EA009188B1 - Screen for controlling sand production in a wellbore - Google Patents

Abstract

A wellbore screen (1) is provided for controlling inflow of solid particles into a wellbore (2). The wellbore screen comprises a conduit (3) for transporting fluid, an outer layer (4) comprising a filter for reducing inflow of solid particles into the conduit (3), the outer layer extending around the conduit and being radially expandable against the wellbore wall, and swelling means arranged between the conduit and the outer layer. The swelling means (6) is susceptible of swelling upon contact with a selected fluid so as to radially expand the outer layer against the wellbore wall.

Description

The present invention relates to a well bore screen for controlling the inflow of solids into the wellbore, the well bore screen comprising a conduit for transferring a fluid and an outer layer comprising a filter for filtering solids from a fluid flowing in the conduit. .

The level of technology

Independent sand separation systems, such as liners with slit-like longitudinal holes or wire screens, are commonly used in wells designed to receive fluid streams from a subterranean formation, and in wells intended to inject a fluid stream into the subterranean formation. The produced and / or injected fluid flow can be, for example, oil, gas or water. A common problem with such sand separation systems is related to the axial flow of fluid in the annular gap between the borehole wall and the screen. Solids from the surrounding formation, which flow along with the fluid flow inside the well, are thus transported along the screen and deposited on the screen in the form of a layer with very low permeability. This problem is particularly pronounced in the case when clay particles fall inside the wellbore. As a result of this fluid flow through the annular space, blocking of the screen along its entire length may occur, which may lead to a decrease in the production of hydrocarbon fluid or water from the well. In addition, if the flow of fluid into the screen is reduced to a local portion of the screen that has not (yet) been blocked, excessive screen erosion may occur.

Summary of Invention

The purpose of the present invention is to create an improved well screen that overcomes the above problems.

In accordance with the invention, a wellbore screen is provided for controlling the inflow of solid particles into the wellbore, the wellbore screen comprising a conduit for conveying fluid, an outer layer comprising a filter for reducing the inflow of solids into the pipeline, the outer layer extending around pipeline and can expand in the radial direction to the walls of the wellbore, and a swelling tool located between the pipeline and the outer layer, and the swelling agent swells upon contact with the selected fluid, as a result of which it radially expands the outer layer, pressing it against the wall of the wellbore.

This ensures that after contact of the swelling agent with the selected fluid, the outer layer with the filter included in it shifts to the wall of the wellbore. Solid particles that are locally entering the wellbore cannot be moved in the longitudinal direction along the entire screen, thereby eliminating the risk of blocking the entire filter due to the local influx of solid particles. In addition, the expanded outer layer supports the walls of the wellbore, as a result of which the collapse of sand inside the wellbore is significantly reduced. In addition, the expanded outer layer provides a large inflow area for the screen.

The well may be, for example, a production well designed to produce a hydrocarbon fluid (crude oil or gas) or water. Alternatively, the well may be an injection well designed to inject water, oil, gas, liquid waste or other fluid into the subterranean formation. In any case, the selected fluid, which can lead to swelling of the swelling agent, may be a produced fluid, such as a hydrocarbon fluid or water, and a pressurized fluid, such as a hydrocarbon fluid (for example, crude oil, diesel or gas) or water.

In the case of a production well intended for the production of a hydrocarbon fluid, rapid activation can be achieved by pumping a hydrocarbon fluid, such as diesel fuel, into the well to induce rapid swelling of the swelling agent. After rapid swelling is obtained, such swelling will be maintained as a result of the contact of the swelling agent with the produced hydrocarbon fluid.

It should be understood that in the case of an injection well, a blockage problem may occur during time intervals when fluid injection is stopped and fluid can flow back from the wellbore to the screen.

Preferably, the swelling agent includes a plurality of swelling rings, each ring extending around the pipeline and may swell upon contact with selected fluids, wherein the rings are mutually arranged along the pipe, for example, at regular intervals.

In another arrangement, the swelling means includes a sleeve extending around the conduit, the coupling comprising a plurality of through holes arranged at a certain distance along the sleeve, for example through holes having a substantially rectangular shape or a substantially circular shape.

In a preferred embodiment, the swelling agent includes a material under

- 1 009188 induced swelling upon contact with a hydrocarbon fluid or water.

In the case of swelling when in contact with water, the material, for example, is a rubber selected from ΝΒΚ-based rubber. (nitrile butadiene rubber), ΗΝΒΒ (hydrogenated nitrile rubber), ΧΝΒΚ. (carboxylate butadiene-nitrile rubber), PCM (fluoroelastomer), PPKM (perfluoroelastomer), ΤΡΕ / Ρ (tetrafluoroethylene / polypropylene) or ΕΡΌΜ (rubber based on a copolymer of ethylene, propylene and diene monomer).

