WO2017079630A1

WO2017079630A1 - Directional control valve condition monitoring system

Info

Publication number: WO2017079630A1
Application number: PCT/US2016/060642
Authority: WO
Inventors: Gregory Allen CARTER
Original assignee: Fmc Technologies, Inc.
Priority date: 2015-11-05
Filing date: 2016-11-04
Publication date: 2017-05-11

Abstract

A condition monitoring system for a directional control valve (DCV) which is operable to selectively connect a source of a first pressurized fluid to a hydraulically actuated device to thereby actuate the device. The DCV is actuated by a second pressurized fluid which is supplied to the DCV through a supply line and is vented from the DCV through a return line. The condition monitoring system includes a flow meter which is connected to the return line and is operable to measure an amount of the second pressurized fluid which is vented through the return line when the DCV is actuated, and a first processor which is configured to compare the amount of the second pressurized fluid vented through the return line when the DCV is actuated to empirical data representative of a relationship between a useful life of the DCV and an amount of second pressurized fluid vented by the DCV when actuated. In this manner, the useful life of the DCV is determined based on the amount of the second pressurized fluid which is vented through the return line when the DCV is actuated.

Description

DIRECTIONAL CONTROL VALVE CONDITION MONITORING SYSTEM This application is based upon and claims the benefit of U.S. Provisional Patent Application No. 62/251 ,676 filed November 5, 2016.

BACKGROUND OF THE INVENTION

The present invention is directed to a system and method for monitoring the condition of one or more directional control valves ("DCV's").

DCV's are used in, e.g., subsea control modules ("SCM's") for

hydrocarbon production and processing systems to control the operation of certain components of the systems, such as flow control valves. DCV's are typically actuated by a low pressure actuating fluid. It is not uncommon for a DCV to fail by not shifting from one position to another during actuation. This is usually due to the condition of the actuating fluid in the DCV. Fluid cleanliness has a direct relation to the useful life of a DCV. The condition of a DCV can be roughly characterized by the amount of actuating fluid that is ejected when the DCV shifts from one position to another. By monitoring the amount of actuating fluid ejected fluid from the DCV when it is shifted from one position to another and trending that value over time, one can monitor the useful life of the DCV.

SUMMARY OF THE INVENTION

The present invention is directed to a condition monitoring system for a directional control valve (DCV). The DCV is operable to selectively connect a source of a first pressurized fluid to a hydraulically actuated device to thereby actuate the device, and is actuated by a second pressurized fluid which is supplied to the DCV through a supply line and is vented from the DCV through a return line. The condition monitoring system comprises a flow meter which is connected to the return line and is operable to measure an amount of the second pressurized fluid which is vented through the return line when the DCV is actuated. The condition monitoring system also comprises a first processor which is configured to compare the amount of the second pressurized fluid vented through the return line when the DCV is actuated to empirical data representative of a relationship between a useful life of the DCV and an amount of second pressurized fluid vented by the DCV when actuated. In this manner the useful life of the DCV may be determined based on the amount of the second pressurized fluid which is vented through the return line when the DCV is actuated. In accordance with one embodiment of the invention, the condition monitoring system may comprise a second processor which is configured to record a total amount of the second pressurized fluid which is vented through the return line during actuation of the DCV over a period of time. In this embodiment, the first processor is configured to compare the total amount to empirical data representative of a relationship between the useful life of the DCV and the total amount of second pressurized fluid vented by the DCV over time. Also, the first and second processors may be the same processor.

In accordance with another embodiment of the invention, the condition monitoring system may comprise a second processor which is configured to record respective amounts of the second pressurized fluid which are vented through the return line during each of a number of actuations of the DCV over a period of time. In this embodiment, the first processor is configured to compare the respective amounts to empirical data representative of a relationship between the useful life of the DCV and the amounts of second pressurized fluid vented by the DCV over time. Also, the first and second processors may be the same processor.

In accordance with yet another embodiment of the invention, the DCV may comprise a piston and valve spool arrangement for selectively connecting the source of the first pressurized fluid to the device, and a first valve member which when the DCV is actuated to open the DCV is moved from a first position to a second position to communicate the second pressurized fluid from the supply line to a first side of the piston and valve spool arrangement to thereby open the DCV and is then moved from the second position to the first position to vent the second pressurized fluid to the return line. In this embodiment, the flow meter is operable to measure the amount of the second pressurized fluid which is vented through the return line at least when the first valve member is moved from the second position to the first position.

