JPS6316559B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention generally shears a pipe, such as a drill string, in a hole in a blowout preventer housing as the ram moves inwardly from an open position, and then The present invention relates to a blowout preventer of the type comprising rams which are adapted to seal against each other and against a guideway in a housing of the blowout preventer in order to close the hole during movement. Thus, the upper sheared end of the drill string can be withdrawn from the wellbore when it is desired to move the drilling rig away from the wellbore in a short period of time.

More particularly, the invention further comprises: moving the ram inwardly to shear the pipe with a first relatively large axial force; and then closing the hole with a second relatively small force; Relating to an improvement in a blowout prevention device having a fluid actuated actuator configured to move the rams inwardly, thus allowing the piping to move without creating excessive pressure during ram packing to seal between the rams and between the rams and their guideways. It is possible to shear.

Thus, the actuator for each shear ram comprises first and second pistons that are reciprocatable in sealing relation to each other and to the cylinder;
and means for selectively supplying or discharging control fluid to or from opposite sides of the piston to force the piston toward or away from the housing bore. More specifically, Rod
connecting each ram to a first piston for inward and outward movement with the first piston, and the second piston having a movement connection to and from the first piston; and thus the second piston moves the ram inward to shear the pipe with the first force due to the fluid acting on both pistons.
Engageable with the first piston in response to supply of actuating fluid to the outer portions of the piston. However, when the ram is moved inward to shear the pipe, a shoulder is provided in each cylinder to stop the inward movement of the second piston, and the rod continues to move into the second piston. The rams seal each other and their guideways by a relatively small force by the control fluid moving inwardly with one piston and acting only on the first piston.

Japanese patent application No. 58-122,462 relates to a ram-type blowout prevention device in which an actuator rod connected to each ram automatically responds to movement to an inward position (closing the ram) and to an outboard position. It is locked against return movement (opening the ram), thus allowing the expulsion of working fluid from the outer sides of the piston on the rod within the cylinder of the actuator. More particularly, the rod is adapted to be unlocked for return movement automatically in response to reversing the supply and discharge of working fluid to and from both sides of the piston. There is. The actuator is covered by U.S. Patent No.
3242826 and 4304565, or the Composite Catalog of Oilfield Equipment and Services.
Catalog of Oil Field Equipment &
Although the construction is much simpler than other actuators with automatic ram locks, such as that shown on page 1432 of the 1980-81 edition of J. It is particularly inappropriate for That is, each includes a radially contracting and expanding locking element carried by a rod to and from an opposite position to an outwardly extending locking shoulder adjacent the inner end of the cylinder. slides along the inner diameter of the Thus, as these actuators are constructed, these locking elements are located in a cylinder that engages the outer piston to stop inward movement following shearing of the pipe. It would not be possible to move axially inwardly past the shoulder.

Therefore, the main object of the invention is to move the ram inwardly in order to shear the pipe with a first relatively large force in a blowout prevention device comprising a shearing ram, followed by a second relatively small force. The force not only moves the ram inward to the closed position, but also
The actuator is configured to automatically lock the ram in the closed position by means of a locking element carried on a rod connecting the ram for locking engagement with a locking shoulder adjacent the inner end of the cylinder of the actuator. It is an object of the present invention to provide a fluid actuated actuator that has the following characteristics.

Now, referring to the details of the attached drawings, the first and second
and 3, and designated generally by the reference numeral 20, comprises a housing 21 having a vertical hole 22 therethrough and flanges at its upper and lower ends; The hole is thus aligned with the hole in the oil source and is aligned as part of the oil source. The pipe 24 extending vertically through the blowout preventer hole may be part of a drill string suspended from a drilling rig and may have a bit at the lower end adapted to extend to the bottom of the wellbore. good. As is well known in well drilling technology, drilling mud is circulated downward through the drill string and
It exits the bit and is then circulated upwardly within the annulus 25 between the drill string and the hole.

