RU2433852C1 - Method of producing borehole filter - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to fabrication and installation of borehole radial-flow filter for water-, gas- and oil production wells. Method of borehole filter production comprises fitting tube of required length and diameter with filtration section into lathe and arranging filtration element on filtration section outer surface. Filtration element with annulus is produced on fitting inner tube whereon outer recesses are made. Note here that rigid spacer and filtration filler are fitted into annulus. Note also that outer recesses on inner and outer tubes allow expansion to produce slots after local destruction of tube material in tube mandrelling after its placing in borehole in installation interval. ^ EFFECT: saving of materials and time, higher efficiency. ^ 2 dwg

Description

The invention relates to a method for manufacturing and installing a downhole filter with a radial fluid flow for oil and gas producing wells.

Known expandable downhole filter to prevent the migration of particulate matter into a hydrocarbon liquid production well, comprising a support pipe configured to expand and provided with slots, on which filter sheets with slots are installed with overlap (patent RU No. 2197600, E21 43/08, publ. Bull. No. 3 dated January 27, 2003), which is produced by applying to the perforated pipe a filter element in the form of sheets with longitudinal slots, which are fixed with an overlap around the perimeter of the pipes.

Its disadvantages are the difficulty of manufacturing due to the presence of a plurality of filter sheets in it on an expandable, slotted supporting pipe at the attachment points located along its length at equal distances from each other. In the manufacture of a downhole filter, high labor costs require ensuring the parallelism of the longitudinal axis of each strip of the central axis of the carrier pipe, as well as the tight pressing of the edges of adjacent filter strips. It is impossible to lower the filter with flushing the well and there is a high probability of rock formation in the cut of the filter strips, as well as under the edge of adjacent filter strips, which can lead to its bending and an emergency situation at the well.

Closest to the proposed one by most coinciding features is a filter with a radial fluid flow for a well and a method for its manufacture (patent PU No. 2159143, IPC 7 B01D 27/06 publ. 20.11. 2000 bull. No. 32), implemented by a method of manufacturing a well filter, including installing a pipe of the required length and diameter with the filtration section in the lathe with the possibility of rotation, placing on the outer surface of the filtration section of the filter element.

A significant drawback is the insecurity of the outer layer of the filter from mechanical stress. It is not possible to run the filter down with flushing the well and there is a high probability of rock formation in the filter holes, which creates additional resistance to the flow of the fluid. The inner diameter of the cased part of the bore is smaller than the diameter of the borehole, and since the filter has to be lowered through the cased part of the borehole, the diameter of the filter is smaller than the diameter of the borehole and, as a result, an annular space is formed between the filter and the wall of the uncased part of the borehole. Over time, the wall of the well collapses and falls asleep on the outer wall of the filter, so that the annular space is filled with rock. During hydrocarbon production, the fluid will flow from water-oil-containing rocks into the annular space and through the openings in the filter into the cased wellbore. The circumference through which fluid enters the cased wellbore decreases from the circumference of the wellbore to the circumference of the outer wall of the filter.

Technical tasks - creating a filter with an increased filtration area, low hydraulic resistance with the ability to capture the specified size of the productive formation fractions, ensuring the safety of the filter element when lowering the filter into the well, eliminating the likelihood of rock formation in the filtering holes when lowering the filter into the well, reducing time and materials by filter manufacturing, increasing the amount of produced fluid. Create the ability to lower the filter with flushing the well.

The technical problem is solved by a method of manufacturing a downhole filter, including installing a pipe of the required length and diameter with a filtration section in a lathe with the possibility of rotation with the creation of a filter element.

New is that in the filter section on the outer surface of the pipe, grooves are made with filling with a filter element, and the filter element is made with the formation of an annular cavity by inserting an inner pipe on which the outer recesses are made, while a rigid spacer element and filter filler are placed in the annular cavity, moreover, the outer recesses on the pipe and the inner pipe are made with the possibility of expansion with the formation of cracks after local destruction of material under them the pipe during its turning after placement in the well in the installation interval.

