WO2014128132A1

WO2014128132A1 - Monitoring system and method

Info

Publication number: WO2014128132A1
Application number: PCT/EP2014/053163
Authority: WO
Inventors: Richard S BAILEY; Greg HICKEY
Original assignee: BP Exploration Operating Co Ltd
Current assignee: BP Exploration Operating Co Ltd
Priority date: 2013-02-20
Filing date: 2014-02-18
Publication date: 2014-08-28
Anticipated expiration: 2015-08-20

Abstract

A monitoring system for monitoring the operation of a relief system is provided. The relief system is connected to one or more sources configured to deliver fluid into the relief system and the sources each comprise one or more source sensors for measuring one or more parameters associated with a respective source. The monitoring system is configured to access data storage arranged to store a first set of one or more sources that have previously been identified as delivering fluid into the relief system. The monitoring system comprises a data receiver arranged to receive substantially real-time measurement data from the source sensors and a processor. The processor is configured to a) determine a second set of sources currently delivering fluid into the relief system based on the received source sensor measurement data, b) access the data storage whereby to determine whether said second set of sources matches the first set of sources, and c) generate a relief system operation assessment based on the determination. A computer-implemented method for monitoring the operation of a relief system is also provided.

Description

MONITORING SYSTEM AND METHOD

Technical Field

The present invention relates to a system and method for monitoring a relief system, such as a flare or venting system.

Background

Flare systems (also known as gas flares or flare stacks) are combustion systems that are typically used in industrial plants and at oil and/or gas production sites. A flare system receives surplus or unusable fluid, such as hydrocarbon fluid, which cannot be processed in certain situations from one, or more often from many, sources. Gas received by the flare system is typically burned and liquid is recycled. There are typically a number of sources which may vent fluid to the flare system and it is not always known when or how much fluid will be vented from each source. Each fluid source is connected to the flare system via a feed line (e.g. a pipe), which has a pressure controlled relief valve or manual valve to permit fluid to be released from the source and into the flare system. Such relief/manual valves can act as a safety device when the fluid pressure in the source reaches a threshold level, or can be operated as a result of certain manual operations, plant depressurisation or inventory removal from a source. The sources may be hydrocarbon processing facilities such as gas/liquid separators or compressors.

Existing hydrocarbon processing facilities comprise sensors such as pressure and temperature sensors, valve position sensors (including manual valve position sensors), bursting disc state sensors and flow meters; these sensors can be used to detect whether the pressure controlled relief valves and other devices such as bursting discs on a given source are open, closed or partially open, and their measurements are generally used to monitor, control and shutdown the associated processing facility.

When a hydrocarbon processing facility is commissioned, estimated values of parameters (pressure, temperature, flow rate) in an associated flare system, when the relief devices of the source are operating, are established.

In existing flare systems, pressure, temperature and fluid level sensors and a flow meter are present in the gas line feeding the flare, which provide alarms or initiate trips when individual pre-defined limits for pressure and temperatures on the flare systems have been reached. Currently, the operation of relief systems such as flare systems is not systematically monitored to predict and/or warn of potential future failures.

Summary

In accordance with one aspect of the present invention, there is provided a monitoring system for monitoring the operation of a relief system, the relief system being connected to one or more sources configured to deliver fluid into the relief system and the sources each comprising one or more source sensors for measuring one or more parameters associated with a respective source, wherein the monitoring system is configured to access data storage arranged to store a first set of one or more sources that have previously been identified as delivering fluid into the relief system, the monitoring system comprising: a data receiver arranged to receive substantially real-time measurement data from the source sensors; and

a processor configured to:

a) determine a second set of sources currently delivering fluid into the relief system based on the received source sensor measurement data;

b) access the data storage whereby to determine whether said second set of sources matches the first set of sources; and

c) generate a relief system operation assessment based on the determination.

The invention provides a way of monitoring the operation of a relief system such as a flare system or a venting system and identifying potential risk situations based on substantially real-time measurements from the sources feeding fluid into the relief system. The invention recognises that the behaviour of certain parameters (e.g. pressure, temperature, flow, liquid levels) in the relief system depends on which sources are feeding fluid into the relief system at that time.