The blowout preventer comprises a pair of rams 26A and 26B received by intersecting chambers 27 on opposite sides of the hole 22, which are positioned in an outboard position as shown in FIG. 1 during drilling of the well. ,
After shearing of the pipe, as shown in FIG. 3, the pipes move between internal locations provided across the hole to close the hole and seal to each other and to the housing. Each ram is moved between open and closed positions by an actuator that includes a cylinder 28 mounted on the outer housing 21 of each ram chamber, a piston 29 reciprocating within each cylinder, and a piston 29 within the chamber. For connection with the ram, a rod 30 is provided which extends sealed with packing 31 in an opening through the wall of the housing separating the ram chamber from the cylinder. Hydraulic fluid from an external source is applied to the piston 29 to selectively move the piston toward or away from the bore, and thus to the open and closed positions of the ram, as will be described later.
is supplied to or discharged from the cylinder on both sides of the cylinder.

Each housing 21 has a main body 21A in which a hole 22 and a guideway on the inner end of the chamber are formed.
and a pair of bonnets 3, each removably connected across the outer ends of the guideway to form the outer ends of the ram chamber.
It consists of 2. Thus, each bonnet is
It is pivotally connected to one side of the main body and has a closed position across the outer end of the guideway and an open position to one side of the guideway to allow the ram to be removed from the chamber for replacement or repair of the ram. Exercise between. Alternatively, and as is well known in the art, the bonnet may be connected to the main body of the housing by an auxiliary fluid actuation system, which auxiliary fluid actuation system is used for ram replacement and repair. The bonnet is moved axially towards or away from the outer end of the guideway of the main body of the housing.

Each ram includes a metal ram body 33 of generally elliptical cross-section and a right and left ram, respectively, for sliding axially inwardly and outwardly within the ram chamber toward and away from the bore 22. 26B and 2
The blades BU and BL on 6A are connected,
As shown in FIG. 2, the blades are provided with cutting edges that shear the pipe 24 as they move into overlapping relationship. More specifically, the right ram 26B
The cutting edge of the upper upper blade BU is located on the right ram 2.
blade 26B is adapted to move over the cutting edge BL of the lower blade 6B, and as the ram moves further inward, shearing the pipe, as shown in FIG. A packing 34 is carried by the ram 26B above the blade BL in sealing engagement by the inner end 35 of the blade BL.

Furthermore, the patent application filed earlier in 1982
102941, each ram includes a laterally extending packing 34 (in the case of the right ram) having inner face portions (not shown) on either side of the packing, a blade end 35, and Also, a side portion 38 extending rearwardly from each such face portion along each side of the ram body, and a top portion 38 connecting the outer ends of the side portions and extending across the top of the ram. It carries the following. As can be seen in the drawings, and also as is known in the art, the top portion 38 remains within the ram chamber as the ram moves to the outer position, thus causing the ram packing to close the hole in the anti-blowout housing. To cut, form a connected seal.

As shown and described in the above-mentioned Japanese Patent Application No. 58-102941, the lower and upper cutting edges are arranged so that in shearing the pipe, as the cutting edges turn toward and past each other, They have a shallow V-shape because they work together to direct the pipe toward the center. The sheared upper pipe end is connected to packing 34 and surface 3 as shown in FIG.
5 and as the rams are moved to the closed position, bringing the rams into sealing engagement with each other, and the lower ends of the sheared pipes are inserted into recesses 36 formed in the lower side of the right ram. so that the pipe does not interfere with the fully closing movement of the ram. However, the structure of this shear ram is for illustration purposes only, and in the blowout prevention device of the present invention,
It should be understood that other conventional structures may also be used.

Ports 39 and 40 connect the outside of cylinder 28 to
It connects to the inner diameter of the cylinder adjacent to its inner and outer ends, respectively, thus providing a device for supplying working fluid to and discharging working fluid from the cylinder alternately on either side of the piston 29. Thus, the introduction of working fluid through port 40 causes the piston to move outwardly, which in turn moves the ram from the open position of FIG. 1 to the closed position of FIG. 3. Instead, the working fluid is introduced into port 39;
Exhaust from port 40 moves the piston outwardly, thus pulling the ram from the closed position of FIG. 3 to the open position of FIG.

