RU55863U1 - Casing Cementing Device - Google Patents

Abstract

The proposal relates to the oil industry, in particular, to the technology of cementing casing strings in oil and gas wells. A device for cementing a casing string in a well includes a flushing pipe string with a nipple at the end having an annular sample in which a snap split ring is mounted. A plugged pipe with an annular groove and an annular protrusion at the bottom is telescopically installed inside the nipple. A pipe inserted telescopically into the nipple has the ability to be limited upward by an annular protrusion until the annular groove of the plugged pipe interacts with the split split ring of the nipple. Bottom casing is equipped with upper and lower non-return valves installed under each other respectively in the upper and lower couplings. The nipple is equipped with radial channels, made with the possibility of their tight shutoff pipe when moving up. The upper and lower couplings are interconnected by an adapter. A shoe pipe having through holes is installed at the lower end of the lower sleeve. The proposed device allows after lowering the device into the well before cementing the casing string to compress the flushing pipe string to the required pressure, in addition, it guarantees that the cement slurry pumped into the annular space of the well returns to the casing string by installing two check valves under each other.

Description

The proposal relates to the oil industry, in particular, to the technology of cementing casing strings in oil and gas wells.

A device for cementing a casing, made in the form of a spring-loaded poppet type check valve, is installed on the lower end of the casing, lowered into the well (patent RU No. 2086752, IPC 6 E 21 B 33/14, published in 1997).

The disadvantages of the device:

- the need to top up the well during the casing run;

- at medium and high casing descent speeds, hydraulic fracturing is possible;

- the need to create backpressure at the wellhead during flushing and injection of cement slurry;

- there is no possibility of manufacturing all valve parts from drilled materials, which may complicate further deepening of the well.

The closest in technical essence is a device for cementing a casing string in a well (patent for utility model RU No. 42855, IPC 7 E 21 B 33/14, published in bulletin No. 35 dated December 20, 2004), including “stop- ring "in the form of a nozzle plugged from below with longitudinal and radial channels with an annular ledge and a conical surface below, to which a support ring is fitted telescopically to the lower sleeve, equipped with shear elements, the free ends of which extend into the longitudinal grooves of the pipe, and have a conical bore in the lower end , adek the conical surface of the nozzle, while on top of the inner surface of the nozzle an annular sampling is made, and the column of flushing pipes is equipped with rigid centralizers and at the end is equipped with a nipple having an annular stop and an outer annular groove with an annular sampling in which a retaining split ring is installed, the outer cylindrical the nipple groove is equal to the inner diameter of the nozzle, while in the working position the ledge of the nipple interacts with the upper end of the nozzle, and the annular sampling of the nozzle interacts with a hundred a split split nipple ring.

The disadvantages of this device design are:

firstly, a high probability of jamming of the pipe in the support ring, which leads to a loss of tightness of the device, and, as a result, to the reverse exit of the grout from the annulus of the well into the casing;

secondly, the inability to crimp the flushing pipe string after the device is lowered into the well immediately before cementing.

The objective of the utility model is to develop the design of the device that allows, after the device is lowered into the well, to compress the flushing pipe string to the required pressure before cementing, and it is also guaranteed to prevent the cement slurry pumped back into the annulus of the well back into the casing.

This problem is solved by the proposed device for cementing the casing string in the well, including a flushing pipe string with a nipple at the end, having an annular sample, in which a retaining split ring is installed, a plugged pipe with an annular groove and an annular protrusion at the bottom, and the annular groove is made to interact with snap split ring.

New is that the bottom of the casing is equipped with non-return valves, and the nozzle is inserted into the nipple with the possibility of limited upward movement of the annular protrusion until its annular groove interacts with the snap split ring, while the nipple is equipped with radial channels that can be sealed by the nozzle when moving it up.

The figure shows the proposed device in longitudinal section, lowered into the well.

A device for cementing a casing string 1 in a well includes a flushing pipe string 2 with a nipple 3 at the end having an annular sampling 4 in which a snap split ring 5 is installed. A plugged pipe 6 with an annular groove 7 and an annular protrusion 8 is installed inside the nipple 3.

