RU2543005C1 - Method of water-producing well recovery - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: according to the method in a watered part of a formation at first remedial cementing is made to cut the inflow of stratal water off and to isolate the watered part of the formation by a cement plug setting. A geophysical survey is performed in the non-watered part of the formation. Intervals are identified with bigger permeability of the productive formation areas. An assembly with an end-to-end channel is run in at the drill string and set by means of an anchor packer device. It is oriented towards one of the permeable areas of the productive formation. Mill equipment with a downhole drilling motor, flexible shaft and cutter is run in to the well at a flexible tube. An opening is cut in the production string wall with the use of an oil-based solution. The mill equipment is run out from the well. A jet nozzle is run in to the well up to a discharge outlet of the guide assembly. Cement stone and rock is washed out behind the production string so that a radial borehole is formed. The radial borehole treatment is made through the jet nozzle by an acid composition so that a cavern is formed. The flexible pipe with the jet nozzle is lifted out of the well. The guide assembly is rotated, for example, per 180 degrees and similar operations are performed to tunnel the next radial borehole. The guide assembly is lifted to the height of the next interval in the permeable areas of the productive formation and the similar operations are performed to tunnel the next radial boreholes. Up to the upper radial boreholes of the well an oil string is run in and the above string is made of tubing strings with the area of a clearance hole equal to the sum of all the clearance holes in the radial boreholes. The well is brought to operation.EFFECT: improved efficiency of the method due to the removal of conditions for swelling of clays contained in the productive formation at tunnelling the radial borehole in low-permeable terrigenous deposits of water-swelling clays.3 ex, 6 dwg

Description

The invention relates to the oil and gas industry, in particular to the restoration of waterlogged wells, in particular to wells located in low permeable terrigenous deposits, composed of water-swellable clays.

Reservoirs in the fields of the north of Western Siberia, in which production wells are located, belong to complex reservoirs, in the lower part of which highly permeable productive deposits are located, and in the upper part - clayed low-permeability terrigenous deposits composed of moisture-swelling clays.

From the experience of repairing such wells, it is known that as the reservoir pressure decreases, plantar waters are introduced into the highly permeable productive reservoir, underlying the reservoir, watering of the reservoir occurs, and repair and insulation works to isolate the influx of produced water in the well are inconclusive, but the opening of upstream clayed low-permeable terrified rocks deposits composed of water-swellable clays by known methods, cumulative perforation or sidetracking using aqueous solutions, leads to swelling of clays that impede subsequent gas production from the reservoir.

To restore waterlogged wells, repair and insulation works are carried out [Reference book on the current and capital repair of oil and gas wells / A.D. Amirov et al. - M .: Nedra, 1979. - S.238-241].

A well-known method of well restoration, including the production of repair and insulation works and the opening of the reservoir [RF Patent No. 2273718, E21B 29/10, filed July 2, 04, published April 10, 2006].

The disadvantage of this method is the insufficient efficiency of the restoration of waterlogged wells, since during the repair and insulation works with longitudinally corrugated plasters the formation water flow into the well is not eliminated, and the probability of destruction of the repair interval of the production string, especially in wells with continuous perforation of the production string with double density, increasing.

A known method of restoring a waterlogged well, including the production of repair and insulation works and opening the reservoir [RF Patent No. 2231630. E21B 43/00, E21B 43/32, claimed 2002, published 2004].

The disadvantage of this method is the lack of efficiency in the restoration of waterlogged wells, since when perforating a production casing with high power punchers, the probability of a leak in the cement stone behind the casing increases, while its complete or partial destruction contributes to an even greater influx of formation water to the bottom of the well.

A known method of well recovery, adopted as a prototype, including the production of repair and insulation works and the opening of the reservoir [RF Patent No. 2370636. E21B 43/00, E21B 43/32, claimed on 04/21/08, published on 10/20/09].

The disadvantage of this method is the lack of effectiveness in the restoration of waterlogged wells, since when used in the process of repairing technological solutions based on water, it leads to swelling of the clay contained in the reservoir.

The challenge faced by the invention is to increase the recovery efficiency of a waterlogged well.

