RU2526044C1 - Device for well cement bridging - Google Patents

Abstract

FIELD: oil-and-gas industry.SUBSTANCE: proposed device comprises hollow cylindrical pipe and bottom separation plug with flow channel equipped with seat for top separation plug. Hollow cylindrical pipe in length larger than absorption zone is connected with pipe string and equipped with shoe at its bottom. Cylindrical pipe outside has several conical resilient collars with lower end rigidly locked and upper bell pressed against cylindrical pipe by shear pins. The latter are fitted in lateral holes arranged in rows over cylindrical pipe perimeter. Space between collar and pipe is filled with grouting mortar filler or chemical reagents for improvement of bridge quality. Bottom separation plug after fitting in seat of the top separation plug displaces downward to open lateral holes to straighten collar bells. Bottom separation plug has the edge made of material harder than that of branch pipe to interact with branch pipe and displace only downward. Lateral hole diameters allow fluid filter return from cement after fixation of separation plugs at bottom position and termination of fluid feed in pipe string.EFFECT: higher quality of cement bridging, lower costs.3 dwg

Description

The invention relates to drilling and can be used to isolate the complication zone when drilling a well by controlled delivery of cement slurry at a specified interval of the well to create a hollow cement bridge.

A device for the controlled installation of cement bridges in wells (patent RU No. 2044864, E21B 33/14, publ. 09/27/1995), including a hollow cylindrical body, a supporting element in the form of knives and dividing plugs, and it is equipped with a casing and a suspension plug with a landing saddle in the upper part and side flushing windows installed in the lower part of the body under the knives on shear elements, and the body opposite the knives is made with through longitudinal grooves, while the knives are made with support heads in the form of segments under the inner Yu outer surface of the casing and the housing bore and placed in a longitudinal slotted holes of the latter, wherein the housing is configured at the bottom with lateral flushing windows of similar openings against the outboard tube.

The disadvantages of this device are:

- the impossibility of creating a central hollow channel in the cement bridge when using the device in the open wellbore, since the suspension plug does not provide tightness in the open wellbore with the absorption zone cavities, because of this, the bit moves away from the cement bridge and the new complication zone is opened to be isolated;

- the impossibility of obtaining a high-quality cement bridge, since the suspension plug does not provide tightness in the open hole of the well with caverns of the absorption zone, therefore, after pumping the cement into the well, it sags or is replaced by well fluid and then eroded.

The closest in technical essence and the achieved result is a device for installing a cement bridge in a well (patent RU No. 2435021, E21B 33/14, publ. 11/27/2011), including a hollow cylindrical body, a lower separation plug with a passage channel made through its axis, equipped with a landing seat on top under the upper separation plug and connected by shear elements to the housing, a casing connected to the housing with side flushing channels, and the casing is made in the form of a pipe longer than the absorption zone and equipped on top there is a groove and a hermetically sealed lower separation plug, and on the bottom - a shoe with a valve and a retainer for the lower separation plug, in addition, the plugs, casing and shoe are made of easily drilled material, and the side channels are sealed with the lower separation plug when moving it down to interact with the shoe latch. The disadvantages of this device are:

- the impossibility of delivering directly to the absorption zone of the cement slurry filler or chemicals the necessary concentration to improve the quality of the cement bridge;

- lack of cuffs, which reduces the quality of the installed cement bridge due to the lack of additional reinforcement of the cuffs, which reduces the possibility of maintaining the column of cement after injection of cement mortar;

- the lack of the possibility of filtrate recovery from cement, which leads to a decrease in the quality of the installed cement bridge.

The technical task of the proposed device is to create a reliable design of the device for isolating the complication zone during well drilling due to the possibility of delivering grouting mortar or chemicals of the required concentration directly to the absorption zone, creating additional cuff reinforcement, as well as the possibility of filtration of liquid from cement, which will improve the quality of the installed cement bridge and reduce material costs by eliminating repeated fillings.

The technical problem is solved by a device for installing a cement bridge in the well, including a hollow cylindrical pipe longer than the absorption zone with side holes, connected from above to the pipe string, equipped with a shoe below, a lower separation tube with a passage channel, equipped with a landing saddle under the upper separation tube on top.

What is new is that the cylindrical nozzle is equipped externally with several conical elastic cuffs, the lower end of which is rigidly fixed, and the upper bell is pressed against the cylindrical nozzle by means of shear pins inserted from the inside, which are placed in rows along the circumference of the cylindrical nozzle, with the space between the cuff and the pipe is filled with grout filler or chemicals to improve the quality of the cement bridge, the lower separation plug is the last e landing in the landing seat of the upper separation plug is made with the possibility of breaking the shear pins when moving down, releasing side holes from them and straightening the cuff sockets, while the lower separation plug is equipped on the outside with an edge made of a harder material than the material of the nozzle and made with the ability to interact with the pipe and move only downward, and the diameters of the side holes are configured to filter the fluid from cement after fixation cation of separation plugs in the lower position and stopping the injection of fluid into the pipe string.

Figure 1 shows a device in section when pumping cement mortar through it into the absorption zone.

Figure 2 shows the device in section at the end of the pumping of the cement and the landing of the upper separation tube in the lower.

Figure 3 shows the device in section after cutting the pins, releasing the side holes from them, expanding the cuff sockets, squeezing the cement mortar into the absorption zone through the side holes and landing the plugs in the shoe latch.