The pipe 6, telescopically inserted into the nipple 3, has the ability to be limited upward by the annular protrusion 8 until the annular groove 7 of the plugged pipe 6 interacts with the snap split ring 5 of the nipple 3.

From the bottom, the casing 1 is equipped with an upper 9 and a lower 10 non-return valves installed one below the other in the upper 11 and lower 12 couplings, respectively. The nipple 3 is equipped with radial channels 13, made with the possibility of their tight shutoff pipe 6 when moving up.

The upper 11 and lower 12 couplings are interconnected via an adapter 14. A shoe pipe 15 having through holes 16 is installed at the lower end of the lower clutch 12.

The device operates as follows.

After preparatory work on the well, casing 1 is lowered to the design depth at the design depth, equipped with the above-described layout from below (see FIG. 1).

Then, into the casing 1, the flushing pipe string 2 is lowered with a nipple 3 at the end and a plugged pipe 6 telescopically installed in the nipple 3, while the borehole fluid inside the casing 1 flows freely into the flushing pipes 2 through the radial channels 13 of the nipple 3.

Next, the length of the column of flushing tubes 2 is adjusted by means of an adjustable nozzle (not shown in FIG.), Taking into account the possibility of tying it with a casting unit (not shown in FIG.) With limited axial movement of the nozzle 6 relative to the nipple 3 of the flushing tubes 2 and further fitting of the flushing column 2 pipes 6 to the upper check valve 9.

Next, the column of flushing pipes 2 is allowed to interact with the annular protrusion 8 of the pipe 6 with the coupling 11 of the upper non-return valve 9. After which the column of the washing pipes 2 is unloaded to the coupling 11 of the upper non-return valve 9, as a result of this, the pipe 6 moves upwardly inside the nipple 3, closing radial channels 13 of the nipple 3, while the snap split ring 5 of the nipple 3 is fixed in the ring groove 7 of the pipe 6, which is opposite to it.

A pressure test of the wash pipe string 2 is carried out at the estimated maximum pressure that occurs when cement is pushed into the annulus 18 of the well.

Next, the washing pipes 2 are raised by 1-2 meters and the excess pressure is again created in the column of washing pipes 2. As a result, the pipe 6 drops down relative to the nipple 3, while its radial channels 13 open, and the retaining ring 5 returns to its original position (see Fig. 1).

At the wellhead, annular space 17 is sealed.

Then, by supplying grouting mortar from the wellhead into the flushing pipes 2 through the radial channels 13 of the nipple 3 and the annular space 18 of the well, cement slurry is circulated, after which it is directed to the averaging tank at the mouth and the filling unit is circulated, constantly monitoring the density of the grouting mortar at the inlet and

exit from the well, while substandard packs of cement slurry are thrown into the barn.

After stabilization of the cement slurry by density, the circulation is stopped. Then, the calculated volume of the squeezing liquid is pumped into the washing pipes 2, leaving about 100 L of grouting mortar in the washing pipes 2 and the cement mortar is pumped from the washing pipes 2 through the casing 1, through the upper 9 and lower 10 check valves and then through the through holes 16 of the shoe pipes 15 into annular space 18.

By backwashing (supplying washing liquid to the annulus 17 of the well), the remains of the cement slurry are washed out of the wash tubes 2 and the annulus 17 of the well.

Next, the wash pipes 2 with the nipple 3 and the telescopic pipe 6 installed in it are raised to the surface, and the well is left on the OZZ (waiting for the cement to harden).

The proposed device allows after lowering the device into the well before cementing the casing string to compress the flushing pipe string to the required pressure, in addition, it guarantees that the cement slurry pumped into the annular space of the well returns to the casing string by installing two check valves under each other.

Claims (1)

A device for cementing a casing string in a well, including a flushing pipe string with a nipple at the end having an annular sample in which a retaining split ring is installed, a plugged pipe with an annular groove and an annular protrusion at the bottom, and the annular groove is configured to interact with the retaining split ring, characterized in that the bottom of the casing is equipped with check valves, and the nozzle is inserted into the nipple with the possibility of limited upward movement by an annular protrusion to the interaction of its annular grooves with a snap split ring, while the nipple is equipped with radial channels, made with the possibility of tight shutoff pipe when moving up.