RU2318986C1 - Well cleaning method - Google Patents

Abstract

FIELD: oil industry, particularly casing pipe, dibhole and well bottom zone cleaning.

SUBSTANCE: method involves arranging slush pump at well bottom; scraping away precipitations from well wall in several strips as slush pump is lowered in well, wherein the precipitation strips are frangible in in-situ conditions; filtering well fluid over scrapers as slush pump moves downwards with the use of filters; forcedly moving filtered precipitations downwards along with slush pump. The scrapers are arranged at different diameters so that the scrapers are distributed along intermittent rings in several layers. One scraper layer is overlapped with another one. Scrapers having maximal diameters are spring-loaded and have diameters greater than or equal to inner well diameter.

EFFECT: improved well cleaning.

3 dwg

Description

The invention relates to the oil industry and may find application in the cleaning of casing, sump and bottom-hole zone of a well.

A known method of cleaning a well by scraping deposits from the walls of the well when lowering the device down (RF Patent No. 2271439, class ЕВВ 37/00, publ. 2006.03.10).

The known method requires additional measures to remove contaminants from the well.

Closest to the proposed invention in technical essence is a device - a bailer for cleaning a wellbore or formation, having on the body a mechanical scraper or riber for cleaning the perforation interval when passing through the formation (Publication number 2005100538, class E21B 37/00, published. 2006.06.20 - prototype).

When descending into the well, the choke removes asphalt-resin-paraffin and other deposits from the well walls that enter the sump under its own weight. After installing the choke in the well, deposits are sucked into the choke, held inside and removed with the choke when it is lifted from the well.

The known technical solution does not provide high-quality cleaning of the well from deposits.

The proposed invention solves the problem of improving the cleaning of the well from deposits.

The problem is solved in that in a method of cleaning a well, including scraping from the walls of the sediments with scrapers while lowering the bastion, placing the bastion on the bottom, trapping deposits and contaminants in the bail and lifting the billet out of the well, according to the invention, the deposits are scraped from the walls of the well with strips that can break into the borehole conditions, organize complete scraping of deposits due to the placement of scrapers on different diameters in the form of discontinuous rings in tiers with overlapping in terms of scrapers of one tier with scrapers of another tier, scratch maximum diameter ki operate the spring-loaded and is equal to or slightly larger internal diameter of the well, while running bailer filter filters the scrapers above the wellbore fluid and force is lowered down together with the bailer filtered deposition.

The features of the invention are:

1. scraping from the walls of the sediments with scrapers when lowering the choke:

2. placement of the baffle on the bottom;

3. trapping sediments and contaminants in the bellow;

4. lifting of the baffle from the well;

5. scraping deposits from the walls of the well in strips capable of breaking under well conditions;

6. Organization of complete scraping of deposits by placing scrapers on different diameters in the form of intermittent rings in tiers with overlapping planes of one tier with scrapers of another tier;

7. the implementation of the scrapers of maximum diameter spring-loaded and equal to or slightly larger than the internal diameter of the well;

8. filtering when the choke is lowered by the filter above the scraper of the borehole fluid and forced lowering along with the choke of the filtered sediments.

Signs 1-4 are common with the prototype, signs 5-8 are the salient features of the invention.

SUMMARY OF THE INVENTION

To clean the walls of the well from asphalt-resin-paraffin and other deposits, a technical solution is described, according to which, when lowering the baffle from the walls of the well, deposits are scraped off which, under their own weight, are lowered down, trapped by the bailer and removed from the well. In a known technical solution, the used design of the scrapers does not provide high-quality cleaning. In addition, exfoliated deposits can fall for a very long time under their own weight into the sump of the well, not fall at all, or even swim to the wellhead. In this case, the collection of sediments and contaminants by the bailer becomes difficult or even impossible. Deposits in the well can be so large that they virtually overlap the cross section of the well. In this case, the descent of the baffle and scraping of deposits becomes difficult or completely impossible.

The proposed method solves the problem of improving the quality of cleaning wells from deposits, providing cleaning from deposits of virtually any type and quantity. The problem is solved as follows.

