranged on the inner wall of the upper centralizing sleeve 2 and the inner wall of the lower centralizing sleeve 13;

The sealing assembly includes a rubber cylinder 9 with a triangular cross-section, the inner wall of the rubber cylinder 9 is a pointed end, the outer wall of the rubber cylinder 9 is a cylindrical surface parallel to the axis of the rubber cylinder, and the two sides of the rubber cylinder 9 are symmetrical A grommet 8 is set, and the grommet 8 is made of a harder PEEK material, and the grommets 8 on both sides cooperate with the rubber tube 9 to form a cylindrical shape; the inner diameter of the rubber tube 9 is smaller than that of the grommet 8 The inner diameter is small, and the inner diameter of the rubber cartridge 9 can be adjusted according to the outer diameter and working pressure of the sucker rod; when the sucker rod passes through the sealing assembly, a seal is formed between the rubber cartridge 9 and the sucker rod, With the movement of the sucker rod, the sucker rod drives the rubber sleeve 9 to one side, but the retaining ring 8 blocks the deviation of the rubber sleeve, thereby reducing the change of the inner diameter of the rubber sleeve 9, so that the distance between the rubber sleeve 9 and the sucker rod Maintain a stable sealing performance; at the same time, the retaining rings 8 on both sides can prevent the rubber tube 9 from falling off.

In addition, since the inner wall of the triangular rubber tube 9 is pointed, the inner wall of the rubber tube 9 can be compressed within a larger diameter variation range, thus reducing the design requirements for the inner diameter of the rubber tube 9 and increasing the process design window.

The centering assembly includes a pressure ring 7 and buckles 6 symmetrically arranged on both sides of the pressure ring 7, the cross section of the pressure ring 7 is in the shape of a middle bulge, and the pressure ring 7 and the two buckles 6 fit together to form a cylinder, preferably, the inner diameter of the pressure ring 7 is smaller than the inner diameter of the buckle 6;

The inner diameter of the rubber cartridge 9 is 0.3mm-1mm smaller than the outer diameter of the coiled tubing; the inner diameter of the pressure ring 7 is 0.1mm-0.5mm larger than the outer diameter of the coiled tubing.

When the sucker rod passes through the dynamic sealing device, the small gap between the righting assembly and the sucker rod can not only ensure the smooth passage of the sucker rod, but also can straighten the sucker rod; The relatively large gap can not only ensure the sealing performance between the rubber sleeve 9 and the sucker rod, but also not cause serious wear of the rubber sleeve 9 .

Further, the sealing assembly also includes a spacer ring 4, which is arranged between the rubber tube 9 and the central tube 3; the spacer ring 4 is L-shaped, and the rubber tube 9 and the center tube 3 The guard ring 8 is embedded in the spacer ring 4, and the rubber cartridge 9, the guard ring 8 and the spacer ring 4 just form a cylindrical structure.

Furthermore, a first groove is provided on the outer wall of the spacer ring 4, and a first sealing ring 12 is arranged in the first groove, and the first sealing ring 12 is preferably an O-ring.

Further, spacer ring grooves are arranged symmetrically on both sides of the central cylinder 3, the upper spacer ring groove is in contact with the upper centering sleeve 2, and the lower spacer ring groove is in contact with the lower centering sleeve 13 The spacer ring 4 is embedded in the spacer ring groove, and the spacer ring 4 is arranged in an upward direction of L shape in the spacer ring groove above, and the spacer ring 4 is arranged in the spacer ring below The grooves are arranged in an L-shaped downward direction.

Further, the lower part of the upper joint 1 is embedded in the upper righting sleeve 2, and the upper joint 1 and the upper righting sleeve 2 are connected by scissors 10, and the upper joint 1 is embedded in the upper A second groove is arranged on the outer wall of the centering sleeve 2, and a second sealing ring 11 is arranged in the second groove, and the second sealing ring 11 is preferably an O-ring.