Achievable technical result, which is obtained as a result of the invention, consists in eliminating the swelling conditions of clays contained in the reservoir when laying a radial trunk in low-permeability terrigenous deposits composed of moisture-swelling clays.

The task and technical result are achieved by the fact that when restoring a waterlogged well, initially in the flooded part of the formation, repair and insulation work is carried out to isolate the influx of formation water and cut off the waterlogged part of the well by installing a cement bridge, then geophysical surveys are carried out in the remaining non-irrigated part of the formation, the intervals are determined more permeable sections of the reservoir, after which the drill pipe is lowered and installed using the anchor packer at the guideway arrangement, equipped with a through channel, orient it in the direction of one of the permeable sections of the reservoir, then drill pipe string is removed from the well, a milling tool, consisting of a downhole screw motor and a flexible shaft, at the lower end of which is placed, is lowered into the well on a flexible pipe milling cutter, cut a hole in the production casing wall using a hydrocarbon-based technological solution, remove milling equipment from the borehole on a flexible pipe y, attach a hydraulic monitor nozzle to the shoe of the flexible pipe by means of a high-pressure transfer sleeve and lower it into the well to the outlet of the guide assembly, spray the cement stone behind the production string with high-pressure hydrocarbon-based spray and then radially displace the hydraulic nozzle in the radial direction rock formation with the formation of a radial shaft, after which the radial shaft is cleaned through a hydraulic monitor nozzle acid composition from a mixture of clay and organic acid, for example, ascorbic, citric or formic, with the formation of a cavity expanding the radial trunk, then a flexible pipe with a high pressure sleeve and a hydraulic nozzle is removed from the well, the guide assembly is rotated in the same plane, for example, 180 degrees of the permeable section of the reservoir and carry out similar operations for laying the next radial shaft, then raise the guide assembly to a height of the next interval of the permeable sections of the reservoir and carry out similar operations for laying subsequent radial shafts, after which an elevator string is lowered from the tubing to the upper radial shafts with the area of the through hole equal to the sum of the areas of the through holes of the radial shafts and the well is put into operation .

In Fig.1 shows a diagram of repair and insulation work to isolate the influx of formation water and cutting off the flooded part of the barrel by installing a cement bridge, Fig.2 - the same when lowering the guide assembly into the well; figure 3 is the same when cutting in the production casing of the hole; in Fig.4 - the same when erosion of cement stone behind the production string and rocks surrounding the well with hydrocarbon-based liquid with the formation of a radial shaft, Fig.5 - the same when washing the radial shaft with an acid composition with the formation of caverns, in Fig. 6 - the same when putting the restored well into operation.

The method is implemented as follows.

During operation of a well located in a complexly constructed formation 1, the lower, most productive part 2 of the formation is opened by perforating the production string 3 with the formation of perforation holes 4 through which gas is produced.

As the reservoir pressure decreases, the bottom water 5, which is initially below the shoe 6 of the production string, begins to be pulled to the perforation holes 4 by means of the bottom water cone 7, encircling the well.

To eliminate the watering of the well, repair and insulation works are carried out in it, pumping a water-proofing composition 8 through the perforations 4 and fixing it with cement to form a cement bridge 9 in the inner cavity of the production casing 3, overlapping the perforations 4.

After that, geophysical studies are carried out, according to the results of which the intervals of the more permeable sections of the low-permeable clayed part of the formation 1 are determined.

Next, on the drill pipe string 11, the guide assembly 12 is lowered, provided with a through channel 13 made in its housing. The guide arrangement 12 is placed in the well so that the outlet 14 of the through channel 13 is located in a selected interval of one of the permeable sections 10 of the low permeability of the clayed part of the formation. The guide arrangement 12 is fixed in the production casing 3 in the selected position by means of the anchor-packing device 15.

Then, the drill pipe string 11 is removed from the well.

Then, a milling tool, consisting of a downhole screw motor 17 and a flexible shaft 18, at the lower end of which a mill 19 is placed, is lowered into the well on a flexible pipe 16 into the cavity of the through hole 13 to the outlet 14.

Using milling equipment, a hole 20 is cut in the wall of the production casing 3 using a hydrocarbon-based technological solution 21, for example, gas condensate, diesel fuel, oil.