In accordance with still another embodiment of the invention, the DCV may also comprise a second valve member which when the DCV is actuated to close the DCV is moved from a first position to a second position to communicate the second pressurized fluid from the supply line to a second side of the piston and valve spool arrangement to thereby close the DCV and is then moved from the second position to the first position to vent the second pressurized fluid to the return line. In this embodiment, the flow meter is operable to measure the amount of the second pressurized fluid which is vented through the return line at least when the second valve member is moved from the second position to the first position.

In accordance with a further embodiment of the invention, the condition monitoring system may also include a second processor which is configured to record a total amount of the second pressurized fluid which is vented through the return line during actuation of the DCV over a period of time. In this embodiment, the first processor is configured to compare the total amount to empirical data representative of a relationship between the useful life of the DCV and the total amount of second pressurized fluid vented by the DCV over time. Also, the first and second processors may be the same processor.

In accordance with still a further embodiment of the invention, the condition monitoring system may include a second processor which is configured to record respective amounts of the second pressurized fluid which are vented through the return line during each of a number of actuations of the DCV over a period of time. In this embodiment, the first processor is configured to compare the respective amounts to empirical data representative of a relationship between the useful life of the DCV and the amounts of second pressurized fluid vented by the DCV over time. Also, the first and second processors may be the same processor.

The present invention is also directed to a method for monitoring the condition of a directional control valve (DCV) which is operable to selectively connect a source of a first pressurized fluid to a hydraulically actuated device to thereby actuate the device. The DCV is actuated by a second pressurized fluid which is supplied to the DCV through a supply line and vented from the DCV through a return line. The method comprises the steps of measuring an amount of the second pressurized fluid which is vented through the return line when the DCV is actuated; comparing the amount of the second pressurized fluid vented through the return line when the DCV is actuated to empirical data representative of a relationship between a useful life of the DCV and an amount of second pressurized fluid vented by the DCV when actuated; and determining the useful life of the DCV based on the amount of the second pressurized fluid which is vented through the return line when the DCV is actuated. In accordance with one embodiment of the invention, the method further comprises the steps of determining a total amount of the second pressurized fluid which is vented through the return line during actuation of the DCV over a period of time; and comparing the total amount to empirical data representative of a relationship between the useful life of the DCV and the total amount of second pressurized fluid vented by the DCV over time.

In accordance with another embodiment of the invention, the method also comprises the steps of determining respective amounts of the second

pressurized fluid which are vented through the return line during each of a number of actuations of the DCV over a period of time; comparing the respective amounts to empirical data representative of a relationship between the useful life of the DCV and the amounts of second pressurized fluid vented by the DCV over time.

In accordance with the present invention, therefore, measurements made by the flow meter when the DCV is actuated can be compared to predetermined empirical data relating the useful life of the DCV to the amount of actuating fluid vented by the DCV during actuation to determine the useful life of the DCV. For example, technical condition indices ("TCI's") can be built using data captured from healthy and degraded DCV's to provide an indication of the health and remaining useful life of the DCV. This information can be used to proactively replace a degraded SCM (Subsea Control Module) before a hard failure. For example, a healthy DCV may eject 10ml of fluid (when shifted) when new and 30 ml when it is at the point of failure. By building a model approximating the consumption of life seen in practice, one can provide an accurate measure of the useful life of a DCV. Swapping a degraded SCM could avoid well downtime, while waiting for a hard failure could cost tens of millions of dollars in lost production.

The features and advantages of the present invention will now be described with reference to the accompanying drawings. In the drawings, the same reference numbers may be used to denote similar components in the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is cross sectional view of a representative DCV in connection with which the condition monitoring system of the present invention can be used; Figures 2A-2B are schematic diagrams of respective parts of a hydraulic circuit which includes a plurality of DCV's, some of which are connected to the monitoring system of the present invention;

Figures 3A-3E are sequential views showing the operation of opening a representative DCV in order to open a connected SCSSV;

Figures 4A-4E are sequential views similar to Figures 3A-3E but showing the operation of closing the DCV in order to close the SCSSV;

Figures 5A-5B are sequential views of the process of venting a high pressure DCV while in the open position; and

Figures 6A-6E are sequential views of the process of venting a low pressure DCV while in the open position.

