RU2424421C1 - Device for cleaning internal surface of casing - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: device consists of case with connecting threads, central channel and retractable cutting elements. On external surface the case is equipped with upper and lower stops. Cylinder axles are installed between the stops symmetrically relative to axis of the case. Cutting elements are made in form of loads with cutters on external surface. The cutting elements have holes for corresponding cylinder axles; the loads are spring loaded to inside and rotate; their rotation under centrifugal force is restricted with the regulated stop. The upper and lower stops are equipped with through washing holes. ^ EFFECT: expanded process functionality and increased service life of device. ^ 2 cl, 3 dwg

Description

The invention relates to the oil industry, and in particular to means and equipment for cleaning well columns from cement crust and asphaltene-paraffin deposits.

It is known "Device for cleaning wells from paraffin-asphaltene deposits" (copyright certificate No. 1652516, IPC 8 ЕВВ 37/02 of 03/11/1988), including a housing with windows in which there are cleaning elements, a pusher interacting with them, made in the form of a wedge , and the position lock of the treatment elements.

The disadvantage of this device is that the treatment elements are always in an extended position, which complicates the descent of the device into the well.

It is also known "Device for cleaning the walls of the borehole" (copyright certificate SU No. 1186788, IPC 8 ЕВВ 37/02, 1985), including a casing with an internal passage channel concentric to it and an annular cavity hydraulically connected to the specified channel, the casing provided with radial holes and an elastic shell placed in the annular cavity with cutting elements included in these holes. When pressure and torque are applied, the cutting elements extend and process the walls of the well.

The disadvantage of this device is the low productivity of the device due to the fact that the pistons on which the cutting elements are placed are small in size, and therefore they cannot develop large efforts to press the cutting elements to the casing, as a result of which hard deposits must be passed several times, which reduces productivity devices in general.

The closest in technical essence is the "Device for cleaning the inner surface of the casing pipe" (patent RU No. 2099507, IPC 8 ЕВВ 37/02 of 12.20.1997), including a housing with a central channel and retractable cutting elements associated with the possibility of being installed in the housing axial movement by a spring-loaded piston, characterized in that it is provided with a wedge configured to interact with the piston, the working surface of the wedge provided with grooves, reciprocal protrusions of the cutting elements, and the angle at its apex is exceeded t wedge angle of friction between the working surfaces and materials cutting elements, wherein the working surface of the cutting element is designed as a multi-start cylindrical thread.

The disadvantages of this device are:

- firstly, a fixed overhang of the incisors increases the likelihood of damage to the inner surface of the casing during its cleaning or insufficient cleaning of the inner walls;

- secondly, insufficient fluid flow during the cleaning of the inner surface of the casing through the cutting tools, which leads to their rapid wear;

- thirdly, the large weight of the device leads to premature failure of the shaft bearings of the downhole screw motor located above the device.

The objective of the invention is the possibility of a controlled departure of the cutters depending on the inner diameter of the cleaned casing, as well as the creation of the optimal fluid flow through the cutting cutters during operation of the device and weight reduction of the device.

The closest in technical essence is a device for cleaning the inner surface of the casing, including a housing with connecting threads, a Central channel and retractable cutting elements.

What is new is that the casing is provided with an upper and lower stop on the outer surface, between which cylindrical axes are mounted symmetrically with respect to the casing axis, and the cutting elements are made in the form of weights with cutters located on the outer surface and holes for the corresponding cylindrical axes on which the loads are installed spring-loaded inward with the possibility of rotation limited by an adjustable stop under the action of centrifugal force, while the upper and lower stops are equipped with through flushing holes rstii.

Also new is that at least one of the stops is removable, and the number of cutting elements is at least two, while the number of through flushing holes on each of the stops is also at least two.

A study of patent and scientific and technical literature showed that such a combination of essential features is new and has not been used before, this, in turn, allows us to conclude that the technical solution meets the criterion of "novelty."

The figure 1 shows a longitudinal section along the axis of the proposed device.

The figure 2 shows a view And the proposed device.

The figure 3 shows the layout of the equipment during the drilling of the cement bridge in the casing, which includes the proposed device.

A device for cleaning the inner surface of the casing pipe includes a housing 1 (see FIGS. 1 and 2) with connecting threads 2 and 3, respectively, from above and below, a central channel 4 and retractable cutting elements 5 and 5 '.

The housing 1 is provided on the outer surface with an upper 6 and a lower 7 stops, between which the cylindrical axes 8 and 8 'are installed symmetrically with respect to the axis of the housing 1, and the cutting elements 5 and 5' are made in the form of weights 9 and 9 'with cutters 10 and 10', located on the outer surface.

