RU2525894C1 - Wellhead box - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: wellhead box comprises cases with through channel for lowering logging instruments on cable. Note here that the case is arranged under spider and consists of the parts (cases) making the through channel composed by communicated "top", "mid" and "bottom" cavities. Case cavities houses detachable automatic check valve, ball valve and starter valve. Wellhead box bearing device incorporates extra free-running hollow rod with adapter at bottom end and pressure transducer.

EFFECT: enhanced performances, safe operation, simplified remote control.

5 dwg

Description

The invention relates to the drilling of oil and gas wells, in particular to testing them in the process of drilling pipe testers formation.

Known wellhead (RF patent No. 2078903, ЕВВ 21/03, 1997), which contains a housing with a tapered thread for docking with drill pipes and a hollow vertical barrel with a tap mounted on bearings in the housing of the device. The tap is made in the form of a tee, in which a locking gland device is located. The locking gland device consists of a horizontal locking shaft with a spool, while the locking shaft is mounted on a tape thread and equipped with a remote drive in the form of a wheel covered by a halyard at an angle of 180 °. The branches of a halyard form a closed ring.

The known technical solution provides remote control of the wellhead, which opens the circulation valve of the formation tester and discharges formation water or oil from the drill pipes whose density is lower than the density of the drilling fluid. Remote manual control of the device is carried out by tensioning the corresponding halyard transmitting torque to the locking shaft.

The disadvantages of this design include the need for constant dismantling of the wellhead for lowering geophysical instruments into the well, which reduces the time of its operation, as well as low reliability, in particular

- to close the wellhead, it is necessary to rotate the wheel an indefinite number of revolutions. With a large shoulder of rotation of a wheel of a known design, situations of jamming of a thread in extreme positions may arise;

- the spool thread is subject to increased wear due to constant friction during the opening / closing of the wellhead;

- a movable flexible element (halyard) can fly off the remote control wheel, which will lead to the necessity of stopping the process and eliminating the emergency situation, and, accordingly, to increase the time required to fill the well;

- the absence of a protective device such as an automatic check valve to close the wellhead in the event of an emergency (abnormally high reservoir pressure, gushing).

The known design of the wellhead with remote control. (Varlamov P.S., Griguletsky V.G., Varlamov G.P., Varlamov S.P. Testing equipment for hydrodynamic studies of oil and gas wells: Production and practical publication. - Ufa. State Unitary Enterprise RB Ufa Printing Plant, 2004 , p. 292 - 298), adopted as a prototype.

The known design comprises a tubular housing made up of upper and lower cavities, a hollow cross, rigidly connected to the upper cavity of the housing and resting on the end of the lower cavity of the housing, a casing with ball bearings and an adapter. In this case, the free end of the housing of the lower cavity is supported by ball bearings located in the casing.

The upper body cavity is equipped with a shut-off valve in the form of a piston rigidly connected to the spring-loaded first differential hollow rod, and a hydraulic chamber with a second differential hollow rod and nozzles for connection to the remote hydraulic control system of the wellhead. The casing of the wellhead is screwed onto the adapter, and then the adapter is screwed onto the upper end of the drill pipe.

The disadvantage of the known design should be attributed to its low reliability, since to ensure and maintain the channel of the device when lowering the downhole tool, it is necessary to constantly maintain pressure on the valve, that is, the valve must be constantly under pressure. Moreover, the pressure on the valve can sometimes reach about 20 MPa. In addition, the remote control of the well-known wellhead is carried out by two hydraulic pumps, which in itself is costly. And in order to prevent automatic closing of the wellhead valve and dumping of cargo over the piston, strict control of the working pressure parameters, calculated for each case according to their specific formula, is necessary, which also affects the reliability of the device, since such control and calculation is carried out by the operator, that is, the human value factor.

A technological feature of the well-known wellheads is that the ball valve is controlled manually - the wellhead is opened with a force of 150 to 200 Nm on the key handle used to open and close the ball valve. It is also necessary to adjust the head of the wellhead in height above the rotor table for manual control of the ball valve. In addition, before opening the ball valve at the wellheads of this type, it is necessary to equalize the pressure above and below the ball valve by applying pressure to the manifold line above the ball valve using a hydraulic unit.

When working in wells that contain hydrogen sulfide or carbon dioxide with a concentration exceeding the established standards, to ensure the safety of work when releasing formation fluid to the surface, the wellhead should be equipped with a remote-controlled shut-off device.