The present invention also provides a computer-implemented method for monitoring the operation of a relief system, the relief system being connected to one or more sources configured to deliver fluid into the relief system and the sources each comprising one or more source sensors for measuring one or more parameters associated with a respective source, the method comprising the steps of:

receiving substantially real-time measurement data from the source sensors;

inputting the received source sensor measurement data into a computer program; and operating the computer program so as to: a) determine a second set of sources currently delivering fluid into the relief system based on the received source sensor measurement data;

b) access data storage arranged to store a first set of one or more sources that have previously been identified as delivering fluid into the relief system, whereby to determine whether said second set of sources matches the first set of sources; and

c) generate a relief system operation assessment based on the determination.

A computer program or a suite of computer programs comprising a set of instructions arranged to cause a computer or a suite of computers to perform the above method steps, and a computer readable medium comprising the computer program, are also provided.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 shows a schematic diagram of a flare system into which a number of sources can feed gas via associated feed lines and valves;

Figure 2 shows a monitoring system according to the present invention;

Figure 3 is a flow diagram of the steps carried out by the monitoring system of Figure 2;

Figure 4a is a flow diagram of the steps taken by the monitoring system of Figure 2 in determining which sources are feeding fluid into the flare system;

Figure 4b shows a schematic diagram of a source that can feed gas into the flare system;

Figure 5 is a flow diagram of the steps taken by the monitoring system of Figure 2 in determining whether a currently active source set is known to the monitoring system;

Figure 6a is a source map of known flare system operating scenarios and

corresponding active sources;

Figure 6b is a signature map of expected flare system parameter values

corresponding to the known operating scenarios of Figure 6a; and

Figure 7 is a flow diagram of the steps taken by the monitoring system in generating a flare system operation assessment based on the signature map of Figure 6b.

Detailed Description

Referring to Figure 1, a plurality of sources such as hydrocarbon production facilities la-lj are connected to a fluid relief system comprising a gas flare system 3, such that fluid can flow from feed lines 2a of the sources to feed lines 2b of the flare system 3. A fixed number of sources can deliver fluid into the system 3 at any one time. In Figure 1, sources la-lc may be one or more liquid/gas separators, sources Id and le may be utilities, source If may be exported gas and sources lg-lj may be one or more compressors. Each of the sources comprises one or more source sensors 4, such as fluid pressure sensors Pi, fluid temperature sensors Ti, valve position sensors Xi, bursting disc state sensors, manual valve position sensors and flow meters, located on or upstream of the valves 5, for measuring one or more parameters associated with the source. A valve 5 such as a manual valve MV 1 , a pressure relief valve PS V 1 -3 , a pressure control valve PC V 1 -2, a "blowdown" (emergency depressurisation) valve BDV1-2 or a bursting disc BD1-2, is associated with each source, and can be partially or fully opened to allow fluid to flow from the source feed lines 2a to the flare system feed lines 2b. A position indication may be provided by one or more of the valve position sensors Xi to provide an indication of the degree to which the respective valves are open. The flare system feed lines 2b feed into further feed lines 2c referred to as "headers".

The flare system 3 includes a flare drum 6 for removing liquid such as oil or water from the fluid that is fed into the flare system 3. A flare liquid pump 7 removes the separated liquid from the flare drum 6, while gas flows from the flare drum 6 and through a flare stack 8 to the flare (flame) 9. The flare system 3 has one or more flare sensors 10 for measuring one or more parameters of fluid in the flare system 3, for example sensors for determining a gas temperature T_¾ drum pressure P_¾ flare drum liquid level L_L and temperature T_L, pumped liquid flow rate F_L and pressure P_L, and flare stack gas flow rate F_G.

In an embodiment, the valves 5 are considered to be the point at which fluid leaves a source and enters the flare system; that is, everything downstream of each valve 5 in the direction of fluid flow is considered to comprise part of the flare system 3, while everything upstream of the valves 5 is considered to comprise part of a source.

