RU2571469C1 - Completion of direct-cementing casing string with return valve - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: assembly of direct-cementing casing string with return valve is suggested, and this assembly comprises a common case for plug catching baffle with feed-through channel made to seal and fix a cementing plug, and return valve including bushing and saddle for the gate formed in the upper part of the bushing connected to the plug catching baffle. At that the return valve is made with the gate made as a ball and extendible saddle with elastic sealing. Moreover the upper part of the return valve bushing is fixed inside the feed-through channel of the plug catching baffle. Besides, the baffle is made with groves while cementing plug is equipped with a latch with scalloped surface to be inserted into the above grooves at setting the cementing plug into the plug catching baffle.

EFFECT: improved reliability of the casing string closure upon completed circulation of grouting mortar both with cementing plug and return valve and fixation of gates from rotation for the purpose of in-line drilling of the assembly upon cementing.

5 cl, 10 dwg

Description

The invention relates to the field of fastening oil and gas wells, and in particular to equipment for cementing casing in vertical and directional wells by direct circulation.

Known equipment for casing, including a spring-loaded poppet type check valve installed above the shoe with the possibility of opening from the action of vertical axial force from top to bottom (see the description of the invention to RF patent No. 2086752, ЕВВ 33/14, publ. 10.08.87).

A disadvantage of the known equipment is the need to use an additional column of flushing pipes, lowering them into the well, creating an axial load on the valve shutoff element and back pressure in the column, monitoring and adjusting these parameters in the cementing process. This greatly complicates the cementing process itself, increases its time and complexity. In addition, there is a risk of spontaneous opening of the non-return valve under the pressure of the liquid in the flushing pipes and the ingress of this liquid into the grouting fluid during flushing of pipes and annular space.

Known equipment for cementing a casing string, including a seating seat configured to fasten in a threaded connection to a casing sleeve, and a tip of the flushing string sealed in the seating saddle, wherein a socket for sealing and fixing the cementing plug extruded through the flushing hole is made in the lower part of the seating saddle the column and equipped with an annular spring retainer with a spacer cone, which are placed on the tube rod above the sealing ring and are made along the rod, and an elastic guide cuff is attached to the upper end of the rod (see utility model description No. 59128, ЕВВ 33/14, publ. 10.12.2006).

Known cementing equipment is applicable as part of a casing of a certain diameter, made with a sleeve for fastening the saddle. The principle of fastening the equipment along the inner diameter of the coupling (in the context between the threaded parts of the casing) limits the possibility of its use and excludes installation in most modern threaded connections. The equipment is not simple and easy to use.

Closest to the proposed tooling is a tooling for cementing the casing string, containing a common housing for the seat saddle made with a socket for sealing and fixing the cement plug, and a check valve including a sleeve and a saddle in the form of a truncated cone for the locking element, and the seat seat for cementing the plugs and the non-return valve seat are made integrally at the same time, the locking unit is made in the form of a stem seat facing the larger base with shear screws and many balls, and part of the ki-return valve secured to the valve seat outside the cementing plug (see U.S. Patent №7533728, E 21 B 33/14, published 19.05.2009 -.. prototype).

Known equipment allows you to perform cementing annular space methods of direct or reverse cementation. In direct cementing, grouting (cement) mortar enters through the inner channel of the casing with its displacement into the annular space from the bottom up. In this case, the cement (grouting) mortar is sold using a separation plug. After the cork is seated in the saddle and the moment “Stop” is received, the cork is fixed in the saddle and the column and annular (annular) spaces are separated (FIG 4A). In this case, the valve 7 remains fixed by shear screws 13 and does not overlap the annular space. Thus, the separation of annular and annular spaces is carried out only by a cork. During reverse cementing, grouting (cement) mortar enters through the annulus with the displacement of the borehole fluid from top to bottom through the internal passage channel. In this case, in order to understand when the grout has reached the final goal, special balls are used that plug the holes 11 around the valve, and the resulting pressure pushes the valve 7 into the seat 2. A cement plug is not used in this case. Thus, with direct or reverse cementing in a known tooling, only one degree of protection is provided (overlapping the passage channel with either a valve or a plug).

The known equipment is not compact in length, has a low reliability of overlapping the casing string after completion of the cement slurry circulation due to the provision of only one level of tightness in the channel of the equipment and the complex design due to the need to use multiple balls, which reduces the speed, maneuverability and ease of operation when lowering it into the casing. Moreover, in the known snap-in there is no fixation of the locking elements (plugs or valves) from rotation around the axis, which is very important for the speed of drilling these elements after the cement has hardened.

