GB2582918A

GB2582918A - Level profiler

Info

Publication number: GB2582918A
Application number: GB1904874.3A
Authority: GB
Inventors: Pettersen Ketil; Fjalestad Kjetil
Original assignee: Equinor Energy AS
Current assignee: Equinor Energy AS
Priority date: 2019-04-05
Filing date: 2019-04-05
Publication date: 2020-10-14
Also published as: GB201904874D0; WO2020204725A1

Abstract

A level profiler for a vessel comprises one or more pipes for extracting fluid from the vessel at a plurality of different locations within the vessel; and a fluid analyser for analysing fluid extracted from the vessel via the one or more pipes. The level profiler may comprise a plurality of pipes, with each pipe for extracting fluid at a different location. Alternatively, or additionally, one pipe may be for extracting fluid from different locations by moving the inlet of the pipe. Also claimed is a method of taking level profile measurements of fluid in a vessel comprising: extracting fluid from a first location within the vessel; analysing the fluid extracted from the vessel at the first location; extracting fluid from a second location within the vessel; and analysing the fluid extracted from the vessel at the second location. The level profiler may be used to determine the level of interfaces within a water / oil separator or a water / oil / gas separator; and to control a separator.

Description

LEVEL PROFILER

The invention relates to a level profiler for a separator and a method of taking level profile measurements of a fluid in a vessel, such as a separator.

Level profile measurements of a fluid in a vessel may be useful for process control of the vessel. Lacking level control may for example lead to process upsets, oil spill, and/or off-specification products from the vessel.

There are a number of commercially available level profiler systems such as nucleonic, capacitive, inductive and pressure'difference level profilers. Whilst these can offer some insight into the fluid inside a vessel such as a separator, they each have their limitations and/or weaknesses.

For example, the nucleonic and capacitive level profilers may be sensitive to scale and other deposits that occur inside the vessel, inductive level profilers can only work in water continuous phase so are not suitable in all applications and pressure difference level profilers can only give limited information and, for example, cannot provide any indication of emulsions or dispersed gas within the vessel.

Thus there is a desire for an alternative and/or improved level profiler that may be able to overcome one or more of these limitations.

In a first aspect the present invention provides a level profiler for a vessel, wherein the level profiler comprises: one or more pipes for extracting fluid from the vessel at a plurality of different locations within the vessel; and a fluid analyser for analysing fluid extracted from the vessel via the one or more pipes.

In a second aspect the present invention provides a method of taking level profile measurements of fluid in a vessel, wherein the method comprises: extracting fluid from a first location within the vessel; analysing the fluid extracted from the vessel at the first location; extracting fluid from a second location within the vessel; and analysing the fluid extracted from the vessel at the second location.

The method of the second aspect may be performed using the level profil r of the first aspect.

The following description, including optional features, may be applicable to both he first and/or second aspect of the invention.

Owing to the fact that fluid can be extracted from the vessel at a plurality of different locations, information about;he level profiles within the vessel is attainable.

Because the analysis of the fluid is performed on extracted fluid there may be more flexibility for the analysis that occurs and the fluid analysis may be more accurate and/or reliable. This is because the fluid analyser may be easier to clean. calibrate, test, repair and/or maintain.

The level profiler may be for taking level profile measurements of a fluid in a vessel.

The vessel may be a structure for containing andlor transporting a fluid. The vessel may be a pressure containing vessel.

The vessel may be a separator, such as a horizontal separator, compact 0 separator, a centrifugal separator, a swirl separator, or a pipe separator.

The vessel may be a pipe, such as a pipe for transporting a fluid. The one or more pipes of the level profiler may be for extracting (i.e. removing) fluid from a first location within the vessel and for extracting fluid from a second location within the vessel. For example, one pipe may be for extracting fluid from a first location and a second pipe may be for extracting fluid from a second location. Additionally or alternatively, one pipe may be for extracting fluid from different locations. This may be achievable if the pipe has an inlet, the location of which can be moved.

