RU2761803C1 - Tool for removing cement - Google Patents

Abstract

FIELD: petroleum industry.

SUBSTANCE: invention relates to the petroleum and gas industry and can be used for performing technological works in an underwater borehole. The tool for removing cement from the intertube space of an underwater column head system comprises a housing in the form of a rotating body with a central hole, inserted whereto is a core with a central hole and holes in the core wall for supplying flushing liquid. The housing is made in the form of a core drill, the housing has holes configured to communicate the flushing liquid from the holes in the core wall to the cleaned processing area. Grooves are made at the end of the cylindrical part of the body placed in the intertube space. A ring is installed on the housing, with protrusions arranged along the circumference and protruding above the outer surface of the housing so as to be able to centre the tool when lowering into the intertube space and prevent damage to the matching surface in the intertube space. A possible is provided of removing the flushing liquid and sludge from the cleaning area through the space between the protrusions.

EFFECT: ensured cleaning of the intertube space, reliable subsequent sealing thereof, prevented damage to the surfaces of underwater column heads during cleaning of the intertube space.

6 cl, 6 dwg

Description

Technology area

The invention relates to the oil and gas industry and can be used in the design of a tool used in carrying out technological and routine maintenance during the installation of subsea column heads during the arrangement of an oil and gas well.

Prior art

From the existing prior art, a device for cleaning the inner surface of pipes is known (RF patent No. 2074312, publ. 02.27.1997), containing a housing mounted on a shaft with the possibility of axial movement and receiving a torque with channels directed to the periphery, elastic rod-shaped scrapers passed through the channels housing, and a unit for fixing elastic rod-shaped scrapers, equipped with an adjustable nut.

A known method of cleaning a cement plug from a wellbore lining (US patent 5282509 A, publ. 02/01/1994), in which the cement plug is drilled with a drill bit with retractable cutting elements.

A common disadvantage of the above technical solutions is that they are not suitable for cleaning the annular space, which is intended for installing the annular seal, and do not exclude damage to the surfaces of the annular space during cleaning.

The essence of the invention

The problem solved by the present invention is the problem of the complexity of cleaning the annular space of a system of subsea casing heads intended for installing an annular seal from various rocks and cement influx formed during cementing of the wellbore.

The technical results are the creation of a tool design suitable for cleaning the annular space of the system of underwater casing heads for installing the annular seal and reliable subsequent sealing of the annular space, avoiding damage to the surfaces of the system of underwater casing heads when cleaning the annular space.

The technical results are achieved by the fact that the tool is made in the form of a core drill with holes for supplying the washing solution, and on the sides of the body there is a ring having T-shaped protrusions, between which there are slots for removing sludge during washing, plates are installed inside the crown, which serve for limiting the tool travel when the plates rest against the chamfer on the casing string bodies.

Brief Description of Drawings

The following is a possible, but not the only, embodiment of a cement removal tool.

The essence of the invention is illustrated by drawings.

FIG. 1 shows a general view of a cement removal tool.

FIG. 2 shows a main view of the cement removal tool.

FIG. 3 shows a top view of a cement removal tool.

FIG. 4 shows a ring.

FIG. 5 shows a tool for removing cement during a cleaning operation.

FIG. 6 shows a tool for removing cement according to US patent 5282509 A (publ. 01.02.1994).

Detailed description of the invention

The tool is included in the subsea casing head system installation toolkit and is designed to flush, clean and remove cement in the annulus, for example, the space between the casing head casing and the casing hanger casing, to enable the installation of a metallic or non-metallic annular seal. seal.

FIG. 1 shows a general view of a cement removal tool.

The tool consists of:

1 - plug;

2 - core;

3, 4, 6, 14, 15 16, 19 - holes;

5 - plate;

7 - ring;

8 - case;

9 - nut;

10 - central hole;

11 - bolts;

12 - clamp;

13, 21, 23, 25, 28, 35 - T-shaped protrusions;

17 - V-shaped grooves;

18, 20, 22, 24, 26, 27 - grooves.

On the core 2, with the help of a nut 9, a body 8 is attached, which has V-shaped grooves 17 at the end.

The core 2 has an external tapered thread at one end, and an internal tapered thread at the other. A plug 1 is attached to the outer tapered thread of the core 2. The end with the inner tapered thread serves to attach the drill string 32. The body 8 is mounted on the core 2. The body 8 is a body of revolution with a central hole, having a U-shape in section. The ring 7 is made of a soft material, for example, from fluoroplastic or caprolon, and serves to exclude the possibility of damage to the inner surface of the mating part when the tool rotates.

The ring 7 is put on the body 8, is fastened by pressing 12 to the body 8 using bolts 11 and has T-shaped protrusions 13, 21, 23, 25, 28, 35, which protrude somewhat above the outer surface of the body 8. The core 2 has a central hole 10 for supplying rinsing solution. Through the central hole 10, closed at one end by the plug 1, the flushing liquid enters the holes 3, 4, 6, 14, 16, 19 and further into the cleaned area of the annular space, removing through the rock and cement (sludge), while the flushing liquid passes through grooves 18, 20, 22, 24, 26, 27. Plate 5 serves to limit the axial movement of the tool when it rests on the chamfer 30 on the suspension of casing strings 34.