A device for installing a cement bridge 1 (Figs. 1-3) in the well 2 includes a hollow cylindrical pipe 3 made of easily drilled material, longer than the absorption zone 4 with side holes 5, connected from above to the pipe string 6 (Fig. ), equipped with a shoe 7 from the bottom, a lower dividing plug 8 with a passage channel 9, equipped with a landing saddle 10 from above under the upper dividing plug 11 (Figs. 2, 3). The cylindrical nozzle 3 (Figs. 1-3) is equipped externally with several conical elastic cuffs 12, the lower end 13 of which is rigidly fixed, and the upper bell 14 is pressed against the cylindrical nozzle 3 (Figs. 1, 2) using inside shear pins 15 inserted into side holes 5 (Figs. 1-3), which are arranged in rows along the perimeter of the cylindrical nozzle 3. Moreover, the space between the cuff 12 and the nozzle 3 is filled with grout grout filler, for example microspheres, RD, etc., or chemical reagents 16, for example CaCl , NaCl, etc., for ulu to improve the quality of the cement bridge 1. The lower dividing plug 8 after landing in the seat saddle 10 of the upper dividing plug 11 (Fig. 2, 3) is capable of breaking the shear pins 15 (Fig. 1, 2) when moving downward, releasing side holes from them 5 (FIGS. 1-3) and expansion of the sockets 14 (FIG. 3) of the cuffs 12. The lower dividing plug 8 (FIGS. 1-3) is equipped on the outside with an edge 17 made of a harder material than the material of the pipe 3 fixed to dividing plug 8, for example, by fitting a preload, soldering, etc. and configured to interact with the pipe 3 and move only down. The diameters of the side openings 5 are configured to filter out the fluid from cement after fixing the separation plugs 8, 11 (Fig. 3) in the lower position and stopping the pumping of fluid into the pipe string 6 (Figs. 1-3).

The device operates as follows.

According to the research results, the device is lowered into the well 2 (Figs. 1-3) into the absorption zone 4 on the drill pipe string 6 so that the side holes 5 of the cylindrical pipe 3 are located opposite the absorption zone 4. Then, along the drill pipe string 6 through the lower separation plug 8 with a passage channel 9 and shoe 7 into the absorption zone 4 pump the calculated volume of cement. After that, the upper separation plug 11 (FIGS. 2, 3) is placed in the drill pipe string 6 and pumped by pumping the wellbore fluid into the seat 10 (FIGS. 1-3) of the lower separation plug 8, while the pressure above the plugs 8 and 11 (figure 2, 3), which leads to a shift downwards, because the lower separation tube 8 (Fig.1-3) in the cylindrical pipe 3 is installed with an interference fit. Next, by pumping the squeezing liquid with plugs 8 and 11 (Figs. 2, 3), the cement mortar is extruded from the nozzle 3 (Figs. 1-3) into the absorption zone 4, while moving down the lower separation plug 8 destroys the shear pins 15 inserted into side holes 5, releases them and straightens the upper bells 14 (Fig.3) of conical elastic cuffs 12 (Fig.1-3), the lower end 13 is rigidly fixed to the cylindrical pipe 3. Filler cement slurry or chemical reagent 16 to improve the quality of the cement bridgeysvobozhdaetsya from the space between the sleeve 12 and the sleeve 3 and is mixed with cement mortar. In addition, the cuffs 12 allow a better installation of the cement bridge 1 due to the creation of additional reinforcement. Upon reaching the plugs 8, 11 (Figs. 2, 3) of shoe 7 (Figs. 1-3), an increase in pressure is recorded on the surface, after which pumping of the squeezing liquid is stopped. Due to the fact that the edge 17, which is equipped with the lower dividing plug 8, cuts into the nozzle 3, there is no extrusion of the plugs 8, 11 (Fig.2, 3) back into the cylindrical nozzle 3 (Fig.1-3). After that make the collar of the drill pipe 6 on the left thread 18 and raise it to the surface. Since the diameters of the side holes 5 are made with the possibility of filtration of liquid from cement after fixing the plugs 8, 11 (Figs. 2, 3), the time to wait for the cement mortar to solidify is reduced and its quality is improved. Due to the fact that the plugs 8 (Figs. 1-3) and 11 (Figs. 2, 3), the nozzle 3 (Figs. 1-3) and the shoe 7 are made of easily drilled material, they are easily destroyed by a bit (in Fig. Not shown) with further deepening of the well, and due to the fact that the device forms a hollow channel in the cement bridge 1, leaving the bit to the side from the cement bridge 1 is excluded, which prevents the opening of a new absorption zone 4.

The proposed device for installing a cement bridge in a well is a reliable design due to the possibility of delivering cement slurry or chemicals of the required concentration directly to the absorption zone, creating additional reinforcement with cuffs, as well as the possibility of filtration of liquid from cement, which will improve the quality of the cement bridge and reduce material costs by eliminating re-fillings.

Claims (1)

A device for installing a cement bridge in a well, including a hollow cylindrical pipe longer than the absorption zone with side openings, connected from above to the pipe string, equipped with a shoe below, a lower separation plug with a passage channel, equipped with a landing seat under the upper separation plug, characterized in that the cylindrical pipe is equipped externally with several conical elastic cuffs, the lower end of which is rigidly fixed, and the upper bell is pressed against the cylindrical patr the flange using inside shear pins inserted into the lateral openings, which are arranged in rows along the perimeter of the cylindrical nozzle, the space between the cuff and the nozzle being filled with grout filler or chemicals to improve the quality of the cement bridge, the lower separation plug after landing in the seat of the upper separation plug made with the possibility of destruction of the shear pins when moving down, releasing side holes from them and expanding the cuff sockets, At the same time, the lower separation plug is equipped on the outside with an edge made of a harder material than the material of the nozzle and configured to interact with the nozzle and move only downward, and the diameters of the side openings are configured to filter the liquid from cement after fixing the separation plugs in the lower position and stopping the injection of fluid into the pipe string.

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