RU2559973C1 - Well expandable screen - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device comprises a support tube, swelling elastomeric shell surrounding it with open longitudinal slots distributed evenly in circumference with cases of screening rack brushes deepened into the above slots with radially oriented bundles of bristles. Brush cases are completed along the whole length with longitudinal flanged edges overlapping cylindrical surface of the elastomeric shell.

EFFECT: simplified structure of the screen and well development by it, increased lifetime of submersible pump due to pumping of formation fluid treated from rock particles.

2 cl, 6 dwg

Description

The invention relates to equipment for well completion, namely to expanding well filters (SRF) installed in the perforation interval of the production string (EC) to reduce the removal of rock particles from the bottomhole formation zone together with the produced fluid.

Known SRF, consisting of a perforated body, a torsion spring and a multilayer filter element made of corrugated mesh, made with the possibility of increasing the size in the radial direction when unwinding the spring (RF patent No. 224103, ЕВВ 43/08, 2005).

The disadvantage of this SRF is the limited spring stiffness and, as a consequence, the possibility of loosely pressing the corrugations of the mesh to the EC. In the gaps remaining between them, rock particles move from the bottomhole formation zone and its destruction occurs.

Known SRF containing a support pipe with many longitudinal slots, made with the possibility of expansion, and rectangular filter sheets in the form of an iris diagram, mounted on a supporting pipe with overlapping each other in axial and circumferential directions (RF patent No. 2197600, ЕВВ 43/08, 1998 ) SRF is known, including a support pipe with many perforations, a drainage and filter sheath made of metal mesh, the warp and weft wires of which are located at an angle to the longitudinal axis (US patent No. 6607032, ЕВВ 43/08, 2003).

A common drawback of these SRFs is the need to use an expanding cone to increase the diameter of the support pipe with filter sheets or shells on it and the possibility of breaking the integrity and ability to retain particles in the latter.

SRF is known, including a perforated case, a cylindrical casing with vertical slots and filter blades of a curved shape, the straight edge of which is fixed to the body, and the opposite edge is pushed through the vertical slots (Patent No. 2289680 of the Russian Federation, ЕВВ 43/08, 2006).

The disadvantage of such a SLF is the limited bending stiffness of the filter blades, which allows them to be repelled by reservoir pressure from the EC wall and the migration of rock particles from the formation into the well through the gaps formed.

Known SRF containing expandable supporting pipe with rows of transverse slots along its axis, equipped with an anchor on top, made in the form of a longitudinally corrugated pipe with an expanding cone at the top (RF patent No. 2421603, ЕВВ 43/08, 2011).

The disadvantage of SRF is limited functionality, in particular, unsuitability for cased hole wells due to the high probability of overlapping perforations in the EC with continuous sections of the carrier pipe, and not with rows of transverse slots.

SRF is known, including a rod and flexible brush disks mounted on it, the outer diameter of which exceeds the inner diameter of the production casing (RF Patent No. 103842, ЕВВ 43/08, 2011).

The disadvantage of SRF is the abrasion of the bristles of the brush discs during descent into the well with the formation of an annular gap with the wall of the EC, as a result of which the bristles do not overlap the perforations in the EC and do not prevent the removal of rock particles into the well.

Closest to the claimed technical essence is SRF, which includes a support pipe with holes and filter round brushes fixed to it in the form of a perforated body with radially oriented tufts of bristles whose diameter exceeds the inner diameter of the production casing of the well. The brushes are placed in a cover to prevent abrasion on the column during descent, and after expanding the brushes, the annulus is blocked by a disconnector (Pat. RF No. 2504643, ЕВВ 43/08, 2014).

The disadvantage of the adopted SRF as a prototype is the design complexity and the need for additional technological equipment for installation, the probability of which decreases with increasing length of the SRF and the depth of the well.

The objective of the present invention is to simplify the construction of the SRF and the technology for equipping it with a well.

The specified technical result is achieved by the fact that in a borehole expanding filter containing a support pipe and filter brushes with radially oriented tufts of bristles, according to the invention, the support pipe is surrounded by a swelling elastomeric sheath with open longitudinal grooves uniformly distributed around the circumference, rack brushes are used as filter brushes, whose bodies are buried in longitudinal grooves and provided with longitudinal flanges along the entire length, overlapping the cylindrical surface of the elastome hydrochloric shell.

In the borehole expanding filter, the flanging of adjacent rack brushes can be overlapped.

In FIG. 1, 2 shows the SRF in the initial state during descent into the well and in working condition after swelling of the elastomeric sheath, longitudinal section; in FIG. 3, 4 - the same, fragments of a cross section, in FIG. 5 - rack brush, in FIG. 6 - support pipe with a swelling elastomeric sheath.