The inner diameter of the cylinder is reduced to include an inwardly directed locking shoulder 41 adjacent to its inner end.
and provides an outwardly directed stop shoulder 42 that is outwardly of the locking shoulder. More specifically, the locking shoulder 41 is conically shaped and extends inwardly and outwardly with respect to the axis of the cylinder, and the shoulder 42 is provided at right angles to the axis of the cylinder. There is. The inner diameters of the shoulders are close together, thus minimizing the inner diameter of the constriction within the cylinder in the axial direction.

Piston 29 includes an inner piston 43 that seals and reciprocates along rod 30, and an outer piston 44 that seals and reciprocates within the cylinder and sealingly reciprocates along the inner piston. Thus, as shown, the inner piston 43 has an O-ring 45 for sealingly sliding along the rod and an outer O-ring 46 for sealingly sliding against the inner diameter of the piston 44.
and the outer piston 44 carries an O-ring 47 around its outer diameter for sealingly sliding within the cylinder. For purposes described in more detail below, the inward motion connection between the inner piston 43 and the rod 30 causes the inner piston to move inwardly and outwardly relative to the rod, and
The external kinematic connection between the pistons is the outer piston 44.
is moved inwardly and outwardly relative to the inner piston. Inner and outer flanges 48 and 49 are thus formed on the inner diameter of piston 44 to provide shoulders that engage the inner and outer ends of piston 43 to limit inward and outward movement of each other.
A nut 50 is also connected around the rod to provide an inwardly directed shoulder at its inner end to limit outward movement of the inner piston 43 and to A coil spring 51 is provided between the flanges on the nut,
This forces the piston 43 inwardly and toward the inner limit position relative to the rod, as will be seen below.

As previously mentioned, a plurality of circumferentially spaced locking elements 52 are attached to the rod 30 for expanding and contracting and for inward and outward axial movement with the rod.
carried around. More particularly, when retracted, the locking element 52 is located in front of the piston intermediate the piston 43 and the flange 5 on the rod, as shown in FIGS. As will be described below, the locking element can move with the rod through an annular constriction in the cylinder, thus causing the stop shoulder 4 formed thereon to move as the rod moves inwardly.
2 and, as the rod moves outward, it can pass through the locking shoulder 41 formed on it.

A locking ring 54 extends inwardly from the piston 43 and engages the outer end of the locking element 52, forcing the inner end of the locking element against the flange 53 and thus from the outside of the piston 29. Moves the rod inward in response to actuation fluid introduced into the cylinder. More specifically, a conical surface 55 formed on the inner end of each locking element is engaged by a conical surface on the inner end of locking ring 54, which, like surface 55, , extends at a relatively small angle to the plane perpendicular to the axis of the cylinder,
Thus, as the piston moves inwardly from the outer position of FIG. It has a radial component force.

During this inward movement of the locking element,
The locking element is attached to a ring 60 which is capable of reciprocating within the cylinder on the side of the piston 44 and which is forced inwardly into a position surrounding the locking element by a spring 61 acting between the ring and the piston. It is thus surrounded and held in the retracted position. At this time, the flange 49 of the piston 44 engages the piston 43, forcing the rod inwardly with great force as the hydraulic fluid acts on the outer ends of both pistons. As the rod is moved inwardly to the position of FIG. 2 to shear the pipe, the inner end of ring 60 engages stop shoulder 42, so that the rod continues into the position of FIG. 3, the locking elements disengage from the ring and are released from their retracted position. More specifically, the locking element is moved past the stop shoulder 42 with a rod, thus
It is located opposite the locking shoulder 41.