DETAILED DESCRIPTION OF THE INVENTION

The directional control valve ("DCV") condition monitoring system of the present invention can be used with a variety of DCV's. For purposes of brevity, the invention will be described in connection with the representative DCV 10 shown in Figure 1 . It should be noted that certain of the internal fluid

passageways and external connections of the DCV 10 have been omitted from Figure 1 for purposes of clarity. However, the internal passageways and external connections which are important to an understanding of the present invention, to the extent they are not within the knowledge of one of ordinary skill in the art, will be made apparent below.

As shown in Figure 1 , the DCV 10 includes a valve body 12 (which may be formed from several parts to facilitate assembly of the DCV), a first solenoid 14 which is connected to a first valve spool 16, a second solenoid 18 which is connected to a second valve spool 20, a first piston 22 which is slidably received in a corresponding first bore 24, a second piston 26 which is slidably received in a corresponding second bore 28, a third piston 30 which is slidably received in a corresponding third bore 32 and is connected to or formed integrally with the second piston, and a shaft 34 which extends between the first and third pistons. The third piston 30 comprises a first portion 36 which is sealed to a first section 38 of the third bore 32 and a smaller diameter second portion 40 which is sealed to a smaller diameter second section 42 of the third bore.

Referring still to Figure 1 , the DCV also includes a third valve spool 44 which is connected to or formed integrally with the shaft 34 intermediate the first and third pistons 22, 30. The third valve spool 44 includes three radial through bores and an axial bore which connects the two leftmost (as viewed in Figure 1 ) through bores. The third spool 44 is positioned in a valve bore 46 to which a main stage supply port 48 and a function or output port 50 are connected. The main stage supply port 48 is connected to a source of pressurized hydraulic fluid (not shown), and the function port 50 is connected to a component to be operated by the DCV, such as a valve actuator (not shown).

As will be described more fully below, by selectively energizing the first and second solenoids 14, 18, low pressure fluid which is communicated to the DCV via a pilot line (not shown) is routed to either the first piston 22 or the second piston 26 to respectively move the third spool 44 between an open position and a closed position. In the open position, the main stage supply port 48 is connected to the function port 50, and in the closed position the main stage supply port is disconnected from the function port. As shown in Figure 1 , the DCV also includes a reset spring 52 which is mounted between the third piston 30 and a portion of the valve body 12 in order to boost the closing force of the second piston 26.

Figures 2A and 2B illustrate respective parts of a hydraulic circuit for a subsea control module ("SCM") which may be used to control, e.g., a subsea hydrocarbon production system, such as a subsea Christmas tree. The hydraulic circuit should be read to be connected between the points "A" in Figures 2A and 2B and between the points B in Figures 2A and 2B. The DCV's in this circuit are designated "CV#", where # is an integer from 3 to 26. As shown in Figure 2A, the main stage supply port 48 of each DCV CV3-CV20 is connected to a low pressure fluid source 54 via a low pressure supply line 56. In addition, the function port 50 of each DCV CV3-CV20 is connectable via a respective coupler 58 to a corresponding component (not shown) to be controlled by the DCV. Each of the DCV's CV3-CV20 is also connected to a low pressure return line 60 and a pilot line 62.

As shown in Figure 2B, the main stage supply port 48 of each DCV CV21 -

CV26 is connected to a high pressure fluid source 64 via a high pressure supply line 66. In addition, the function port 50 of each DCV CV21 -CV26 is connectable via a respective coupler 58 to a corresponding component (not shown) to be controlled by the DCV. Each of the DCV's CV21 -CV24 is connected to a smart return line 68, while the DCV's CV25 and CV26 are connected to a high pressure return line 70. As with the DCV's CV3-CV20, the DCV's CV21 -CV26 are also connected to the pilot line 62.

As discussed above, it is not uncommon for DCV's to fail by not shifting from one position to another. In accordance with the present invention, a system is provided to monitor the condition and useful life of the DCV's. Each time the DCV shifts between its positions, it expels a small amount of fluid through the return line. The system of the present invention provides a means for periodically measuring the fluid which is so expelled and comparing these amounts to empirically obtained data in order to determine the condition of the DCV.

