RU55864U1 - 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 “stop ring” in the form of a nozzle with an annular sample plugged at the bottom, as well as a support ring sealed in the lower sleeve of the casing, having telescopic interaction with the nozzle, and a flushing pipe string equipped with rigid centralizers. The flushing pipe column at the end is equipped with a nipple with an annular groove at the bottom and an annular sampling at the top. In the annular sampling of the nozzle, a snap split ring is installed, which has the ability to fix the nozzle when it moves from the bottom upwards relative to the support ring. An adapter is screwed onto the lower end of the lower sleeve, which is rigidly connected from below to the intermediate sleeve, in which the non-return valve is sealed. The pipe is fixed on the annular groove of the nipple with a shear element. The inner diameter of the support ring is made with the possibility of tight interaction with the outer diameters of the pipe and nipple. The nipple is sealed from below and provided with radial channels that are hermetically sealed from the outside by the sleeve. The sleeve is fixed on the nipple with a destructible element and is provided with an inner annular recess with a spring split ring. The sleeve is made with the possibility of axial movement upward, opening the radial channels and fixing at the top with a spring split ring interacting with the annular selection of the nipple. A shoe pipe having through holes is mounted at the lower end of the intermediate sleeve. The proposed device allows after lowering the device into the well before cementing the casing to compress the flushing pipe string to the required pressure, and also eliminates the use of averaging tanks, which simplifies the technology of preparation of cement slurry. In addition, the device guarantees that the cement slurry pumped into the annulus of the well returns to the casing due to the installation of a “stop ring” and a check valve 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 selection of the nozzle interacts with a hundred a split split nipple ring.

The disadvantages of this device design:

firstly, jamming of the nozzle in the support ring is possible, which leads to a loss of tightness of the device, and as a result, to the reverse outlet of the grouting solution from the annulus of the well into the casing;

secondly, it is necessary to use averaging tanks in the preparation of cement slurry;

thirdly, it is not possible 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, which allows it to pressure the flushing pipe string to the required pressure after lowering it into the well before cementing, and also to exclude the use of averaging tanks in the preparation of grouting mortar and to ensure that grouting grout injected back into the annulus is returned to the casing.

This problem is solved by the proposed device for cementing the casing string in the well, including a “stop ring” in the form of a nozzle with an annular sample plugged at the bottom, a support ring installed in the lower sleeve of the casing with telescopic interaction with the pipe, a shear element, a flushing pipe string, equipped rigid centralizers and at the end with a nipple with an annular groove at the bottom and an annular selection, snap split ring.

New is that the bottom of the casing is equipped with a check valve, the annular sampling of the nipple is made at the top, and the nozzle is fixed on the annular groove of the nipple by a shear element, while the retainer is split, the ring is installed in the annular sampling of the nozzle with the possibility of fixing the nozzle from the bottom upward relative to the support ring, inner the diameter of which is made with the possibility of tight interaction with the outer diameters of the pipe and nipple, muffled from the bottom and provided with radial channels that seal They are clearly overlapped externally by a sleeve fixed on the nipple with a destructible element, the sleeve being provided with an internal annular recess with a spring split ring and configured to axially move upward, opening the radial channels and locking at the top by a spring split ring interacting with the ring selection of the nipple.

Figure 1 shows the proposed device in longitudinal section, lowered into the well.

Figure 2 is the same in the process of circulation in the preparation of cement slurry.

A device for cementing a casing string 1 in a well (see FIG. 1) includes a groan-ring in the form of a pipe 2 plugged from below with an annular selection 3, as well as a support ring 5 sealed in a lower sleeve 4 of a casing string 1, which has the possibility of telescoping interaction with the pipe 2, the column of washing pipes 6, equipped with rigid centralizers 7.

The column of flushing pipes 6 at the end is equipped with a nipple 8 with an annular groove 9 at the bottom and an annular sample 10 at the top.

In the annular sample 3 of the pipe 2, a snap split ring 11 is installed, which has the ability to fix the pipe 2 when moving it from the bottom upward relative to the support ring 5. An adapter 12 is screwed onto the lower end of the lower sleeve 4, which is rigidly connected from the bottom to the intermediate sleeve 13, in which the reverse is sealed valve 14. The pipe 2 is fixed on the annular groove 9 of the nipple 8 with a shear element 15.

The inner diameter of the support ring 5 is made with the possibility of tight interaction with the outer diameters of the pipe 2 and the nipple 8. The nipple 8 is muffled from the bottom and provided with radial channels 16, which are hermetically closed from the outside by the sleeve 17.

The sleeve 17 is fixed on the nipple 8 with a destructible element 18 and is equipped with an inner annular recess 19 with a spring split ring 20. The sleeve 17 is made with the possibility of axial movement upward, opening the radial channels 16 and fixed at the top with a spring split ring 20 interacting with the annular selection 10 of the nipple 8.

At the lower end of the intermediate sleeve 13, a shoe pipe 21 is installed having through holes 22.

The device operates as follows.

After preparatory work, the casing 1 is assembled with the above-described arrangement at the end to the design depth at the design depth (see FIGS. 1 and 2).

Then, into the casing 1, the flushing pipe 6 is lowered, equipped with a nipple 8 at the end with a pipe 2 and a sleeve 17 placed on them. During the descent, the flushing pipes 6 are centered by means of rigid centralizers 7 relative to the casing 1, which ensures a subsequent “stop” hit rings ", made in the form of a nozzle 2 muffled from below, into a support ring 5, hermetically placed in the lower sleeve 4 of the casing string 1.

The descent of the washing pipes 6 (by calculation) is continued until the pipe 2, which is muffled from below, reaches the support ring 5 in about 3-5 meters.