In the case of swelling when in contact with a hydrocarbon fluid, the material preferably includes rubber selected from natural rubber, nitrile rubber, hydrogenated nitrile rubber, acrylate-butadiene rubber, polyacrylate rubber, butyl rubber butadiene, sulphurized polyethylene, ethylene-acrylate rubber, copolymer of epichlorohydrin and ethylene oxide, copolymer of ethylene and propylene (cross-linked formed by peroxide), a copolymer of ethylene and propylene (with cross links formed by sulfur), rubber based on a ternary copolymer of ethylene, propylene and a diene, a copolymer of ethylene and vinylacetate, fluororubber, fluorosilicone rubber and silicone rubber.

Preferably said material is selected from ΕΡ (Ό) Μ rubber (ethylene-propylene copolymer or a crosslinked formed by peroxide or sulfur), EPT rubber (rubber of terpolymer of ethylene propylene and diene), butyl rubber, bromobutyl rubber, chlorinated butyl rubber, and chlorinated polyethylene.

Preferably, the outer layer includes an annular filter layer and an annular band extending around the annular filter layer.

Brief Description of the Drawings

The invention will be described in more detail below by example with reference to the accompanying drawings, in which FIG. 1 schematically shows a longitudinal sectional view of an embodiment of a borehole screen according to the invention before swelling the swelling means;

in fig. 2 shows a schematic longitudinal sectional view of the embodiment of FIG. 1 after swelling of the swelling agent;

in fig. 3 schematically shows a view in cross section 3-3 of FIG. one;

in fig. 4 shows a view in cross section 4-4 of FIG. 2

In the figures, the same reference numerals denote the same components.

Information confirming the possibility of carrying out the invention

FIG. 1 and 2 show a screen 1 of a well bore mounted in a bore 2 of a well for the production of a hydrocarbon fluid. The screen 1 comprises a tubular element 3, a permeable annular outer layer 4 extending at some distance along the radius around the tubular element 3, the outer layer 4 being formed of a filter layer 4a and a bandage 4b located outside the filter layer 4a, and a plurality of swellable elements made in the form of rings 6 located between the tubular element 3 and the outer layer 4. The rings 6 are located at regular intervals along the tubular element 3. The upper layer 4 is made flexible and with the possibility of radial expansion, at least e, a spreading factor, whereby the shroud 4b comes into contact with the borehole wall. In addition, the filter layer 4a has a screen opening size adapted to prevent the flow of solid particles into the tubular element 3. The rings 6 are made of elastomer, which swells when in contact with the hydrocarbon fluid, and the elastomer is, for example, rubber. The tubular element 3 has a plurality of perforations 7 intended for the inflow of the produced hydrocarbon fluid inside the tubular element 3, and at its ends corresponding connecting sections 8, 10 are provided for interconnecting the well screen 1 with the pipeline 9 intended for transporting the produced hydrocarbon fluid to the surface.

FIG. 1 shows the screen 1 of the wellbore before swelling of the rings 6 in contact with the produced hydrocarbon fluid so that the outer layer 4 is in an unexpanded state, with the result that there is a gap 11 between the bandage 4b and the wall of the wellbore.

FIG. 2 shows the borehole screen 1 after the swelling of the rings 6 after contact with the hydrocarbon fluid, as a result of which the outer layer 4 was radially expanded by the swelling rings 6 so that the ring band 4b comes into contact with the wall of the wellbore 2.

FIG. 3 shows the wellbore screen 1 and the wellbore 2 in cross section before swelling the rings 6. As can be seen, the filter layer 4a is formed from a plurality of mutually superimposed filter sheets 5. Each filter sheet 5 at one end is connected to one or more rings 6 by means of a corresponding clip 14 and is applied to the adjacent filter sheet 5. The bandage 4b is made in the form of a thin metal coupling, on which a grid of longitudinal slits (not shown) is provided, mutually overlapping in the longitudinal direction, which gives the bandage 4b exceptional flexibility during radial expansion, which provides appropriate protection for the filter layer 4a.

FIG. 4 shows a screen 1 of a well bore and a bore 2 of a well in cross section after a nab

- 009188 rings 6. The outer layer 4 was expanded to the borehole wall, as a result of which, during the expansion of the filter layer 4a, adjacent filter sheets 5 slid relative to each other and during the expansion of the band 4b, the bandages of the band 4b were expanded.

To simplify the drawings, not all rings 6 and perforations 7 are indicated by reference numerals.

During normal use, the borehole screen 1 is immersed in the wellbore 2 and installed in the zone carrying the hydrocarbon fluid in the surrounding formation, with the result that the rings 6 are in the corresponding non-swollen state and a gap 11 is present between the outer layer 4 and the wall of the well 2 (Fig. 1). When production begins in well 2, the flow of crude oil flows from the surrounding formation into the interior of well 2 and from there through the outer layer 4 and the perforation 7 to the tubular element 3. In this case, the flow of hydrocarbon fluid flows along the rings 6, which as a result swell out of their non-expanded state (Fig. 1) to the expanded state (Fig. 2). After swelling, the rings 6 are pushed out radially outwards towards the outer layer 4, which as a result expands towards the wall of the bore 2 of the well. Since the swelling force applied by a set of rings is distributed along the length of the outer layer 4, the outer layer 4 after its expansion will essentially correspond to large irregularities in the wall of the borehole. The opening size of the sieve in the filter layer 4a does not change as a result of radial expansion, since during the expansion of the filter layer 4a, the individual filter sheets 5 slide relative to each other, resulting in a decrease in the degree of overlap of the adjacent filter sheets 5. At the same time, some degree of overlap of adjacent filter sheets 5 remains, which ensures the absence of open spots that could pass the fluid past the filter layer 4a.