Figure 2 shows a monitoring system 200 for monitoring the operation of a flare system, such as the flare system 3 of Figure 1. In one arrangement, the monitoring system 200 comprises a processing system arranged to operate a computer program such as an operation monitoring program 201, as explained further below with respect to Figures 3 to 7. The processing system may be a control system on a platform, which can comprise conventional operating system and storage components such as a system bus connecting a central processing unit (CPU) 202, a hard disk 203, a random access memory (RAM) 204, and input/output and network adaptors 205 facilitating connection to user devices and interconnection with other devices on a network Nl . The Random Access Memory (RAM) 204 contains operating system software 206 which controls, in a known manner, low-level operation of the monitoring system 200. The server RAM 204 contains operation monitoring program 201 during execution thereof. The operation monitoring program 201 is configurable with measurement data received from external sensors 4, 10 by data receiver 205 (for example a network adaptor that receives data over a network such as network l), and with pre-defined data stored in a database or other storage component which is operatively coupled or connected to the processing system 200; in the system of Figure 2, storage component DB stores all such stored data and is accessible by the operation monitoring program 201. The system 200 can be operatively connected to a display, a flare system controller of the flare system 3, or a source controller associated with one or more of the sources (denoted generally as 207 in Figure 2), for example via the network Nl . The controller 207 of the flare system 3 can be automatically configured with the one or more operating modes determined by the monitoring system 200, the controller 207 being arranged to apply the one or more operating modes to the flare system 3.

The data receiver 205 is arranged to receive substantially real-time measurement data from the source sensors 4 and the flare sensors 10, and the data storage DB is arranged to store a "source map" of pre-defined sets of sources that are actively delivering (or

"feeding") fluid into the flare system, defined as "active" sources, as explained below with reference to Figure 6a. A set may comprise one source or a combination of multiple sources. Each of the pre-defined sets corresponds to an operating scenario of the flare system 3 for which the flare system parameters (e.g. pressure, flow rate, temperature) have been established as "acceptable"; the database DB stores the expected flare system parameter values for each operating scenario in a "signature map", as explained below with reference to Figure 6b.

An overview of the steps performed by the operation monitoring program 201 when executed by the flare monitoring system 200 will now be explained with reference to Figure 3. The monitoring system receives real-time measurements from the source sensors 4 at step S301. The flare monitoring system 200 is preferably configured to monitor the sensor measurements at pre-determined time intervals and to recognise each change in the currently active sources as the start of a new relief event on which a flare system operation assessment must be generated. The source sensor 4 measurements are applied, at step S302, as inputs into the operation monitoring program 201 and the flare monitoring system 200 executes the program 201 at step S303. When there is a change in the currently active sources, the monitoring system 200 detects the start of a new relief event (step S304) and continues to receive and monitor the sensor measurements at pre-determined time intervals throughout the event. The monitoring system 200 can also monitor a rate of change of one or more parameters based on the received sensor measurements. For a given set of sources, the resulting behaviour in the system may vary over the relief event, as in practice the flow of gas from active sources may vary in flow rate over time, or the gas flowing from sources that are sensed as being active may take varying amounts of time to reach the flare system and hence affect the flare system parameters in the expected way. As the sensor measurements are frequently monitored, the operation monitoring program 201 is able to take this into account, for example by ignoring transient measurements within a certain time frame of the start and end of the relief event and considering peak condition and the rate of change of one or more parameter values during the remainder of the relief event, that is, when conditions are more stable.

The monitoring program 201 uses the received source sensor 4 measurement data to determine, at step S305, a set of active sources 1 currently feeding fluid into the flare system 3, as will be explained further below with reference to Figures 4a and 4b. The monitoring program 201 then accesses the data storage DB and analyses (step S306) the stored pre-defined sets of active sources, determining whether the current set of active sources matches a pre-defined set of active sources, as explained further below with reference to Figures 5 and 6a. Where a match exists, the analysis further comprises comparing received flare sensor 10 measurement data to acceptable flare system parameters correlating to the stored set of active sources, as explained further below with reference to Figures 6b and 7. The monitoring program 201 then generates a flare system operation assessment based on the analysis at step S307.

