Pressure control apparatus inserts

A blowout preventer includes a main body having a through bore. A pressure chamber is located adjacent to and transverse to the through bore. A gate is disposed in the pressure chamber. An insert is disposed in the main body and defines an opening therethrough parallel to the through bore. The insert also defines a passage therethrough transverse to the through bore for passage of the gate.

BACKGROUND

This disclosure relates to the field of well pressure control apparatus, more particularly blowout preventers (BOPs). More specifically, the disclosure relates to structures for gates used in BOPs.

BOPs for oil and gas wells are used to prevent potentially catastrophic events known as a blowouts, where high well pressures and uncontrolled flow from a subsurface formation into the well can expel tubing (e.g., drill pipe and well casing), tools and drilling fluid out of a well. Blowouts present a serious safety hazard to drilling crews, the drilling rig and the environment, and can be extremely costly. Typically BOPs have “rams” that are opened and closed by actuators. The most common type of actuator is operated hydraulically to push closure elements across a through bore in a BOP housing (itself sealingly coupled to the well) close the well. In some cases, the rams have shears to cut through a drill string or other tool which may be in the well at the time it is necessary to close the BOP.

Pyrotechnic gas pressure operated BOP rams have been proposed. An example of such a pyrotechnic gas pressure operated BOP ram is described in International Application Publication No. WO 2016/176725 filed by Kinetic Pressure Control Limited. The pyrotechnic gas pressure is used to urge a gate to accelerate in a bore, whereby kinetic energy of the gate may be used to shear any devices disposed in a BOP housing through bore, thus closing the BOP. Such rams are referred to as “kinetic” BOP rams. In such kinetic BOP rams, a gate traverses through the BOP housing to shear an object within the through bore and close off the well bore. The housing passage for the gate needs to provide adequate sealing to prevent undesired fluid migration and maintain system integrity.

SUMMARY

One aspect of the present disclosure is a blowout preventer. A blowout preventer according to this aspect includes a main body having a through bore and a pressure chamber adjacent to and transverse to the through bore. A gate is disposed in the pressure chamber. An insert is disposed in the main body and defines an opening therethrough parallel to the through bore. The insert also defines a passage therethrough transverse to the through bore for passage of the gate.

In some embodiments, the insert is formed from a first segment and a second segment.

In some embodiments, at least one spreader is disposed between the first segment and the second segment. The at least one spreader comprises means for adjusting a distance between the first segment and the second segment.

In some embodiments, the at least one spreader comprises a first component and a second component each having tapered ends. An end piece is disposed between the first component and the second component at each longitudinal end of the first component and the second component. Each end piece comprises tapered surfaces cooperatively engaged with the tapered ends. An adjuster screw is engaged with the end pieces to change a distance between the end pieces by rotation of the adjuster screw.

In some embodiments, one of the end pieces comprises a hole for through passage of the adjuster screw and another of the end pieces comprises a threaded opening for threadedly engaging the adjuster screw.

Some embodiments further comprise a seal disposed in a surface of the first segment and a seal disposed in a surface of the second segment of the insert to engage an interior surface of the main body surrounding the through bore.

Some embodiments further comprise a seal at each longitudinal end of the insert to engage an interior bore surface of the main body.

Some embodiments further comprise a ring cutter disposed in the insert passage.

In some embodiments, the ring cutter comprises seals arranged to seal the through bore from the passage.

Some embodiments further comprise a spreader on each lateral side and between the first segment and the second segment.

Some embodiments further comprise a propellant charge disposed proximate and end of the pressure chamber.

A method for closing a blowout preventer according to another aspect of this disclosure includes accelerating a gate disposed in a pressure chamber adjacent to a blowout preventer main body having a through bore. The pressure chamber is transverse to the through bore. The gate is moved into a passage transverse to the through bore defined by an insert disposed in the main body. The insert defines an opening through the insert parallel to the through bore.

In some embodiments, the insert is formed from a first segment and a second segment.

In some embodiments, a spreader is disposed between the first segment and the second segment of the insert to maintain a set distance between the first segment and second segment.

In some embodiments, the spreader comprises a first component and a second component each having tapered ends. An end piece is disposed between the first component and the second component at each longitudinal end of the first component and the second component. Each end piece comprises tapered surfaces cooperatively engaged with the tapered ends. An adjuster screw is engaged with the end pieces to change a distance between the end pieces by rotation of the adjuster screw.

