RU2343272C2 - Cementing valve of casing string - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to technical means employed at boring of well bore with simultaneous casing with casing string, notably for process set of casing strings. There is suggested cementing valve of the casing string; case 4 of the valve is positioned in sub 1 of the casing string made with circular groove 3 on the interior surface, back valve is installed in central channel 5 of the case; seals 25 and 28 are assembled between the case of the valve and inside surface of the sub; also there are installed indicator 17 of fixating the case in the sub and a locking element designed to interact with circular groove 3 of the sub. Cylinder seats 21 are made in part of the valve case located under the back valve; the seats receive locking elements designed to radially rotate; the said locking elements are made as spring loaded holders 22 with a spherical head. The back valve is made as spring loaded cap 6 with plunger 7 in a lower part of which neck 20 is installed; the neck is designed to break.

EFFECT: reduces friction forces and prevents jam of cementing back valve at its trip inside casing string and also ensures receiving clear signal of valve fixation in sub of casing string.

6 dwg

Description

The invention relates to technical means used in the process of drilling a wellbore with its simultaneous casing casing, which grows as the hole deepens and is not removed from the well to change the bit.

Known check valve for casing [1], used in the traditional technology of well construction - when the borehole is drilled at the beginning, and then after removing the rock cutting tool, the walls of the well are fixed with casing pipes, followed by cementing the space between the well wall and deflated casing pipes.

The valve, consisting of an outer casing, a seating seat for a locking element, is mounted at the bottom of the casing. The supporting end surface in the upper part of the valve acts as a “stop ring” to stop the cementing separation plug.

In the method of drilling on the casing using an insert tool fixed to the bottom of the casing - shoe of the casing (SOC) during drilling and removed to replace a worn-out sliding rock cutting tool, it is necessary to have an equal passage internal channel for transporting the insert tool. The presence of a check valve rigidly connected to the casing with elements overlapping the internal bore during drilling using the casing is unacceptable.

The closest in technical essence and the achieved result is a casing cementing valve, in the sub of which, made with an annular groove on the inner surface, there is a valve body, in the central channel of which a check valve is mounted, located between the valve body and the inner surface of the seal sub, the fixation indicator valve bodies in the sub and a locking element installed with the possibility of interaction with the annular groove of the sub [2].

The disadvantage of this cementing valve is the degree of contact of the locking element of the device with the inner surface of the casing during transportation. The locking element of the device, consisting of an external spring split shell with liners mounted inside it, is located in the annular groove of the housing. During transportation, the locking element is in a recessed position, but the outer surface of the locking element under the action of the elastic forces of the shell is in constant contact with the walls of the casing over the entire surface.

With its lower end surface, the shell has the ability to abut the joint of the elements of the casing string. As a result of the emphasis, an increase in the pressure of the flushing fluid and the release (cutting) of the fixation-plug signaling device located in the central channel are possible. After that, further transportation of the valve to the place of fixation is impossible.

In addition, the disadvantage of the said cementing valve is the unstable value of the signal obtained during the cutting of the pinched edges of the fixation indicator (plug) at the moment of fixation of the valve in the casing sub.

The objective of the invention is to increase the reliability of the cementing valve of the casing string in operation.

The technical result obtained by carrying out the invention is to reduce the friction forces of the cementing valve with the casing string during its transportation inside the casing string and to obtain a clear signal when fixing the valve in the casing string sub.

The specified technical result is ensured by the fact that in the cementing valve of the casing string, in the sub of which, made with an annular groove on the inner surface, there is a valve body, in the central channel of which a non-return valve is mounted, located between the valve body and the inner surface of the seal adapter, the housing fixation indicator valve in the sub and a locking element installed with the possibility of interaction with the annular groove of the sub in the part of the valve body, size cylindrical under the check valve, cylindrical sockets are made for locating locking elements made in them in the form of spring-loaded clamps with a spherical head, and the check valve is made in the form of a spring-loaded tip with a plunger, and the housing fixation indicator is in the form of a diaphragm associated with the plunger , in the lower part of which a neck is made with the possibility of its rupture.

The essence of the invention lies in the fact that due to the presence in the part of the valve body located under the check valve of cylindrical sockets for placement in them with the possibility of radial movement of the locking elements, made in the form of spring-loaded clamps with a spherical head, it is possible to reduce friction forces during transportation due to point contact of the clamps with the casing and prevent jamming of the valve body on the ledges of the inner surface of the casing, available at the joints Ub

The presence of a non-return valve, made in the form of a spring-loaded tip with a plunger, a housing fixation indicator in the form of a diaphragm connected with a plunger, in the lower part of which a neck is made with the possibility of its rupture, provides a clear signal of fixing the valve body in the sub according to the specific pressure drop required to break the neck in the plunger.

The invention is illustrated by graphic images.

Figure 1 shows a longitudinal section of a siege column cementing valve.

Figure 2 shows a longitudinal section of the inner part of the cementing valve in the position of its transportation inside the casing.

Figure 3 shows a longitudinal section of a cementing valve in the locked position in the casing sub and triggering the valve body fixation indicator.

Figure 4 is a cross section aa of figure 3 on the latches.

Figure 5 is a view B of figure 2.

Figure 6 shows a longitudinal section of a cementing valve in the closed position of the check valve in the form of a spring-loaded tip with a plunger to prevent back flow of cement.