The objective of the present invention is to increase the reliability of the construction of the wellhead, as well as expanding its functionality, providing remote control of the flow of the working fluid, the process of controlling the pressure in the cavity of the drill pipe, as well as remote control of the process of opening / closing the circulation valve (with the assembled manifold) for direct or reverse circulation of the working environment.

The problem is solved as follows.

In the wellhead, including the tubular housing, a locking device installed in the body cavity and fittings for connecting to the remote control system of the locking device, a hollow spider for hydraulic communication / separation between the body cavity, the pipe string and the wellhead manifold, and a bearing device providing movable communication between the spider with a pipe string, according to the invention, the tubular body is composed of three parts (bodies) forming a through channel of the upper, middle, communicating with each other and lower cavities and is installed below the cross, rigidly connecting the upper end to the latter. At the same time, a removable automatic non-return valve is installed in the upper cavity; A ball valve is installed in the middle cavity, and a container with a starter valve installed in it is made in the side wall of the lower cavity, and the bearing device is equipped with a hollow rod installed with the possibility of free rotation around the longitudinal axis. Moreover, the hollow stem is equipped with sealing cuffs installed on the upper end, and a sub, rigidly mounted on the lower end and equipped with a pressure sensor.

The proposed technical solution has the following advantages compared to the known ones:

- installation of the tubular body below the crosspiece, as well as the execution of the tubular body of three parts (cases), in the form of a sequence of upper, middle and lower cavities communicating with each other, provide the possibility of the formation of a through passage through the wellhead for lowering the research equipment into the pipe string without dismantling the wellhead heads;

- the presence of an automatic check valve in the upper cavity of the casing ensures the closure of the through passage in the event of an emergency (abnormally high pressure, threat of gushing) without operator intervention;

- the presence of a ball valve in the middle cavity of the housing provides reliable closure of the through channel by the operator from the remote control panel;

- the design of the valve-actuator can significantly reduce its response time due to the short stroke of the pistons and small (3-4 MPa) magnitude of the working pressure to bring them into action. Moreover, the working pressure of the opening / closing of the ball valve does not depend on the pressure under the wellhead, which increases the reliability and safety of the device design when working with a high pressure hydraulic line;

- the presence of a starter valve in the chamber of the lower cavity of the housing provides control of the circulation valve located below the wellhead, carried out by dumping the ball of the valve starter inside the pipe string. In this case, the ball does not block the through passage channel and does not interfere with the passage of the flow and / or lowering of the geophysical equipment on the cable through the through channel. Moreover, the proposed design makes it possible to install balls of various diameters into the starter valve, depending on the size of the used circulation valve;

- in general, the proposed design of the wellhead ensures the operation of this device at lower compared to the prototype, the values of the working pressure in the hydraulic communication line, which significantly increases the reliability and safety of its operation in the well. At the same time, a reduced pressure in the hydraulic communication line increases the service life of both individual elements of the proposed design (rubber rings, cuffs, etc.) and the entire device. Moreover, the maximum internal pressure (105 MPa) and the maximum working pressure (70 MPa) of the proposed wellhead is not inferior to the prototype.

The proposed technical solution is distinguished by a reliable design that provides remote safe and efficient work with wellhead equipment. When working with the proposed wellhead, there is no need to prepare a special site with a ladder for emergency closing of the tap according to paragraph 4.5.13 of the Safety Rules in the oil and gas industry (Moscow, 1993, NPO OBT), which reduces the material costs of its installation and operation.

Figure 1 shows a modular design diagram of the proposed wellhead in connection with the manifold line and the remote control.

Figure 2 shows a design variant of an automatic check valve installed in the "upper" cavity of the wellhead.

Figure 3 shows a design variant of the ball valve installed in the "middle" cavity of the wellhead.

Figure 4 shows the implementation of the container with the starter valve in the "lower" cavity of the wellhead.

Figure 5 shows the design of the bearing device of the wellhead.

The wellhead is a tubular body composed of bodies 1, 2, 3, forming a through channel of communicating with each other "upper", "middle" and "lower" cavities, respectively; a casing 4, worn on the housing 2, partially covering the lower end of the housing 1, and rigidly connected with the lower end to the cover 5, and the bearing device 6. The upper end of the housing 1 is rigidly connected to the cross 7, through which the cavity of the housing communicates with the manifold line 8. The lower the end of the housing 3 is rigidly connected to the bearing device 6, which is connected by a free end to the drill pipe 9. At the same time, a removable automatic check valve 10 is installed in the “upper” cavity of the wellhead (FIG. 2), a piston is installed in the “middle” cavity 11 with radial through slots on the surface and with a ball valve 12 at the end (figure 3), and the housing 3 is equipped with a container 13 with a valve-actuator 14.

