RU2250358C1 - Method and tool for construction of filtering well - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: method includes mounting tool with filtering channel on well shaft. Soil backfill is fed and washed. Washing liquid is fed range-wise through streaming device. Washing liquid is fed with direction of jets into ring-shaped hollow between well shaft walls and filtering column walls from calculation of ceiling by streams of cross-section of ring-shaped hollow. Tool has filtering column with soil backfill and exposure tank, wherein check valve is mounted, tool also has washing pipe with blocking means and check valve, fixed to exposure tank with possible disconnection. Tool is also provided with streaming device, mounted between blocking means. Streaming device is made in form of ring-shaped nozzles set. Nozzles are formed by spherical rinds, curvature radiuses of which are taken with center at axis of filtering column, with cylindrical support portions, uppermost of which are made with radial channels for feeding washing liquid through them with direction of streams from calculation of overlapping by them of cross-section of ring-shaped hollow between well shaft walls and filtering column walls.

EFFECT: higher efficiency.

2 cl, 2 dwg, 1 ex

Description

The invention relates to the field of mining, in particular to methods and devices for constructing wells for the extraction of water and other fluid, and can be used when pumping wells during drilling or repairing wells to combat the removal of sand from weakly cemented and non-cemented reservoirs.

A known method of constructing a filter well with gravel packing [1], which consists in installing a filter column, filling and flushing gravel packing. The known method provides the equipment of wells with gravel-bulk filters in an upward flow of flushing fluid, in conditions with low reservoir pressure of productive horizons and absorption of flushing fluid is not very effective, due to the inability to completely clean the well from drilling cuttings, removal of formation sand and the formation of a gravel filter.

There is also known a method for gravel packing an interval inside a wellbore, including operations for lowering the pipeline with the main filter section and the upper bypass filter [2]. The presence of a bypass filter somewhat equalizes the rates of gravel washing and particle fractionation.

However, the problem of insufficient cleaning of drill cuttings and formation sand is also not solved, especially when the pressure of the flushing fluid exceeds the formation.

The closest analogue of the invention is a method of constructing a filter well according to the invention [3], including the installation of the tool with the main and additional filters, a flushing pipe with means to block the flow of flushing liquid, filling and flushing gravel packing.

The disadvantage of this method is its lack of effectiveness, especially when used in productive formations with low reservoir pressure and absorption of drilling fluid.

In accordance with the present invention, there is provided a method for constructing a filter well that provides optimal distribution of gravel throughout the filter zone, and reliable complete removal of drill cuttings and formation sand and enables the formation of a natural filter.

This problem is solved in that the method of constructing a filter well, which consists in installing a tool with a filter column in the wellbore, filling and flushing gravel packs according to the invention, the flushing fluid is supplied intervalwise through the jet device with the direction of the jets along radius curves with overlapping section of the annular cavity between the walls of the borehole filter column by changing the magnitude of the radius of curvature of the jets.

A known tool for the construction of a filter well with gravel packing [1], including a pipeline with a filter and a sealing tip, lowered on drill pipes, removably connected to a non-return valve fixed in the filter sump.

A well-known tool provides the equipment of wells with gravel-bulk filters in an upward flow of flushing fluid in conditions with low reservoir pressure of productive horizons and the absorption of flushing fluid is not very effective, due to the impossibility of completely cleaning the well from drill cuttings, removing sand and forming a gravel filter.

Also known is a downhole tool for gravel packing an interval inside a wellbore, including a pipeline with a main filter section and an upper bypass filter [2]. The presence of a bypass filter somewhat equalizes the rates of gravel washing and particle fractionation.

However, the problem of insufficient cleaning of drill cuttings and formation sand is also not solved, especially if the pressure of the flushing fluid exceeds the formation.

The closest analogue of the invention is a tool for constructing a filter well [3], including a pipeline with primary and secondary filters, a flushing pipe with means to block the flow of flushing liquid.

The disadvantage of the tool is its low efficiency, especially when used in productive formations with low reservoir pressure and absorption of drilling fluid.

Due to the fact that the supply of the tool with a washing pipe with blocking means and the presence of a bypass filter make it possible to control the flow of washing liquid for a good packing of the annular cavity of the filter, but they do not provide complete cleaning of the filter from drill cuttings, formation sand.

In accordance with the present invention, there is provided the creation of a tool for constructing a filter well that provides optimal distribution of gravel throughout the prefilter zone, and reliable complete removal of drill cuttings and formation sand, and enables the formation of a natural filter.

This problem is solved in that the tool for constructing a filter well, including a filter column with gravel packing, a sump in which a non-return valve is fixed, a flushing pipe with blocking means and a non-return valve fixed to the sump with the possibility of separation.

According to the present invention, the tool is equipped with an inkjet device installed between the blocking means mounted on the housing fixed to the flushing pipe with an upper part and made with radial channels.

In addition, the housing of the locking means is equipped with a spring-loaded radial valve pivotally connected in the upper part to the check valve of the flushing pipe and is connected to the lower part by a separator through a sub with a pusher that can be disconnected.

Also, the jet device is made in the form of a set of annular nozzles formed by spherical rings, the radii of curvature of which are taken with the center on the axis of the filter string based on the overlap of the cross section of the annular cavity between the walls of the wellbore and the filter string, provided with cylindrical supporting sections, the upper of which with radial channels.

The invention is illustrated by drawings. Figure 1 shows the cross section of the tool in the initial position. Figure 2 - during the flushing.