SRF contains a supporting metal pipe 1 with restrictive rings 2 at the ends, a swelling elastomeric sheath 3 placed around it with open longitudinal grooves 4 evenly distributed around the circumference, into which the bodies 6 of the filter rack brushes 5 with radially directed tufts of bristles 8 are buried (Fig. 1- 4, 6). The housing 6 and the tufts of bristles 8 are made of metal or polymer materials that are resistant to formation fluid and chemicals used for processing wells. The shape of the longitudinal groove 4 in the elastomeric sheath 3 coincides with the shape of the housing 6 of the rack brush 5 she covers. The longitudinal groove 4 can have, for example, a trapezoidal shape (FIG. 6). The tufts of bristles 8 are mounted in the housing 6 of the rack brush 5 at such a distance from each other that their free ends form a continuous brush field. Cases 6 have flanges 7, which completely overlap the cylindrical surface of the elastomeric sheath 3 by overlapping them with adjacent rack brushes 5 (Fig. 3-5). In the circumferential direction between the tufts of bristles 8 near the body 6 there are longitudinal channels 9 (Fig. 3-4). In the initial state, the outer diameter of the SRF along the bundles of bristles 8 is less than the inner diameter of the EC 10 by the size of the annular gap 11, and in working condition after the swelling of the elastomeric sheath 3, the bundles of bristles 8 are tightly adjacent to the EC 10 (Fig. 2, 4).

SRF works as follows.

SRF is suspended by means of a support pipe 1 to the base of a submersible electric motor and lowered as part of the ESP into the perforation interval 12 EC 10; during the descent between the SRF and EC, an annular gap 11 remains (Fig. 1, 3). In the well, formation fluid containing hydrocarbon compounds and water penetrates under flanging 7 of the housing 6 of the rack brushes 5 and interacts with the elastomeric sheath 3, causing it to swell. Being placed on a strong metal support pipe 1 and sandwiched between the restrictive rings 2, the elastomeric sheath 3 swells in the radial direction towards EC 10. The flanges 7 do not prevent its diameter from increasing, but only prevent the elastomer from penetrating the bundles of bristles 8. The overlap of the flanges 7 decreases until they adjoin each other after swelling of the elastomeric sheath 3 (Fig. 4). The rack brushes 5 inserted into the elastomeric sheath 3 move with it to the wall of the EC 10, and the annular gap 11 between the tufts of bristles 8 and the wall of the EC 10 disappears. Next, the tufts of bristles 8 penetrate the perforations 12 EC 10, partially blocking their section, and reach the perforation channels 13 in the bottomhole formation zone (Fig. 2, 4).

When you turn on the submersible pump (not shown), the fluid with particles of rock moves along the perforation channels 13 to the well. In the perforation channels 13 near the EC 10 and in the perforations 12, the rock particles collide with the tufts of bristles 8 of the rack brushes 5, lose speed and get stuck in the space between the bristles (Figs. 2, 4). Given the significant gaps between the bristles, mainly coarse particles are retained in their bundles, from which permeable structures are formed, acquiring the function of an artificial filter. Due to the slight deformation of the tufts of bristles 8 during longitudinal flow around the formation fluid, the stability of permeable structures and the stability of the filtration properties of the SRF are maintained. Over time, the region of the resulting artificial filter expands beyond the bundles of bristles 8 deep into the perforation channels 13, thereby reducing the number of rock particles carried out from the bottom-hole zone of the formation and maintaining well productivity. After filtering through the tufts of bristles 8, the purified liquid continues to move in the radial direction, enters the longitudinal channels 9 between the tufts of bristles 8, changes direction by 90 ° and moves to receive a submersible pump. Pumping the cleaned liquid reduces wear and increases the running time of the submersible pump. SRF is characterized by low hydraulic resistance and, accordingly, a slight loss of fluid pressure.

The inventive SRF without difficulty descends into the well, without requiring additional devices, for example, a protective cover, while the abrasion of the tufts of bristles against the EC wall is completely eliminated and the subsequent fulfillment of the SRF assigned to it is guaranteed. Since the already cleaned reservoir fluid enters the EC, there is no need for an annulus disconnector above the SRF, which simplifies the completion of the cased well and reduces the time and cost of its implementation.

Claims (2)

1. A downhole expanding filter comprising a support pipe and filter brushes with radially oriented tufts of bristles, characterized in that the support pipe is surrounded by a swellable elastomeric sheath with open longitudinal grooves evenly distributed around the circumference, rack brushes are used as filter brushes whose bodies are recessed into longitudinal grooves and provided with longitudinal flanges along the entire length, overlapping the cylindrical surface of the elastomeric shell. 2. The downhole expanding filter according to claim 1, characterized in that the flanging of adjacent rack brushes is overlapped.

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