As piston 44 then moves against ring 60, piston 43 continues to move the rod inwardly with less force, and as the rams engage each other, piston 43 continues to move inwardly against the rod. , sliding the conical surface 55 on the locking element over the inner end of the locking ring 54 and sliding the inner end of the locking element along the conical surfaces on the outer sides of the flange 53. make it slide. Then, the inner end of the locking ring is
Outer conical surface 56 on the locking ring and off past the conical surface 55 of the locking element.
runs into a similarly shaped conical surface 57 on the inner diameter of the locking element. These latter conical surfaces form a relatively small angle with respect to the axis of the cylinder, so that the subsequent inward movement of the inner piston and locking element relative to the rod is relatively small due to the working fluid acting on the piston 43. The large force forces the locking element radially outward into locking engagement with the shoulder 41.

As shown and described in Japanese Patent Application No. 58-122,462 previously filed by the applicant, the circumferentially spaced locking element has a pin 58 extending therethrough into the rod. It is therefore guided for expansion and contraction. Also, the fourth
As shown, the locking ring 54 consists of a plurality of fingers with a circumferential space between them and is mounted on the rods by one or more pins 59 extending into the space. , are held in alignment with pins 58. As described in the above-mentioned Japanese Patent Application No. 58-122462, the conical surfaces 56 of the locking rings extend at an angle to the axis of the actuator that is less than the friction angle between them and the locking elements, thus , in conjunction with the tight fit of the locking finger on the rod, prevents unlocking in the event of hydraulic fluid being expelled from the outer sides of the piston.

The locking element automatically responds to the supply of hydraulic fluid to the left side of the piston and the discharge of hydraulic fluid from the right side of the piston to the locking shoulder 41.
is released from locking engagement with the rod and is moved outwardly with the rod through a constriction within the cylinder. Thus, piston 44 has its flange 48
moves outwardly until it engages piston 43, then moves the inner piston with it and withdraws locking ring 54 from within the locking element. The piston 43 moves against the nut 50, moving the rod outwardly, and the flange 53 on the rod slides the locking element 52 downwardly and inwardly along the locking shoulder 41, thus causing the rod to move into the cylinder. pass through the annular constriction.

Upon passing through the annular constriction, the locking elements 52 return within the ring 60 and are thus held against expansion as the rods subsequently move outwardly from the position of FIG. 2 to the position of FIG. be done. Although the outer piston 44 moves outwardly, the spring 61 holds the ring 60 in engagement with the shoulder 42, thus holding the locking element in a receiving position as it passes through the cylinder constriction. do. When placed within retaining ring 60, conical surface 64 around the locking element engages conical surface 62 on the retaining ring, and cylindrical surface 65 on the locking element engages conical surface 62 on the retaining ring. facing the shaped surface 63. These cylindrical surfaces cause the rod to continue to move as the locking element is moved outward.
Prevents wedging of the retaining ring around the locking element from the enclosing position. Also,
Of course, the spring 61 acting between the outer piston 44 and the retaining ring 60 forces the retaining ring inwardly around the locking element.

As shown, a bearing ring 65 of Teflon (registered name of DuPont) or other low friction material is carried around the retaining ring 60 to reduce the frictional resistance of its reciprocating movement within the cylinder. This frictional resistance is also due to the fact that as the retaining ring moves with the locking element and rod between the positions of FIG. 1 and the position of FIG. due to the fact that it is engaged by a shaped surface and is thus forced radially outwardly against only a relatively small axial component of the hydraulic fluid on the piston, as mentioned above. is considered to be the minimum.

