SU1717797A1 - Well program - Google Patents

Abstract

The invention relates to the technology and technology of thermal insulation of the annulus of wells and will be used to prevent the thawing of permafrost around the wells during their operation, and can also be used to prevent the cooling of produced oil or thermal water. Purpose invented Shadowing is the expansion of technological capabilities by ensuring the creation of a layer of thermal insulation behind the production string when fixing wells in permafrost. The well design has a casing (OK) with a sleeve for step cementing consisting of two parts. An additional column is installed in the cavity OK, forming an OK hermetic annular space. A clutch for step cementing is installed below the permafrost zone. The lower part of the coupling housing is made with a conical groove and forms with the upper housing a cavity filled with lubricant. The upper part of the coupling has radial holes blocked by discontinuous diaphragms. Spring-loaded perforated dampers are installed in front of the radial openings of the coupling. During operation, the annular gap above the device is filled with a hydrophobic heat insulating suspension to the mouth. Then, the OK is slowly emptied below the device to the rated height by lifting from the well a second row of pipes, the boot of which is blocked by a squeeze plug. After the occurrence of a pressure drop from the heat insulating suspension, the liquid phase is filtered into the interior of the empty OK through the radial holes of the stepped cementing sleeve, 6 sludge. V4 VI About NJ

Description

The invention relates to the technique and technology of thermal insulation between the well piping space and will be used to prevent the thawing of everlasting rocks around the skins during their operation, and can also be used to prevent the cooling of produced oil or thermal water.

A device is known for insulating the annular space of wells, which involves the use of double-wall tubing, the annular gap is filled with polyurethane, and the joints of the inner pipes are sealed with metal or rubber rings.

A disadvantage of the known device lies in the difficulty of concentrating the inner tube relative to the outer tube, filling the gap between the pipes with polyurethane, sealing the joints of the ends of the inner tubes and the need to weld the outer tubes when the string is lowered into the well.

Closest to the present invention is a method of cementing wells, which provides for the casing to be lowered into the well, in which a sleeve for stepwise cementing, lowering the second row of pipes into the casing, connecting the shoes of the first and second rows of pipes and simultaneously pumping and displacement through the second row of cement mortar pipes, and in the annular gap between the first and second rows of pipes and the annulus, above the coupling for stepped cementing, injection of lightweight drilling solution, water, or aerated water to control the pressure on the reservoir to be cemented.

The disadvantage of this method is that with its help it is impossible to remove the liquid phase from the heat-insulating suspension, which is located in the annular gap between the intermediate and production columns.

The aim of the invention is to expand the technical capabilities by ensuring the creation of a layer of thermal insulation behind the production string when fixing wells in permafrost.

The goal is achieved by the fact that, in a well design including a conductor, a casing with a sleeve for stepwise cementing, containing upper and lower parts of the body, interconnected by threads and having radial holes, an additional column installed in the casing cavity and forming the hermetic seal space, the step cementing sleeve is mounted on the casing below the permafrost zone, and the lower part of the sleeve body is made with a conical point and forms a cavity filled with grease with the coupling, the coupling holes are blocked by discontinuous diaphragms, and spring-loaded perforated dampers are installed on the outer surface of the coupling, in front of the holes.

, FIG. Figure 1 shows the well design in which a coupling for step cementing is installed below the zone of perennially frozen rocks; in fig. 2 clutch for step cementing in transport position; in fig. 3 - the same, in the process of forcing the heat insulating suspension into the annular gap; in fig. Figure 4 shows the position of the coupling parts when filtering the liquid phase from the slurry into the interior of the emptied column; 5 and 6 of the layout of the coupling parts after the radial circulation channels are closed and the upper and lower parts of the coupling housing are sealed.

The well contains a guide plug 1, a shoe 2, a check valve 3, a nozzle 4, a casing stop ring 5,

5 a landing nest 6, a landing cone of the second row of pipes 7, a stop ring of the second row of pipes 8, a casing 9. a second row of pipes 10, a coupling 11 for step cementing 11, pressure pipes 12-15, a seal 16, pushing plugs 17 and 18, cement head 19, jig 20. Intermittent line 21 indicates that perennial frozen rocks are ending at this point. The coupling 11 for step cementing consists of the upper element 22 of the split housing, the lower housing element 23, the coupling sleeve 24, through which the upper and lower housing elements are connected, radial circulating channels 25, bursting diaphragms 26, clamping nuts 27, perforated the shutters 28, the flat gland springs 29, the coupling 30, and the sealing composition 31. Thermal insulation

5, the work is performed using the elements included in the well design as follows.