The distances B from the ends of the cutting elements 5 and 5 'and, respectively, to the ends of the upper 6 and lower 7 stops are symmetrical and are selected empirically.

Also, the cutting elements 5 are equipped with holes 11 and 11 'under the corresponding cylindrical axes 8 and 8', on which the loads 9 and 9 'are mounted spring-loaded by means of springs 12 and 12' and stoppers 13 and 13 'inward with the possibility of rotation limited by adjustable stops 14 and 14 ', made in the form of pairs of screws 15 and 15' - nuts 16 and 16 'under the action of centrifugal force. The nuts 16 and 16 'are fixed rigidly to one of the stops 6 or 7, for example, to the upper stop 6. The screws 15 and 15' are screwed into the nuts 16 and 16 ', respectively, based on the maximum outgoing cutters 10 and 10', which should correspond to the inner diameter of the column cleaned casing, taking into account the exclusion of damage to the latter.

The upper 6 and lower 7 stops of the housing 1 are provided with through flushing holes 17 and 17 '.

At least one of the stops 6 or 7 is removable in order to be able to assemble (disassemble) the device.

The number of cutting elements 5 and 5 'is not less than two.

The number of through flushing holes 17 and 17 'on each of the stops 6 and 7 is not less than two.

The device operates as follows.

Before lowering into the borehole on the bridges, the device 18, intended for cleaning the inner surface of the casing 19 (see Figs. 1 and 3), is installed in the arrangement between the downhole screw motor (VZD) 20 and connected to the connecting thread 2 of the housing 1 (see Fig. .2) and a chisel 21 (see Fig. 3) using the connecting thread 3 of the housing 1 (see Fig. 2), after which the entire assembly is lowered into the well to drill a cement bridge 22 (see Fig. 3).

During drilling, the bit 21 rotates with a frequency within certain limits, for example, from 100-200 rpm, while the cutting elements 5 (see figure 1) are in the initial position, because springs 12 and 12 'overcome the centrifugal forces acting on the cutters 10 and 10', i.e. in the process of drilling cement bridge 22 (see figures 1 and 3) they do not work and do not create a load on the shaft of the VZD 20.

To clean the inner surface of the casing pipe 19 of the remnants of cement cake 23 (cement cake, resin, etc.), the axial feed to the bit 21 is stopped, the VZD 20 starts idling at a frequency of 250-400 rpm, at these speeds the centrifugal force acting on the cutters 10 and 10 ', increases several times, overcomes the force of the springs 12 and 12', the cutting elements 5 and 5 'extend outward, while the cutters 10 and 10' are pressed against the inner surface of the pipe (see figure 3) and remove cement peel 23 from the inner surface of the casing 19, wherein the narrower the radius of extension of the cutters 10 and 10 '(see figure 1), the greater the centrifugal force acting on them.

Adjustable stops 14 and 14 ', made in the form of a pair of screws 15 and 15' - nuts 16 and 16 ', hold the cutters 10 and 10' in a certain radius by touching the ends of the nuts 16 and 16 'with the end face of the loads 9 and 9', which eliminates excessive pressure on the inner walls of the casing 19 and the possibility of damage to the body of the casing 19 during prolonged cleaning in one interval. Rotating, the cutters 10 and 10 'begin to clean the inner walls of the casing 19 (see figure 3), while the bit 21 does not work, and rotates in the mode of development, that is, the VZD 20 does not experience additional load from the work of the bit 20.

The proposed device allows you to adjust the outset of the cutters depending on the inner diameter of the casing being cleaned and to exclude possible damage to the casing pipes, while the presence of flushing holes made in the upper and lower stops, allows you to create the optimal fluid flow through the cutting tools during operation and thereby extend tool life. Reducing the weight of the device with the possibility of rotation of the bit in the mode of working out the VZD, when the VZD shaft does not experience additional load from the work of the bit, allows you to remove a significant part of the load from it and, accordingly, extend the time of the VZD failure-free operation.

Claims (2)

1. A device for cleaning the inner surface of the casing pipe, comprising a housing with connecting threads, a central channel and retractable cutting elements, characterized in that the housing is equipped with upper and lower stops on the outer surface, between which cylindrical axes are mounted symmetrically with respect to the housing axis, and the cutting elements made in the form of goods with cutters located on the outer surface, and holes for the corresponding cylindrical axis, on which the goods are installed spring-loaded inward with the possibility of rotation limited by an adjustable stop, under the action of centrifugal force, while the upper and lower stops are provided with through flushing holes. 2. The device for cleaning the inner surface of the casing according to claim 1, characterized in that at least one of the stops is removable, and the number of cutting elements is not less than two, while the number of through flushing holes on each of the stops is also not less than two.

Images