Further, the upper part of the lower joint 5 is embedded in the lower centralizing sleeve 13, the lower joint 5 and the lower centralizing sleeve 13 are connected by shear nails, and the lower joint 5 is embedded in the lower centralizing sleeve 13. A third groove is arranged on the outer wall of the sleeve 13, and a third sealing ring 14 is arranged in the third groove, and the third sealing ring 14 is preferably an O-ring.

Further, the lower part of the upper centralizing sleeve 2 is embedded in the upper end of the central cylinder 3, and the upper centralizing sleeve 2 and the central cylinder 3 are connected by scissors; the upper centralizing sleeve 2 is embedded in the central cylinder 3. A fourth groove is arranged on the outer wall of the central cylinder 3, and a fourth sealing ring is arranged in the fourth groove; the upper part of the lower centralizing sleeve 13 is embedded in the lower end of the central cylinder 3, and the lower centralizing sleeve 13 The cylinder 13 is connected with the central cylinder 3 through shear nails; the outer wall of the lower centralizing sleeve 13 embedded in the central cylinder 3 is provided with a fifth groove, and a fifth sealing ring is arranged in the fifth groove .

Further, a first centering groove is arranged above the upper centering sleeve 2, and the centering assembly is arranged in the first centering groove; a second centering groove is arranged under the lower centering sleeve 13, so that The centralizing assembly is arranged in the second centralizing groove.

Further, both the pressure ring 7 and the buckle 6 are made of PEEK material.

Further, the number of sealing assemblies is 12 groups, and 6 groups are arranged on both sides of the central cylinder 3; 4 groups are set in each.

In order to verify the pressure bearing capacity and sealing performance of the present invention, the dynamic sealing device of the present invention is subjected to three kinds of combined tests under simulated situations, which are respectively pressure simulation, temperature simulation and lowering wear simulation,

The pressure simulation is to put the sucker rod into the dynamic sealing device of the present invention, and then install the joint device at the reserved pressure hole in the middle of the central cylinder 3, and the sealing components on both sides of the central cylinder 3 and the outer wall of the sucker rod form a seal. Space, by reserving pressure holes to input the bottom hole pressure to the present invention, simulating the downhole pressure environment, so as to test the performance of the tool.

The temperature simulation is based on the pressure simulation device, and the heating device is loaded on the outer surface of the present invention corresponding to the position of the sealing assembly, heated to a specified temperature, and kept for a certain period of time, so that the heat is fully transferred to the sealing assembly and the sealing assembly maintains a certain temperature at high temperature. Time, measured the pressure bearing capacity and sealing performance of the present invention again.

The water wear simulation is to push and pull the continuous rod with the same size as the actual sucker rod inside the dynamic sealing device of the present invention, and complete the required stroke, and then measure the pressure bearing capacity and sealing performance of the present invention.

The test condition that the present invention adopts is as follows:

The pressing pressure of the pressure simulation is 35MPa; the heating temperature of the temperature simulation is 150°C, and the temperature is kept for 60 minutes; the stroke of the water wear simulation is 150 meters.

The experimental results are as follows:

As shown in Figure 4, under normal temperature conditions, the present invention is subjected to pressure simulation, the pressing pressure is 35MPa, and the pressure is maintained for a certain period of time. The pressure sensor is placed in the bee space formed by the sealing components on both sides of the central cylinder, and the pressure sensor is measured. The pressure value has no obvious pressure drop, and the sealing performance of the present invention is good.

As shown in Figure 5, under normal temperature conditions, after the continuous rod reciprocates for 150 meters in the dynamic sealing device of the present invention, the pressure simulation is carried out, and the pressing pressure is 38MPa, 55MPa, 70MPa, and the pressing pressure is maintained for a certain period of time under each pressing pressure. There was no significant pressure drop.

As shown in Figure 6, the temperature simulation of the present invention is carried out by heating the heating temperature to 150°C, and then keeping it warm for 60 minutes. During the heating process, the continuous rod is used to simulate the water wear of the dynamic sealing device of the present invention. The pressure simulation is carried out, the pressing pressure is gradually increased to 70MPa, and the pressure is maintained for a certain period of time, and there is no obvious pressure drop. The sealing performance of the present invention is good.