Some embodiments further comprise causing the gate to move a ring cutter disposed in the passage about the opening.

Some embodiments further comprise decelerating the gate after it is moved into the insert passage.

In some embodiments, the accelerating the gate is performed by actuating a propellant charge.

In some embodiments, the moving the gate comprises disposing the gate across the through bore.

Other aspects and possible advantages will be apparent from the following description and claims.

DETAILED DESCRIPTION

Illustrative embodiments are disclosed herein. In the interest of clarity, not all features of an actual implementation are described. In the development of any such actual implementation, numerous implementation-specific decisions may need to be made to obtain design-specific goals, which may vary from one implementation to another. It will be appreciated that such a development effort, while possibly complex and time-consuming, would nevertheless be a routine undertaking for persons of ordinary skill in the art having the benefit of this disclosure. The disclosed embodiments are not to be limited to the precise arrangements and configurations shown in the figures, in which like reference numerals may identify like elements. Also, the figures are not necessarily drawn to scale, and certain features may be shown exaggerated in scale or in generalized or schematic form, in the interest of clarity and conciseness.

FIG.1shows a pyrotechnic gas pressure operated BOP10, referred to as a “kinetic” BOP. The general structure of the kinetic BOP10may be made from steel or similar high strength material. The kinetic BOP10comprises a main body12having a through bore14. The main body12may be coupled to a wellhead, another BOP (kinetic or other type) or a similar structure (not shown in the figures), so that flow via the through bore14may be closed off by operating the kinetic BOP10. A passageway16is formed in a receiving cover18coupled to one side of the main body12. The main body12may comprise a part16B of the passageway adjacent to the passageway16in the receiving cover18. A further part16C of the passageway may be formed in a housing20defining a pressure chamber20A, adjacent to an opposed side of the main body12. The embodiment shown inFIG.1has a separate housing for the pressure chamber, however, such structure is not a limit on the scope of the disclosure. The main body12may be shaped to define a pressure chamber in a unitary structure. The passageway16and its parts16B,16C provide a travel path for a gate22. The travel path enables the gate22to attain sufficient velocity resulting from actuation of a pyrotechnic charge24and subsequent gas expansion against a piston26such that kinetic energy in the gate22may be sufficient to sever any device disposed in the through bore14and to enable the gate22to extend into the passageway16across the through bore14.

An insert28may provide effective flow closure between the through bore14and the passageway16and its parts16B,16C such that fluid pressure in the through bore14is excluded from the passageway16and its parts16B,16C thereof. A ring cutter30may be positioned in the part16B of the passageway16. The ring cutter30comprises a central opening, which is shown in alignment with the through bore14inFIG.1, and which central opening may comprise one or more geometric features that act to increase the capability of the ring cutter30to sever any device in the through bore14when the ring cutter30is moved by the gate22. When the gate22is disposed across the through bore14after actuation of the pyrotechnic charge24, the through bore14is thereby effectively closed to flow across the gate22. The pyrotechnic charge24may be actuated by an initiator32of types well known in the art. The piston26may be decelerated by an energy absorbing element (brake)34such as a crush sleeve or similar device such that the piston26does not strike the pressure chamber20A wall, preventing damage to the pressure chamber20A or any part of the main body12or the receiving cover18.

FIG.2shows a schematic of an embodiment of the main body13(similar to the main body12ofFIG.1) with an expanded view of an example embodiment of an insert28according to the disclosure. InFIG.2, the main body13is shown without a receiving cover18or pressure chamber20A (seeFIG.1) for clarity of illustration. The insert28may be configured as a modular assembly having a first segment, shown as a first insert segment28A and a second segment, shown as a second insert segment28B. The first28A and second28B insert segments may be formed from any suitable material, e.g., steel or other high strength metal, and can vary in size and dimensions depending on the dimensions of and the pressure rating of the main body13used for the particular embodiment of the BOP as known in the art. Each insert segment28A,28B has an opening29formed proximate its central region, passing all the way through the insert28body. When disposed in the main body13, the first28A and second28B insert segments are positioned such that the respective openings29in the insert segments28A,28B are aligned with the main body13through bore14(seeFIG.1). An upper O-ring36and a lower O-ring38may be respectively positioned in lands29A formed around the circumference of the openings29on the first28A and second28B insert segments to provide a fluid seal for the through bore14when the insert28is mounted within the main body13.