[Brief explanation of the drawing]

Like reference numbers indicate like parts throughout the figures. FIG. 1 is a longitudinal cross-sectional view of one side of a blowout prevention device with a shear ram in an open position and an actuator for the ram constructed in accordance with the present invention; FIG. FIG. 2 is a longitudinal section similar to FIG. 1, but with the ram moving inward to shear the pipe and the ring of the actuator FIG. 3 is another longitudinal cross-sectional view of the blowout preventer and actuator similar to FIGS. 1 and 2; The figure shows the ram being moved further inwardly to close the blowout preventer and the locking element being moved inwardly out of the ring and into locking engagement with the locking shoulder in the cylinder. ;3rd A
The figures are an enlarged cross-sectional view of a portion of the actuator shown in FIG. 3; and FIG. 4 is a cross-sectional view of the actuator taken along dashed line 4--4 of FIG. 20...Blowout prevention device, 21...Housing, 2
2... Hole, 24... Pipe, 25... Annular part, 26A,
26B... Ram, 27... Chamber, 28... Cylinder, 29... Piston, 30... Rod, 31, 34
... Packing, 39, 40... Port, 41... Locking shoulder, 42... Stop shoulder, 43... Inner piston, 44... Outer piston, 48, 49... Flange, 50... Nut, 52... Locking element, 53... Flange , 54... Locking ring,
55, 56, 57... Conical surface, 58, 59... Pin, 60... (retaining) ring, 61... Spring, 62,
64... Conical surface, 63, 65... Cylindrical surface.

Claims (1)