The flare monitoring system 200 may be configured to output (step S308) the generated operation assessment to one or more of a display, a flare system controller and a source controller associated with one or more of the sources 1 (denoted generally as 207 in Figure 1). Additionally or alternatively, software executed by the CPU 202 of the system 200 can determine, on the basis of the generated operation assessment, one or more operating modes of flare system controller or source controller 207. The operating mode may be determined, for example, by an appropriate algorithm within the operation monitoring program 201 or using a separate software component (not shown), which is executed by the CPU 202 of the monitoring system 200.

The operation monitoring program 201, or the separate software component for determining the operating mode, is configured to use a predetermined set of rules in conjunction with the generated operation assessment, in order to determine the operating mode. These rules are stored in and accessible from the database DB as necessary. The computer-implemented method can further include an optional step of applying or inputting the determined operating mode into the controller 207 of the flare system or source(s).

Figure 4a shows the steps taken by the operation monitoring program 201 of the monitoring system 200 in determining the current set of active sources in step S305 of Figure 3. The received source sensor 4 measurements are input, in step S401, into a state detection algorithm, which is then executed in respect of each of the sources 1 in step S402. The state detection algorithm may be executed as part of the operation monitoring program 201, or the monitoring system 200 may comprise a separate state detection program (not shown) whose results are fed back into the operation monitoring program 201. The state detection algorithm is a mathematical algorithm which uses the sensor measurements to determine whether fluid is flowing through the respective valves 5, and hence decide whether the source can be classified as "active" or "inactive" (step S403). Some types of variable flow valve 5 may be determined as being partially open, in which case the degree to which they are open can be sensed and its state considered based on a threshold parameter value (e.g. flow rate); for example, a valve that is determined as being partially open so as to allow a 10% flow rate of the maximum possible fluid flow (i.e. when the valve is fully open) may result in the associated source being considered to be inactive by the state detection algorithm, as in practice such low flow rates from certain sources may not appreciably contribute to the overall flare system parameters, or may do so within a tolerable margin of the acceptable operating limits of the flare system 3. Figure 4b shows a schematic diagram of source If of Figure 1, which connects to the flare system 3 and is arranged to feed (or export) gas into the flare system 3 via a manual valve MV1. The source includes a test separator 11 and various other valves 12, including a pressure relief valve PSV4, pressure control valves PCV3-4 and emergency shut down valves ESDV1-4. In this example, source sensors 4 include pressure sensors P_l5 P₂, temperature sensors Ti, valve position indicators Xi, fluid level sensor Li and flow meter Fi. In one example, the state detection algorithm uses combinations of the sensor 4 measurements in a decision tree to determine whether the manual valve MV1 is active, for example:

IF >L_mm) AND ESDVl=Closed AND ESDV2=Closed AND ESDV3=Closed

AND ESDV4=Closed AND P₂>0 AND DELTAP₂<0 Bar/minute AND DELTAP^O Bar/minute 7¾ENMVl=Active

Where:

LI(MIN) is a minimum threshold fluid level value;

DELTAP_1;2 represents a change in the respective pressure over time.

The above algorithm determines that the test separator 11 is isolated, that it is not depressurised or empty, and that the pressure is falling. If every other avenue is closed off, then the gas must be flowing via valve MV1 by a process of elimination.

Once each of the source states is known, the current active source set is considered to be determined (step S404).