The casing cementing valve consists of a casing sub 1; An annular groove 3 is made on the inner surface of the sub 3. Inside the sub 1 there is a valve body 4 with a central flushing channel 5, in which a check valve is mounted in the form of a tip 6 with a plunger 7 supported by a spring 8. The tip of the plunger contacts the seat 9 located in the housing . The contact point is sealed by a cuff 10. The valve plunger 7 is centered in a plate 12 having holes 13 and sandwiched between the upper 15 and lower 16 of the housing 4. In the lower part of the plunger 7 there is a diaphragm 17 rigidly connected with it with seals 18 and 19 along the outer and inner diameters. A neck 20 is made in the lower part of the plunger 20. On the outer surface of the lower part 16 of the housing 4 there are cylindrical sockets 21 in which the clamps 22 with springs 23 are mounted. The head of the clamp is spherical in shape. The latch in the socket is locked with a screw 24. Seals 25 are mounted in the upper part 15 of the housing 4, separated by shaped spacers 26, 27 and ring stops 28. The seals are fixed on the outer surface of the housing with a nut 29 and a lock washer 30. The upper part of the central channel 5 is made boring, forming a ledge 31 for interaction with the levers of the gripping tool (overshot). At the end of the lower part 16 of the housing 4, grooves 32 are made. In the coupling of the sub 1, as in the entire casing between the couplings and pipe nipples, a spacer ring 33 is installed.

All parts of the check valve assembly located inside the sub 1 are made of materials drilled with a bit: aluminum alloy, silicon-manganese bronze, rubber.

Cementing valve casing operates as follows.

A method for drilling a well using a casing as a drill string is provided. Wellbore drilling is carried out using a removable insert tool fixed to the bottom of the casing string - casing shoe (BOC) and extracted to the surface to replace the rock cutting tool (sliding bit, sliding expander, etc.). During drilling, the casing is constantly in the well. The casing must have a uniform bore with a certain inner diameter.

Due to the fact that blocking the inner channel of the casing string is unacceptable, the cementing valve of the casing string 2 during drilling is represented by a sub 1 with an internal annular groove 3, which is mounted in the casing string at a distance of 10-20 m from the lower end of the shoe. The size (width) of the inner annular groove is selected so as not to impede the descent of the retrievable insert tool, and its height position relative to the bottom of the well eliminates the accumulation of slurry material in the groove.

Upon reaching the design bottom of the well, the insert tool is removed to the surface, and the cementing check valve is inserted into the casing 2 with recesses 22 recessed into the sockets 21 of the valve body 4.

The transportation of the check valve inside the casing is carried out by pumping the flushing fluid (Fig. 2) with the central channel 5 of the valve body 4 closed by the diaphragm 17. When moving, the valve contacts the casing wall with rubber seals 25 and the points of the spherical heads of the spring-loaded clamps 22. As a result, friction forces from the contact of the outer parts of the valve with the inner surface of the casing are negligible. Spacer rings 33 installed in the joints of the casing pipes make the inner path continuous, and the execution of the head of the retainer 22 of a spherical shape allows you to overcome the ledges (due to misalignment of the pipes, the scatter of the internal diameter of the pipes, etc.) at the joints of the pipes.

The moment of connection of the valve body 4 with the sub 1 of the casing 2 by locking tabs 22 in the annular groove 3 is fixed by the increase in pressure and its discharge after breaking the neck 20 of the plunger 7 and releasing the check valve from the diaphragm 17 (Fig. 3)

After landing of the valve body, it is possible to check its position by grabbing the ledge 31 of the valve body by the overshot arms lowered on the rope.

The presence of the tension of the rope and its specific length indicate the fixation of the valve body in the casing.

Cementing the annulus of the well. The upper end of the valve body acts as a stop ring to stop the cementing separation plug. At the moment the plug is planted, the membrane breaks on it and the cement mortar enters the annulus through an open check valve. After turning off the pumps, the tip 6 under the influence of the spring 8 and the pressure of the column of cement slurry moves up and sits in the seat 9 with the collar 10, preventing the flow of cement from the annulus into the inner region of the casing (Fig.6). Cement mortar fills the inner and outer space of the valve body before sealing, the annular groove 3 between the retainers 22 (Fig. 4), and also the grooves 32 (Fig. 5) of the lower end portion 16 of the valve body 4. After the cement mortar is finally hardened, the valve body is reversed the valve and seals are drilled. Hardened cement in the above locations creates resistance to torque when drilling.

Using the proposed technical solution when drilling a well while lowering the casing string will improve the reliability of transportation of the cementing check valve body in the casing string and its landing with a clear signal about fixing the working position.

Information sources

1. A.I. Bulatov, A.G. Avetisov. Handbook of a drilling engineer. M .: Nedra, 1985, vol. 1, p. 326 fig. 2.02.

2. United States Patent Application Pub. No .: US 2004/0060700 A1 of 04/01/2004, ed. Vert J.W., Angman P.G. "Method for drilling and casing a wellbore with a pump down cement float."

Claims (1)

The casing cementing valve, in the sub of which is made with an annular groove on the inner surface, has a valve body, in the central channel of which a check valve is mounted, located between the valve body and the inner surface of the seal sub, an indicator for fixing the valve body in the sub and a locking element installed with the possibility of interaction with the annular groove of the sub, characterized in that in the part of the valve body located under the check valve, cylindrical sockets for placement in them with the possibility of radial movement of locking elements made in the form of spring-loaded clamps with a spherical head, the check valve being made in the form of a spring-loaded tip with a plunger, and the housing fixation indicator in the form of a diaphragm connected to the plunger in the lower part which made the neck with the possibility of its rupture.

Images