Empirical data relating the useful life of a DCV to the amount of actuating fluid vented by the DCV during actuation may be obtained in a conventional fashion. For example, observation or experimentation may reveal that a DCV vents 10ml of actuating fluid when new, 30 ml of actuation fluid near the end of its useful life, and other amounts of actuation fluid at various points during its useful life. This data may then be used to establish a relationship between the volume of actuation fluid vented during actuation and the remaining useful life of the DCV. For example, based on the empirical data, relationships may be defined between the amount of actuation fluid vented during a single actuation and the remaining useful life of the DCV, the total amount of actuation fluid vented during a number of actuations over a specific period of time and the remaining useful life of the DCV, and the rate of increase in the amounts of actuation fluid vented over a succession of activations during a specific period of time and the remaining useful life of the DCV. One or more of these relationships may then be programmed into a performance monitoring system which is located, e.g., in the master control station on a surface vessel. In one embodiment of the invention, technical condition indices ("TCI's") can be built using data captured from healthy and degraded DCV's to provide an indication of the health and remaining useful life of the DCV. This information can be used to proactively replace a degraded SCM (Subsea Control Module) before the DCV fails. By building a model approximating the consumption of life seen in practice, one can provide an accurate measure of the useful life of a DCV.

Referring to Figure 2B, the volume of actuation fluid vented by the DCV is measured by a fluid flow meter 72 which is positioned in the low pressure return line 60. A suitable fluid flow meter for purposes of the present invention is the Flow Technology FT6-800XBBLEA-1046 fluid meter, which is available from FMC Technologies, Inc. of Houston, Texas as the FMC part 200006498 meter. The meter 72 may generate one or more measurements by which the volume of fluid vented through the low-pressure return line 60 can be determined. For instance, the meter 72 may constantly monitor flow via the frequency or pulse repetition rate of the volumetric flow, in which case the accumulated pulse total will represent the total volume measured. In one embodiment of the invention, the measurements generated by the meter 72 may be transmitted or otherwise made available to a processor, such as the SCM's CPU, which is configured to track and store the volumes of actuation fluid vented by the DCV during actuation. This data may then be transmitted or otherwise made available to another processor in, e.g., the performance monitoring system, which may be configured to determine the remaining useful life of the DCV by comparing the volumes of actuation fluid vented during actuation to one or more of the relationships described above. This processor may then estimate the time until failure and alert the operator of a likely leak. The alert of a likely degraded DCV and leak allows for a planned SCM change-out so as to avoid production down time. In an alternative to the embodiment just described, a single processor may be used to both track and store the amounts of actuation fluid vented during actuation and compare these amounts to the relationships described above in order to determine the remaining useful life of the DCV.

As an alternative to the single fluid meter 72, individual fluid meters 74 may be positioned in the respective return lines of one or more DCV's in order to monitor the condition of particular DCV's.

Figures 3A-3E shown the use of the condition monitoring system in a representative DCV which is being operated to open a surface controlled subsurface safety valve ("SCSSV"). In this sequence of operations, the fluid meter 72 monitors the amount of fluid expelled through the return line during operation of the DCV.

Figures 4A-4E shown the same DCV as in Figures 3A-3E, but this time in the process of closing the SCSSV.

Figures 5A-5B show what happens when the low pressure supply is vented with a high pressure DCV in the open position. Figures 6A-6E show what happens when the low pressure supply is vented with a low pressure DCV in the open position.

It should be recognized that, while the present invention has been described in relation to the preferred embodiments thereof, those skilled in the art may develop a wide variation of structural and operational details without departing from the principles of the invention. Therefore, the appended claims should be construed to cover all equivalents falling within the true scope and spirit of the invention.