If required, accelerated swelling of the rings 6 may be provided as a result of pumping diesel fuel or any other suitable fluid into the well 2 prior to the start of the well.

This prevents the flow of hydrocarbon fluid in the axial direction along the outer side of the outer layer 4, as a result of which sand and clay particles that can locally enter the hydrocarbon fluid flow do not flow in the longitudinal direction along the entire outer layer 4. As a result, an important an advantage due to the fact that such a stream of particles along the entire outer layer 4 could otherwise lead to blockage of the entire layer 4b of the filter, in particular in the case when clay particles fall into the barrel Azhinov.

Additional benefits of the borehole screen are associated with the use of a pre-drilled solid tubular element that has high fracture resistance, with an annular space between the tubular element and the outer layer that provides good flow characteristics for the produced fluid, and the expansion mechanism eliminates the need for mechanical expansion of the tubular an item.

Instead of making all the rings of elastomer that swells when in contact with the hydrocarbon fluid, one or more rings can be made of a material that swells when in contact with water produced from the subterranean formation. For example, the rings may include a first set of rings susceptible to swelling upon contact with a hydrocarbon fluid and the second set of rings may be susceptible to swelling in water, with the result that the rings from the first and second set are arranged in rotation.

In addition, instead of connecting each sheet of the filter at one end to one or all of the rings, any other relevant filter section can be connected to the rings. In addition, the filter sheets can be held in place by a bandage, thus eliminating the need to connect the filter sheets with some or all of the rings.

Alternatively, instead of a bandage with overlapping longitudinal slits, you can use any other suitable bandage, such as a folding bandage, on which hinges are provided to allow the bandage to unfold, or a bandage formed from a plurality of interconnected small tubes, with individual tubes being flattened when the bandage expands.

Claims (10)

CLAIM 1. A borehole screen designed to control the inflow of solid particles into the borehole, which contains a pipeline for transporting fluid, an outer layer covering the pipeline and containing a filter designed to reduce the inflow of solid particles into the pipeline and made with the possibility of radial expansion to the wall of the wellbore, and means capable of swelling upon contact with the selected fluid, located between the pipeline and the outer layer. 2. The screen according to claim 1, in which the means capable of swelling, made in the form of a set of rings placed at intervals between each other along the pipeline. 3. The screen according to claim 2, in which the rings are located at regular intervals. - 3 009188 4. The screen according to claim 1, in which the means capable of swelling, made in the form of a coupling with many through holes located at intervals along the coupling. 5. The screen according to claim 4, in which each through hole has an essentially rectangular shape or a substantially circular shape. 6. The screen according to any one of claims 1 to 5, in which the said means is made of a material capable of swelling upon contact with a hydrocarbon fluid or water. 7. The screen according to claim 6, wherein said material is capable of swelling upon contact with water and is a rubber selected from nitrile butadiene rubber, hydrogenated nitrile butadiene rubber, carboxylate nitrile butadiene rubber, fluoroelastomer, tetrafluoroethylene / polypropylene, rubber-based copolymer of ethylene, propylene and diene monomer, chloroprene rubber, chlorosulfurized polyethylene, chloropolyethylene and polyurethane rubber. 8. The screen according to claim 6, wherein said material is capable of swelling upon contact with a hydrocarbon fluid medium and is a rubber selected from natural rubber, acrylate butadiene rubber, butyl rubber, bromobutyl rubber, chlorobutyl rubber, chloropolyethylene, chloroprene rubber, couch rubber, chloroprene rubber, chloroprene rubber, chloroprene rubber, chloroprene rubber, chloroprene rubber, chlorobutyl rubber, chloropolyethylene, chloroprene rubber, chloroprene rubber. butadiene, sulphurized polyethylene, ethylene-acrylate rubber, copolymer of epichlorohydrin and ethylene oxide, ternary copolymer of epichlorohydrin and ethylene oxide, copolymer of ethylene and propylene with transverse yazyami formed by peroxide-based rubber terpolymer of ethylene, propylene and diene, and silicone rubber. 9. The screen of claim 8, wherein said material is selected from a copolymer of ethylene and propylene with cross-links formed by rubber peroxide based on a ternary copolymer of ethylene, propylene and diene, butyl rubber, bromobutyl rubber, chlorobutyl rubber and chloropolyethylene. 10. The screen according to any one of claims 1 to 9, in which the outer layer consists of a layer of an annular filter and an annular band placed on it.