Then, the length of the column of washing pipes 6 is adjusted by means of a fitting pipe (not shown in FIGS. 1 and 2), taking into account the possibility of tying it with a filling unit (not shown in FIGS. 1 and 2) when the washing pipes 6 are axially moved downward until until the lower end of the pipe 2 plugged from below is in the adapter 12 (the space between the support ring 5 and the check valve 14).

A pressure test of the wash pipe string 6 is carried out at the estimated maximum pressure that occurs when cement is pushed into the annulus 23 of the well.

After making sure that the wash tubes 6 are tight, they are let down until the sleeve 17 interacts with the upper end of the support ring 5, as evidenced by the partial weight loss of the wash tubes 6 on the weight indicator installed on the wellhead (in Fig. 1 and 2 not shown).

Next, the discharge of the column of washing pipes 6 to the support ring 5 is continued, while the destructible element 18 is cut off, and the column of washing pipes 6, equipped at the end with a nipple 8 and a pipe 2 located in it with an annular groove 9, is moved downward, while the sleeve 17 remains stationary on the support ring 5.

At a certain point, the spring split ring 20, located in the inner annular recess 19 of the sleeve 17, falls into the ring sample 10 of the nipple 8 and fixes the sleeve 17 in the upper part of the nipple 8 motionless (see figure 2).

Next, the column of washing pipes 6 is lifted up until the retaining split ring 11 installed in the annular sample 3 of the nozzle 2 is not fixed from the bottom relative to the support ring 5, while the nozzle 2 seals tightly in the support ring 5, excluding the passage of grouting mortar down when its subsequent preparation, and the radial channels 16 of the nipple 8, muffled from below, will be placed above the support ring 5 (see figure 2).

The annular space 24 between the flushing tubes 6 and the casing 1 is sealed at the wellhead.

After that, by pumping the fluid through the wash tubes 6, the radial channels 16 of the nipple 8 into the annulus 24 of the well, and then again into the wash tubes 6, grout is prepared by circulation (the annulus 24 of the well is used as an averaging tank).

Next, the column of washing pipes 6 (see Fig. 1) is pulled down until the radial channels 16 of the nipple 8 are between the support ring 5 and the return

valve 14, while the support ring 5 will enter into tight interaction with the nipple 8 inside it, excluding the entry of grouting mortar and squeezing fluid into the casing 1.

The grouting mortar is continued to be pumped into the flushing pipes 6, but now the grouting mortar through the adapter 12 and the check valve 14, through the through holes 22 of the shoe 21, enters the annular space 23 of the well until the grouting solution exits at the wellhead, and then again into the flushing tubes 6 Thus, the cement slurry is circulated through the annulus 23 of the well.

After stabilization of the cement slurry by density, the circulation is stopped.

Next, the calculated volume of the squeezing liquid is pumped into the washing pipes 6, leaving about 100 L of grouting mortar in the washing pipes 6. Then the grouting mortar is squeezed out of the washing pipes 6 through the adapter 12 and the check valve 14 through the through holes 22 of the shoe 21 in the annular space 13 wells.

Then the washing pipes 6 begin to rise, while the check valve 14 prevents the cement mortar from flowing back from the annulus, which, after reaching the mouth, is sent to the tank of the filling unit and circulated, constantly monitoring the density of the cement at the inlet and outlet of the well.

In the process of lifting the wash tubes 6 up, the snap split ring 11 installed in the annular sample 3 of the nozzle 2 is again fixed from the bottom relative to the support ring 5, while the nozzle 2 is sealed again in the support ring 5, and the radial channels 16 of the nipple 8, muffled from below, are located above the support ring 5. After which, backwash (by supplying washing liquid to the annular space 24) is used to wash the remnants of the cement slurry from the annular space 24 of the well and the wash tubes 6.

Next, the flushing pipes 6 are stretched upward, and the shear element 15 is destroyed and the pipe 2, which is plugged from below, remains hermetically in the support ring 5 of the lower sleeve 4, reliably blocking the cross-section of the casing 1 from the penetration of the cement slurry due to the annular space 23 in case of a check valve 14. Next, the washing pipes 6 with the nipple 8 are raised to the surface and the well is left on the OZZ (waiting for cement to harden).

The proposed device allows after lowering the device into the well before cementing the casing to compress the flushing pipe string to the required pressure, and also eliminates the use of averaging tanks, which simplifies the technology of preparation of cement slurry. In addition, the device guarantees that the cement slurry pumped into the annulus of the well returns to the casing due to the installation of a “stop ring” and a check valve under each other.

Claims (1)

A device for cementing a casing string in a well, including a “stop ring” in the form of a nozzle with an annular sample plugged from below, a support ring mounted in the lower sleeve of the casing with telescopic interaction with the pipe, a shear element, a flushing pipe string equipped with rigid centralizers and the end with a nipple with an annular groove at the bottom and an annular selection, a snap split ring, characterized in that the casing is equipped with a check valve at the bottom, the annular extraction of the nipple flax at the top, and the nozzle is fixed on the annular groove of the nipple by a shear element, while the snap split ring is installed in the annular sampling of the nozzle with the possibility of fixing the nozzle from below to the top relative to the support ring, the inner diameter of which is made with the possibility of tight interaction with the outer diameters of the nozzle and the nipple, muffled from below and provided with radial channels that are hermetically sealed from the outside by a sleeve fixed on the nipple with a destructible element, the sleeve being provided with an internal annular recess with a spring split ring and is made with the possibility of axial movement upward, opening the radial channels and fixed at the top with a spring split ring interacting with the annular selection of the nipple.