Referring to Figure 5, once the current active source set that defines the current operating scenario is known (step S501), the program 201 determines whether the scenario is known to the monitoring system 200. Operating scenarios, as defined by the active sources operating at any one time, can be pre-defined for known scenarios and stored as a "source map" in data storage DB. The program 201 can access (step S502) a library of source maps in the data storage DB and, at step S503, analyse the stored data to determine whether the current set of active sources matches a pre-defined set of active sources of one of the source maps. If there is no source map operating scenario that matches the current set of active sources, the operating scenario is classified as "unknown" (step S504), and the operation assessment generated according to step S307 of Figure 3 comprises an alert that the current active source set is unknown to the system, which is output, for example to a display 207, at step S505. An operator or user can then act appropriately, for example by controlling the operation of the flare system manually. Alternatively, the unknown scenario operation assessment can be output as an operating mode to a flare system controller 207 of the flare system 3 or a source controller associated with one or more of the sources, for example via the network Nl, as an instruction for the respective controller to perform an appropriate action, such as closing an associated valve 5, altering other flare system 3 components or if necessary shutting down a source.

An example of a source map is shown in Figure 6a. For each of the scenarios listed, the corresponding active valves 5 are stored, as marked with an "X" in the table. For example, in a first scenario "Manual Gas Export Depressurising", the manual valve MV1 of Figure 1 is detected by the state detection algorithm to be open, and is the only open valve; therefore, the associated source If is the only active source. In a second scenario, "Separator Pressure Control", only the pressure control valve PC VI is determined to be open and hence its associated source la is active. If, during this pressure control scenario, the pressure relief valve PS VI associated with source lb is opened (either fully, or partially to allow fluid flow above a pre-determined threshold), this is detected by the monitoring system 200 as a new relief event according to step S304 of Figure 3, and the steps of Figures 4 and 5 are carried out for this new relief event until the monitoring system 200 determines that the current active source set n matches the "Separator Full Flow Relief scenario of Figure 6a.

The data storage DB is further arranged to store correlations between the pre-defined sets of active sources in the sources maps and corresponding expected flare system parameters, known as flare system "signatures". For example, if only source la is releasing gas into the flare system, the parameters in the flare system will exhibit a given behaviour - "signature A". If only source lb is active, the parameters in the flare system will exhibit a different behaviour - "signature B". If sources la and lb are both active, "signature C" is recorded by the sensors in the flare system which is again different from signatures A and B. The correlations effectively indicate what the flare system 3 signature should be for a known set of active sources. The signatures preferably include expected operating limit error margins within which measured flare system parameters are acceptable. Figure 6b shows an example signature map of acceptable flare system 3 parameters for each of the scenarios listed in Figure 6a. The parameter values are shown as ranges with lower and upper acceptable, expected operating limits. The expected limits are determined by carrying out a sensitivity analysis on each flare operating scenario, for example using known engineering design programs. The signature map can also store acceptable rates of change (not shown) for one or more parameters, and can be used to monitor the rates of change based on the received sensor measurements. The acceptable rate of change of a given parameter may vary depending on how close the parameter value is to an acceptable operating limit.

The monitoring system 200 can learn whether certain combinations of parameters are acceptable as each scenario occurs and the combinations can be stored as being "acceptable" or are otherwise acted upon manually by a user. The flare system 3 has inherent engineering design limits that are pre-determined when designing the flare system 3. The expected limits provide an early warning of any impending escalation in the flare system parameters which will take the flare system 3 beyond the engineering design limits.

The measurement data received from the sensors 4, 10 may, if necessary or preferred, be manipulated by appropriate software, for example using an appropriate algorithm within the operation monitoring program 201 or using a separate program (not shown), which is executed by the CPU 202 of the monitoring system 200, in order to generate input data that are suitable for further use in the operation monitoring program 201. For example, Figure 6b shows an "average flare liquid flow rate" as one of the stored parameters, but it may be the case that there is no flow meter present to measure the flow rate of the liquid. In this case, the operation monitoring program 201 (or a separate software component, not shown) is used to create a "virtual sensor" by applying an algorithm to measured values to determine an average flare liquid flow rate value.

For example, the volume of liquid flowing from the flare drum 6 is calculated as the pump 7 flow rate (which is measured) multiplied by the time for which the pump 7 is "on":

Flare liquid flow (volume) = Pump flow rate x Time.

