RU2739179C1 - Well ball catcher - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to devices for servicing wells in oil and gas industry and can be used for gripping and extraction of balls from well after various process operations. Device comprises a cylindrical hollow body, a ball retaining hook installed in the body and made in the form of elastic plates with the possibility of angular displacement of the plates in relation to the body when the forces are exerted on them, adapter for connection with pipe string. Plates are made in form of split collet with lower clamping grip. Collet is installed inside the case, in the initial position of the collet plate are spring-loaded outside to the case. Housing outside is equipped with annular recess, on it at angle of 180° relative to each other there are two L-shaped slots in form of interconnected from below long and short sections. Funnel is fixed from below on the external circular recess of the housing. Catcher is equipped with two guide pins, which on one side are screwed into upper part of funnel, and on other side are inserted into L-shaped slots of housing. Cone has the possibility of longitudinal and transverse movement relative to the housing within L-shaped slots. From below funnel is equipped with radial holes, and on top funnel is equipped with internal annular stop limiting movement of housing downwards relative to funnel. In initial position pins are located in lower ends of long sections of L-shaped slots. Funnel relative to the body is fixed with a destructible screw. In the working position, the body can be limitedly moved relative to the funnel until it stops in the inner ring stopper of the funnel with movement of guide pins from lower ends of long sections to extreme right ends of short sections of L-shaped grooves and compression of collet plates inside from housing under effect of force created by lower end of housing, and closing of chuck grips.

EFFECT: increased reliability of operation at balls catching and efficiency during flushing, expanded functionality, reduced length and metal consumption.

1 cl, 5 dwg

Description

The invention relates to a device for servicing wells in the oil and gas industry and can be used to capture and retrieve balls from a well during well workover, including from non-magnetic materials left in the well after various technological operations.

A well-known downhole catcher of a shut-off body (patent RU No. 2622963, publ. 06/21/2017), containing a cylindrical body, a stationary stop for lifting the shut-off body installed in a cylindrical body and located in the upper part of the catcher, fixing an insert of a substantially cylindrical shape installed in a cylindrical body and located in the lower part of the catcher, and a retaining element pivotally mounted in the fixing insert and configured to hold the closure member while allowing fluid to flow. The lift limiter is made in the form of a cruciform element rigidly fixed in the upper part of the safety catch. The retaining element is substantially U-shaped or H-shaped and is secured to a pivot shaft capable of free rotation in the fastening holes provided in the fixing insert. A gap is provided between the body and the retaining insert to further fluidize the area within the safety body and the area below the retaining insert. The gap is substantially cylindrical and extends along the entire length of the retaining insert. A side opening is provided in the locking insert near the location where the retaining member is installed. The body of the catcher is coupled to a pipe sub in the upper and lower parts of the catcher. The body is made of a tubing branch pipe (tubing) with a diameter of 89 mm and a length of 1 meter, and the subs, provided in the lower and upper parts of the catcher, are tubing subs of 73-89 mm.

Disadvantages of the device:

- firstly, low reliability of the catcher when catching the shut-off element. This is due to the presence of a retaining element in the safety device that is pivotally installed in the locking insert and configured to overlap the cross-sectional area of the locking insert to hold the closure and ensure fluid flow. This condition, at low fluid pressures, with a high probability can lead to a failure in the actuation of the restraining element of the safety;

- secondly, the complexity of the safety device, due to the large number of units and parts;

- thirdly, high metal consumption and overall dimensions of the catcher body;

- fourthly, limited functionality. The catcher is designed to catch only one shut-off element (ball) and only one diameter, for example 35 mm.

The closest in technical essence and the achieved result is a downhole ball catcher containing a cylindrical hollow body, a hook for holding balls installed in the body and made in the form of elastic plates with the possibility of angular movement of the plates relative to the body when a force is applied to them, an adapter for connecting a catcher with a string of pipes, rigidly fixed to the upper end of the body. (patent RU No. 2594825, publ. 08/20/2016). The body consists of rigidly interconnected separate hollow sections, inside the cavity of each of the sections there is at least one hook for holding the balls, made in the form of an elastic, at least one-layer plate, rigidly attached by one of its edges to the section body. The plate is installed relative to the section body at an acute angle with the possibility of angular movement of the plate towards the body when a force is applied to it. The plate in cross section has an arcuate shape, with the convex surface of the plate facing the longitudinal axis of symmetry of the section, and in the body of the section opposite the concave surface of the plate a through groove is made, the shape and dimensions of which correspond to the shape and dimensions of the plate in plan. A protective tip is rigidly attached to the lower section of the downhole catcher.