The technical result of the invention is the creation of a compact, stand-alone universal robust construction of cementing equipment with quick, easy and convenient installation in the casing, high reliability of the casing closure after completion of the cement slurry circulation (due to the provision of two levels of tightness in the equipment channel simultaneously with a plug and a non-return valve) and fixing locking elements from rotation for quick drilling of equipment after cementing.

This goal is achieved by the fact that in the snap direct cementing of the casing with a check valve, containing a common housing for the seat saddle with a through channel made with the possibility of sealing and fixing the cement plug, and a check valve comprising a sleeve and a saddle for the locking element formed in the upper the part of the sleeve connected to the seat, the check valve is made with a locking element in the form of a ball and a sliding seat with an elastic seal, and the upper part of the sleeve of the check valve fixed inside the valve seat through-channel for cementing plug, the mounting seat is grooved and wiper plug is provided with a clamp with a toothed surface for insertion into said bore during installation in the cementing plug landing seat.

The cementing plug is preferably made with a persistent protrusion at the end, and the landing seat is made with a locking element to limit the rotation of the cementing plug when drilling the equipment after cementing.

It is advisable to make the locking element in the form of a nut with two restrictive protrusions for placing between them the thrust protrusion of the cementing plug in its final position.

It is preferable to fix the upper part of the non-return valve sleeve inside the seat for the cement plug with a threaded connection.

It is advisable to check the valve throttle type TsKOD.

When conducting patent research, no solutions were found that are identical to the declared one, and, therefore, the proposed solution meets the criterion of "novelty." The invention does not follow explicitly from the known solutions, therefore, the proposed invention meets the criterion of "inventive step".

In FIG. 1 shows a tool for cementing a casing in a section without a ball.

In FIG. 2 shows a cement plug in section.

In FIG. 3 shows an enlarged fragment A in FIG. 2.

In FIG. 4 shows the tip of a cement plug with a persistent protrusion at the end.

In FIG. 5 shows a locking element in the form of a nut with restrictive protrusions.

In FIG. 6 shows the end position of the cementing plug relative to the locking element.

In FIG. 7 shows a tool for cementing a casing in a section with a ball.

In FIG. Figure 8 shows a tool for cementing a casing string in a section with a ball and a cementing plug (in the final position).

In FIG. 9 shows an enlarged fragment D in FIG. 5.

FIG. 10 illustrates a casing cementing scheme in steps a), b), c), d).

In FIG. 1-10 the following notation is accepted:

1 - general building;

2 - a landing saddle;

3 - cementing plug;

4 - check valve;

5 - ball (locking element);

6 - grooves;

7 - a clamp;

8 - locking element (in the form of a nut);

9 - sleeve;

10 - pressure ring;

11 - rubber cuff;

12 - upper split clip;

13 - lower split clip;

14 - a persistent ring;

15 - ring limiter;

16 - fifths;

17 - spring;

18 - movable hollow rod;

19 - emphasis;

20 - outlet (stop 19);

21 - hole (annular stop 15);

22 - persistent protrusion (at the end of the tip 23 of the cementing plug 3);

23 - tip (cementing plug 3);

24 - restrictive protrusion (locking element 8 in the form of a nut);

25 - casing string;

26 - shoe;

27 - drilling fluid (flushing fluid);

28 - cement mortar;

29 - annulus.

The casing cementing equipment contains (Fig. 1, Fig. 7) a tubular-shaped common housing 1 in which a seat seat 2 with a through channel is placed, which is capable of sealing and fixing the cementing plug 3 (Fig. 2), and a check valve 4 type TsKOD (reverse throttle circulation valve) with a locking element in the form of a ball 5 with free movement. In the seat saddle 2 there are special grooves 6, and in the cementing plug (Fig. 2) the corresponding retainer 7 (Fig. 3) with a serrated surface (for insertion into the indicated grooves 6), made for reliable fixation of the cementing plug 3 in the axial direction after it installation in the seat saddle 2. In the seat saddle 2, a locking element 8 is also installed in the form of a nut, which prevents the cementing plug 3 from turning when rotating the casing after cementing.

The non-return valve 4 includes a sleeve 9, in the upper part of which a sliding seat is formed with a seal for seating the locking element in the form of a ball 5, the upper part of the sleeve 9 being fixed inside the through channel of the landing seat 2 for cement plug 3. The upper part of the sleeve 9 of the non-return valve 4 is fixed inside the seat 2 for the cement plug 3 with a threaded connection.

