Flow responsiveness enhancer for a blowout preventer

Abstract

A flow responsiveness enhancer apparatus may include a stack of manifolds with at least one manifold dedicated to each of the rams of the blowout preventer. The flow responsiveness enhancer includes a shared pressure line coupled to each of the manifolds, and a shared tank line coupled to each of the manifolds. Each manifold can include a 4-way directional valve that is piloted by the pressure levels in a pair of input ports. Each 4-way directional valve can couple the shared pressure line and the shared tank line to a pair of output ports.

Claims

1. A flow responsiveness enhancer for improved time responsiveness of a blowout preventer, comprising: a first section; a shared pressure line coupled to the first section; a second section coupled to the shared pressure line; wherein the first section includes: a pair of input ports; a pair of output ports; a first valve system that controls flow from one port of the pair of input ports into the shared pressure line; and a second valve system that controls flow from the shared pressure line into one port of the pair of output ports, and wherein the second section includes: another pair of input ports; another pair of output ports; a third valve system that controls flow from one port of the other pair of input ports into the shared pressure line; and a fourth valve system that controls flow from the shared pressure line into one port of the other pair of output ports.

2. The flow responsiveness enhancer of claim 1, further comprising a shared tank line coupled to the first section and the second section, and wherein the first section further includes a fifth valve system that controls flow from the shared tank line into another port of the pair of input ports of the first section.

3. The flow responsiveness enhancer of claim 2 wherein the fifth valve system comprises check valves.

4. The flow responsiveness enhancer of claim 1 further comprising a shared tank line coupled to the first and second sections, and wherein the second valve system further controls flow from another port of the pair of output ports of the first section into the shared tank line.

5. The flow responsiveness enhancer of claim 1 wherein the second valve system comprises a 4-way directional valve that is piloted by the pressure levels in the pair of input ports of the first section.

6. The flow responsiveness enhancer of claim 1 wherein the first valve system comprises a shuttle valve.

7. The flow responsiveness enhancer of claim 1 further comprising a check valve to limit flow from the shared pressure line to be toward the one port of the pair of output ports of the first section.

8. The flow responsiveness enhancer of claim 1 further comprising an accumulator coupled to the shared pressure line.

9. The flow responsiveness enhancer of claim 1 wherein the shared pressure line is coupled to a power pack to supply fluid to the first and second sections.

10. The flow responsiveness enhancer of claim 1 further comprising a check valve disposed along the shared pressure line between the first and second sections.

11. The flow responsiveness enhancer of claim 1 wherein each of the first and second sections is a manifold.

12. A system for improved time responsiveness of a blowout preventer, comprising: a power pack to supply pressurized fluid; a control valve system; a blowout preventer having one or more rams; a flow responsiveness enhancer having one or more sections, each section being operatively associated with one ram and fluidly coupled thereto; one or more pairs of control flowlines, each pair of control flowlines being operatively associated with one section of the flow responsiveness enhancer; wherein the control valve system includes a plurality of banked directional valves to selectively flow and return fluid between each section of the flow responsiveness enhancer and the power pack through one pair of control flowlines; wherein the flow responsiveness enhancer comprises a shared pressure line running through each section, and a shared tank line running through each section; and wherein each section of the flow responsiveness enhancer includes a first valve system that controls flow from one pair of control flowlines into the shared pressure line, a second valve system that controls flow from the shared pressure line to one ram and from the one ram into the shared tank line, and a third valve system that controls flow from the shared tank line into the one pair of control flowlines.

13. The system of claim 12 wherein the first valve system comprises a shuttle valve.

14. The system of claim 12 wherein the second valve system comprises a 4-way directional valve that is piloted by the pressure levels in one pair of control flowlines.

15. The system of claim 12 further comprising one or more check valves to limit flow from the shared pressure line to be toward the blowout preventer.

16. The system of claim 12 wherein the flow responsiveness enhancer has at least two sections, the system further comprising a check valve coupled on the shared pressure line, the check valve being disposed between the at least two sections.

17. The system of claim 12 wherein the flow responsiveness enhancer has at least two sections, the system further comprising a check valve coupled on the shared tank line, the check valve being disposed between the at least two sections.

18. The system of claim 12 further comprising an accumulator coupled to the shared pressure line.

19. The system of claim 12 further comprising an accumulator coupled to the shared tank line.

20. The system of claim 12 further comprising a common pressure flowline coupled to the shared pressure line and to the power pack for supplying pressurized fluid to the one or more sections, and a common return flowline coupled to the shared tank line and to the power pack for returning fluid to the power pack.

21. The system of claim 12 wherein the one or more sections are manifolds forming a stack of one or more manifolds.

Description

(1) Embodiments of method and apparatus for flow responsiveness enhancer for a blowout preventer are now described with reference to the following figures. Like numbers are used throughout the figures to reference like features and components.