The different locations from which fluid is extracted may be different heights at he same length and width position within the vessel.

The different locations may span the full height of the vessel. For example, e location may be at or rear the top of the vessel, one location may be at or near the bottom of the vessel and there may be one or more locations between the uppermost:and lowermost locations. This is so that fluid can be analysed from a series of different locations across the height of the vessel.

The fluid analyser may be for analysing the fluid extracted from the vessel at the first location and for analysing the fluid extracted from the vessel at the second location. The fluid analyser may be for analysing fluid extracted from the vessel at a plurality of different locations. Therefore:a single fluid analyser may be used to analyse the fluid removed from a plurality of different locations within the vessel.

This may allow the level profile of the fluids within the vessel to be determined.

In addition to the first and second locations, fluid may be extracted from third, fourth, fifth etc. locatons and analysed.

Fluid may be extracted from the vessel at a plurality of different cations and each analysed separately, e.g. analysed in turn. -,3

Fluid may be extracted, or extractable from three, five, ten, twenty, fifty, one hundred or more locations. The number of different locations (e.g. different heights) from which fluid in the vessel may be extractable may be very large if the location of the net of the one or more pipes is adjustable. The more locations fluid may be extracted or extractable from, the more information that can be obtained about the fluid and levels within the vessel. However, there may be a compromise to be made regarding how many locations fluid is extracted from. When fluid is extracted from more locations, the more information that can be attained, however, this also means that the analysis will take longer. There will also be a certain point at which extracting and analysing fluid from further locations provides limited, if any further information about the level profiles witnin the vessel. As a result, the number of locations from which it is desired that fluid is extracted will depend on a number of factors such as the fluids in the vessel, how quickly the fluid profiles within the vessel are changing, how quickly the analysis can be performed, how much the installation, running and maintenance of the level profiler costs etc. The method may comprise extracting fluid from the vessel at a plurality of different locations within the vessel.

Fluid may be extractable from at /east one or more locationswithin each level/layers, e.g, within each constituent, such as water, oil or gas, in the vessel.

This is so that profile information may be attained about the fluids within each layer a I as about the fluids at and near each interface. The level profiler may be arranged to allow the measurement of many properties in each layer.

The fluid analyser and/or the steps of analysing the fluid extracted from the vessel at a plurality of different locations may provide level profile measurements.

The level profile measurements may be used in process control of the

VO

The method may be a method of king level profile measurements using the level profiler.

The fluid analyser may be fluidly connected to the one or more pipes of the profiler. This is so that uid can pass from the vessel, via the one or more pipes to the uid analyser.

The fluid analyser may be used to analyse fluid extracted from the vessel at different locations The fluid extracted from different locations may be analysed separately. The fluid extracted from different locations may be analysed sequentially Fluid may be extracted and analysed from each of the different locations repeatedly. This is so that the monitoring of the level profiles may be performed repeatedly and/or continuously over time.

In tne case that there more than two locations, such as 4, 5, 10, or even 20 or more, fluid may be analysed sequentially from the top to the bottom (or vice versa) of the vessel. Fluid may be analysed from every other (or some other interval) location, and then the cycle may repeat analysing the other set of every other locations. For example, first odd numbered locations from top to bottom (or vice versa), i.e. the first, third, fifth, etc locations fluid may be extracted from and analysed and then the even numbered locations, i.e. the second, fourth, sixth etc. locations fluid may be extracted from and analysed. This allows the fluid to be extracted and analysed across the entire range of locations more frequently whilst not jeopardising the total number of locations from which fluid can be extracted and analysed.

Fluid may be selectively extracted and analysed from any location and in any order. Thus the locations from which fluid is extracted and analysed may be intelligently selected. For example, extraction and analysis may occur at selected locations where more information is desired. This may for example be at or near a detected interface/boundary.

Only a single fluid analyser may be required to analyse the fluid from different locations within the vessel. This may allow the level profiler to be simplified and hence possibly cheaper than a level profiler that requires sensors and detectors for each location being analysed, for example.