The bearing device 6 is equipped with a rod 15 freely rotating around the longitudinal axis with a sub 16 at the lower end, equipped with a pressure sensor 17 (Fig. 5) mounted in a through channel of the sub, perpendicular to the longitudinal axis of the device. The casing 4 covers the housing 2 with a gap, forming a hydraulic line 18 pressure equalization (figure 3), communicating in the process of working with the cavity of the through channel of the wellhead. The housing 3 is equipped with fittings 19 and 20 for connecting the wellhead with a remote control 51.

The automatic check valve 10 (figure 2), mounted in the cavity of the housing 1, is a sleeve 21, at the upper end of which is installed a rubber sleeve 22 with a washer 23, covering the sleeve 22 from above and having a diameter smaller than the diameter of the sleeve 22, and with the washer 24, covering the cuff 22 from below, of equal diameter with it. A washer-trap 25 is installed at the lower end of the sleeve 21 with a chamfer around the perimeter of the central hole. A metal ball 26 is freely placed in the cavity of the sleeve 21, having a diameter equal to the inner diameter of the cuff 22, which is in a free state on the chamfer of the washer-trap 25.

The ball valve 12, mounted in the "middle" cavity formed by the housing 2 and the casing 4 (Fig.3), is a ball 27, fixed along the longitudinal axis of the device in the reciprocal grooves of the bushings 28 and 29 inside the stem 30 with the fingers 31, closed by a cover 32 Thus, the sleeve 28 is hermetically pressed from above to the axis of the ball 27 by the seat 33 by means of a spring 34 installed in the housing 1, and the sleeve 29 is pressed from below to the axis of the ball 27 by the housing 3 by means of the bushes 35 and 36. Closing / opening of the ball valve 12 is carried out by means of a movable rod 30, progressive moved which is controlled by the pressure of the fluid entering the "middle" cavity through a hydraulic line 18.

In the "lower" cavity in the wall of the housing 3 there is a container 13 with a trigger valve installed in it (Fig. 4) in the form of a ball 37 pressed by a spring 38. A sleeve 39 with a movable stem 40 is installed perpendicular to the axis of the container 12 in the housing 3, which ensures actuation starter valve. The cavity of the container 13 is in communication with the cavity of the housing 3. In the initial position, the ball 37 pressed by the spring 38 abuts against the stem 40 and is held by it.

The bearing device 6, rigidly connected to the lower end of the housing 3, comprises a housing 41, a sleeve 42, a cover 43, bearings 44, 45, 46 spaced apart from each other along the device axis and an intermediate sleeve 47 installed between the bearings 44, 45. A rod 15 is installed inside the housing 41 with the possibility of free rotation around the longitudinal axis of the device. The upper end of the rod 15 is equipped with sealing cuffs 48, clamped bushings 49 and 50. The lower end of the rod 15 is equipped with a sub 16 with a remote pressure sensor 17.

The operation of the wellhead is controlled by a remote control 51 equipped with a winding block of coils 52 and connected to a high pressure pump 53 and a drain tank 54. The remote control 51 is connected via a high pressure sleeve 55 through a unit with fittings 19, 20 with a “lower” cavity housing 3.

In practice, work with the proposed wellhead is carried out as follows.

After the formation testing equipment is lowered into the well, the wellhead head is strapped by means of a spider 7 with a manifold 8 and connected via a high pressure sleeve 55 to the hydraulic system of the remote control 51.

The high-pressure hose 55 is a system of high-pressure hoses combined in one line with the help of intermediate blocks of steel winding, which are connected at one end to the wellhead by means of a hydraulic decoupling block with fittings 19, 56 on the housing 3 and the valve-actuator 14, respectively, and free end connected to the control panel 51. For mounting the high pressure sleeve 55 with the downhole equipment, use the coil unit 52 mounted on the same platform with the control panel 51, which ensures Vaeth convenience of winding the high pressure hose 55 during its operation in the well and prevents it from damage during assembly and / or transport.