(2) FIG. 1 is a schematic view illustrating a blowout preventer control system.

(3) FIG. 1A is a schematic view of a portion of FIG. 1 illustrating a control valve system.

(4) FIG. 1B is a schematic view of a portion of FIG. 1 illustrating a flow responsiveness enhancer.

(5) FIG. 2 is a schematic view illustrating an embodiment of a manifold shown in FIG. 1B.

(6) FIG. 3 is a schematic view illustrating a flow responsiveness enhancer comprising a stack of manifolds having check valves added between a manifold dedicated to a shear ram another manifold. While one manifold is shown dedicated to one shear ram in FIG. 3, two or more manifolds may be dedicated to two or more shear rams.

(7) FIG. 4 is a schematic view illustrating an embodiment of a manifold for a flow responsiveness enhancer, the manifold having one or more check valves configured to maintain flow in a single direction from flow responsiveness enhancer to blowout preventer, or to limit the flow from the shared pressure line to be toward the first or second output port of the pair of output ports.

(8) FIG. 5 is a schematic view illustrating an embodiment of a manifold for a flow responsiveness enhancer, the manifold including two 4-way directional valves that are piloted by the pressure levels in one pair of control flowlines.

(9) In the following description, numerous details are set forth to provide an understanding of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure may be practiced without these details and that numerous variations or modifications from the described embodiments are possible.

(10) Turning now to FIGS. 1 and 1A, a blowout preventer control system 10 for use with coiled tubing unit is shown, in accordance with embodiments of the present disclosure.

(11) The coiled tubing unit may be a known, frequently used apparatus that can be stationed at a well site 14 during the phase in which a BOP 9 is installed over a wellbore 11. The coiled tubing unit may include a reel of coiled tubing used to shuttle equipment up and down the wellbore 11, and to inject process fluids as the reel winds and unwinds the tubing. Operation of a coiled tubing unit often includes use of a hydraulic fluid in hydraulically manipulated components. Examples of hydraulically manipulated components often found in a coiled tubing unit include a coiled tubing reel, a coiled tubing injector, and a BOP system (e.g., the BOP 9) and multiple pumps.

(12) In a coiled tubing BOP, the number of rams can vary from one ram to eight rams (only four are illustrated in FIG. 1). A hydraulic power pack 3 including a hydraulic tank 7T, a hydraulic pump 7P coupled to an engine 7M, and hydraulic power storage accumulators (e.g., in the accumulator system 7A), can supply pressure and flow to the BOP 9 via a control valve system 6 that has multiple banked directional control valves and that is located in the control cabin 4. For example, a common configuration may include an 8 to 10 banked directional control valves (only four are illustrated in FIG. 1), where each control is assigned to a BOP ram 9a, 9b, 9c and 9d, and directs an inlet supply 7 and a hydraulic return 8 to each ram individually in the form of a pair of control flowlines 16a-d and 17a-d, one of which supplies pressured hydraulic fluid and the other of which returns the hydraulic fluid. The controls of the control valve system 6 are engaged to open or close each ram in operation by switching which flowline of the pair is at a high pressure and supplies the hydraulic fluid and which flowline of the pair is at low pressure and returns the hydraulic fluid.

(13) The blowout preventer control system 10 may utilize small flowlines 16a-d and 17a-d that are routed through an optional hydraulic swivel 23 of a reel 22 to manage long flowlines (typically hundreds of feet, and in a particular practical embodiment, 150 to 200 feet) to enable placement of the control cabin 4 at a safe distance from the wellbore 11. Each ram 9a, 9b, 9c or 9d having two control flowlines, respectively 16a and 17a, 16b and 17d, 16c and 17, or 16d and 17d, necessarily results in two to sixteen flowlines (only 8 are illustrated in FIG. 1) being connected to the flow responsiveness enhancer 20. In a typical embodiment, each flowline is approximately inch in diameter.

(14) The hydraulic power pack 3 operates on hydraulic fluid to power the coiled tubing operation. The hydraulic fluid usually becomes increasingly viscous with lower temperatures. The temperature in flowlines that do not continuously flow, such as the BOP control lines, can be below water freezing temperatures in certain environments. Viscous fluid in long, small diameter flowlines can result in dangerously slow BOP actuation.

(15) In the configuration shown in FIGS. 1 and 1B, a flow responsiveness enhancer device 20 may include a set of manifolds 21a, 21b, 21c and 21d (or stack of manifolds 21) positioned near to the BOP 9, sharing the flow path of all the control flowlines to the flow responsiveness enhancer 20, optionally without additional flowlines. With the flow responsiveness enhancer 20 positioned very near to the BOP 9, very short, high flow rate lines may be used to connect from the flow responsiveness enhancer 20 to the BOP 9, ensuring fast response times for the rams of the BOP 9.