On the outer surface of the housing of the flap and the bottom of the flap, scrapers are arranged around the circumference in the form of discontinuous rings with overlapping cutting edges and with a stepwise increase in the diameter of the discontinuous rings. The ring of scrapers of the maximum diameter is spring loaded and equal to or slightly larger than the inner diameter of the well, so that when the spring element is compressed, the scrapers are placed in the well. Scrapers scrape deposits from the walls of the well in strips. Organize the complete scraping of deposits by placing scrapers with overlapping scrapers in the plan. Above the scrapers, a filter is placed on the housing of the chipper. During the descent, the baits filter the well fluid with a filter, capture sediments separated from the walls of the borehole and force it down with the bailer.

After the descent and placement of the baits on the bottom, the baulk is opened, deposits and contaminants are caught in the bailer and the baulk is lifted from the well along with sediments and contaminants.

Figure 1 shows the bailer with scrapers and a filter, figure 2 shows the layout of the scrapers, figure 3 shows the upper row of spring-loaded scrapers.

Scrapers 1-4 are mounted on frames 5-8 and are summarized in sections 9-12. In each section 9-12, scrapers 1-4 are arranged in at least two tiers 13 and 14 in the form of discontinuous rings with overlapping planes of one tier with scrapers of the other tier. Frames from 5 to 8 have an increasing diameter. Section 12 has a frame 8 with the largest diameter, but slightly smaller than the diameter of the well casing 15. The scrapers 4 of the upper section 12 are mounted on springs 16, during compression of which the scrapers 4 are placed in the casing of the well 15. The scrapers 4 have a height greater than the gaps between the pipes casing string of the well 15. Scrapers 1 of section 9 with a frame 5 of minimum diameter are located in front of the choke 17 and shank 18. The remaining scraper 2-4 are located on the shank 18 in front of the choke 17 or on the outer surface of the choke 17. Above section 12 on the outer the surface of the flap 17 is placed a filter 19, overlapping the space of the borehole above the section 12.

A device for cleaning a well works as follows.

During the descent of the baffle 17 with scrapers 1-4 down inside the casing of the well 15, scrapers 1-4 destroy the asphalt-resin-paraffin and other deposits on the walls of the well. Well cleaning is possible if there is a minimum opening in the sediments where the scrapers of the lower section 9 penetrate. Scrapers 1-4 cut deposits in the form of strips that break into segments of different lengths, are held by the filter 19 and are forced to go down to the bottom of the well. The ability to break the strips is ensured by placing the scrapers in tiers, due to the intermittent placement of the scrapers, a small change in the diameter of the frame when moving from one step to another, which determines the number of strips and their thickness. The smaller the thickness of the scraped strips, the easier the strips break. The ability to break in the well provides the ability to not completely clog the filter 19.

The number of sections 9-12 can be more or less than four and depends on the degree of well colmatization. With almost complete clogging, a complete set of sections is required from the minimum to the maximum.

The number of tiers 13 and 14 of the placement of the scrapers in the section is minimum two. However, for cutting smaller strips of sediment, it is possible to use three or more tiers.

The filter 19 is performed with sufficiently large openings or slots capable of freely passing the well fluid and retaining large mechanical particles. The filter 19 may be made of a spring wire in the form of a ruff, a perforated plate with large holes, etc.

After the descent and placement of the baits on the bottom, the baulk is opened, sediments and contaminants are caught in the bailer, and the baulk is lifted from the well along with sediments and contaminants.

The application of the proposed method will allow to improve the cleaning of the well from deposits.

Claims (1)

A method of cleaning a well, including scraping scraps from the walls of the deposits with scrapers while lowering the chutes, placing the chutes on the bottom, trapping sediments and contaminants in the chasers and raising the chutes from the borehole, characterized in that the deposits are scraped from the walls of the borehole with strips that can break under borehole conditions; scraping of deposits due to the placement of scrapers on different diameters in the form of intermittent rings in tiers with overlapping in the plan of scrapers of one tier with scrapers of another tier, scrapers of maximum diameter they are spring loaded and have a diameter equal to or slightly larger than the internal diameter of the well; when lowering the choke, filter the fluid above the scrapers with a filter and forcibly lower the filtered sediments along with the chipper.

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