Disadvantages of the device:

- firstly, low reliability of the device when capturing balls. This is due to the fact that the ball outside the catcher is drawn by the fluid flow and enters the inner cavity of the lower section, begins to interact with the hook plates, bending them towards the body and passes into the next section located above, and if the ball weight is greater than the fluid flow force, acting on the ball from below, the ball does not rise at all upward relative to the device body, and if the force of the fluid flow is sufficient to lift the ball, then this force of the fluid flow may not be enough to bend the hooks towards the body, therefore the ball cannot rise above the hooks of the safety body;

- secondly, the low efficiency of the device during the washing process. This is due to the fact that the protective tip, after stopping against the bottom of the wellbore, does not allow circulation of the liquid, therefore, the ball located in the catcher below the hook cannot rise upward due to the lack of fluid flow from bottom to top inside the catcher;

- thirdly, the limited functionality of the safety device. The catcher is designed to catch balls of only one diameter, for example, 38 mm;

- fourthly, the length and high metal content of the catcher, due to the fact that the number of hull sections with a hook depends on the number of balls to be extracted, therefore, the more balls to be removed from the well, the greater the length and metal consumption of the catcher.

The technical objectives of the invention are to increase the safety of the catcher when catching balls and the efficiency of the catcher in the washing process, expanding the functionality of the catcher with the ability to catch balls of different diameters, as well as reducing the length and metal consumption of the catcher.

Technical problems are solved by a downhole ball catcher containing a cylindrical hollow body, a hook for holding balls installed in the body and made in the form of elastic plates with the possibility of angular movement of the plates relative to the body when a force is applied to them, an adapter for connecting the catcher with a pipe string, rigidly fixed to the upper end of the body.

The novelty is that the plates are made in the form of a split collet with a lower clamping grip, while the collet is installed inside the body, and in the initial position, the collet plates are spring-loaded outward to the body, and the body is equipped with an outer annular recess on the outside, on the outer annular recess of the body at an angle of 180 ° relative to each other, two L-shaped grooves are made in the form of long and short sections connected to each other from below, moreover, a funnel is fixed on the bottom of the outer annular sample of the body, the catcher is also equipped with two guide pins, which are screwed into the upper part of the funnel on one side, and the other sides are inserted into the L-shaped grooves of the body, while the funnel has the possibility of longitudinal and transverse movement relative to the body within the L-shaped grooves, moreover, the funnel is equipped with radial holes from below, and the funnel is equipped with an internal annular stop on top, limiting the movement of the body downward relative to the funnel, while in the original position, the pins are in the lower ends of the long sections of the L-shaped grooves, while the funnel relative to the body is fixed with a destructible screw, and in the working position the body has the possibility of limited movement relative to the funnel until it stops against the inner annular stop of the funnel with the movement of the guide pins from the lower ends of the long sections to the extreme right ends of the short sections of the L-shaped grooves and the compression of the collet plates inward from the body under the influence of the force created by the lower end of the body and the clamping grips of the collet.

FIG. 1 schematically depicts a downhole ball catcher in the initial position.

FIG. 2 schematically shows the downhole ball catcher in working position.

FIG. 3 shows a section A-A of the split sleeve in the initial position.

FIG. 4 schematically shows a reamer B of the groove made on the outer annular recess of the body.

FIG. 5 shows a section B-B of the split sleeve in the initial position.

The downhole ball catcher contains a cylindrical hollow body 1 (see Fig. 1-2, 4-5), in which a hook 2 (Fig. 1-2) is installed to hold balls 3 '... 3 ⁿ , for example, three balls. The hook 2 is made in the form of elastic plates 4 (Figs. 1-3, 5), for example, in the amount of four pieces, with the possibility of angular movement of the plates 4 relative to the body 1 when a force is applied to it.

An adapter 5 (Figs. 1-2) is rigidly attached to the upper end of the housing 1 for connecting the catcher with the pipe string 6. Plates 4 are made in the form of a split collet 7 with a lower clamping grip 8. Collet 7 is installed inside the housing 1.

In the initial position of the plate 4, the collet 7 is spring-loaded outward to the body 1. The body 1 is equipped on the outside with an outer annular recess 9 (Fig. 1-2, 4).