The non-return valve 4 has two main nodes - shut-off and throttle. The locking unit is mounted in the cavity of the sleeve 9 and contains a pressure ring 10, a rubber sleeve 11 for elastic sealing of the sliding seat formed by the upper and lower split cages 12, 13, the thrust ring 14 and the ball 5, made with the possibility of free movement inside the casing. The throttle assembly consists of an annular stopper 15 fixed in the sleeve 9, a heel 16, a spring 17 for springing the movable hollow rod 18, a stop 19 with the formation of a snap outlet 20. The spring 17 is fixed between the heel 16 and the emphasis 19 with the possibility of overlapping the fifth 16 outside the outlet openings 21 in the annular limiter 15.

To exclude the rotation of the squeezing cement plug 3 when drilling the internal tooling elements after cementing, said plug 3 is made with a thrust protrusion 22 at the end of its tip 23 (Fig. 4) with the possibility of its location between the limiting protrusions 24 (Fig. 5) of the locking element 8 in the form nuts in the final position of the cement plug 3 (Fig. 6).

The check valve 4 is designed to self-fill the descent casing 25 with the shoe 26 with drilling mud 27 (flushing fluid), to prevent the movement of cement mortar 28 or flushing fluid from the annulus 29 into the casing 25 during cementing.

The equipment is disposable, maintenance free and not repairable. The working environment in which the equipment works is drilling and grouting solutions treated with chemical reagents, mineralized flippers, oil and gas.

Equipment works as follows (Fig. 7). The common housing 1 is twisted with a shoe 26 (Fig. 7a) and a casing 25. After lowering the casing 25 to a predetermined depth, a ball 5 is thrown into its internal passage channel. The pumped drilling mud 27 carries the ball 5 along it (through the through channel inside the landing seat 2 through the ring 10, the pressure, upper and lower split cages 12, 13, the rubber sleeve 11 and the thrust ring 14) and carries the ball 5 into the cavity of the check valve 4. In the check valve 4, the ball 5 does not interfere with the passage of cement mortar 28 from top to bottom. After pouring into the casing 25 of the cement slurry 28, the cement plug 3 is launched (Fig. 7c) and the squeezing fluid begins to pump.

Cement plug 3, moving along the inner channel of the casing 25, drives the cement slurry 28 in front of him. Cement mortar 28 passes through all the equipment, then through the holes in the shoe 26 and rises up the annulus 24 (Fig. 7d) to the desired level, usually to the mouth. The cementing plug 3 sits in the seat saddle 2, is fixed by the toothed surface of the retainer 7 (Fig. 8, Fig. 9) in the grooves 6 and holds the hydrostatic pressure created by the column of cement mortar 28. The location of the thrust protrusion 22 at the end of the tip 23 of the cementing plug 3 between the limiting protrusions 24 (Fig. 6) of the locking element 8 in the form of a nut eliminates the possibility of rotation of the cementing plug 3 when it is being drilled. Ball 5, having a lower density than cement mortar 28, rises up and is pressed firmly against the part of the non-return valve seat 4, which is formed by an elastic rubber sleeve 11 and a lower split ring 13. After the cement has set, the cement plug 3, as well as all internal parts in General housing 1 drilled. A different sequence of snap operation is possible when step a) in FIG. 7. In this case, the equipment with the ball 5 installed in the check valve 4 is lowered into the casing 25. Further, the operation of the equipment does not differ from the described option.

The equipment provides a double level of protection against the flow of cement from the annulus into the internal passage channel. At the same time, the equipment is compact, convenient in storage, transportation, installation and operation; it is reliably fixed from rotation during drilling.

Claims (5)

1. Equipment for direct cementing of a casing string with a check valve, comprising a common housing for a seat saddle with a through channel configured to seal and fix the cement plug, and a check valve comprising a sleeve and a seat for a locking element formed in the upper part of the sleeve connected to landing seat, characterized in that the non-return valve is made with a locking element in the form of a ball and a sliding seat with an elastic seal, and the upper part of the sleeve of the non-return valve is fixed in utri through channel to the valve seat wiper plug, the landing seat is grooved and wiper plug is provided with a clamp with a toothed surface for insertion into said bore during installation in the cementing plug landing seat. 2. Equipment according to claim 1, characterized in that the cementing plug is made with a persistent protrusion at the end, the seat saddle is made with a locking element to limit the rotation of the cementing plug when drilling the equipment after cementing. 3. The equipment according to claim 2, characterized in that the locking element is made in the form of a nut with two restrictive protrusions for placing the persistent protrusion of the cementing plug between them in its final position. 4. Equipment according to claim 1, characterized in that the upper part of the check valve sleeve is fixed inside the seat for the cement plug by a threaded connection. 5. Equipment according to claim 1, characterized in that the check valve is made of a throttle type TsKOD.

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