The level profiler may comprise a manifold between the one or more pipes and the fluid analyser. The method may comprise passing fluid from the one or more pipes through a manifold to the fluid analyser.

The manifold may be for fluidly connecting the one or more pipes to the fluid analyser. The manifold may have a plurality of inlets and one outlet The manifold may be arranged to facilitate the transmission of a plurality of fluids from different locations along a single pipe to the fluid analyser.

In the case that the level profiler comprises a plurality of pipes for extracting fluid from the vessel, the manifold may be arranged to fluidly connect the plurality of pipes to the fluid analyser.

The level profiler may comprise one or more valves. The one or more, valves may be within and/or part of the manifold. The one or more valves may be operable to control the flow of fluid from the vessel to the fluid analyser such that fluid from different locations,passes through the fluid analyser selectively and/or sequentially.

In the case that the level profiler comprises a plurality of pipes for extracting fluid from the vessel, each pipe may have an associated valve.

The valves (e.g. valves in the manifold) may be multiplexing valves.

The valves may be arranged to allow flow of fluid from each pipe to the fluid analyser sequentially, i.e. in turn. This may mean that at any one time fluid from a single location is flowing through and/or within the fluid analyser.

The valves may be arranged so that at any one time, fluid can only flow from one location within the vessel to the fluid analyser. The valves may be operated so that at any one time only one of the valves is open.

The level profiler may be arranged so that the fluid being analysed at any one time is from a known location within the vessel. This allows information about the profiles within the vessel to be determined and/or mapped.

The different locations within the vessel may be different heights within the vessel.

The one or more pipes may be for extracting fluid from the vessel at plurality of different heights.

One or more or each pipe may be for extracting luid from the vessel at a single location within the vessel.

One or more or each pipe may be for extracting fluid fro he vessel at a plurality of different locations within the vessel.

Each pipe may have an inlet for fluid passing out of the vessel and into the level profiler.

The inlet of one, or more, or each pipe may be in a fixed location relative to the vessel, In this case the level profiler may comprise a plurality of pipes (i.e. each with an inlet at a fixed position within the vessel) so that fluid that can extracted from a plurality of different locations. The fluid may be extracted from a plurality of different locations by extracting the fluid through a plurality of different pipes, wherein each pipe has an inlet at a different (e.g. fixed) location within the vessel, The method may comprise extracting fluid through a first pipe from a first locatton within the vessel and extracting fluid through a second pipe from a second different location within the vessel. -6 -

The different, locations, e.g. inlets to the pipes, may each be at the same longitudinal and/or lateral position within the vessel. The different locations, e.g. inlets to the pipes, may be at different vertical positions within the vessel.

The different locations may each be closer to the outlets of the vessel than the inlet of the vessel. This is so that information can be obtained about the fluids within the vessel in closer proximity (in time and/or distance) to the outlets. This is because it may be more desirable to know the condition and position eta of fluids at or near the point of exiting the vessel.

One or more or each pipe may have an inlet that is in a non-fixed location relative to the vessel. The position of the inlet ofthe pipe may be adjustable relative to the vessel. The position of the inlet of one or more or each pipe may be adjustable during use of the level profiler.

The method may comprise extracting fluid from a first location within the vessel via an inlet of a pipe, then adjusting the location of the inlet of the pipe and then extracting fluid from a second location within the vessel.

The method may comprise a first step of extracting and analysing fluid from a plurality iocations within the vessel, then adjusting the position of the iniet(s) of one or more pipes, and then a second step of extracting and analysing fluid from a plurality locations within the vessel, wherein the plurality of locations in the second step is different to the plurality of locations in the first step. The data obtained from the first step may be used to determine now to adjust the position of the inlet(s) of the one or more pipes. For example, the first step may be used to work out approximately where the locations of interest are, e.g. where the heights of the interfaces are, and then woming out what adjustments are required to obtain the most useful information from the second' step.