FIG. 2 shows a main view of the cement removal tool.

On the outer surface, a ring 7 is attached, the upper part is attached by means of a clamp 12 with bolts 11 to the body 8. Slots 18, 20, 22, 24, 26, 27 are designed to remove flushing liquid and sludge from the cleaning zone.

FIG. 3 shows a top view of a cement removal tool.

T-shaped protrusions 13, 21, 23, 25, 28, 35 are located around the circumference. T-shaped protrusions 13, 21, 23, 25, 28, 35 serve to center the tool when running into the annular space and prevent damage to the surface, which ensures reliable sealing of the space when installing the annular seal. Slots 18, 20, 22, 24, 26, 27 serve to remove flushing fluid and sludge from the cleaning zone.

FIG. 4 shows a ring.

The ring 7 with T-shaped projections 13, 21, 23, 25, 28, 35 has the shape of a crown, and the vertical elements of the T-shaped projections form the teeth of the crown. The ring 7 is installed on the housing 8 so that the teeth, which are protrusions 13, 21, 23, 25, 28, 35, are directed downward.

FIG. 5 shows a tool for removing cement during a cleaning operation.

The image shows the moment when the tool has lowered to the stop with the plate 15 into the chamfer 30 on the suspension of the casing strings 34. The cylindrical part of the body 8 is located in the annular space.

To perform its function, the tool is attached to the drill string 32 and lowered to the surface of the conductor string 31 with the suspension of the casing strings 34 installed in it. When approaching the conductor string 31, the speed of lowering the tool decreases. In this case, the tool begins to slowly rotate and the supply of drilling fluid begins through the central hole 10, then the rotation of the tool is turned on and translational movement begins along the axis of the tube until the plate 5 stops in the chamfer 30 of the casing strings 34. The drilling fluid through the central hole 33 on the drill string 32, the central hole 10 in the core 2 and holes 3, 4, 6, 14, 16, 19 enter the annular space in the processing zone. Due to the pressure of the drill string 32, the rotation of the cement removal tool, the presence of V-shaped grooves 17 at the end of the housing 8 and the supply of the drilling solution under pressure to the treatment zone, the cement plugs are destroyed in the annular space. Flushing is carried out until the purity of the flushing fluid is achieved, the absence of cement crumbs and until the stop of plate 5 against the casing body. After the flushing is completed, rotation stops and the tool rises to the surface and the trace on the plate 5 is monitored.

FIG. 6 shows a tool for removing cement according to US patent 5282509 A (publ. 01.02.1994).

When the cement plug 35 is formed, the drill bit 37, at the end of which the leading cutting surface 36 is located, including the retractable cutting elements 40 above the leading cutting surface 36, is attached to the drill string 32 and lowered to the stop against the cement plug 35, after which cement removal begins. Retractable cutting elements 40 are initially positioned by fluid pressure, mechanical action, or other device in an extended position, where they contact the outer ring of cement, not removed by the bottom of the bit 37. These cutting elements, in addition to cutting cement, have a scraping or cleaning effect on the inner surface of the casing columns 38.

The design of the US5282509A tool allows for the removal of cement build-up in pipes, but is not adapted to remove cement in a narrow annular space.

Unlike the technical solution presented in the patent US 5282509 A (publ. 02/01/1994) in the claimed technical solution, the design of the tool is made in the form of a core drill, i.e. specially adapted for cleaning a narrow annular space, has a body with holes for supplying flushing fluid directly to the treatment zone, a ring with T-shaped protrusions is put on the body to protect the mating part of the pipe string from damage, while the thickness of the body depends on the size of the annular space and size annular seal, the body has V-grooves at the end.

Claims (6)

1. A tool for removing cement from the annular space of a system of underwater casing heads, comprising a body in the form of a body of revolution with a central hole, into which a core is inserted, having a central hole and holes in the core wall for supplying flushing fluid, characterized in that the body is made in the form core drill, the body has holes made with the possibility of communicating the flushing liquid from the holes in the core wall to the cleaning zone to be cleaned, grooves are made at the end of the cylindrical part of the body, located in the annular space, a ring is installed on the body with protrusions located along the circumference and protruding above the outer surface of the housing with the possibility of centering the tool when lowering into the annular space and preventing damage to the mating surface in the annular space, and it is possible to remove the flushing liquid and sludge from the cleaning zone through the space between the protrusions. 2. Tool according to claim 1, characterized in that the grooves are V-shaped. 3. Tool according to claim 1, characterized in that the projections on the ring are T-shaped. 4. Tool according to claim 3, characterized in that the ring is made of fluoroplastic. 5. Tool according to claim 3, characterized in that the ring is made of caprolon. 6. The tool according to claim 3, characterized in that the ring is made in the form of a crown, where the teeth of the crown are vertical elements of the T-shaped protrusions.

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