(16) The valve system 6 includes multiple banked directional valves, and allows multiple flow paths to communicate pressure signals and to supply hydraulic fluid to the flow responsiveness enhancer 20. The flow responsiveness enhancer 20 comprises elements that are reactive to differential pressure signals. Thus, relative pressure levels in the pair of control flowlines 16a and 17a select the open or close state of ram 9a. However, supply or return of hydraulic fluid in the control flowlines 16a and 17a without change of relative pressure may not always imply movement of the ram 9a, because this supply or return of hydraulic fluid may also be used by the flow responsiveness enhancer 20 to move the other rams 9b, 9c, or 9d. The behavior of the flow responsiveness enhancer 20 in response to pressure changes and fluid flow in the pairs of control flowlines 16b and 17b, 16c and 17c, or 16d and 17d may be similar to behavior of the flow responsiveness enhancer 20 in response to pressure changes and fluid flow in the pair of control flowlines 16a and 17a. As such, the flow responsiveness enhancer 20 may separate flow and pressure signals so that the flow and pressure signals work differently on ram actuation. Further, the flow responsiveness enhancer 20 permit the flows through the pairs of control flow lines, 16a and 17a, 16b and 17b, 16c and 17c to work together on the actuation of any of the rams 9a, 9b, 9c and 9d.

(17) Typically, at least one manifold per BOP ram is used in a stack in the flow responsiveness enhancer device 20. Accordingly, a flow responsiveness enhancer 20 may include between two and eight manifolds as described with respect to FIG. 2, and more preferably, may include eight manifolds. The function of flow responsiveness enhancer 20 is exhibited by further examination of each manifold thereof, with reference to FIGS. 1B and 2. While the manifolds 21a, 21b, 21c or 21d are described herein as a discrete physical device, it is also envisioned that a plurality of circuits accomplishing the same ends may be employed within a single discrete device or a stack of several discrete devices.

(18) Each manifold 21a, 21b, 21c or 21d may be coupled to an associated BOP ram 9a. 9b, 9c or 9d by a pair of relatively larger diameter, short length flowlines or hoses 25a and 26a, 25b and 26b, 25c and 26c, 25d and 26d. Because the BOP 9 may have between one and eight rams, there may be between two and sixteen flowlines between the flow responsiveness enhancer 20 and the BOP 9 (only eight are shown in FIG. 1). In a typical embodiment, each flowline may be approximately inch in diameter.

(19) FIG. 2 shows a schematic for a single manifold 40a of the flow responsiveness enhancer of the present disclosure. Label 35 represents a shared pressure line and label 36 represents a shared tank line. The shared pressure line 35 may run through several manifolds identical to manifold 40a, and may be formed from several pressure line segments, one segment in each manifold of the stack of manifolds. Similarly, the shared tank line 36 may run through several manifolds identical to manifold 40a, and may be formed from several tank line segments, one segment in each manifold of the stack of manifolds.

(20) For purposes of explanation, consider ports A and A as on the engage or close side of the hydraulic circuit to actuate one of the BOP rams 9a, 9b, 9c or 9d, and ports B and B as on the disengage or open side of the hydraulic circuit to actuate the same BOP ram. Ports A and B of the manifold 40a couple via relatively smaller diameter, longer length flowlines or hoses to the control valve system 6, for example via pair of control flowlines 16 and 17. Thus the flowline 16 may be the control flowline referred to as control-close, and the flowline 17 may be referred to as control-open. Ports A and B couple via relatively larger diameter, short length flowlines or hoses to one BOP ram, via pair of flowlines 25 and 26. Thus the flowline 25 may be referred to as actuate-close and the flowline 26 may be referred to as actuate-open.

(21) Ports P and T carry fluid in shared pressure and tank flowlines 35 and 36 within a stack of manifolds 21, and couple to adjacent manifolds for supply and return of fluid to or from others of the BOP rams. A shuttle value 30 compares the pressure between port A and port B, passing fluid from the port having the higher pressure of the two ports to the shared pressure line 35. Check valves 31 and 32 restrict flow to a single direction, passing fluid from the shared tank line 36 to any of the two ports that has a lower pressure, out of the manifold stack 21 and toward the control valve system 6 and the tank 7T. When the pressure on port A is greater than the pressure on port B, directional valve 33 shifts down, such that the shared tank line 36 connects to port B and the shared pressure line 35 connects to port A. Alternatively, when the pressure on port B is greater than the pressure on port A, directional valve 33 shifts up, such that the shared tank line 36 connects to A and the shared pressure line 35 connects to port B.

(22) When a plurality of manifolds such as the one shown in FIG. 2 are combined in a stack 21 shown in FIG. 1B, the fluid in the shared pressure line may flow to any of the manifolds in the stack of manifolds 21, as well as the fluid in the tank line may flow to any of the manifolds in the stack of manifolds 21.