On the outer annular sample 9 of the housing 1 at an angle of 180 ° relative to each other, two L-shaped grooves 10 'and 10 "are made, in the form of long 11' and 11" (Fig. 4) sections of length - a and short 12 'and 12 "sections long - b.

A funnel 13 is fixed on the bottom of the outer annular recess 9 of the body (Figs. 1-3, 5).

The borehole ball catcher is equipped with two guide pins 14 'and 14 "(Figs. 1-2, 4), which are screwed into the upper part of the funnel 13 on the one hand, and are inserted into the L-shaped grooves 10' and 10" of the housing 1 on the other side ...

The funnel has the ability to move longitudinally and laterally relative to the body within the L-shaped grooves 10 'and 10 "of the body 1.

From the bottom, the funnel 13 is equipped with radial holes 15 (Fig. 1-2) with a diameter d _about , for example, equal to 20 mm in an amount of 12 pieces, while the total cross-sectional area of the radial holes 15 must be greater than or equal to the area of the minimum cross-section of the body 1 of a safety catcher with a diameter D _l , for example, D _l = 60 mm. This is a necessary condition that excludes the loss of pressure (effort) of the ascending fluid flow on the balls 3 '... 3 ⁿ in the body 1 of the safety device.

The top of the funnel 13 is provided with an inner annular stop 16 (Fig. 1-2), which limits the movement of the housing 1 downward relative to the funnel 13.

In the initial position, the guide pins 14 'and 14 "are in the lower ends of the long sections 11' and 11" L-shaped grooves 10 'and 10 ", while the funnel 13 relative to the body 1 is fixed by a breakable screw 17.

In the working position, the housing 1 has the possibility of limited movement relative to the funnel 13 until it stops against the inner annular stop 16 of the funnel 13 and the compression of the plates 4 of the collet 7 inwardly from the housing 1 under the action of the force created by the lower end 18 (Figs. 1-2) of the housing 1 and closing the clamping jaws 8 of the collet 7.

In this case, the guide pins 14 'and 14 "(see Fig. 4) move from the lower ends of the long sections 11' and 11" to the extreme right ends (in Fig. 4 is shown conditionally) of the short sections 12 'and 12 "of the L-shaped grooves 10 'and 10 ".

O-ring 19 (see Fig. 1 and 2) ensures the tightness of the mating surfaces during the operation of the safety device.

The device works as follows.

First, based on the diameter - d _w balls 3 '... 3 ⁿ (see Fig 1-2..) Subject to capture and retrieve selected communicating diameters D (Figure 1). Claw 8 split collet 7 in the initial and operating positions.

Ball 3 'has a minimum diameter d _w1 of all balls, for example equal to 37 mm.

Ball 3 "has a diameter d _w2 , for example equal to 40 mm.

Ball 3 ⁿ has a maximum diameter d _wn of all balls, for example equal to 45 mm.

Then, in the initial position, the clamping grip 8 of the split collet 7 has a bore diameter D greater than the maximum diameter of the ball 3 ⁿ : d _w = 45 mm, for example, D = 50 mm.

And in the working position, the clamping grip 8 of the split collet 7 has a bore diameter d (Fig. 2) less than the minimum diameter of the ball 3 ': d _w = 37 mm, for example, d = 30 mm.

The catcher assembly, as shown in FIG. 1 is lowered into the borehole 20 (Fig. 1-2) until the stop of the funnel 13 on the bottomhole 21 (Fig. 2) of the borehole 20, while the diameter D _in (Fig. 1) of the funnel 13 is less than the inner diameter of the borehole 20, but it has such diameter, which ensures that the balls 3 '... 3 ⁿ get inside the funnel 13 in the process of lowering the catcher. For example, the inner diameter of the well D _c is 132 mm, then we take the diameter D _in = 120 mm. Reaching the bottom of the well is fixed partially by unloading the pipe string 6 onto the funnel 13, for example, by 30 kN.

Then, the well 20 is flushed by pumping the process fluid into the annular space 22 (Fig. 1) between the pipe string 6 and the well 20, for example, for 30 minutes.