The milling equipment is removed from the well on the flexible pipe 16. Attach to the shoe of the flexible pipe 16 by means of a high pressure transfer sleeve 22, a hydraulic monitor nozzle 23 and lower it into the well. The length of the high pressure transfer sleeve 22 is selected from the calculation of the maximum possible length of the radial shaft 24, designed in the selected interval of one of the permeable sections 10 of the low permeability of the clayed part of the reservoir.

The jets of a hydrocarbon-based solution 21, for example, gas condensate, diesel fuel, oil, under high pressure not exceeding the hydraulic fracturing pressure, erode the cement stone 25 behind the production string 3 and then radially move the nozzle 23 radially erode the permeable rock formations section 10 of the low-permeable part of the formation with the formation of a radial shaft 24 of small diameter, depending on the thickness of the selected interval of one of the permeable sections in 10 low permeability clayey part of the reservoir.

After the formation of the radial barrel 24 is completed, the radial barrel 24 is cleaned by washing it with an acid composition 26 of a mixture of clay acid, consisting of hydrochloric acid of 10-12% concentration and hydrofluoric acid of 3-5% concentration, as well as an organic acid, for example, ascorbic acid 1-2 % concentration, or citric acid 1-3% concentration, or formic acid 5-7% concentration, with the formation behind the walls of the radial shaft 24 of the cavity 27, expanding the radial barrel 24.

After that, a flexible pipe 16 with a high pressure sleeve 22 and a hydraulic nozzle 23 is removed from the well, the guide assembly 12 is rotated in the same plane, for example, by 180 degrees, depending on the direction of stretching of the next selected interval of the permeable sections 10 of the low permeability of the clay part of the formation and carry out similar operations for laying the next radial shaft.

Next, the guide assembly 12 is raised to the height of the next selected interval of the permeable sections 10 of the low-permeability clayed part of the formation and similar operations are carried out for laying subsequent radial shafts.

After the completion of the repair work to restore the waterlogged well, the hydraulic nozzle 23 and the guide assembly 12 are removed from it, the elevator string 28 is lowered from the tubing to a depth of the upper radial shaft 28 from the tubing with a diameter corresponding to the area of the through holes equal to the sum of the areas of the through holes of the radial shafts.

Next, the well is mastered and put into operation.

Examples of the implementation of the proposed method.

Example 1

The restoration of a waterlogged well with a production string with a diameter of 168 mm was carried out as follows. Initially, repair and insulation works were carried out in the flooded part of the reservoir to isolate the influx of formation water and cut off the flooded part of the trunk by installing a cement bridge. A composition based on organosilicon liquid GKZh-11N, polyvinyl alcohol PVS-V1N with the addition of aluminosilicate microspheres as a thickener was used as a water-insulating composition, and a composition based on PTC 1-100 with the addition of superplasticizer SP-1 was used as a cement mortar. Then, in the remaining non-irrigated part of the formation, geophysical studies were carried out and intervals of more permeable sections of the productive formation were determined. After that, on a drill pipe string with a diameter of 89 mm, the guide assembly, equipped with a through channel, was lowered and installed using an anchor-packing device, oriented in the direction of the permeable section of the reservoir selected in the range of 696-700 m. As an anchor-packing device, the PRO-YAMO packer 168 × 35 NPF “Packer” (Oktyabrsky, Republic of Bashkortostan) was used. Then, a drill pipe string was removed and a milling tool, consisting of a downhole screw motor of the D1-54 type and a flexible shaft, at the bottom of which the FRP-57 milling cutter was lowered, was lowered into the well on a flexible pipe with a diameter of 48 mm. A hole with a diameter of 60 mm was cut in the wall of a production casing with a diameter of 168 mm using gas condensate. The milling equipment was removed from the well on a flexible pipe and a hydraulic monitor nozzle was attached to the flexible pipe shoe using a high-pressure transfer sleeve, lowered into the well to the outlet of the guide assembly. By streams of gas condensate under a pressure of 35 MPa, the cement stone was washed off behind the production casing. Subsequent movement of the nozzle in the radial direction along the selected permeable section of the 4 m thick productive formation eroded the rock with the formation of a radial shaft with a diameter of 50 mm and a length of 100 m. After that, the radial shaft was cleaned with an acid composition from a clay mixture containing hydrochloric and hydrofluoric acid through a hydraulic nozzle acids of 12% and 5% concentrations, respectively, and ascorbic acid of 1% concentration with the formation of a cavity expanding a radial trunk with a diameter of up to 80 mm. Then, a flexible pipe with a high-pressure sleeve and a hydraulic nozzle was removed from the well, the guide assembly was rotated 180 degrees in the same plane, and similar operations were carried out to lay the next radial shaft of a similar design. Then they lifted the guide assembly to a height of 30 m and carried out similar operations for laying the following radial shafts. After that, an elevator column with a diameter of 114 mm was lowered into the well to the upper radial shafts and the well was put into operation.