(23) In an embodiment, the shared pressure line 35 and the shared tank line 36 may be sealed or capped at each end of a stack of manifolds 21. Alternatively, the shared pressure line 35 may be extended by a common pressure flowline 35a to the control valve system 6 (shown in FIG. 1) and to the power pack 3 (shown in FIG. 1) or directly to the power pack 3. Similarly the shared tank line 36 may be extended by a common return flowline 36a to the control valve system 6 and to the power pack 3 or directly to the power pack 3. Furthermore, the common pressure flowline 35a and or the common return flowline 36a may be provided as separate high rate flowlines connected to the swivel 23 and running along the long pairs of control flowlines or hoses 16a-d and 17a-d.

(24) In a further embodiment, a high flow rate supply of fluid can be added to some or all of the manifolds (or to the stack of manifolds 21) by adding one or more high pressure accumulators 37 (e.g., over 1000 psi gas charge) at or near the position of the flow responsiveness enhancer 20, and coupling the accumulators 37 to shared pressure line 35.

(25) In a further embodiment, a high flow rate return of fluid can be added to some or all of the manifolds (or to the stack of manifolds 21) to reduce back pressure, by adding one or more low pressure accumulators 38 (e.g., under 300 psi gas charge) at or near the position of the stack of manifolds 21, and coupling the accumulators 38 to shared tank line 36.

(26) In some BOPs, one or more rams of the plurality of rams are shear rams which can require dedicated accumulators and pressure/control lines. Due to the critical nature of a shear ram, in an embodiment of the present disclosure illustrated in FIG. 3, check valves 41 and 42 may be added in the shared pressure and tank lines 35 and 36 between the manifolds dedicated to shear rams (only one dedicated manifold 21e is shown) and the other manifolds in the stack (only one other manifold 21f is shown). The check valves 41 and 42 serve to isolate the shear rams from the other rams, and ensure that the fluid that is supplied to the manifolds dedicated to the shear rams is conveyed to the shear rams even to the detriment of fluid responsiveness of other rams.

(27) In an alternative embodiment, a stack of manifolds 21 may be replaced instead by separate manifolds each coupled to separable BOPs, with the improved responsiveness being maintained by joining the pressure line sections and tank line section of each manifold by flowlines or hoses to form the shared pressure and tank lines.

(28) Referring to FIGS. 3 and 4, at least one of the manifolds (21f, 40b) may include one or more check valves 45 that maintain flow in a single direction from flow responsiveness enhancer 20 to BOP 9, or that limit flow from the shared pressure line 35 to be toward the first or second output port A or B of the pair of output ports. For example, check valve 45 may be dispose between the shared pressure line 35 of one manifold and the first or second output port A or B. The check valve may allow fluid flow only from the shared pressure line 35 to the first or second output port A or B, and thus to a ram 9a, 9b, 9c or 9d of the BOP 9.

(29) Turning to FIG. 5, an embodiment of a manifold 40c having two 4-way directional valves that are piloted by the pressure levels in one pair of control flowlines is illustrated. The first 4-way directional valve 33 is similar to the 4-way directional valve 33 shown in FIG. 2 or 4 for example. The function of the first 4-way directional valve 33 is to control flow between the shared pressure and tank lines (respectively 35 and 36) on the one hand, and the pair of output ports A and B on the other hand. The second 4-way directional valve 39 combines the functions of shuttle valve 30 and the check valves 31 and 32 shown in FIG. 2 or 4. Thus, the second 4-way directional valve 39 controls flow from one port A or B of the pair of input ports into the shared pressure line, as well as flow from the shared tank line into the other port of the pair of input ports respectively B or A. For example, if the pressure in the control flowline 16 is higher than the pressure in the control flowline 17, the second 4-way directional valve 39 shifts down, allowing flow from port A into the shared pressure line 35, and flow from the shared tank line 36 into port B. The flow is crossed when pressure in the control flowline 17 is higher than the pressure in the control flowline 16.

(30) While the disclosure has been disclosed with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. While the disclosure has been described in the context of applications in improving responsiveness of flow to a BOP, the apparatus of the disclosure can be used in many applications. Likewise, while particular configurations involving check valves, shuttle valves, and/or directional valves are expressly noted, all logical equivalents to such devices are contemplated as within the design considerations of one of ordinary skill in the art.

(31) Although 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 disclosure. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not simply structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words means for together with an associated function.

(32) The preferred aspects and embodiments were chosen and described in order to best explain the principles of the invention and its practical application. The preceding description is intended to enable others skilled in the art to best utilize the invention in various aspects and embodiments and with various modifications as are suited to the particular use contemplated. In addition, the methods may be programmed and saved as a set of instructions, that, when executed, perform the methods described herein. It is intended that the scope of the invention be defined by the following claims.