This is the case for a pump 7 that uses on/off level control and operates to pump the liquid in "batches" of time (e.g. 5 minute periods) as and when pumping is required, so:

Time = Sum of "Pump On" periods,

where the Time is generally calculated by the operation monitoring program 201 or other monitoring system 200 software. The pump flow rate is a function of the difference between the drum pressure and the discharge pressure as determined from the pump 7 manufacturer's flow curve.

An "average" flare liquid flow rate in terms of the volume per hour can then be calculated, and for acceptable scenarios this can be stored in the signature map such as is shown in Figure 6b.

Returning briefly to Figure 5, if, at step S503, a source map is found to match the current operating scenario, then at step S506 the scenarios are compared and analysed further in order to assess the acceptability of the current scenario and generate an appropriate operation assessment, as shown in Figure 7. The flare system signature correlating to the matching source map is retrieved or accessed and the corresponding flare operating limits are determined at step S701. At step S702, real-time flare system sensor 10 measurement data are received; frequent and regular collection of the flare sensor measurement data by the monitoring system 200 may begin in response to a flare monitoring system 200 request (triggered by, for example, a positive source map match), or the flare system sensor measurements may be collected at frequent, pre-determined time intervals by the system in response to the detection of a new relief event. At step S703, any virtual sensor values that are required are calculated. At step S704, the received flare sensor 10 measurement data are compared to the corresponding flare operating limits, to determine whether the current operating scenario is within the acceptable operating limits throughout the relief event.

If the flare sensor 10 measurement data is within pre-defined limits of the expected signature (which may be defined as the ranges given in Figure 6b) and the rate of change of each parameter indicates no breach is imminent, then the monitoring system 200 determines that the flare system 3 is operating acceptably at step S705. The monitoring system 200 outputs an acceptable operating scenario alert to the user at step S706, indicating that the flare system is operating according to a known scenario and is within expected operating limits.

If the actual signature is outside the pre-defined operating limits of one or more of the expected signature parameters, or the rate of change of a parameter is not acceptable (for example, the rate at which a measured parameter is approaching an acceptable operating limit means that the operating limit will be approached or reached within an unacceptable timeframe), then the monitoring system classifies the scenario as an

"excursion" from the expected signature at step S707 and outputs an excursion alert to the user at step S708, so that any necessary manual action can be taken by the user.

The pre-defined operating scenarios may be established and stored when a source 1, such as a hydrocarbon processing facility, is commissioned. In addition, the flare monitoring system is able to learn from unknown operating scenarios it encounters. For example, if a set of active sources is detected which is not present in the library, and

(whilst being manually monitored by the user) the flare system operates acceptably for that set of sources, the flare monitoring system 200 can add that set of sources (and the correlating expected flare parameters it measures in the flare system 3) to the library of source maps stored in the database DB. Preferably, the user is required to confirm to the flare monitoring system 200 at the end of an unknown scenario that the scenario was acceptable. In this way, the next time that specific set of active sources is encountered, the flare monitoring system 200 can refer to the library and retrieve the expected signature.

It is possible that a signature measured for the first encounter of a particular operating scenario does not represent a typical signature for that set of sources. The limits of acceptable operation are initially set relatively widely and the expected signature can then be modified and refined based on further experiences of that operating scenario, by the monitoring system 200 learning from each scenario based on user input in response thereto, and/or by the user refining the limits manually using historical data for that scenario and judgement. The user may use an engineering simulator to understand the operating scenario and set limits.

As explained above, where the set of active sources 4 is one which is already in the library but the monitoring system 200 decides that the actual signature is outside the predefined expected operating limits, the monitoring system alerts the user. If the user monitors this operating scenario and decides that the flare system is operating acceptably in practice, the user can change the expected operating limits stored for that scenario in the signature map accordingly.

The operation monitoring program is preferably implemented as bespoke software and is installed on a central computer.