Example 2

The restoration of a waterlogged well with a production string with a diameter of 146 mm was carried out as follows. Initially, repair and insulation works were carried out in the flooded part of the reservoir to isolate the influx of formation water and cut off the flooded part of the trunk by installing a cement bridge. A composition based on GKZh-10 organosilicon liquid and PVA-18/11 polyvinyl alcohol was used as a water-insulating composition, and a composition based on PTC 1-50 with the addition of C-3 superplasticizer and Fiber polypropylene fiber was used as a cement mortar. Then, in the remaining non-irrigated part of the formation, geophysical studies were carried out and intervals of more permeable sections of the productive formation were determined. After that, a guide assembly equipped with a through channel was lowered on a string of drill pipes with a diameter of 73 mm and installed using an anchor-packing device, oriented in the direction of the permeable section of the reservoir selected in the range of 682-690 m. As an anchor-packing device used packer G size 146 × 35 company Guiberson. Then, a drill pipe string was removed and a milling tool, consisting of a downhole screw motor of the D1-48 type and a flexible shaft, at the bottom of which a FRP-52 type cutter was lowered, was lowered into the well on a flexible pipe with a diameter of 38 mm. A hole with a diameter of 50 mm was cut in the wall of the production string with a diameter of 146 mm using diesel fuel. The milling equipment was removed from the well on a flexible pipe and a hydraulic monitor nozzle was attached to the flexible pipe shoe using a high-pressure transfer sleeve, lowered into the well to the outlet of the guide assembly. Jet of diesel fuel under a pressure of 35 MPa washed out the cement stone behind the production casing. Subsequent movement of the nozzle in the radial direction along the selected permeable section of the 2 m thick productive formation eroded the rock with the formation of a radial shaft with a diameter of 20 mm and a length of 50 m. After that, the radial shaft was cleaned with an acid composition from a clay mixture containing hydrochloric and hydrofluoric acid through a nozzle acids of 10% and 3% concentrations, respectively, and citric acid of 3% concentration with the formation of a cavity expanding a radial trunk with a diameter of up to 40 mm. Then, a flexible pipe with a high-pressure sleeve and a hydraulic nozzle was removed from the well, the guide assembly was rotated 90 degrees in the same plane, and similar operations were carried out to lay the next radial shaft of a similar design. Then they lifted the guide assembly to a height of 50 m and carried out similar operations for laying the following radial shafts. After that, an elevator string with a diameter of 89 mm was lowered into the well to the upper radial shafts and the well was put into operation.

