GB2472191A

GB2472191A - Method and apparatus for characterising a medium

Info

Publication number: GB2472191A
Application number: GB0912885A
Authority: GB
Inventors: Laurie Linnett
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-07-24
Filing date: 2009-07-24
Publication date: 2011-02-02
Also published as: GB0912885D0; WO2011010095A1

Abstract

Methods and apparatus for determining the presence of an interface region, such as an interface region defined between first and second layers of a medium, for example, mediums comprising hydrocarbons, such as oil and/or gas. An interface region can be determined in a pipeline, or the like, by comparing a flight characteristic, for example, the ratio of a time of flight against distance travelled of a first acoustic signal passing through the medium with a flight characteristic of a second acoustic signal passing through the medium. In cases when these flight characteristics are determined to be different, the presence of an interface can be determined. A conduit 100 is provided with a first transmission path through first layer 110 and second layer 120 separated by interface region 115 and of known distance D1 between transmitter 210a and receiver 210b. Second transmitter 220a and second receiver 220b are configured to transmit and receive a second interface signal across the second transmission path D2.

Description

A method for characterising a medium, and associated apparatus

Technical Field

The invention relates to a method for characterising a medium, and associated apparatus. In particular, the invention relates to a method for determining the presence of an interface region in a medium, such as a medium in a conduit, tubular, container, pipeline, reservoir, or the like.

Background

In certain industries it is desirable to measure properties of a medium, such as properties of solids, liquids or gases (or combinations thereof). Such mediums may be provided in a container, pipeline, reservoir, conduit, or the like. An example of a medium might be a coolant in a cooling system conduit, or a flow of hydrocarbons in a transportation/production pipeline. In some instances, mediums can comprise two or more layers, each layer being a different density and/or different phase. Such mediums may be considered to be multi-layered.

An example of a multi-layered medium may be hydrocarbon gas and oil, provided in a pipeline, in which the gas and oil are provided as different layers due to the difference in their relative densities. In an alternative example of a multi-layered medium, a conduit comprising a deposited build-up of matter on the inner wall may be considered to be a first layer, while the material passing through the conduit may be considered to be a second layer of the multi-layer medium.

An interface region is provided between such layers. An example of an interface region may be a boundary layer defined between two immiscible layers (e.g. at the interface provided between water and oil), or as an interface layer provided between a layer of deposition in a pipeline and material flowing through a pipeline, for example. In such cases, it can be desirable to determine the presence or existence of the interface region so as to allow the location of the interface region to be measured or monitored. This may assist with providing a helpful profile of the interface region, and/or layers of the medium.

Additionally, when two layers of a medium are being stored or transported, or the like, it can be helpful to determine if those components, or layers, are being stored or transported immiscibly, or whether they have formed an emulsion. The determined presence of an interface region may be considered as being an indication of a defined laminar or stratified arrangement within a medium, whereas the lack of an interface region may be considered as an indication minimal or non-stratified layering.

In that regard, the determined presence of an interface region may allow for the medium to be characterised as being laminar or non-laminar. Characterisation of the flow can allow for flow regime change to be implemented and/or monitored.

Inaccurate measurements and harm to processing equipment can occur if a medium is not suitably characterised. This can often occur in the oil and gas exploration and production industry, such as when monitoring the fluid flow in a multi-fluid/multi-layered pipeline, which can result in serious processing hazards, and/or an undesirable increase in operational costs.

Summary

According to a first aspect of the invention, there is a method for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, the method comprising: using a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a second transmission path in the medium in order to determine the presence of an interface region in the medium, the first and second transmission paths being of different known distances.

The first and second layers may comprise adjacent layers. The first and second layers may be stratified, or substantially stratified. The first and second layers may be substantially continuously stratified such that said layers are of a substantially equivalent dimension in at least one direction, such as the direction of the interface region. The first and second layers may be discretely stratified. In this arrangement one of the first and second layer may be at least partially contained within the other of the first and second layer. For example, one of the first and second layers may comprise a bubble, core, slug, droplet, bead, ball or the like contained within the other of the first and second layer.

The interface region may comprise an interface layer, boundary layer or the like. The interface region may comprise a region of emulsion. The interface region may comprise a region of gas and liquid foam defined between the first and second layers.

The time of flight of the first and/or second interface signal may be determined from the time of receipt of the first and/or second interface signal. The method may comprise using the time of receipt of the first and/or second interface signal to provide the first and/or second flight characteristic. The time of receipt of the first and/or second interface signal may be considered to be the time of flight of the first and/or second interface signal.