A filter string 2 with a sump 3 is lowered into the wellbore 1, in which a check valve 4 and an adapter 5 are fixed, connected to the casing in blocking means 7, 8. The upper part of the casing 6 is fixed to the flushing pipe 9. The casing 6 is made with radial valves that are closed a radial valve 10, to which in the upper part the check valve 11 of the flushing pipe 9 is pivotally connected.

An inkjet device is installed between the blocking means 7, 8, the distance between the blocking means 7, 8 is regulated by the distance sleeve 12. The sub 5 is made with a pusher 13.

The inkjet device is made in the form of a set of annular nozzles formed by spherical rings 14 provided with cylindrical supporting sections, the upper of which are made with radial channels 15.

The radii of curvature of the rings are taken with the center on the axis of the filter string based on the calculation of the overlap of the cross section of the annular cavity between the walls of the wellbore and the filter string.

The construction of the gravel filter in accordance with the present invention is as follows.

Downhole tool on the wash pipe 9 is lowered into the wellbore 1.

For the filter column 2 to be completely planted at the bottom, include flushing fluid for bottom hole flushing, in which flushing fluid passes through flushing pipe 9, a check valve 4 into the annular space between the settler 3 and the wellbore 1. In this case, drill cuttings and sand are washed out of the well and the filter column is lowered to the bottom of the well. Washed sludge and sand through the filter column flow into the internal cavity. After the filter column is planted on the bottom, the direct bottom-hole washing is turned off and a portion filling is performed. The number of gravel packs per serving is taken from the calculation to overlap the annular space between the blocking means 7, 8.

After filling the first portion of the gravel pack, the housing 6 of the blocking means 7, 8 is disconnected from the sub 5, the tool is lifted above the sump 3 and a direct washing is started (see FIG. 2).

In this case, the check valve 11 of the washing pipe 9 becomes a socket made in the upper part of the radial valve 10 and the radial valve 10 is moved to the lower position, opening the radial channels of the housing 6 of the locking means 7, 8.

The flushing fluid through the radial channels 15, made in the cylindrical sections of the upper conical rings, penetrates into the annular nozzles of the inkjet device.

During washing, along with leaching of drill cuttings and sand, the optimal packing of gravel pack fractions is carried out, corresponding to laying in natural conditions. Parts of drill cuttings and leached sand with fine gravel packs are transported to the surface through a filter column.

Further operations for backfilling and washing gravel packing are carried out similarly.

After flushing, the well is pumped out with a back flushing.

The technical result.

1. The construction of a filter well with an optimal distribution of gravel throughout the filter zone.

2. Reliable and complete cleaning of the well from drill cuttings and formation sand.

3. Ensuring the formation of a natural filter.

An example implementation of the method.

The well No. 102273/16 of the Oksky aquifer of the Lukovskiy Les water intake, Ryazan, is to be repaired and reconstructed due to long-term operation.

The well is filterless, depth 160 m, cased to a depth of 123 m from the mouth of the casing string 324 mm to failure, was operated using pumps of type ЭЦВ 8-16-140.

Specific reasons for shutting down a well: increased turbidity of pumped water.

The following operations are performed to repair a well:

1. Cleaning the wellbore and expanding the filter zone of 125-160 m to 350 mm.

2. Lowering the ⌀245 mm casing string with a filter in the lower part 35 m long on the tool for constructing a filter well.

3. Flushing the well with the simultaneous filling of gravel with a grain size of fractions from 0.5 to 10 mm to a level of 125 m from the wellhead and backfilling as fine fractions and sand are removed and a natural filter is formed.

4. Measurement of the dynamic level for a given well, it is 75 m from the wellhead.

5. Final flushing of the well with reverse flushing.

6. Conducting construction pumping wells.

7. Sampling of pumped water and chemical analysis.

Sources of information

1. Onoprienko M.G. Drilling and equipment of hydrogeological wells. M .: Nedra, 1978.- p. 90.

2. RF patent No. 2169254, IPC 7 E 21 V 43/04, 06/20/2001.

3. RF patent No. 2209943, IPC 7 E 21 V 43/04, 08/10/2003.

Claims (2)

1. The method of constructing a filter well, which consists in installing a tool with a filter column in the wellbore, filling and flushing gravel packs, characterized in that the flushing fluid is supplied intervalwise along radius curves through an inkjet device made in the form of a set of annular nozzles formed by spherical rings the radii of curvature of which are taken with the center on the axis of the filter column, with cylindrical supporting sections, the upper of which are made with radial channels, moreover, th liquid is supplied through the annular nozzle with the direction of the jet into the annular cavity between the walls of the wellbore and a filter column at the rate of overlap of the jets sectional annular cavity. 2. A tool for constructing a filter well, including a filter column with gravel packing and a sump, in which a non-return valve is mounted, a flushing pipe with blocking means and a non-return valve fixed to the sump with the possibility of separation, characterized in that it is equipped with an inkjet device installed between blocking means mounted on the housing fixed to the flushing pipe with the upper part and made with valves, and the inkjet device is made in the form of a set of annular nozzles formed by spherical rings, the radii of curvature of which are centered on the axis of the filter column, with cylindrical support sections, the upper of which are made with radial channels for supplying washing fluid through them with the direction of the jets, based on the calculation of their overlap of the cross section of the annular cavity between the walls of the wellbore and the filter the columns.

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