The level profiler may comprise a single pipe for extracting fluid from plurality of locations within the vessel. 'The position of the inlet of the pipe may be adjustable relative to the vessel.

In the case'that the level profiler comprises a plurality of pipes for extracting fluid from the vessel, the position of the inlets of the pipes may be adjustable relative to the vessel. The position between the inlets of the pipes may be fixed relative to each other, even if the position of the inlets of the pipes may be adjustable relative to the vessel The one or more pipes may extend through a wall of the vessel, e.g. through an aperture in the wall of the vessel. This may for example be through a flange in the vessel wall. The pipes may extend though a pre-existing aperture in the vessel, This may mean that, it is possible to provide the level profiler without having to structurally modify the vessel.

The level profiler may comprise a pipe for receiving fluid external of the vessel. The pipe'may be for'receiving fluid that is not extracted from the vessel.

The pipe may be referred to as an external pipe. The external pipe may be for receiving fluid that passes to the fluid analyser. The external pipe may be fluidly connected to the manifold (if present). Thus fluid may flow through the external pipe to the manifold and to the fluid analyser. The additional, i.e. external, pipe may be for calibration.

The fluid provided through the external pipe may be a reference fluid. The reference fluid may be for calibrating the one or more devices of the fluid analyser.

The fluid through the external pipe may be some other fluid, such as a fluid sample from a test well. The external pipe may mean that the fluid profiler can be used to analyse fluids other than those within the vessel.

The level profiler may be a unit (e.g. installable and/or self-contained unit) that comprises the one or more pipes for extracting fluid from the vessel, the pipes being fluidly connected to the fluid analyser and the level profiler optionally comprising a manifold, valves, a pump, and/or manual sampling outlet in fluid communication with the other components of the level profiler.

The level profiler may be for retrofit to an existing vessel, e.g. an existing separator. The method may comprise retrofitting the level profiler to a vessel.

The fluid analyser may be external of the vessel, e.g. outside of the vessel that contains the fluid being separated. This means that the fluid analyser (and hence the instruments that are in the fluid analyser) may be easier to maintain (e.g. clean), calibrate, replace etc. It also means that the instruments may be less prone to scale build up and deposits and/or they are easier to clean if such debris does build up This is achievable because the fluid being analysed is extracted from the vessel.

The fluid analyser may comprise one or more measurement instruments. The fluid analyser may for example comprise one or more or all of the following devices: MR (near infrared) meter, a viscosity meter, a Coriolis meter, a vibration meter, a sound meter, imaging devices (such as a video or photo recorder), a differential pressure meter, a displacement pump etc. The fluid analyser may be configured to measure one or more of flow rate (e.g. volume flow rate), density, oil:water ratio, water cut, viscosity, composition of the fluid passed through the fluid analyser, state and/or phase of the fluid, images, vibrations and/or sounds, macro properties such as droplet sizes, whether it is water in oil or oil in water, where there are solids, such as sand or mud present, whether there are certain chemicals, detecting tracers etc. For example the fluid analyser may be configured to detect gas, foam, emulsions. The fluid analyser may measure, e.g. using imaging devices such as a video recorder or camera, droplet sizes.

The fluid analyser may be configured to detect tracers. This may be useful for providing flow assurance in a new well or confirmation that a well clean-up has occurred.

For example the fluid analyser may comprise a Coriolis meter. This may measure flow rate and/or density of the fluid passing through the fluid analyser.

Additionally or alternatively the fluid analyser may comprise an infrared instrument. This may measure oil in water and/or water in oil ratio.

Additionally or alternatively the fluid analyser may comprise a capacitive and/or inductive instrument.

In the casethat the fluid analyser comprises a plurality of measurement instruments, the instruments may be provided in series along the flow path.

The flow rate measurements may additionally or alternatively be used for control andlor monitoring of the level profiler itself. The flow rate measurements may be used to check that the flow through the fluid profile is acceptable and/or as expected. Thus, flow rates through the profiler may be used to monitor the status of the profiler.