Figure 1 shows a filter in a transport position with a partial longitudinal section; figure 2 - filter in the well with a partial longitudinal section.

The filter contains a pipe 1 (Fig. 1), the ends of which are provided with threads 2, and on the outer surface of the pipe 1, when it is rotated, recesses are made on the lathe 3. In the recesses 3, filter elements 4 are placed with the help of a lathe (for example, in the form of metal strips mesh, the ends of which are fixed on the pipe 1 by welding).

An inner pipe 5 is inserted into the pipe 1, on the outer surface of which the recesses 6 are preliminarily made on the lathe. Between the pipe 1 and the inner pipe 5, that is, in the annular cavity 7, a rigid spacer element 8 made of strong material (for example, made in the form of a coil spring ) The rigid spacer element 8 has the ability to increase the outer dimensions while expanding the inner pipe 5, changing shape, without breaking with small radial forces. The dimensions of the recess 3 of the pipe 1 and the recess 6 of the inner pipe 5 provide the destruction of the material under the recess during the expansion of the pipes. After filling the annular cavity 7 with a filter filler 9 (for example, fractions in the form of balls) to create a filter element, the filter is ready to be lowered into the well 10 (Fig. 2). Using thread 2, connect the filter pipe 1 to the casing string 13 and lower it into the well 10 in the interval of the productive horizon. Depending on the power of the productive horizon, the required number of filters is determined. The proposed method of manufacturing a filter allows its descent with direct flushing of the well 10.

The filter is put into working position after it is lowered into the interval of the productive formation of the well 10. Expansion of the inner diameter of the inner pipe 5 during its turning (not shown) with local destruction of the wall under the recesses 6 causes cracks 11 to form due to stress concentration and small thickness of the material. Expansion the inner pipe 5 is transmitted to the pipe 1 through a rigid spacer element 8. Due to the concentration of stresses and the small thickness of the material under the recesses 3, the pipe 1 is locally destroyed with the formation of slots 12.

Preservation from mechanical destruction of the filter element 4 (Fig. 1) when the filter is lowered into the well 10 (Fig. 1) is provided by recesses 3 (Fig. 1) in which the filter elements are located 4. Preservation from mechanical destruction of the filter element of the filter (Fig. 2) ) when expanding the inner pipe 5 and pipe 1, it is ensured by the high strength of the rigid spacer 8. The low hydraulic resistance of the filter is ensured by the increased filtration area due to the increase in the outer diameter of the pipe 1 and the filter filling elem 9, the size of which corresponds to the granulometric fractions composition productive horizon. By changing the size and composition of the filter filler fractions 9, we can obtain a different degree of filtration of the produced fluid from the well.

The filtering gap 12 formed at the installation site and the filtering element 4 located above it are not clogged with rock, clay mud, etc. The filter filler 9 and the filtering gap 11 are not clogged with rock, clay mud, etc.

Reducing time and saving materials in the manufacture of the filter is achieved by performing all technological operations on a lathe (not shown). Low hydraulic resistance of the filter allows to increase the amount of produced fluid from the well.

The proposed method allows you to create a filter with an increased filtration area, low hydraulic resistance with the ability to capture the specified sizes of fractions of the reservoir, to ensure the safety of the filter element when lowering the filter into the well, to eliminate the likelihood of stuffing rock into the filtering holes when lowering the filter to the well, to reduce material consumption and time to manufacture the filter, increase the amount of produced fluid, create the possibility of lowering the filter with flushing the well.

Claims (1)

A method of manufacturing a downhole filter, including installing a pipe of the required length and diameter with a filtration section in a lathe with the possibility of rotation, creating a filter element, characterized in that in the filter section on the outer surface of the pipe, recesses are filled with a filter element, and the filter element is made to form the annular cavity by inserting the inner pipe, on which the outer recesses are performed, while a rigid spacer is placed in the annular cavity th element of the filter and a filler, wherein the recesses in the outer tube and the inner tube is made with possibility of expansion to form the gaps after local destruction of the tube material beneath it when dornirovanii after placement downhole in the range of installation.

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