In the casing 9, equipped with a shoe stopper 1, a shoe 2,

0 by a check valve 3, a stop ring 5, a landing nest 6 and a coupling 11 for stepwise cementing, lower the second row of pipes 10. The bottom of the second row of pipes is equipped with a stop ring 8, the landing

5 with a cone 7, a cementing head 19, inside of which, two separator plugs 17 and 18 are installed between the discharge lines 14 and the plug 17 has a smaller outer diameter than the plug 18.

0 Then, they seal the annular gap between the first and second rows of pipes 9 and 10 by fitting the cone 7 on the landing nest 6 and closing the annular gap with seal 16. After that, through pipe 13,

5 on reassembly of the tightness of the articulation of the fitting cone 7 with the socket 6.

After crimping the articulation, the calculated volumes of buffer fluid and cement mortar are pumped through the injection nozzle 14 into the second row of pipes 10.

Then through the discharge pipe 15 is pumped through the liquid. Water is pumped through the discharge pipe 13 into the annular gap between the first and second rows of pipes, creating an overpressure in the annular space until the diaphragms 26 are destroyed. Subsequently, the injection of buffer fluid, cement slurry, squeezing fluid into the second row of pipes and water in the annular gap between the first and second rows of pipes are produced simultaneously before landing the plugs 17 and 18, respectively, on the grooves-rings 5 and 8. Then the calculated volumes are pumped through the nozzle 13 into the annular space between the first and second rows of pipes oizol translational slurry and displacement fluid.

In the process of pumping the heat insulating suspension into the recessed space, the perforated shutters 28 are pressed by the flow of the suspension, the circulation channels remain open during the process of pumping and pushing the suspension. After completion of the displacement, the spring 29 presses the flaps to the seats in the sleeve 24 (Fig. 4). Then, the annular gap between the first and second rows of pipes is depressurized, the second row of pipes is lifted from the well to the calculated height. When the second row of pipes are lifted, the shoe of which is blocked by the plug 18, the squeezing fluid in them rises along with the pipes. This is done in order to gradually reduce the level of drilling fluid in the column below the radial circulation channels of the coupling 11 and create a pressure differential between the annular and tubular spaces to filter out the liquid phase from the heat insulating suspension into the inside of the casing. The depth of the emptying of the casing below the radial channels of the sleeve is determined by calculation from the condition that the entire liquid phase, filtered from the heat insulating suspension, should be placed in the empty column.

After filtering the liquid phase from the heat insulating suspension, a second row of pipes are extracted from the inside of the casing string and the oil is rotated.

the upper non-cemented part of the column to the right to the articulation of the upper and lower elements of the coupling housing for step cementing. The presence on the elements of the housing coupling

The threads and sealing composition in the gap between the elements of the body allows to reliably seal the radial circulation channels of the sleeve for staged cementing.

The use of the proposed well design will allow for thermal insulation of the annular space against the occurrence of permafrost and prevent thawing during well operation and reverse freezing during stops.

Formula of the inventive well design, including conductor, casing with coupling for

step cementing containing the upper and lower parts of the body with radial holes, an additional column installed in the cavity of the casing and forming with it an airtight

annular space, from l and h and y and a - so. that, with the aim of expanding technological capabilities by ensuring the creation of a layer of thermal insulation behind the production string when attaching a well

in permafrost rocks, the clutch for step cementing is located below the permafrost zone, and the lower part of the clutch housing is made with a conical groove and forms with the casing

in the upper part, a cavity filled with lubricant, the radial apertures of the coupling being blocked by discontinuous diaphragms, and spring-loaded perforated dampers mounted on the outer surface of the coupling, in front of the apertures.

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Claims (1)

Claim The design of the well, including a conductor, a casing with a coupling for step cementing, containing the upper and lower parts of the casing with radial holes, an additional column installed in the cavity of the casing and forming a sealed annular space with it, which is clear from the fact that , in order to expand technological capabilities by ensuring the creation of a layer of thermal insulation behind the production string when fastening the well in permafrost, a coupling for step cementing times eschena lower zone mnogolotnemerzlyh rocks, and the lower part of the housing sleeve is formed with a conical bore and forms with the housing upper part of the cavity filled with lubricant, and radial coupling holes overlapped discontinuous apertures and coupling the outer surface perod holes perforated mounted spring-loaded flap. Figure 2