In the process of production of the test equipment in normal operating conditions, the automatic check valve 10 of the wellhead is in its original state, that is, the ball 26 lies freely on the chamfer of the washer-trap 25. In this case, the ball valve 12 of the “middle” cavity is in the open state, and the movable stem 40 holds the ball 37 of the starter valve of the "lower" cavity in the container 13.

The value of the borehole pressure during the operation of the formation testing equipment is monitored by a remote pressure sensor 17. The signal from the pressure sensor 17 is received by the control panel 51 by means of waves (for example, ultrasonic waves, radio waves, etc.). Due to the design features of the proposed wellhead due to the rotation of the rod 15 with a sub 16 pressure sensor 17 provides continuous monitoring of the fluid pressure during operation of the downhole equipment, which is monitored by the operator on the control panel 51.

In the case of increasing the borehole pressure relative to the operating value, the operator closes the ball valve 12 from the control panel 51 via a hydraulic line 12, as a result of which the possibility of a sharp discharge of formation fluid to the surface is prevented. Namely, the operator along the high pressure sleeve 55 from the control panel 51 from the pump 53 delivers, under a certain pressure, a portion of liquid (oil) to the fitting 19, which enters the movable rod 30. The rod 30, moving on a given stroke, transfers its translational motion to the fingers 31, through which the groove on the surface of the ball 27 is the turn of the latter around its axis. The ball 27 is pressed against the seat 33 with sealing elements, providing a tight seal through the passage channel of the wellhead. When closing the ball valve 12, the radial slots of the rod 11 are combined with the hydraulic communication line 18, ensuring the passage of the borehole fluid into the cavity above the ball valve 12 and preventing the possibility of a sharp discharge of the formation fluid to the surface. Next, the operator from the control panel 51 gives a command to open the ball valve 12, providing a smooth opening of the through passage channel of the wellhead. When this occurs, the pressure is equalized above the ball valve 12 and below it and trouble-free pressure relief through the hydraulic line 18 through the manifold line.

In the event of an emergency associated with the occurrence of an abnormally high reservoir pressure (gushing), an automatic non-return valve 10 is activated in the wellhead 10. An automatic non-return valve 10 is triggered by a sharp influx of formation fluid. The ball 26 under the influence of the potential energy of the fluid flow rises sharply and hermetically sealed by the cuff 22, blocking the through passage channel of the wellhead. After eliminating the emergency situation, the ball 26 under the action of pressure supplied through the manifold line 7 is lowered to the chamfer of the washer-trap 25.

Upon completion of work with formation testing equipment or for lowering geophysical equipment on the cable into the pipe string to release the latter from the well fluid, the operator sends a signal to the nozzle 56 for the trigger valve to operate from the control panel 51 along the high pressure sleeve 55. Under the influence of a pressure pulse from the control panel 51, the rod 40 moves away, releasing the ball 37. The spring 38 pushes the ball 37 out of the container 12, and the ball 37 due to its own weight falls through the through passage of the wellhead into the seat of the circulation valve of the borehole assembly, thereby launching mechanism of its operation.

Depending on the research task being solved, which involves the launching of geophysical equipment into the well on a cable, an stuffing box with a lubricator (not shown) is attached to the upper end of the housing 1 of the wellhead instead of the crosspiece 7. In this case, when installing the wellhead, the automatic check valve 10 is not installed in the “upper” cavity, since it will interfere with the descent of the device on the cable through the through channel of the wellhead.

Thus, the proposed design of the wellhead provides remote monitoring and operational closure of the pipe channel of the drill string and eliminates the possibility of open flowing of the fluid flow from the well during hydrodynamic study of formations by formation testers on pipes.

Claims (1)

Wellhead, including a tubular housing, a locking device installed in the housing cavity, fittings for connecting the remote control system to the locking device, a hollow spider providing hydraulic communication / disconnection between the body cavity, pipe string and wellhead manifold, and a bearing device providing movable communication of the spider with a column of pipes, characterized in that the tubular body is made up of three parts (cases) forming a through channel of the upper communicating with each other, the middle and lower cavities, and is installed below the crosspiece, is rigidly connected with the upper end to the latter, while the upper cavity is additionally equipped with a removable automatic non-return valve; the middle cavity is additionally equipped with a ball valve, and the lower cavity is additionally equipped with a container with a starter valve installed in the side wall of the housing, and the bearing device is additionally equipped with a hollow rod installed with the possibility of free rotation around the longitudinal axis, and the hollow rod is equipped with sealing cuffs mounted on it the upper end, and a sub, rigidly mounted on its lower end and equipped with a pressure sensor.

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