RU2739882C1 - Multi-stage hydraulic fracturing coupling - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil and gas equipment, in particular, to equipment for completion of wells, and can be used for formation hydraulic fracturing and other operations for well treatment, as well as for selective oil and gas extraction. Coupler for hydraulic fracturing of the formation comprises a body made of interconnected upper and lower branch pipes, inner sleeve with holes, locking ring for fixation of internal bushing in open or closed position, seals for sealing, protected against direct contact with flow. Lower branch pipe has holes matching the holes in the internal bushing allowing flow transition from the internal space to the external one. In the lower branch pipe there is a centring pin. On the internal bushing the profile is cut out, in which the centring pin is installed for protection against rotation of the internal bushing and ensuring of complete matching of holes in the lower branch pipe and in the internal bushing relative to each other. Locking ring is installed inside upper sleeve. Profiles are inserted on inner bushing to receive lock ring.

EFFECT: technical result is improved product reliability in process of reusable opening or closing of coupling due to simplified design and providing insulation of seals against direct contact with flow.

4 cl, 14 dwg

Description

The invention relates to oil and gas equipment, in particular to equipment for well completion. The invention can be used for hydraulic fracturing and other well treatment operations, as well as for the selective production of oil and gas.

Hydraulic fracturing is a way to enhance the production of oil and gas wells and increase the injectivity of injection wells. Hydraulic fracturing is performed to create a highly conductive fracture in the target formation under the action of a fluid pumped under pressure. Hydraulic fracturing technology allows the commissioning of inactive wells, in which production by traditional methods is impossible or unprofitable. The collar is the same size as the casing to which it is attached. The method of completing wells using hydraulic fracturing sleeves includes running sleeves as part of a liner into an open or cemented borehole and further performing high-precision and efficient hydraulic fracturing. A key is used to control the clutches. The method assumes the ability to add new perforation intervals at any desired depth.

Known hydraulic fracturing coupling with soluble saddle RU181716 U1, publ. 26.07.2018. Activation of the sleeve occurs when the ball lands during the hydraulic fracturing process while pumping the fracturing fluid. After the hydraulic fracturing operation, all parts of the sleeve seat dissolve in the wellbore environment.

Known breakaway coupling and positive indication of the opening of the coupling for hydraulic fracturing RU 2611083 C2, publ. 02/21/2017 (prototype). A coupling for hydraulic fracturing, consisting of a body with holes to provide a connection with the formation, made of two elements connected to each other, these holes allow the flow from the internal space to the outside, an inner sleeve with holes, a retaining ring for fixing the inner sleeve in open or closed position, seals for sealing, protected from direct contact with the flow. The disadvantage of the known device is the unreliability and complexity of the design.

The technical result of the invention is the possibility of increasing the reliability of the product in the process of multiple opening or closing of the sleeve, which allows multiple transition from the hydraulic fracturing mode to the one-piece liner mode. Also, the invention provides for ease of manufacture and assembly of the product. By "opening" the collar is meant a position of the collar that provides free access for fluid flow into the formation to create fractures in the formation, by "closing" the collar is meant to stop fluid flow into the formation and completely isolate the interior from the outside.

A coupling for hydraulic fracturing, consisting of a body made of interconnected upper and lower nozzles, an inner sleeve with holes, a retaining ring for fixing the inner sleeve in an open or closed position, sealing seals protected from direct contact with the flow, while the lower the branch pipe is made with holes that coincide with the holes in the inner sleeve, allowing the flow from the inner space to the outer one, moreover, a centering pin is installed in the lower branch pipe, and a profile is cut on the inner sleeve, in which a centering pin is installed to protect the inner sleeve from rotation and ensure complete coincidence of holes in the lower branch pipe and in the inner sleeve relative to each other, while the retaining ring is installed inside the upper pipe, and on the inner sleeve, profiles are cut into which the retaining ring enters.

The upper and lower nozzles of the body are connected by means of a threaded connection, and a set screw is used to protect against unwinding.

The openings of the lower branch pipe and the inner sleeve are designed to minimize the likelihood of sludge getting inside and loss of flow.

The minimization of the probability of sludge getting inside and the loss of the flow rate is ensured by the presence of identical holes in the lower branch pipe and the inner sleeve and making them flat-oval (as follows from Figs. 1, 6, 8). The flat-oval shape of the holes in the lower branch pipe and the inner sleeve reduces the flow loss, and the very fact of the presence of the same holes in the lower branch pipe and the sleeve minimizes the ingress of sludge.

The retaining ring is designed for reusable opening or closing of the sleeve.

The retaining ring is made with the possibility of adjusting to the required force of opening or closing.