Claims

What is Claimed is:

1 . A condition monitoring system for a directional control valve (DCV) which is operable to selectively connect a source of a first pressurized fluid to a hydraulically actuated device to thereby actuate the device, the DCV being actuated by a second pressurized fluid which is supplied to the DCV through a supply line and is vented from the DCV through a return line, the condition monitoring system comprising:

a flow meter which is connected to the return line, the flow meter being operable to measure an amount of the second pressurized fluid which is vented through the return line when the DCV is actuated; and

a first processor which is configured to compare the amount of the second pressurized fluid vented through the return line when the DCV is actuated to empirical data representative of a relationship between a useful life of the DCV and an amount of second pressurized fluid vented by the DCV when actuated;

whereby the useful life of the DCV is determined based on the amount of the second pressurized fluid which is vented through the return line when the DCV is actuated.

2. The condition monitoring system of claim 1 , further comprising: a second processor which is configured to record a total amount of the second pressurized fluid which is vented through the return line during actuation of the DCV over a period of time;

wherein the first processor is configured to compare the total amount to empirical data representative of a relationship between the useful life of the DCV and the total amount of second pressurized fluid vented by the DCV over time.

3. The condition monitoring system of claim 2, wherein the first and second processors are the same processor.

4. The condition monitoring system of claim 1 , further comprising: a second processor which is configured to record respective amounts of the second pressurized fluid which are vented through the return line during each of a number of actuations of the DCV over a period of time;

wherein the first processor is configured to compare the respective amounts to empirical data representative of a relationship between the useful life of the DCV and the amounts of second pressurized fluid vented by the DCV over time.

5. The condition monitoring system of claim 4, wherein the first and second processors are the same processor.

6. The condition monitoring system of claim 1 , wherein the DCV comprises a piston and valve spool arrangement for selectively connecting the source of the first pressurized fluid to the device, wherein the DCV comprises a first valve member which when the DCV is actuated to open the DCV is moved from a first position to a second position to communicate the second pressurized fluid from the supply line to a first side of the piston and valve spool arrangement to thereby open the DCV and is then moved from the second position to the first position to vent the second pressurized fluid to the return line, and wherein the flow meter is operable to measure the amount of the second pressurized fluid which is vented through the return line at least when the first valve member is moved from the second position to the first position.

7. The condition monitoring system of claim 6, wherein the DCV comprises a second valve member which when the DCV is actuated to close the DCV is moved from a first position to a second position to communicate the second pressurized fluid from the supply line to a second side of the piston and valve spool arrangement to thereby close the DCV and is then moved from the second position to the first position to vent the second pressurized fluid to the return line, and wherein the flow meter is operable to measure the amount of the second pressurized fluid which is vented through the return line at least when the second valve member is moved from the second position to the first position.

8. The condition monitoring system of claim 7, further comprising: a second processor which is configured to record a total amount of the second pressurized fluid which is vented through the return line during actuation of the DCV over a period of time;

9. The condition monitoring system of claim 8, wherein the first and second processors are the same processor.

10. The condition monitoring system of claim 7, further comprising: a second processor which is configured to record respective amounts of the second pressurized fluid which are vented through the return line during each of a number of actuations of the DCV over a period of time;

1 1 . The condition monitoring system of claim 10, wherein the first and second processors are the same processor.

12. A method for monitoring the condition of a directional control valve (DCV) which is operable to selectively connect a source of a first pressurized fluid to a hydraulically actuated device to thereby actuate the device, the DCV being actuated by a second pressurized fluid which is supplied to the DCV through a supply line and vented from the DCV through a return line, the method

comprising:

measuring an amount of the second pressurized fluid which is vented through the return line when the DCV is actuated; and

comparing the amount of the second pressurized fluid vented through the return line when the DCV is actuated to empirical data representative of a relationship between a useful life of the DCV and an amount of second pressurized fluid vented by the DCV when actuated; and

determining the useful life of the DCV based on the amount of the second pressurized fluid which is vented through the return line when the DCV is actuated.

13. The method of claim 12, further comprising:

determining a total amount of the second pressurized fluid which is vented through the return line during actuation of the DCV over a period of time;

comparing the total amount to empirical data representative of a relationship between the useful life of the DCV and the total amount of second pressurized fluid vented by the DCV over time.

14. The method of claim 12, further comprising: determining respective amounts of the second pressurized fluid which are vented through the return line during each of a number of actuations of the DCV over a period of time;

comparing the respective amounts to empirical data representative of a relationship between the useful life of the DCV and the amounts of second pressurized fluid vented by the DCV over time.