Example 3

The restoration of a waterlogged well with a production string with a diameter of 140 mm was carried out as follows. Initially, repair and insulation works were carried out in the flooded part of the reservoir to isolate the influx of formation water and cut off the flooded part of the trunk by installing a cement bridge. A composition based on silicone liquid GKZH-10 and a hydrophobizing additive ETS-40 ethyl silicate was used as a water-insulating composition, and a composition based on PTC 1-50 with the addition of C-3 superplasticizer was used as a cement mortar. Then, in the remaining non-irrigated part of the formation, geophysical studies were carried out and intervals of more permeable sections of the productive formation were determined. After that, a guide assembly equipped with a through channel was lowered on a string of drill pipes with a diameter of 73 mm and installed using an anchor-packing device, oriented in the direction of the permeable section of the reservoir that was selected in the range of 679-680 m. The packer PRO-YaJ-0-140-35 NPF “Packer” (Oktyabrsky, Republic of Bashkortostan) was used as an anchor-packing device. Then, a drill pipe string was removed and a milling tool, consisting of a downhole screw motor of the D1-43 type and a flexible shaft, at the lower end of which a FRP-47 type cutter was lowered, was lowered into the well on a flexible pipe with a diameter of 33 mm. A hole with a diameter of 45 mm was cut in the wall of the production string with a diameter of 140 mm using oil. The milling equipment was removed from the well on a flexible pipe and a hydraulic monitor nozzle was attached to the flexible pipe shoe using a high-pressure transfer sleeve, lowered into the well to the outlet of the guide assembly. By streams of oil under a pressure of 35 MPa, the cement stone was washed off behind the production casing. Subsequent movement of the nozzle in the radial direction along the selected permeable section of the 1 m thick productive formation eroded the rock with the formation of a radial shaft with a diameter of 10 mm and a length of 25 m. After that, the radial shaft was cleaned with an acid composition from a clay mixture containing hydrochloric and hydrofluoric acid through a hydraulic nozzle acids, respectively, at 10% and 4% concentrations, and formic acid at 7% concentration with the formation of a cavity expanding a radial trunk with a diameter of up to 20 mm. Then a flexible pipe with a high pressure sleeve and a hydraulic nozzle was removed from the well, the guide assembly was rotated by 45 degrees in the same plane, and similar operations were carried out to lay the next radial shaft of a similar design. Then they lifted the guide assembly to a height of 60 m and carried out similar operations for laying the following radial shafts. After that, an elevator string with a diameter of 73 mm was lowered into the well to the upper radial shafts and the well was put into operation.

A feature of the proposed method for restoring a waterlogged well by laying radial shafts is that it is carried out in a complex formation having several permeable sections of the low-permeability clayed part of the formation, including those made up of low-permeability highly clayed terrigenous deposits of small thickness, including moisture-swelling clays, and laying of each radial shaft is carried out using a hydrocarbon-based fluid that is not harmful influence, in particular, that does not lead to the swelling of moisture-containing clays, and the radial shaft is cleaned of rock residues and the radial shaft is expanded using an acid composition of a mixture of clay acid and an organic acid, for example, ascorbic, citric or formic, which well destroys the cementing component of low permeability terrigenous reservoir. This ensures an increase in the effective area and opening depth of the productive formation of small thickness while eliminating the swelling conditions of the clays contained in this reservoir.

Claims (1)

A method of restoring a waterlogged well, in which repair and insulation work is initially carried out on the waterlogged part of the reservoir to isolate the inflow of formation water and cutting off the waterlogged part of the well by installing a cement bridge, then geophysical studies are carried out in the remaining waterless part of the reservoir, the intervals of more permeable sections of the reservoir are determined, after whereupon on the drill pipe string they lower and install using the anchor-packing device a guide arrangement equipped with a borehole the channel, they are oriented in the direction of one of the permeable sections of the reservoir, then a drill pipe string is removed from the well, a milling tool, consisting of a downhole screw motor and a flexible shaft with a milling cutter at its lower end, is cut into the wall on a flexible pipe, cut into the wall production casing hole using a hydrocarbon-based technological solution, the milling equipment is removed from the borehole on the flexible pipe, attached to the shoe of the flexible pipe by the high pressure transfer sleeve and the hydraulic nozzle is lowered into the well to the outlet of the guide assembly, the cement stone behind the production string is blown under high pressure with a jet of a hydrocarbon-based technological solution and subsequent radial movement of the nozzle in the radial direction erodes the rock to form a radial shaft, after which through the hydraulic nozzle, the radial trunk is cleaned with an acidic composition of a mixture of clay acid and organic acid, for example, ascorbic, citric or formic, with the formation of a cavity expanding the radial trunk, then a flexible pipe with a high pressure sleeve and a hydraulic nozzle is removed from the well, the guide assembly is rotated in the same plane, for example, by 180 degrees, of the permeable section of the productive formation and carry out similar operations of laying the next radial shaft, then raise the guide arrangement to the height of the next interval of permeable sections of the productive layer and carry out similar operations for laying subsequent radial shafts, after which an elevator string is lowered from the tubing to the upper radial shafts with the area of the through hole equal to the sum of the areas of the through holes of the radial shafts, and the well is put into operation.

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