A flare monitoring system according to the invention uses the measurements of sensors (e.g. pressure, temperature, flow meters, valve position sensors) associated with the sources to determine which sources are active using mathematical algorithms, and uses this information in substantially real time to monitor the operation of the flare system and predict potential risks or failures. Flare system signatures (in terms of measured flare system parameters) that correspond to certain combinations of the states (e.g. active, inactive) of one or more sources can be pre-defined. The system can compare current measured flare system parameters with stored acceptable parameters, to assess operation of the relief system. The monitoring system can also identify unknown scenarios, in order to determine whether the current operating scenario (and hence the current set of active sources) is acceptable.

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged, for example, although a relief system comprising a flare system has been described in detail with reference to the figures, the monitoring system and computer-implemented method of the invention can monitor the operation of any type of relief system. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments.

Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

1. A monitoring system for monitoring the operation of a relief system, the relief system being connected to one or more sources configured to deliver fluid into the relief system and the sources each comprising one or more source sensors for measuring one or more parameters associated with a respective source, wherein the monitoring system is configured to access data storage arranged to store a first set of one or more sources that have previously been identified as delivering fluid into the relief system, the monitoring system comprising:

a data receiver arranged to receive substantially real-time measurement data from the source sensors; and

a processor configured to:

c) generate a relief system operation assessment based on the determination.

2. The system of claim 1, wherein:

the monitoring system is configured to access data storage arranged to store acceptable relief system parameters correlating to the first set of sources;

the relief system comprises one or more relief system sensors for measuring one or more parameters of fluid in the relief system; and

the data receiver is arranged to receive measurement data from the relief system sensors,

wherein, if the second set of sources matches the first set of sources, the processor is further configured to:

compare the received relief system sensor measurement data to the acceptable relief system parameters correlating to the first set of sources; and

generate the relief system operation assessment based on the comparison.

3. The system of claim 2, wherein the processor is configured to change the stored acceptable relief system parameters correlating to the first set of sources based on the comparison between the received relief system sensor measurement data and the acceptable relief system parameters.

4. The system of any preceding claim, wherein the processor is configured to output the generated operation assessment to one or more of a display, a relief system controller and a source controller.

5. The system of any preceding claim, wherein the processor is configured to generate an operating mode for a relief system controller and/or a source controller based on the generated operation assessment.

6. The system of claim 5, wherein the processor is configured to apply the operating mode to the relief system controller and/or the source controller.

7. The system of any preceding claim, wherein the processor is configured to determine the second set of sources by applying an algorithm to the received source sensor measurement data.

8. The system of any of claims 2 to 7, wherein the acceptable relief system parameters comprise one or more of a value of the parameters, a range of values for the parameters and a rate of change of the parameters.

9. The system of any preceding claim, wherein the relief system comprises at least one of a flare system and a venting system.

10. The system of claim 1, wherein, if the second set of sources does not match a stored set of sources, the operation assessment generated by the processor comprises an alert that the second set of sources is unknown to the monitoring system.

11. The system of claim 10, wherein the processor is configured to store the second set of sources in the data storage after the second set of sources has delivered fluid into the relief system and while the relief system operates within acceptable limits for a predetermined period of time.

12. A computer-implemented method for monitoring the operation of a relief system, the relief system being connected to one or more sources configured to deliver fluid into the relief system and the sources each comprising one or more source sensors for measuring one or more parameters associated with a respective source, the method comprising the steps of:

receiving substantially real-time measurement data from the source sensors;

c) generate a relief system operation assessment based on the determination.

13. The method of claim 12, wherein the relief system comprises one or more relief system sensors for measuring one or more parameters of fluid in the relief system, the method further comprising the steps of:

receiving measurement data from the relief system sensors; and

operating the computer program so as to:

access data storage arranged to store acceptable relief system parameters correlating to the first set of sources;

if the second set of sources matches the first set of sources, compare the received relief system sensor measurement data to the acceptable relief system parameters correlating to the first set of sources; and

generate the relief system operation assessment based on the comparison.

14. A computer program or a suite of computer programs comprising a set of instructions arranged to cause a computer or a suite of computers to perform the steps according to claim 12 or 13.

15. A computer readable medium comprising the computer program of claim 14.