The instruments in the fluid analyser may be changeable. This may mean that the instruments in the analyser may be changed. For example, for different applications and/or based on initial measurements etc, alternative or additional measurement instruments may be used in the fluid analyser. The method may comprise changing the instruments in the fluid analyser. This may be before or after the level profiler is installed on a vessel. The instruments in the fluid analyser may be changed after measurements have been taken with the level profiler.

The extraction of fluid from the vessel may be driven. For example, it may be driven by one or more pumps and/or a pressure differential between the fluid in the vessel and a location downstream of the fluid analyser, e.g. a low pressure unit, -9 -such as a low pressure drain, a second vessel such as a second stage separator or an oil spill tank etc. The level profiler may comprise one or more pumps. The one or more pumps may be located downstream of the one or more pipes. If a manifold is present, the one or more pumps may be located downstream of the manifold. By providing a pump downstream of the one or more pipes and/or manifold, it may be possible to extract fluid from the vessel at a plurality of different locations using a single pump, even in the case that the level profiler comprises a plurality of pipes, for extracting fluid from the vessel.

The pump may be upstream or downstream of the fluid analyser. Having the pump downstream of the fluid analyser may have the advantage that the fluid properties of the fluid extracted from the vessel may have less scope to be affected by the pump.

The level profiler may comprise one or more pipes for extracting fluid from a plurality of different locations within the vessel, a single fluid analyser and, if present, a single pump. This may be achievable by the level profiler being arranged to allow fluid from a plurality of different locations, e.g. different heights, to be directed to a single fluid analyser and by a single pump (if present).

This may be achieved by the use of a manifold, one or more valves and/or adjustable position pipe inlets that allow fluid from different locations to be directed to a single pipe and/or the single fluid analyser in turn.

The pump may be provided between the one or store pipes and the fluid analyser.

After the fluid has been analysed it may be directed back into the vessel.

The fluid may be directed back into the vessel through the aperture, e.g. flange, through which the one or more pipes for extraction extends.

The fluid analyser may be fluidly connected downstream to a drain. Fluid from the fluid analyser may pass to the drain where it is disposed of or directed back into the vessel.

The drain may be a low pressure drain. In this case, the level profiler may not comprise a pump. This is because fluid flow from the vessel and through the manifold if present) and the fluid analyser may be driven by a pressure differential between the pressure inside the vessel and the pressure of the drain. The flow of fluid from the vessel to and through the level profiler may be controlled by one or more valves.. The valve(s) may be used instead of one or more pumps to control the flow.

Fluid may be extracted from the vessel by one or more valves associated with the one or more pipes being opened or closed so as to selectively extract fluid from different locations.

For example, in the case of a level profiler with a plurality of pipes for extraction, each pipe may have an associated valve. Each valve may be opened (and then closed) in turn so as to extract fluid (and pass it to the fluid analyser) from a different location in turn.

In the case of a level profiler with a pipe with a moveable inlet for extraction from different locations (which may be a level profiler with one or a plurality of pipes), the pipe with moveable inlet may have an associated valve. The valve may be opened (and then closed) between the inlet being moved to a different location so as to extract fluid (and pass it to the fluid analyser) from a different location in turn.

The level profiler may have a sample outlet that may be used for removing fluid (e.g. physical samples of fluid) from the level profiler which may for example be used for manual sampling. This outlet may allow samples to be extracted for manual sampling and/or testing. Physical samples extracted from this outlet may be taken for additional analysis, e.g. to a lab where more and more sophisticated analysis equipment may be present.

The sample outlet may be immediately before or downstream from the fluid analyser. The level profiler may be arranged so that a single sampling outlet can be used to extract samples that have been extracted from the vessel at different locations. This may be achieved by locating the sampling outlet downstream of the manifold (if present).

