EA028029B1 - Design of a groundwater well - Google Patents

Abstract

The invention is related to water supply and can be used as a water-intake structure for groundwater production from subsurface sources. The objective of the invention is a wider application area of wells of similar design and their longer service life due to higher repairability during overhaul. Said objective is attained by that the design of a groundwater well comprising a conductor with annular cementation and a shoe mounted on the roof of the producing water-bearing horizon, a production string consisting of pipes with bell-and-spigot joints, a filter with a working portion and a settling tank packed with gravel, delivery pipes having valves at the inlet and perforation in the bottom part, in the area of gravel packing, the delivery pipes being mounted in the space between the production string and the conductor, further comprises a filter string consisting of several sections with flare joints, thrust rings fixed rigidly at the ends of the flare and the smooth part of the section, an expanding gland mounted between the thrust rings, a clevis mounted in the bottom part of the settling tank, and expanded-clay packing with a clay retainer at the well mouth, above the gravel packing.

Description

The invention relates to water supply and can be used as a water intake for the extraction of groundwater from underground sources.

Known water well [1], containing a conductor to the aquifer with annular cementation, production casing, consisting of pipes with sleeve connections, a filter with a working part, sprinkled with gravel, and a sump.

The design disadvantages include the rather high cost of such a well due to the increased metal consumption for the construction of the conductor to the aquifer and the inability to replace the filter when it fails due to significant friction forces arising between the filter column and sprinkling.

Known water well [2], containing a conductor with annular cementation and a shoe mounted in the roof of the aquifer, production casing, consisting of pipes with sleeve connections, a filter with a working part, sprinkled with gravel, sump, inside equipped with a threaded sleeve with left-hand thread, discharge pipes with inlet valves and perforations in the lower part in the area of gravel sprinkling are mounted in the cavity between the production casing and the conductor, and the conductor is also operational The columns have a corrosion-resistant coating and a tight flange connection at the wellhead.

This design of the well allows for preventive measures to regenerate the filter and the filter zone from clogging deposits. These measures allow not only to increase the life of the well, but also to maintain a high specific production rate in this well.

The disadvantages of the design include the high cost and the possibility of using this design only for the capture of low-powered aquifers. This limitation is associated with the inability to use long filters due to the significant friction forces arising between the sprinkling and the well filter when it is removed for overhaul. Under the action of traction forces to remove the filter with the production string due to high friction and shear resistances, contact between the filter surface and cemented soil is formed as a result of sediment deposition in the filter holes and rock pores, significant tensile forces arise. Typically, such tensile forces cannot withstand welds and filter material, resulting in rupture or destruction in the filter column. Such an accident does not allow further exploitation of the well, it is being plugged and a new one is being drilled, which requires the attraction of significant funds.

The problem solved by the invention is to expand the scope of wells of a similar design and increase their durability by increasing maintainability during major repairs.

The problem is solved in that the design of the water well, consisting of a conductor with annular cementation and a shoe installed in the roof of the aquifer, production casing, consisting of pipes with sleeve connections, a filter with a working part and a sump, sprinkled with gravel, pressure pipes with valves at the entrance and perforation in the lower part, in the area of gravel sprinkling, installed in the cavity between the production casing and the conductor, further comprises a filter casing, complements of several sections having a flare connection, wherein the ends of the socket and the smooth part sections are rigidly fixed thrust ring between which is mounted expansible gland gripping bracket mounted in the lower part of the settler, and keramzite filling clay lock wellhead over gravel package.

The scheme of the water well is illustrated in the drawing (Fig. 1). The well consists of a conductor 1 with annular cementation 2, a production string 3 with sleeve connections 4, a filter pipe 5, a filter string divided into filter sections 6, 7, 8, interconnected by bell-shaped connections 9 (bell-shaped connection 9 consists of a bell 10, thrust rings 11 and expanding gland 12), gripping bracket 13, welded to the bottom 14 of the settler 15. Also, this design of the well is equipped with injection pipes 16 with perforation 17 and a valve 18 at the inlet. As dusting, gravel dusting 19 and expanded clay 20 with clay castle 21 are used.

A well can be constructed as follows. They drill a prospecting trunk and carry out a complex of geophysical research in it. After decoding the logs, the location of the aquifer is determined. The sump is torn off, the guide column is installed, the conductor 1 is drilled and cemented, then the guide column is removed and the trunk is drilled under the conductor 1 to the roof of the aquifer with annular cementation 2 to the full height to the wellhead.

The opening of the aquifer is carried out either using a bit whose diameter corresponds to the inner diameter of the conductor, or using an expander, after expanding the bottom to the desired size, a rock-cutting tool is removed from the well and the filter column is started to sink.