The ring cutter30may be configured in a generally rectangular shape with flat, planar surfaces. An opening31is formed in the central region of the ring cutter30, passing from the top surface through to the bottom surface of the ring cutter30. In assembly, the ring cutter30is disposed between the first28A and second28B insert segments. As shown inFIG.1, when the first28A and second28B insert segments are positioned within the main body13, the two segments28A,28B define the passageway16B. In some embodiments, the ring cutter30may be configured with an O-ring40disposed on a land formed on its surface surrounding the opening31. In some embodiments, the ring cutter30may be implemented with an O-ring40on one surface and another O-ring in a land formed on the opposite surface. Seals42,44may be disposed on each longitudinal end of the insert segments28A,28B to provide a fluid seal at the interface between the insert28ends and the main body13.

FIG.2further shows an exploded view of spreaders46that are positioned between the first28A and second28B insert segments when the insert28is assembled. Both spreaders46may be positioned to reside within the passageway16B, with one spreader disposed on each side of the insert28.FIG.3shows a cutaway side view of one of the spreaders46disposed on one side of the insert28when the insert28is positioned within the main body13.

An embodiment of the spreaders46as shown inFIG.3comprises an assembly including a first component48, a second component50, a first end piece52, a second end piece54, and an adjuster screw56. As shown inFIG.3, the first component48may be configured with an outwardly (with reference to the center of the first component) tapered first end48A and an outwardly tapered second end48B opposite the tapered first end48A. The first component48first and second tapered ends48A,48B each form angled ramp surfaces narrowing toward the center of the first bracket48. The second component50may also be configured with an outwardly tapered first end50A and an outwardly tapered second end50B opposite the tapered first end50A. The second component50first and second tapered ends50A,50B each forming angled ramp surfaces narrowing toward the center of the second component50. The first end piece52may be configured with inwardly tapered sides52A,52B, forming a wedge that matches the respective first and second component48,50tapered first ends48A,50A. Similarly, the second end piece54may be configured with inwardly tapered sides54A,54B forming a wedge that matches the respective first and second component48,50tapered second ends48B,50B. The adjustment screw56extends through a hole52C in the first end piece52to engage with receiving threads58formed in the second end piece54.

When assembled and disposed in the housing12,13, each spreader46is mounted within the passageway16B formed between the first and second insert segments28A,28B, generally in alignment with the longitudinal axis of the insert28. The second end piece54may be configured with receiving threads58to receive the adjustment screw56end, as explained above. When the adjuster screw56is turned (e.g., with a screwdriver using a slotted screw head60or any other combination of screw head and tool, e.g., Phillips, socket head, TORX® head (reg. trademark of Acument Intellectual Properties LLC, Troy, Mich.), to engage with the second end piece54, the tapered surfaces of the pieces52,54cooperate with the tapered surfaces of the end pieces54,56to force the first and second components48,50to move apart from one another perpendicular to the longitudinal axis of the insert28. Such movement applies an expanding or spreading force to the first and second insert segments28A,28B. As the first and second insert segments28A,28B are expanded apart from one another due to the force applied by the first and second components48,50, the O-rings36,38on the outer surfaces of the insert segments28A,28B are correspondingly pressed against the housing12,13interior surfaces (seeFIG.1), which aids energizing the O-rings36,38to provide a better fluid seal. Once the insert28is positioned within the main body (13inFIG.2), the adjuster screw56may be rotated to cause the spreader46to maintain a set distance between the insert segments28A,28B.

In light of the principles and example embodiments described and illustrated herein, it will be recognized that the example embodiments can be modified in arrangement and detail without departing from such principles. It will be appreciated by those skilled in the art that embodiments of this disclosure may be implemented using conventional materials, hardware, and components (e.g. suitable conventional seals) as known in the art. Although the foregoing discussion has focused on particular embodiments, any embodiment is freely combinable with any one or more of the other embodiments disclosed herein, and any number of features of different embodiments is combinable with one another, unless indicated otherwise.