As a result, the process fluid from the annular space 22 through the radial holes 15 enters the funnel 13, where the balls 3 '... 3^n.... Under the action of the pressure of the process fluid, creating a force directed from the bottom up, the process fluid together with balls 3 '... 3ⁿ moves up through the inner annular stop 16 of the funnel 13, and since D> d_w, then balls 3 '... 3ⁿ through the lower clamping grip 8 of the split collet 7 fall into the inner cavity of the split collet 7 and the body 1 of the safety device. After the end of the washing time, the pipe string 6 is completely unloaded onto the funnel 13, for example, with a force of 120 kN, while, for example, with a force of 50 kN, the screw 17 to be destroyed is sheared off.

In this case, the body 1 goes down relative to the funnel 13, rested against the bottom hole 21 of the well 20, to a length equal to the length - a of the long sections 11 'and 11 "L-shaped grooves 10' and 10", respectively, for example, a = 0.5 m, while the body 1 with the lower end 18 abuts against the inner annular stop 16 of the funnel 13.

Further, from the wellhead 20, the pipe string 6 is turned clockwise by an angle corresponding to the length - b of the short sections 12 'and 12 "of the L-shaped grooves 10' and 10". For example, at an angle of 90 °, which with the outer diameter of the body equal to 114 mm corresponds to the length of the sections 12 'and 12 ": b = 89.5 mm = 0.0895 m.

As a result, the guide pins 14 'and 14 "(see Fig. 4) move from the lower ends of the long sections 11' and 11" to the extreme right ends of the short sections 12 'and 12 "- L-shaped grooves 10' and 10", and plates 4 (see Fig. 2) of the expanding collet 7 are compressed into the body 1 under the influence of the force created by the lower end 18 of the body 1, while the clamping grips 8 of the collet 7 are closed to a diameter d = 30 mm, which is less than the minimum diameter ball 3 ': d _w = 37 mm.

Then, using the pipe string 6, the catcher is removed from the well 20.

The reliability of the downhole catcher is increased when trapping balls. This is due to the fact that structurally from the process of catching the balls, the dependence of the bend of the hooks towards the body on the force of the fluid flow created from the bottom up onto the ball and the weight of the ball itself is excluded. In this case, the catching of the balls occurs due to the circulation of fluid after the stop of the catcher at the bottom of the well due to the free passage of the balls into the catcher, therefore, the parts that create an obstacle (hooks bent by the ball) to the lifting of the balls are excluded from the design of the catcher.

The efficiency of the downhole catcher in the process of catching the balls increases due to the presence of radial holes made in the funnel, which allow flushing (fluid circulation) after the catcher stops against the bottom of the well, therefore, the balls to be caught and removed are carried away by the fluid flow from bottom to top inside the catcher.

The functionality of the downhole catcher is expanding, which allows you to catch balls of various standard sizes in terms of diameter, as well as the compact length of the catcher, which is up to 2 m and low metal consumption.

The proposed downhole catcher of balls allows increasing the reliability and efficiency of work, expanding the functionality, reducing the length and metal consumption of the downhole catcher.

Claims (1)

Downhole ball catcher containing a cylindrical hollow body, a hook for holding balls installed in the body and made in the form of elastic plates with the possibility of angular movement of the plates with respect to the body when a force is applied to them, an adapter for connecting the catcher with a pipe string, rigidly fixed to the upper the end of the body, characterized in that the plates are made in the form of a split collet with a lower clamping grip, while the collet is installed inside the body, and in the initial position, the collet plates are spring-loaded outward to the body, and the body is equipped with an outer annular recess on the outside, on the outer annular recess of the body under at an angle of 180 ° relative to each other, two L-shaped grooves are made in the form of long and short sections connected to each other from below, moreover, a funnel is fixed on the bottom of the outer annular sample of the body, and the catcher is equipped with two guide pins, which are screwed into the upper part of the funnel on one side, and on the other hand, are inserted into the L-shaped grooves of the body, while the funnel has the possibility of longitudinal and transverse movement relative to the body within the L-shaped grooves, moreover, the funnel is equipped with radial holes from below, and the funnel is equipped with an internal annular stop on top, limiting the movement of the body downward relative to the funnel, while in the initial position, the pins are in the lower ends of the long sections of the L-shaped grooves, while the funnel relative to the body is fixed with a destructible screw, and in the working position the body has the possibility of limited movement relative to the funnel until it stops against the inner annular stop of the funnel with the movement of the guide pins from the lower ends of the long sections to the extreme right ends of the short sections of the L-shaped grooves and the compression of the collet plates inward from the body under the influence of the force created by the lower end of the body, and the clamping grips of the collet are closed.

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