First, production casing 3 with a filter casing and a stand 15 is lowered into the open barrel, then injection pipes 16 with a perforation 17 and a valve 18 are immersed. The filter casing is immersed in sections, starting from the lower filter section 8. Filter section 8 with a settling tank 15 , an expanding gland 12 and a thrust ring 11, rigidly fixed on the smooth part of the socket connection, are hung on a clamp at the wellhead. Using a lifting winch of the drilling rig, the filter section 7 with the bell 10 in the lower part, the expanding gland 12 and the thrust ring 11 in the upper part are lifted vertically upwards and put on the smooth part of the bell joint of the lower filter section 8. The filter section 7 is held in place so that the lower end of the bell 10 is lower than the expanding gland 12. Then, the stop ring 11 is fixed by welding to the end of the bell 10. After that, the hoisting winch is turned on and the filter section 7 is moved upward at the same time, the expanding gland 12 is compressed, and the winch traction is transferred to the filter section 8. After this, the clamp is released, the two connected filter sections 8 and 7 are lowered into the open shaft and hung on the clamp at the wellhead. Then, using the lifting winch of the drilling rig, the next filter section 6 is lifted vertically upward and put on with the wide part of the socket 10 on the smooth part of the socket connection of the filter section 7. Then the above operations for the device of the socket connection 9 are repeated. sections 6 are welded over the filter pipe 5, having in its upper part a bell-shaped connection 9 with an expanding gland 12 and a thrust ring 11 rigidly fixed to a smooth hour tee. Using the socket connection 9, the filter string is fastened to the production string 3, consisting of pipes on the coupling joints 4. Then, the production string 3 with the filter string and sump 15 is lowered and centered. After the production string 3 is lowered with the filter string and sump 15, 4 injection pipes 16 are immersed with perforation 17 in the area of the filter column. Then create a gravel sprinkle 19 around the filter column, for which gravel is poured almost to the top of the filter pipe. Produce pumping wells. After the pumping is completed, expanded clay 20 is filled up and the clay castle 21 is mounted.

During the operation of the well in the pores of gravel sprinkling and in the holes of the filter accumulation of deposits occurs - products of chemical and biological mudding. The permeability of the filter decreases, the productivity of the well decreases, the cost of produced water increases.

This problem is solved by washing the filter and gravel sprinkling 19 with water or with the addition of acids through the injection pipes 16. However, despite periodic washing and regeneration of the filter and gravel sprinkling 19, complete removal of clogging deposits is impossible and the use of the well will become very expensive over time and impractical. Such a well requires major repairs with the replacement of the filter and gravel sprinkling 19 with the extraction of production casing 3 with a filter column and sump 15.

To facilitate the extraction of the filter column, hydrodynamic pressure pulses are produced in the filter cavity, violating the continuity of the layers of sealed gravel adjacent to the outer surface of the filter.

Before extraction, the clay castle 21 is destroyed and expanded clay 20 is washed out using a high pressure water jet (due to porosity, low mass and high strength, expanded clay begins to float to the surface under the action of a water jet). Then, a reagent is fed into the injection pipes 16, which loosens the gravel sprinkler 19 and destroys the clogging bonds between the filter and gravel sprinkler 19. A cargo hook is lowered into the well, which is engaged with the gripping bracket 13 and the lower filter section 8 is lifted by means of a winch. Since the section does not have welded joints, and the used bell-shaped joints 9 provide the possibility of displacing the section 100-150 mm upwards for breaking the clogging bonds between the filter and gravel sprinkling 19, then the lower section is shifted without damaging the filter. A gripping tool is used to offset subsequent sections. After the destruction of the colmatation bonds between all sections of the filter string and sprinkling 19, and also after the production string 3 has been removed from expanded clay 20, the filter and production string 3 are removed by applying traction forces applied to the gripping bracket 13 and the head of the production string 3. If it is impossible to extract filter, the operation to shift the sections is repeated until the friction forces between the filter sections and gravel sprinkling are reduced to acceptable values.

After the filter column and production casing 3 are removed, the injection pipes 16 are removed. Then, the old gravel pack contaminated with colmatant is drilled with a rock cutting tool and expander 19, the well is washed, the filter column, injection pipes 16 are replaced and all components of the well are put back into working position.

The proposed well design makes it possible to ensure not only high-quality ongoing repairs during the entire period of operation due to the availability of injection pipes 16, but also the possibility of overhaul with extraction of production casing 3 and filter casing.

The use of bell-shaped compounds 9 in the filter string allows for sectional collection of a long filter for use in powerful aquifers in high-yield wells. The use of expanded clay 20 instead of the usual filling of sand allows you to reduce the horizontal stress transmitted to the production casing 3 due to the high porosity of the material, and the use of clay lock 21 protects the well from surface water entering the production horizon.

Thanks to the introduction of new improved designs of water wells in the water supply systems of the Republic of Belarus, it is possible to achieve a visible economic and environmental effect by expanding the field of application of wells of a similar design, increasing their service life and the possibility of overhauling with filter replacement.

Information sources

1. Belyakov V.M. The training book of the master in water well drilling. (Second edition, revised and supplemented) / B.M. Belyakov, V.A. Popkov, G.M. Krasnoshchekov. M .: Kolos, 1983, p. 316-317, fig. 156e.

2. The design of the water well during rotary drilling. Patent of the Republic of Belarus No. 9453 IPC C1, ЕВВ 43/00, В03В 03/00, publ. 06/30/2005, the official bulletin, 2007, No. 3, p.

Claims (1)

CLAIM A water well containing a conductor with annular grouting and a shoe installed in the roof of the production aquifer, a production string consisting of pipes with coupling joints, a filter with a working part and a sump sprinkled with gravel, discharge pipes with inlet valves and perforations in the lower part the zone of gravel sprinkling, installed in the cavity between the production casing and the conductor, characterized in that the filter column is made of several sections that have a socket At the ends of the socket and the smooth part of the section, stop rings are rigidly fixed, between which an expansion gland is installed, a catch bracket is mounted in the lower part of the settler and above the gravel sprinkling there is claydite with a clay lock at the wellhead.