The level profiler may be automatic, i.e. may be arranged to operate automatically and/or continuously. This may mean that it is arranged to extract and analyse fluid from a plurality of different locations within the vessel without human intervention. The data obtained by the fluid analyser may be sent to a controller that may be used to control the vessel.

The level profiler may be arranged to operate continuously. The level profiler may provide rapid, continuous and/or real time information about the fluids and their interfaces within the vessel.

The level profiler may be arranged to repeatedly extract fluid from a plurality of different locations within the vessel and analyse fluid from each location in turn.

The volume of fluid that is extracted for analysis in the level profiler may be small compared to the total volume of fluid in the vessel. The volume of fluid that is extracted for analysis in the level profiler may be negligible in view of the total volume of fluid in the vessel. Of the order of htres/minute of fluid may pass through the level profiler when it is in operation.

The level profiler may be used to obtain data on the fluids inside the vessel at the plurality of locations. The level profiler may be used to provide information on the height of interfaces (e.g. between water and oil and oil and gas) within the vessel, what is happening at the interfaces (e.g. emulsion formations and the size of these formations), and/or what is happening at each height etc. The data obtained by the level profiler, i.e. from the fluid analyser, may be used to control the vessel. Thus, the level profiler may be used in process control of the vessel. For example, the data from the level profiler may be used to determine whether to increase or decrease the inlet and/or outlet flow rates from the vessel, to increase, decrease or change the addition of chemicals such as emulsion breakers, adjust the pressure and/or temperature etc. The data from the level profiler may be automatically and/or continuously sent to a controller for controlling the vessel The level profiler may be used with any known vessel, e.g. fluid separator, for which it is desired to obtain level profile measurements.

The vessel may be a water/oil or water/oil/gas separator.

The separator may be a test separator with a new well This is because the information about what is in the separator is potentially more valuable in this case compared to a separator with a well that has been producing for some time, The level profiler may provide analysis of fluids in a vessel from well clean-ups.

The level profiler may be provided with a vessel, e.g. a separator.

There may be °a vessel assembly comprising a vessel and a level profiler or taking level profile measurements of fluid in the vessel. The level profiler may comprise one or more or all of the above described features, including optional features.

Certain preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawing, in which: Figure 1 schematically illustrates a separator with a level profiler.

In Figure 1 there is shown a separator 1 and a level profiler 2 for taking level profile measurements of fluid within the separator 1. The separator 1 illustrated in figure '1 is a water/oil/gas separator, however, the level profiler 2 may be used with any known vessel (such as a pipe or any other known type of separator) for which it is desired to obtain level profile measurements.

As shown schematically, within the separator 1 are a plurality of fluids. In this example, within the separator is water 3 that can be removed via water outlet 4, oil '5 that can be removed via oil outlet 6 and gas 7 that can removed via gas outlet The level profiler 2 comprises a plurality of pipes 10 (in this example nine pipes) with a pluraiity of inlets for extracting fluid from the separator at a plurality of different locations/heights within the separator 1. The pipes 10 are shown schematically in a bundle in figure 1 with only the inlets being individually shown. The inlets of each of the pipes 10 may be at a fixed location within the separator 1 or the location, e.g, height, of the inlets may be adjustable. Although in this example there are a plurality of pipes 10 with a corresponding plurality of inlets, the level profiler 2 may comprise a single pipe for extracting fluid from the separator. The single pipe may be able to extract fluid from a plurality of different locations within the separator 1 by virtue of the location of the pipe inlet being adjustable.

The pipes 10 extend through a flange 12 in the separator wall.

The pipes 10 are fluidly connected to a manifold 14 which in turn is fluidly connected to a fluid analyser 16.