The above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without Any deviation from the scope of the technical solution of the present invention shall be covered by the scope of the claims of the present invention.

Claims (10)

1. The dynamic sealing device for the sucker rod comprises an upper joint, an upper centralizing sleeve, a central cylinder, a lower centralizing sleeve and a lower joint which are sequentially arranged from top to bottom, wherein a plurality of sealing assemblies for sealing the continuous oil pipe are arranged in the central cylinder, and a plurality of centralizing assemblies for centralizing the continuous oil pipe are arranged on the inner wall of the upper centralizing sleeve and the inner wall of the lower centralizing sleeve; it is characterized in that the method comprises the steps of,

the sealing assembly comprises a rubber cylinder with a triangular section, the inner wall of the rubber cylinder is a tip, the two sides of the rubber cylinder are symmetrically provided with guard rings, and the guard rings on the two sides are matched with the rubber cylinder to form a cylinder; the inner diameter of the rubber cylinder is smaller than that of the guard ring;

the centering component comprises a pressing ring and two buckles symmetrically arranged on two sides of the pressing ring, the cross section of the pressing ring is in the shape of a middle bulge, and the pressing ring and the two buckles are matched to form a cylinder;

the inner diameter of the rubber cylinder is 0.3mm-1mm smaller than the outer diameter of the continuous oil pipe; the inner diameter of the compression ring is 0.1mm-0.5mm larger than the outer diameter of the continuous oil pipe.

2. The sucker rod dynamic seal apparatus of claim 1 wherein the seal assembly further comprises a spacer ring disposed between the packing element and the center tube; the spacer ring is L-shaped, the rubber cylinder and the guard ring are embedded into the spacer ring, and the rubber cylinder, the guard ring and the spacer ring just form a cylindrical structure.

3. The sucker rod dynamic seal device of claim 2, wherein the spacer ring outer wall is provided with a first groove, and a first sealing ring is arranged in the first groove.

4. The sucker rod dynamic seal device according to claim 2, wherein spacer ring grooves are symmetrically formed in two sides of the central cylinder, the spacer rings are embedded in the spacer ring grooves, the spacer rings are arranged in the upper spacer ring grooves along the L-shaped upward direction, and the spacer rings are arranged in the lower spacer ring grooves along the L-shaped downward direction.

5. The sucker rod dynamic seal device according to claim 1, wherein the lower part of the upper joint is embedded into the upper centralizing sleeve, the upper joint is connected with the upper centralizing sleeve through a shear pin, a second groove is formed in the outer wall of the upper joint embedded into the upper centralizing sleeve, and a second sealing ring is arranged in the second groove.

6. The sucker rod dynamic seal device according to claim 1, wherein the upper part of the lower joint is embedded into the lower centralizing sleeve, the lower joint is connected with the lower centralizing sleeve through a shear pin, a third groove is formed in the outer wall of the lower joint embedded into the lower centralizing sleeve, and a third sealing ring is arranged in the third groove.

7. The sucker rod dynamic seal device of claim 1, wherein the lower part of the upper centralizing sleeve is embedded into the upper end of the central cylinder, and the upper centralizing sleeve is connected with the central cylinder through a shear pin; the upper part of the lower centralizing sleeve is embedded into the lower end of the central cylinder, and the lower centralizing sleeve is connected with the central cylinder through a shear pin.

8. The sucker rod dynamic seal device of claim 1, wherein a first centralizing groove is arranged above the upper centralizing sleeve, and the centralizing assembly is arranged in the first centralizing groove; the lower centralizing sleeve is provided with a second centralizing groove below, and the centralizing assembly is arranged in the second centralizing groove.

9. The sucker rod dynamic seal apparatus of claim 1 wherein said compression ring and said retaining ring are each made of PEEK material.

10. The sucker rod dynamic seal device according to claim 1, wherein the number of the seal assemblies is 12, and 6 groups are respectively arranged on two sides of the central cylinder; the number of the centralizing assemblies is 8, and 4 groups of centralizing sleeves are respectively arranged in the upper centralizing sleeve and the lower centralizing sleeve.

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