RU2213848C2 - Device for sand bridge removal from well - Google Patents

Abstract

FIELD: well operation and servicing. SUBSTANCE: device has breaking mechanism consisting of hollow cylindrical body accommodating coaxially installed movable shaft whose upper part is made in form of turbine. Breaking mechanism upper part is rigidly connected with hollow rod spring-loaded with return spring and ensuring its mobility in axial direction. Breaking mechanism lower part has crown rigidly connected to cylindrical body. Crown is made in form of sleeve. Sleeve upper part is hollow. Sleeve lower part has vertical water holes symmetrical to axis and mutually perpendicular plates rigidly secured to sleeve lower side surface. End lower surface of said plates is reinforced with hard-alloy cutters and is trapezoidal in shape. Mounted on movable shaft are upper disk and lower disk with circulating channels. Disks are mounted on journals of movable shaft. Rigidly fitted on movable shaft is cam. Sleeve lower part has end teeth and radial channels communicating device internal cavity with annulus. Circulating channels of disks are located symmetrically relative to device axis. EFFECT: higher efficiency of breakage of sand bridge. 2 dwg

Description

 The invention relates to the operation and repair of wells and can be used to clean wells from sand plugs and sludge.

Analysis of the existing level showed the following:
- a device is known for cleaning the bottom of wells, including from sand plugs and sludge, containing a fracture mechanism consisting of an internal nozzle, a sleeve acting as a hydraulic nozzle, a cutter and a sleeve (external nozzle) concentrically mounted and movable relative to the fracture mechanism (see AS 973799 dated 05.25.81 according to class E 21 B 43/00, published in OB 42.1982)
A disadvantage of the known device is the low efficiency of cleaning the well from sand plugs.

This is due to several reasons:
- the movement of the outer pipe downward under the action of gravity under water-sand pulp is difficult, which leads to jamming of the device;
- the inner and outer nozzles are in constant contact with the sand, which can also lead to the possibility of jamming.

 As a prototype, a device was taken to clean a well from a sand plug, containing a fracture mechanism, consisting of a hollow body, a movable shaft (cup) coaxially mounted in it with a turbine and a sleeve, concentrically mounted and spring-loaded relative to the fracture mechanism (see a.s. 829877 from 05/31/79, class E 21 B 37 / 00,21 / 00, published in BI 18, 1981).

 The disadvantage of this device is the inefficiency of the destruction of the sand cork.

This is due to several reasons:
- the immobility of the fracture mechanism in the axial direction does not allow mechanical impact on the sand cork;
- the coincidence of the lower end surfaces of the fracture mechanism and the sleeve leads to clogging of their vertical channels and, as a consequence, jamming of the fracture mechanism;
- the absence of radial channels in the sleeve makes it difficult to circulate the flushing fluid;
- the absence in the design of the mechanism of destruction of the crown, reinforced with carbide cutters, and the front teeth on the lower surface of the liner, that is, using only shock pulses of liquid to destroy the sand plug does not provide mechanical destruction of strong sections of rocks.

 The technical result that can be obtained by implementing the present invention provides an increase in the efficiency of destruction of a sand cork due to the special design of the fracture mechanism, providing hydromechanical effects on the rock of various strengths and eliminating jamming of the tool.

 The technical result is achieved using a known device containing a fracture mechanism, consisting of a hollow body, a coaxially mounted movable shaft with a turbine and a sleeve concentrically mounted and spring-loaded relative to the fracture mechanism, which further comprises a spring-loaded hollow rod rigidly connected to the fracture mechanism in the upper parts and ensuring its mobility in the axial direction, and the destruction mechanism further comprises a crown rigidly connected to the housing in the lower parts made in the form of a sleeve with vertical washing channels and mutually perpendicular plates rigidly fixed on its lower side surface, the lower end surface of the plates reinforced with carbide cutters and has a trapezoidal shape, as well as the upper and lower disks mounted on the axles of the movable shaft, with symmetrical circulation channels located relative to the axis of the device and a cam rigidly mounted on the movable shaft, and the sleeve further comprises a mechanical tooth in the lower part and radial channels.

 The analysis of the inventive step showed the following: from the sources of patent documentation and scientific and technical literature, we did not identify technical solutions that are based on features that coincide with all the distinguishing features of the claimed technical solution, namely, the structural features of the fracture mechanism and its fastening. Thus, the achieved technical result is due to the unknown properties of the parts of the device in question and the relationships between them. The invention does not explicitly follow from the prior art, that is, it meets the condition of an inventive step.

The design of the claimed device is illustrated by the following drawings:
figure 1 shows the design of the device in longitudinal section;
figure 2 presents a horizontal section in the plane aa.