The example level profiler 2 in figure 1 comprises a pump 18 that drives the fluid from the separator 1 through the manifold 14 and through the fluid analyser 16 and ultimately to a drain 19. The pump 18 is shown upstream of the fluid analyser 16 in figure 1. However, the pump 18 may alternatively be downstream of the fluid er 16 so as to minimise any impact the pump 18 has on the fluid before it is analysed in the fluid analyser 16. Additionally or alternatively the drain may be a low pressure drain 20 such that fluid flow from the separator 1 through the manifold 14 and through the fluid analyser 16 is driven by a pressure differential between the 35= separator 1 and the drain 20. -13-

The manifold 14 comprises a valve 22 for each associated pipe 10. The valves 22 may be controlled so that fluid is selectively extracted from different locations (by virtue of being extracted by a different pipe) in turn and then passed to the fluid analyser 16, Thus the fluid analyser 16 may analyse the fluid from different locations within the separator 1 in turn.

The fluid analyser 16 may comprise one or more analysis instruments 17.

The fluid analyser 16 may be for measuring one or more of flow rate, density, oil:water ratio, water cut, viscosity, composition of the fluid passed through the fluid analyser etc. Each instrument 17 may obtain data indicative of different fluid properties.

The fluid analyser 16 may comprise a Coriolis meter 17. This may measure flow rate and/or density of me fluid passing through the fluid analyser 16.

Additionally or alternatively the fluid analyser 16 may comprise an infrared instrument 17. This may measure oil in water and/or water in oil ratio.

Additionally or alternatively the fluid analyser 16 may comprise a capacitive and/or inductive instrument 17.

The fluid may pass through each of the instruments 17 in series.

The instruments 17 may be changeable such that the fluid properties analysed by the fluid analyser 16 may be tailored depending on factors such as the type of separator, the source of the fluid, and the fluid in the separator 1 etc. The fluid once analysed in the fluid analyser 16 may pass to drain 19, 20. The drain may feed back into the separator 1, to a disposal area and/or a pipe upstream or downstream of the separator 1. The drain 19 may pass fluid back into the separator 1 through the same flange 12 that the extraction pipes 10 pass through.

The level profiler 2 may comprise a fluid outlet 22 that permits physical samples of fluid to be extracted from the level profiler 2 This may, allow fluid from different locations within the separator 1 to be easily extracted for further analysis in a different location such as a lab. -4

Claims

CLAIMSA level profiler for a vessel, wherein the level profiler comprises: one or more pipes for extracting fluid from the vessel at a plurality of different ocations within the vessel; and a fluid analyser for analysing fluid extracted from the vessel via he one or more pipes.
2. A level profiler according to claim 1, wherein the level profiler is arranged to analyse fluid extracted from tne vessel at different locations sequentially.
3. A level profiler according to claim 1 or 2, wherein each pipe of the one or more pipes for extracting fluid from the vessel has an associated valve for controlling fluid flow to the fluid analyser.
4. A level profiler according to claim 1, 2 or 3 wherein the level profiler comprises a sample outlet for manually removing samples of fluid from the level profiler.
5. A level profiler according to any preceding claim, wherein the level profiler comprises a plurality of pipes for extracting fluid from the vessel and each pipe is for extracting fluid from the vessel at a different location within the vessel.
6. A ievel profiler according to any preceding claim, wherein h fluid analyser is for determining one or more of flow rate, density, oil:water ratio, water cut, viscosity, composition of fluid passed through the fluid analyser.
7. A level profiler according to any preceding claim, wherein the fluid analyser is arranged to send data obtained by the fluid analyser to a controller for controlling the vessel.
8. A method of taking level profile measurements i fluid in a vessel, wherein the method comprises: extracting fluid from a first location within the vessel; analysing the fluid extracted from the vessel at the first location: extracting fluid from a second location within the vessel; and analysing the fluid extracted from the vessel at the second locat.on.
9. A method according to claim 8, wherein the method comprises taking the level profile measurements repeatedly over time.
10. A method according to claim B or 9, wherein the level profile measurements are used in process control of the vessel.
11. A method according to claim B. 9 or 10, wherein the method is performed using a level profiler according to the level profiler of any of claims 1 to 7.
12. A method according to claim 11, wherein the method comprises providing the level profiler and retrofitting the level profiler to the vessel.