The design of the invention is shown in the drawings, where:

FIG. 1 - clutch elements;

FIG. 2 - clutch assembly in longitudinal section;

FIG. 3 - inner sleeve in the closed position;

FIG. 4 - inner sleeve in open position;

FIG. 5 - a retaining ring on an enlarged scale;

FIG. 6 - inner sleeve with profiles for engaging with a key;

FIG. 7 - for an explanation of the principle of operation of the centering pin;

FIG. 8 - to the explanation of the clutch anti-sludge holes;

FIG. 9 - to the explanation of the seal protection mechanism;

FIG. 10 is a diagram of a collar in a well;

FIG. 11 is a diagram of a key located inside the clutch;

FIG. 12 - activation of the key, engagement of the key with the inner sleeve;

FIG. 13 - opening the sleeve, ensuring the connection of the pipe space with the formation;

FIG. 14 - the occurrence of fractures in the well.

FIG. 1-2 shows the construction of the clutch. FIG. 3-9 shows the design features, Fig. FIG. 10-14 - the principle of the clutch.

The coupling includes a body, which consists of two elements: the upper branch pipe 3 and the lower branch pipe 2. Holes 18 in the lower branch pipe 2, which coincide with the holes 17 in the inner sleeve 1. The centering pin 8 is installed in the lower branch pipe 2, profile 11 is located on inner sleeve 1. In the upper branch pipe 3 there is a retaining ring 4, which fixes the inner sleeve 1 in the open or closed position. Also, on the inner sleeve 1, profiles 14, 15 are cut into which the retaining ring enters with a shoulder (protrusion, not marked in Fig.) Located on the inner side of the retaining ring. To seal the system, seals 7 are installed in the upper nozzle 3 and the lower nozzle 2, which are protected by the inner sleeve 1. The upper nozzle is connected to the lower nozzle by means of a threaded connection, and set screws 5 are provided for protection against unwinding. To protect against premature opening of the coupling, Shear screws 6, which coincide with the profile 16 on the inner sleeve 1. With the help of the shear screws 6, the force of the first opening of the coupling is regulated.

FIG. 3 shows the clutch in the closed position. In this position, the flow 21 freely passes through the sleeve, the holes 14 in the inner sleeve 1 do not coincide with the holes 18 in the lower branch pipe 2. The retaining ring 4 with a collar enters the profile 14, which provides protection against premature opening. In this position, the seals 7 are not in direct contact with the flow 21.

FIG. 4 shows the clutch in the open position. In this position, access is opened for flow 21 into the outer space of the coupling. The holes 18 in the lower nozzle 2 completely coincide with the holes 17 in the inner sleeve 1. The centering pin 8 provides protection against rotation of the inner sleeve when moved to the open position, and the holes 17 and 18 are in line. Retaining ring 4 enters profile 15, which provides protection against premature opening. Seals 7 are not in direct contact with flow 21.

The principle of operation of the product (see Fig. 10-14).

The sleeve is run into the well as part of the liner. The collar is connected to the casing between the two packers. When descending, the clutch is in the closed position. The wellbore fluid flow freely passes through the interior without access to the exterior (FIG. 10).

For hydraulic fracturing, packers are first activated to isolate the intervals. Then a key is lowered into the well on coiled tubing (CT). After reaching the required depth, the key is activated by pumping fluid into the CT (Fig. 11). Further, the key rises up. When the key hits the profile 13 on the inner sleeve 1, a change in force is recorded on the surface (Fig. 12). Then, with an increase in the tractive force, the shear screws 5 are cut off, and the inner sleeve 1 moves to the open position. The holes 18 on the lower branch pipe 2 coincide with the holes 17 in the inner sleeve 1, which ensures the connection of the pipe space with the outer one. The wrench is then lifted to the surface or at the next interval to open the next clutch (Fig. 13). Further injection of fluid leads to the creation of fractures in the rock, an increase in injection pressure leads to expansion of the fractures (Fig. 14). After the operation, the injectivity of the well increases.

Claims (4)

1. A coupling for hydraulic fracturing, consisting of a body made of interconnected upper and lower nozzles, an inner sleeve with holes, a retaining ring for fixing the inner sleeve in an open or closed position, seals for sealing, protected from direct contact with the flow, when the lower branch pipe is made with holes that coincide with the holes in the inner sleeve, allowing the flow from the inner space to the outer one, characterized in that a centering pin is installed in the lower branch pipe, and a profile is cut on the inner sleeve, in which a centering pin is installed to protect it from rotation of the inner sleeve and ensuring complete coincidence of the holes in the lower pipe and in the inner sleeve relative to each other, while the retaining ring is installed inside the upper pipe, and profiles are cut on the inner sleeve into which the retaining ring enters. 2. The coupling according to claim 1, characterized in that the upper and lower nozzles of the body are connected by means of a threaded connection, and a set screw is used to protect against unwinding. 3. The coupling according to claim 1, characterized in that the openings of the lower branch pipe and the inner sleeve are made with the possibility of minimizing the likelihood of sludge getting inside and loss of flow. 4. The coupling according to claim. 1, characterized in that the retaining ring is made for multiple opening or closing of the coupling.

Images