 The inventive device comprises a fracture mechanism, consisting of a hollow cylindrical body 1, in the inner part of which a movable shaft 2 is coaxially placed, made in the upper part in the form of a turbine. The destruction mechanism in the upper part is rigidly connected to the hollow rod 3, spring-loaded return spring 4, providing mobility of the destruction mechanism in the axial direction. In the lower part, the destruction mechanism contains a crown rigidly connected to the hollow body 1. The crown is made in the form of a sleeve 5, the upper part of which is hollow, and vertical washing channels 6 are made in the lower inner part, symmetrically located relative to the axis of the device. Mutually perpendicular plates 7 are rigidly fixed on the lower side surface of the sleeve 5, the lower end surface of which is reinforced with carbide cutters 8 and has a trapezoidal shape. On the pins of the movable shaft 2, an upper disk 9 and a lower disk 10 are installed with circulation channels 11 and 12 symmetrically located relative to the axis of the device, respectively. On the lower surface of the upper disk 9 and the upper surface of the lower disk 10, grooves 13 and 14 are made coaxially with the bushings 15 and 16 pressed into them, which are sliding bearings for the movable shaft 2. Above the lower disk 10, the cam 17 is rigidly mounted. Mechanism the destruction concentrically mounted in the sleeve. The sleeve consists of a hollow cylinder 18, rigidly connected to the nipple 19 and the sleeve 20. In the lower part of the sleeve there are made end teeth 21 and radial channels 22 connecting the internal cavity of the device with the annulus. The lower inner surface of the sleeve has an annular protrusion 23. The upper part of the coupling 20 is rigidly connected with the hollow stem 24 having a sealing ring 25 in the upper part. A spring 26 is installed on the hollow stem 24, closed by a casing 27. The lower part of the spring 26 abuts the coupling 20, providing the mobility of the sleeve relative to the fracture mechanism, and the upper one presses the hollow cylinder 28, into the upper part of which a sub 29 is screwed to connect the device to the general layout of the tool.

The device has the following dimensions:
outer diameter mm - 56
length, mm - 860
weight, kg ~ 7.5
The quality of the blanks used to manufacture the parts of the device should correspond to:
- chemical composition standards for carbon steel, high-quality, structural according to GOST 1050-88, alloyed structural steel for GOST 4543-71;
- for winding a spring wire made of spring steel GOST 9389-78;
- the design and dimensions of the sealing rings GOST 9833-73, and the quality - GOST 18829-73.

 The roughness of metal parts must comply with GOST 2789-73 and the technical requirements of the drawings.

 Metric threads should be made in accordance with GOST 8724-81 with a profile in accordance with GOST 9150-81, the main parameters in accordance with GOST 24705-87 and tolerances in accordance with GOST 16093-81.

Device operation
The principle of operation of the device for cleaning sand plugs is based on the use of the action of water hammer. The device is lowered into the well using small diameter flexible or tubing pipes to the depth of sand plug formation (the well medium is a water-based drilling fluid, oil, gas, gas condensate, foam systems). Under the influence of the weight of the layout of the tool, the spring 26 is compressed, transmitting force to the sleeve, while the end teeth 21 abut against the sand cork. Flushing fluid is pumped through the internal cavity of the device with a flow rate of up to 0.005 m ³ / s and a pressure drop of up to 25 MPa. The flushing fluid flows through the circulation channels 11 of the upper disk 9 to the turbine of the movable shaft 2 and rotates it together with the cam 17. When the cam 17 is rotated, the circulation channels 12 of the lower disk 10 periodically overlap, resulting in spasmodic pressure drops and water hammering. Under the influence of hydraulic shocks, the fracture mechanism, spring-loaded with a return spring 4, makes reciprocating movements, while a crown reinforced with carbide cutters 8 acts on a sand cork. At the same time, a hydro-jet effect occurs on the sand plug due to the passage of fluid through the flushing channels 6 of the crown. The impact force of the cutters 8 on the sand plug depends on the pressure of the flushing fluid and can reach 2000-4000 N. The cycle of impacts of the crown is repeated with the rotational speed of the movable shaft 2. Simultaneously, under the influence of the spring 26 and impacts of the crown on the sand plug, the shell vibrates as a result, the end teeth 21 also act on the sand cork. In the process of destruction of a sand cork or a section of rock, washing and removal of sludge to the surface through radial channels 22 of the sleeve is carried out.

 Thus, the use of the invention allows highly efficient cleaning of wells of sand plugs and sludge, since the design of the device with a slight pressure drop provides an intensive hydromechanical effect on rocks of various strengths and eliminates jamming of the tool.

Claims (1)

 A device for cleaning a well from a sand plug, comprising a fracture mechanism consisting of a hollow body, a movable shaft coaxially mounted in it with a turbine and a sleeve, concentrically mounted and spring-loaded relative to the fracture mechanism, characterized in that it further comprises a spring-loaded hollow rod rigidly connected to the destruction mechanism in the upper part and ensuring its mobility in the axial direction, and the destruction mechanism further comprises a crown, rigidly connected to the body in the lower parts made in the form of a sleeve with vertical washing channels and mutually perpendicular plates rigidly fixed on its lower side surface, the lower end surface of the plates reinforced with carbide cutters and has a trapezoidal shape, as well as the upper and lower disks mounted on the axles of the movable shaft, with symmetrical circulation channels located relative to the axis of the device, and a cam rigidly mounted on the movable shaft, and the sleeve further comprises a mechanical tooth in the lower part me and radial channels.

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