[Claims] 1. A blowout prevention device comprising a housing, the housing having a hole passing through the housing and a chamber intersecting the hole,
and inwardly within each chamber toward and away from the other ram;
Rams are provided which are movable outwardly and are provided with cutting edges at their inner ends, the cutting edges being arranged as the rams move inwardly relative to each other.
Cooperating with each other to shear the pipe within the hole, the rams also act against each other and into the chamber to shear the pipe and subsequently move inward to close the hole. and an actuator is provided for so moving each ram, the actuator including a cylinder near its inner end facing inwardly. It has a locking shoulder and an outwardly directed stop shoulder outside the locking shoulder to connect with a ram in the chamber so that an axially reciprocating rod extending from the cylinder into the chamber can be connected to the ram in the chamber. provided, respectively,
Then, inside the cylinder, along the rod,
A pair of sealingly reciprocable pistons is provided, with a device providing a kinetic connection between the pistons and for moving the pistons inwardly and outwardly;
A device is provided for alternately supplying and discharging hydraulic oil to the cylinder on each side of the piston, and includes a locking element disposed around the rod for movement inwardly and outwardly with the rod; and a retracted position that moves with the rod through the stop shoulder, opposite the locking shoulder, and away from the locking shoulder;
radially expands and contracts between a locking shoulder and an engageable extended position to lock the ram in the closed position and stop inward movement of one of the pistons when the pipe is sheared. , as the locking element moves axially inwardly with the rod and the other piston over the shoulder,
to hold the locking element in the retracted position and then enter into locking engagement with the locking shoulder as the rod continues to move inwardly with the other piston to move the ram connected to the rod to the closed position. A device is provided for engaging the stop shoulder to release the locking element for radial expansion and for engaging the locking shoulder to expand the locking element when the locking element is released. in response to inward movement of the other piston relative to the rod, and in response to outward movement of the other piston relative to the rod to release the locking element from locking engagement, thus causing the locking element to anti-blowout device, characterized in that it is provided with a device that is moved outwardly with the rod and the other piston over the stop shoulder as the ram is retracted and the ram is withdrawn to the open position. 2. The blowout prevention device according to claim 1, wherein one of the pistons is an outer piston. 3. The device engaging the stop shoulder and retaining the locking element consists of a ring, which ring is movable axially within the cylinder, and
2. A blowout prevention device as claimed in claim 1, characterized in that it surrounds the locking element on the inner sides of one of the pistons to hold the locking element in the retracted position. 4. The ring is separate from the one piston and is engaged by subsequent inward movement of the one piston after engagement of the ring with the stop shoulder, and the ring and the piston are engaged by a subsequent inward movement of the one piston. A spring acts between one of the pistons to force the ring against the stop shoulder as the locking element is retracted and moved outwardly over the stop shoulder. The blowout prevention device according to item 3. 5. The locking element comprises a substantially cylindrical outer surface surrounded by a substantially cylindrical surface on the retaining ring. Blowout prevention device. 6. The locking shoulder is conical, and
2. A blowout prevention device according to claim 1, wherein the locking element has a conical surface for locking engagement therewith. 7. The inner diameter of the cylinder is provided with an annular constriction, and locking shoulders are formed on the inner sides thereof,
2. A blowout prevention device according to claim 1, further comprising a stop shoulder formed on each outer side thereof. 8. A device on the other piston shall be provided which acts to prevent contraction of the locking element when the locking element is extended to the locking position and hydraulic fluid is discharged from the outer sides of the piston. A blowout prevention device according to claim 1, characterized in that: 9 a housing having a hole extending therethrough and a chamber intersecting the hole;
Rams are provided which are movable inwardly and outwardly within each chamber toward and away from the other ram, the rams having cutting edges at their inner ends. The cutting edges cooperate to shear the pipe within the hole as the rams move inwardly relative to each other, the rams also shearing the pipe and subsequent inward movement. In an actuator for so moving each ram for use in a blowout prevention device which is provided with means for sealing against each other and against the chamber to close the hole, the actuator comprising: , a cylinder comprising:
Near its inner end, it has an inwardly directed locking shoulder and, outwardly of the locking shoulder, an outwardly directed stop shoulder for connection with the ram in the chamber. Axially reciprocatable rods are provided extending within the chamber, each and each other within the cylinder.
A pair of pistons is provided for sealing and reciprocating movement along the rod, with a device providing a kinematic connection between the pistons and a device on either side of the pistons to the cylinders for moving the pistons inwardly and outwardly. A device for alternately supplying and discharging hydraulic oil is provided,
a locking element disposed around the rod for movement inwardly and outwardly with the rod, the locking element also passing through and opposite the stop shoulder with the rod; and The piston expands and retracts radially between a retracted position in which it moves out of the locking shoulder and an extended position in which it can engage the locking shoulder to lock the ram in the closed position, and when the pipe is sheared, the piston stops inward movement of one of the pistons, holds the locking element in the retracted position as it moves axially inwardly with the rod and the other piston over the shoulder, and then to move the ram connected to the piston into the closed position, as the rod continues to move inwardly with the other piston, releasing the locking element toward radial expansion into locking engagement with the locking shoulder. Devices are provided for engaging the stop shoulder and for inward movement of the other piston relative to the rod to cause the locking element to engage and expand with the locking shoulder when the locking element is released. and in response to outward movement of the other piston relative to the rod to release the locking element from locking engagement, thus as the locking element is retracted and the ram is withdrawn to the open position. An actuator, characterized in that, beyond the stop shoulder, a device is provided which is moved outwardly together with the rod and the other piston. 10. The actuator according to claim 9, wherein one of the pistons is an outer piston. 11. The device for engaging the stop shoulder and retaining the locking element consists of a ring which is movable axially within the cylinder and which, in order to hold the locking element in the retracted position, 10. An actuator as claimed in claim 9, characterized in that it surrounds a locking element on the inner sides of the piston. 12 the ring is separate from the one piston and is engaged by subsequent inward movement of the one piston after engagement of the ring with the stop shoulder; A spring acts between one of the pistons to force the ring against the stop shoulder as the locking element is retracted and moved outwardly over the stop shoulder. The actuator according to item 11. 13. The locking element according to claim 12, characterized in that the locking element comprises a substantially cylindrical outer surface surrounded by a substantially cylindrical surface on the retaining ring. Actuator. 14. The actuator of claim 9, wherein the locking shoulder is conical and the locking element has a conical surface for locking engagement therewith. 15. Claims characterized in that the inner diameter of the cylinder is provided with an annular constriction, with locking shoulders formed on its inner sides and stopping shoulders formed on its outer sides. Actuator according to clause 9. 16. A device on the other piston is provided which acts to prevent contraction of the locking element when the locking element is extended to the locking position and hydraulic fluid is discharged from the outer sides of the piston. The actuator according to claim 9, characterized in that: