ONE WAY FLOW BLOWOUT PREVENTER SIDE PORT

Abstract

A blowout preventer stack may include a body with a vertical bore and a horizontal bore intersecting the vertical bore. The blowout preventer stack may include a side port extending from the vertical bore to an outer side surface of the body. The blowout preventer stack may also include a pair of rams disposed in the horizontal bore, each ram disposed at opposite ends of the horizontal bore and moveable within the horizontal bore to and from the vertical bore. The blowout preventer stack includes a one-way check valve coupled to the side port of the body. The one-way check valve may allow fluid flow into the blowout preventer stack and block fluid flow from exiting the blowout preventer stack.

Description

BACKGROUND

Well control in a petroleum field operation requires Pressure Control Equipment (PCE). PCE is an important part of almost all operations conducted in the field and proper design of such tools is important for safety.

Blowout preventers (BOPs) are a common form of PCE that are used whenever a surface facility is exposed to hazards coming out of a borehole. A BOP is a large assembly of piston induced rams in which the ram movement is enabled by either hydraulic fluid injection or mechanical forces. BOPs are installed on a well to safely control well kicks and prevent blowouts (loss of control of well fluids) during any situation that requires well control, including drilling operations. The BOP is usually controlled remotely and may be closed to facilitate regaining control of the well. Mud may be pumped into a well or, alternatively, the mud density may be increased to regain and maintain pressure control; the BOP may then be reopened. There are various BOP designs that allow for an open wellbore to be closed, for the wellbore to be sealed around a tubular component in the well, or for the wellbore to be closed by shearing through a tubular component, such as the drill pipe. A ram-type BOP includes a set of rams disposed opposite one another that move toward each other to close an open wellbore, to seal against a tubular component, or to shear through a tubular component. Annular-type BOPs include a large toroidal-shaped seal that is squeezed inward to seal on a tubular component or the open wellbore. One or more BOPs installed together on a well may be called a BOP stack.

SUMMARY

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

In some aspects, the techniques described herein relate to a blowout preventer stack. The blowout preventer stack may include a body with a vertical bore and a horizontal bore intersecting the vertical bore. The blowout preventer stack may include a side port extending from the vertical bore to an outer side surface of the body. The blowout preventer stack may also include a pair of rams disposed in the horizontal bore, each ram disposed at opposite ends of the horizontal bore and moveable within the horizontal bore to and from the vertical bore. Furthermore, the blowout preventer stack may include a one-way check valve coupled to the side port of the body.

In some aspects, the techniques described herein relate to a method. The method includes installing a blowout preventer stack on a well, the blowout preventer stack including a body with a vertical bore, a horizontal bore intersecting the vertical bore, and a side port extending from the vertical bore to an outer side surface of the body. The blowout preventer stack further includes a pair of rams disposed in the horizontal bore, each ram disposed at opposite ends of the horizontal bore and moveable within the horizontal bore to and from the vertical bore. The blowout preventer also includes a one-way check valve coupled to the side port of the body. The method includes flowing fluid into the side port of the blowout preventer stack through the one-way check valve while restricting flow out of the side port.

In some aspects, the techniques described herein relate to a system. The system includes a blowout preventer stack, the blowout preventer stack including a body having a vertical bore extending through the body, a first horizontal bore extending across the body and intersecting the vertical bore, a second horizontal bore an axial distance below the first horizontal bore and extending across the body and intersecting the vertical bore. Furthermore, the body includes a side port extending from the vertical bore to an outer side surface of the body. The blowout preventer stack further includes a first pair of rams disposed in the first horizontal bore, each ram of the first pair of rams disposed at opposite ends of the first horizontal bore and moveable within the first horizontal bore to and from the vertical bore, and a second pair of rams disposed in the second horizontal bore, each ram of the second pair of rams disposed at opposite ends of the second horizontal bore and moveable within the second horizontal bore to and from the vertical bore. The blowout preventer stack also includes a side port disposed through a side wall of the body. The system further includes a one-way check valve coupled to the side port of the body.

Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.

FIG. 1 shows a drilling system with a BOP, in accordance with one or more embodiments of the present disclosure.

FIG. 2 shows a BOP with four rams, in accordance with one or more embodiments of the present disclosure.

FIG. 3 shows a BOP with two combined rams, in accordance with one or more embodiments of the present disclosure.

FIG. 4A shows a design of a one-way check valve in a closed position in accordance with one or more embodiments of the present disclosure.

FIG. 4B shows the design of the one-way check valve of FIG. 4A in an open position in accordance with one or more embodiments of the present disclosure.

FIG. 5 shows a workflow of a method in accordance with one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

In the following description of FIGS. 1-5, any component described with regard to a figure, in various embodiments disclosed herein, may be equivalent to one or more like-named components described with regard to any other figure. For brevity, descriptions of these components will not be repeated with regard to each figure. Thus, each and every embodiment of the components of each figure is incorporated by reference and assumed to be optionally present within every other figure having one or more like-named components. Additionally, in accordance with various embodiments disclosed herein, any description of the components of a figure is to be interpreted as an optional embodiment which may be implemented in addition to, in conjunction with, or in place of the embodiments described with regard to a corresponding like-named component in any other figure.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a seismic dataset” includes reference to one or more of such seismic datasets.

Terms such as “approximately,” “substantially,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

It is to be understood that one or more of the steps shown in the flowcharts may be omitted, repeated, and/or performed in a different order than the order shown. Accordingly, the scope disclosed herein should not be considered limited to the specific arrangement of steps shown in the flowcharts.

Although multiple dependent claims are not introduced, it would be apparent to one of ordinary skill that the subject matter of the dependent claims of one or more embodiments may be combined with other dependent claims.

Blowout preventers (BOPs) are commonly used in well control situation as well as to kill wells in emergency situations, thus ensuring the safety of operating crews, preservation of the asset, and protection of the environment. BOP side ports aid in this process by allowing fluid to be pumped through the BOP into the well. However, side ports have the drawback that they can flow both in both directions, which may allow for debris to clog the port. Embodiments disclosed herein provide a unique modification to a conventional BOP that may prevent this problem by adding a one-way check valve to the BOP side port. This modification is applicable to many BOP designs, including ram-type BOPs and annular BOPs.

In well control situations, side ports on a BOP are used to allow fluid to be pumped into the well, thus equalizing pressure. Flow in the opposite direction (out of the BOP) may block the BOP with debris and significantly increase risk to personnel on location, the environment, as well as company assets. As such, the present application provides a mechanism that prevents flow out of the borehole to the surface through the side port of the BOP.

FIG. 1 illustrates systems in accordance with one or more embodiments. Specifically, FIG. 1 shows a well (102) that may be drilled into the subsurface by a drill bit (104) attached by a drillstring (106). A BOP stack (100), comprising one or more BOPs, is constructed at the well head located on the Earth's surface (116). In one or more embodiments, the well head and BOP stack (100) may be located below a surface of the ocean (i.e., subsea). The borehole corresponds to the uncased portion of the well (102). The borchole of the well (102) may traverse a plurality of overburden layers (110) and one or more cap-rock layers (112) to a hydrocarbon reservoir (114). One of the layers drilled into by the drill bit (104) may be over pressured relative to the fluid in the borehole, thus causing a pressure kick that may reach the surface (116). The BOP stack (100) is essentially a large valve at the top of the well (102) that may be closed in case an overpressure situation causes fluids and gas to escape at the surface (116) of the well (102). Without the BOP stack (100), the escape of fluids and gas could have catastrophic consequences, leading to the loss of life and equipment. The BOP stack (100) may be closed manually or remotely with, for example, hydraulic actuators, at which point an operator may attempt to regain control and regulate pressure in the well (102). Regaining control of the well (102) usually involves increasing the density of the fluid in the well (102) to a point where an overpressure zone is stabilized and the BOP stack (100) may be opened again.

FIG. 2 illustrates systems in accordance with one or more embodiments of a BOP stack (100). In general, a BOP stack (100) may include one or more BOPs, where each BOP may have different styles, sizes, and pressure ratings. As shown in FIG. 2, one or more embodiments of the BOP stack (100) in accordance with the present application has a body (216) with a vertical bore (218) that extends from an upper surface of the BOP stack (100) to a bottom surface of the BOP stack (100) and that is in fluid communication with the borehole of the well (102) below it. The body (216) of the BOP stack (100) may include one or more horizontal bores (214) configured to receive one or more pairs of rams (200). The BOP stack (100) shown in FIG. 2 has four horizontal bores (214) separated by an axial distance and extending perpendicularly across and intersecting the vertical bore (218). Within each of the horizontal bores (214), pairs of rams (200) may be disposed. The rams (200) of each pair of rams (200) are positioned opposite one another at opposite ends of one of the horizontal bores (214). The rams (200) are configured such that, upon actuation, the rams (200) of a pair of rams (200) are moveable toward one another to seal the vertical bore (218). Rams (200) come in various designs, including pipe rams, slip rams, shear rams, and blind rams. A BOP stack (100) may include one or more different kinds of rams (200). For example, a combination of pipe rams, slip rams, shear rams, and blind rams may be used on a single BOP stack (100).

Pipe rams have a half-circle hole or cutout formed on the edge of each of the pair of shafts that corresponds to a drill pipe, coiled tubing. E-line, slickline, borehole tool, or other tubular component (hereafter collectively referred to generically as “pipe”), such that upon actuation of the pipe rams, the pipe rams move toward the vertical bore (218) and into scaling engagement with the pipe to form a seal around the pipe. Slip rams have slips that prevent upward and downward movement of a drillstring (106), but do not isolate pressure or prevent flow. Shear rams have steel blades designed to cut a drillstring (106) or tubing when the BOP stack (100) is closed, and then fully close to provide isolation or sealing of the borehole. Shear rams are usually the last rams (200) to be engaged; cutting the drillstring (106) will leave it stranded in the borehole, thus making it harder to regain control and restart production. Blind rams are similar to pipe rams, but do not have the half-circle holes. Blind rams seal against each other and are used to seal the borehole of the BOP stack (100) when no drillstring (106) is inside the BOP stack (100).

After the bore of the BOP stack (100) is closed by actuation of the rams (200), pressure within in the BOP stack (100) may be controlled by pumping a fluid into the BOP stack (100). The BOP stack (100) includes a BOP side port (208) that extends through a side wall of the body (216) from the vertical bore (218) to an outer side surface of the BOP stack (100). The side port (208) is typically located beneath the shear ram and above the pipe ram (but other arrangements are possible). A conventional quad BOP stack has the following ordering of rams from top to bottom: blind ram, shear ram, pipe ram, and slip ram. For combi BOPs, there is typically a blind/shear ram located above a pipe/slip ram, with the side port (208) between them. If a BOP stack (100) consists of a single pair of rams, it doesn't qualify as a fully functional BOP stack (100) and a side port (208) cannot be used.

BOP side ports (208) may be used to kill wells (102) by pumping a heavy fluid through the side port (208) into the BOP stack (100) until pressure equalizes within the BOP stack (100) and the well (102). Once the pressure in the well (102) is controlled, the rams (200) of the BOP stack (100) may be opened. One or more equalizing valves may be coupled to the BOP stack (100) and in fluid communication with the vertical bore (218) to allow for pressures above and below a particular pair(s) of rams (200) to be equalized. For example, as shown in FIG. 2, a top equalizing valve (210) and a bottom equalizing valve (212) may be coupled to the BOP stack (100) to further ensure that the pressure above and below the rams (200) is equal before opening the rams (200). If the pressure is not equal on each side of closed rams (200), the top equalizing valve (210) and bottom equalizing valve (212) may be used to adjust the pressure on either side of the rams (200). Equalizing the pressure on both sides of the rams (200) permit opening the BOP stack (100).

FIG. 3 shows another embodiment of a BOP stack (100) with a side port (208) in accordance with the present application. The BOP stack (100) shown in FIG. 3 is a dual or combination BOP stack where both the blind ram and the shear ram are combined together into a first ram pair (300), and the slip ram and the pipe ram are combined together into a second ram pair (302). Like the BOP stack (100) in FIG. 2, the BOP stack (100) of FIG. 3 also has a side port (208) formed in a body (216) of the BOP stack (100) with a one-way check valve (220) connected to it, allowing fluid flow only into the BOP stack (100) and restricting or preventing fluid from exiting through the side port (208).

As shown in FIG. 3, the dual or combination BOP stack (100) may also include a top equalizing valve (210) and a bottom equalizing valve (212) coupled to the BOP stack (100) and in fluid communication with the vertical bore (218) to allow for pressures above and below a particular pair(s) of rams (200) to be equalized. For example, as shown in FIG. 3, a top equalizing valve (210) and a bottom equalizing valve (212) may be coupled to the BOP stack (100) to further ensure that the pressure above and below the ram pairs (300, 302) is equal before opening one or more of the rams (200). If the pressure is not equal on each side of the closed rams (200), the top equalizing valve (210) and bottom equalizing valve (212) may be used to adjust the pressure on either side of the rams pairs (300, 302). Equalizing the pressure on both sides of the ram pairs (300, 302) permit opening the BOP stack (100).

A side port (208) typically allows for bidirectional flow into and out of the well (102). However, bidirectional flow through the side port (208) may present a potential safety issue if solid matter flowing out of the BOP stack (100) clogs the side port (208), thereby preventing the side port (208) from being closed and/or preventing fluid from being pumped in. The systems and method described herein provide a unique improvement to the conventional BOP stack (100) that includes adding a one-way check valve (220) to the side port (208). The one-way check valve (220) allows flow into the BOP stack (100), for example, to help kill the well (102). The one-way check valve (220) restricts flow from the well (102, FIG. 1) to the surface (116, FIG. 1) through the side port (208) and prevents debris from the borehole from becoming lodged inside the side port (208).

FIGS. 4A and 4B show an example of a one-way check valve (220) that may be installed in the side port (208, FIGS. 2, 3) of the BOP stack (100, FIGS. 2, 3) in accordance with embodiments of the present disclosure. As shown in FIGS. 4A and 4B, the one-way check valve (220) has a valve body (404) with a ball (400) and spring (402) disposed inside the valve body (404). As shown, the ball (400) is provided within a valve bore (406) or channel of the one-way check valve (220) and is configured to move within the valve bore (406). The spring (402) is also positioned within the valve bore (406) adjacent to the ball (400) such that movement of the ball (400) in a direction toward the spring (402) compresses the spring (402). Movement of the ball (400) in a second direction away from the spring (402) is limited by a shoulder or narrowed diameter (generally indicated by the dashed line labeled 408) of the valve bore (406) of the one-way check valve (220). As discussed above, the one-way check valve (220) is installed in the side port (208) of the BOP stack (100) such that fluid is allowed to flow through the one-way check valve (220) into to well (102), but fluid is not allowed to flow through the one-way check valve (220) out of the well (102). With respect to the example one-way check valve (220) shown in FIGS. 4A and 4B, when installed in the side port (208) of the BOP stack (100), the opening of the one-way check valve (220) near the spring (402) faces toward the vertical bore (218) of the BOP stack (100), while the opening of the one-way check valve (220) near the ball (400) faces toward the outside the BOP stack (100). Thus, as shown in FIG. 4A, if there is flow from the well to the surface through one-way check valve (220) (indicated by the arrow), the ball (400) will lodge against the shoulder or narrowed diameter (408) of the valve bore (406) of the one-way check valve (220), thus blocking flow through the opening of the one-way check valve (220), and therefore blocking flow out of the BOP stack (100) through the side port (208). Conversely, in FIG. 4B, if there is flow into the well (102) through the one-way check valve (220) (indicated by the arrow on the left), the ball (400) is pushed inwards towards the spring (402), thus allowing unimpeded flow through the one-way check valve (220), and allowing flow out of the BOP stack (100) through the side port (208). Arrows in FIGS. 4A and 4B indicate the direction of fluid flow; x's indicate blocked flow.

FIG. 5 presents the workflow of the method. In Step (500), a BOP stack (100) is installed on a well (102). The BOP stack (100) includes a body (216), a pair of rams (200), a side port (208), and a one-way check valve (220) coupled to the side port (208). The one-way check valve (220) includes a valve body (404). Within the valve body (404) is a valve bore (406), and within the valve bore (406) are a ball (400) and a spring (402) which may move within the valve bore (406).

During an event that activates the BOP stack (100), in Step (502), fluid may be flowed into the side port (208) of the BOP stack (100) through the one-way check valve (220). Flow into the side port (208) will compress the spring (402), thus leaving the passage through the valve bore (406) to the BOP stack (100) open. Flow in the opposite direction out of the side port (208), however, will be restricted due to the interaction between the ball (400) and the spring (402). In that case, the force of the fluid flow will extend the spring (402) and push the ball (400) into the narrowed diameter (408), thus closing the one-way check valve (220).

Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function(s) and equivalents of those structures. Similarly, any step-plus-function clauses in the claims are intended to cover the acts described here as performing the recited function(s) and equivalents of those acts. It is the express intention of the applicant not to invoke 35 U.S.C. § 112(f) for any limitations of any of the claims herein, except for those in which the claim expressly uses the words “means for” or “step for” together with an associated function.

Claims

1. A blowout preventer stack, comprising:

a body comprising: a vertical bore extending through the body, a horizontal bore extending across the body and intersecting the vertical bore, and a side port extending from the vertical bore to an outer side surface of the body;

a pair of rams disposed in the horizontal bore, each ram disposed at opposite ends of the horizontal bore and moveable within the horizontal bore to and from the vertical bore; and

a one-way check valve coupled to the side port of the body.

2. The blowout preventer stack of claim 1, wherein the one-way check valve allows flow into the body and blocks flow from exiting the body.

3. The blowout preventer stack of claim 2, wherein the one-way check valve comprises a ball and a spring moveable within a bore of the one-way check valve.

4. The blowout preventer stack of claim 1, further comprising at least one of a top equalizing valve or a bottom equalizing valve.

5. The blowout preventer stack of claim 4, wherein the top equalizing valve and the bottom equalizing valve equalize a pressure in the blowout preventer stack.

6. The blowout preventer stack of claim 1, wherein the pair of rams is selected from the group consisting of a pair of blind rams, a pair of shear rams, a pair of slip rams, and a pair of pipe rams.

7. The blowout preventer stack of claim 1, wherein the body further comprises a plurality of horizontal bores extending across the body and intersecting the vertical bore, the blowout preventer stack further comprising a plurality of pairs of rams, a pair of rams disposed in each of the plurality of horizontal bores, each pair of rams of the plurality of pairs of rams disposed at opposite ends of the plurality of horizontal bores and moveable within the plurality of horizontal bores to and from the vertical bore.

8. A method, comprising:

installing a blowout preventer stack on a well, the blowout preventer stack comprising: a body comprising: a vertical bore extending through the body, a horizontal bore extending across the body and intersecting the vertical bore, and a side port extending from the vertical bore to an outer side surface of the body; a pair of rams disposed in the horizontal bore, each ram disposed at opposite ends of the horizontal bore and moveable within the horizontal bore to and from the vertical bore; a one-way check valve coupled to the side port of the body; and

flowing fluid into the side port of the blowout preventer stack through the one-way check valve while restricting flow out of the side port.

9. The method of claim 8, further comprising actuating at least one pair of rams of the blowout preventer stack while flowing fluid into the side port.

10. The method of claim 8, wherein the one-way check valve comprises a ball and spring, the method further comprising:

moving the ball in a first direction within a bore of the one-way check valve toward the spring and compressing the spring, thereby allowing fluid flow through the one-way check valve and into the blowout preventer stack; and

moving the ball in a second, opposite direction within the one-way check valve against a narrowed diameter of the bore of the one-way check valve, thereby restricting fluid flow through the one-way check valve and out of the blowout preventer stack.

11. The method of claim 8, further comprising adjusting a fluid flow through at least one of a top equalizing valve or a bottom equalizing valve coupled to the body.

12. The method of claim 11, wherein adjusting a pressure through the top equalizing valve and adjusting the pressure through the bottom equalizing valve equalizes the pressure in the blowout preventer stack to permit opening of the blowout preventer stack.

13. The method of claim 8, wherein the body further comprises a plurality of horizontal bores extending across the body and intersecting the vertical bore, the blowout preventer stack further comprising a plurality of pairs of rams disposed in the plurality of horizontal bores, each ram of the plurality of pairs of rams disposed at opposite ends of each of the plurality of horizontal bores and moveable within the plurality of horizontal bores to and from the vertical bore.

14. A system, comprising:

a blowout preventer stack, the blowout preventer stack comprising: a body having a vertical bore extending through the body, a first horizontal bore extending across the body and intersecting the vertical bore, a second horizontal bore an axial distance below the first horizontal bore and extending across the body and intersecting the vertical bore, the body comprising a side port extending from the vertical bore to an outer side surface of the body; a first pair of rams disposed in the first horizontal bore, each ram of the first pair of rams disposed at opposite ends of the first horizontal bore and moveable within the first horizontal bore to and from the vertical bore; a second pair of rams disposed in the second horizontal bore, each ram of the second pair of rams disposed at opposite ends of the second horizontal bore and moveable within the second horizontal bore to and from the vertical bore; and a side port disposed through a side wall of the body; and

a one-way check valve coupled to the side port of the body.

15. The system of claim 14, wherein the one-way check valve allows flow into the body and restricts flow from exiting the body.

16. The system of claim 14, further comprising a top equalizing valve coupled to the body of the blowout preventer stack.

17. The system of claim 16, further comprising a bottom equalizing valve coupled to the body of the blowout preventer stack.

18. The system of claim 17, wherein the top equalizing valve and the bottom equalizing valve equalize a pressure in the blowout preventer stack to permit opening of the blowout preventer stack.

19. The system of claim 14, wherein the first pair of rams and the second pair of rams is selected from the group consisting of a pair of blind rams, a pair of shear rams, a pair of slip rams, and a pair of pipe rams.

20. The system of claim of claim 14, wherein the body further comprises a plurality of horizontal bores extending across the body and intersecting the vertical bore, the blowout preventer stack further comprising a plurality of pairs of rams with one pair of rams disposed in each of the plurality of horizontal bores, each pair of rams of the plurality of pairs of rams disposed at opposite ends of the plurality of horizontal bores and moveable within the plurality of horizontal bores to and from the vertical bore.