The first flight characteristic may be associated with the ratio of the time of receipt/flight of the first interface signal and the distance of the first transmission path.

The second flight characteristic may be associated with the ratio of the time of receipt/flight of the second interface signal and the distance of the second transmission path.

The first flight characteristic and the second flight characteristic may be compared in order to determine the presence of an interface region.

The method may comprise determining the presence of an interface region when the first flight characteristic and second flight characteristic are compared to be the same, substantially the same, similar, etc. The method may comprise determining the lack (or absence) of an interface region when the first and second flight characteristics are compared to be different, substantially different, etc. The method may comprise determining the lack (or absence) of an interface region when the first and second flight characteristics are compared to be different beyond a particular threshold (e.g. a predetermined threshold).

The first flight characteristic may be related to the average speed of the first interface signal having been communicated across the first transmission path. The second flight characteristic may be related to the average speed of the second interface signal having been communicated across the second transmission path. The first/second flight characteristic may be the average speed of the first/second interface signal having been communicated across the first/second transmission path.

The determined absence of an interface region may be provided for determining that the medium through which the first and second transmission paths pass is homogenous (e.g. an emulsion, the same material, the same density, etc.). The method may comprise using the determined absence of an interface region to determine that the medium through which the first and second transmission paths pass is homogenous (e.g. an emulsion, the same material, the same density, etc.).

The determined presence of an interface region may be provided for determining, or distinguishing, a laminar or substantially stratified arrangement in the medium, for example, a laminar or substantially stratified arrangement of a multi-layered medium.

A non-laminar or non-stratified arrangement may be determined in the absence of an interface region. A non-laminar or non-stratified arrangement may be determined as being an emulsion, such as a fine emulsion. The determined presence or absence of an interface region may provide for characterising the medium. For example, characterising the medium as one particular material, substance, density, etc., rather than another. The method may comprise determining, or distinguishing, a laminar or substantially stratified arrangement in the medium. The method may comprise characterising the medium.

Determination of the presence (or absence) of an interface region in a medium may be the determination of an interface region along the first and/or second transmission paths in the medium. The first and second transmission paths may pass across similar regions of the medium. That is to say the interface signals may be passed across transmission paths having paths at similar locations, regions, etc. in the medium. The first and second transmission paths may partially overlap. For example, the first and second transmission paths may pass in part through the same region of the medium. For example, a portion of the first transmission path may be the same as a portion of the second transmission path. All of one of the first or second transmission path may be same as a portion of the other transmission path.

The method may comprise using the flight characteristics associated with more than two interface signals. The method may comprise using the flight characteristics associated with more than two interface signals having been communicated across more than two transmission paths. Each further first and second interface signal may have further respective first and second transmission paths being of different known distances.

At least two of the interface signals may have been transmitted from a common transmitter. At least two of the interface signals may have been received at a common receiver. One, some or all of the transmission paths may intersect. This may provide for using the time of flight/receipt associated with two or more transmission paths for every one transmitted/received interface signal.

The method may comprise using a determined interface region (or determined lack of interface region) with further measurements of the medium.

The determined interface region may provide for determining the location (or relative location) of the interface region at regions, such as different regions, in the medium.

For example, the different regions of a medium may be in a conduit, container, reservoir, or the like. The determined interface region may provide for determining a profile of the interface region of the medium, such as a profile of the interface region provided in a conduit, etc. The profile may be a cross-sectional profile. The profile may be a two-dimensional profile, or may be a three dimensional profile. The profile may be time variant. That is to say, the profile may change as the medium/interface region changes.

The method may comprise providing the determined presence of an interface region to allow for a visual representation of the profile or change in profile. Such visual representation may be provided on a user interface, such as an output user interface (e.g. Liquid Crystal Display, Organic Light Emitting Diodes, etc.). The method may comprise providing the determined presence for use with flow visualisation (e.g. visualisation of the flow of a medium, such as real time visualisation). The method may comprise providing visual representation, such as flow visualisation.

The method may comprise determining the presence of an interface region in a conduit. The method may comprise using the time of flight/receipt of two or more first and second interface signals having been communicated across a conduit. The conduit may comprise a pipeline, such as an oil and gas pipeline (e.g. production and/or exploration pipeline). The method may comprise using the time of flight/receipt of two or more first and second interface signals having been communicated across two or more first and second transmission paths of a conduit at different interval orientations. For example, two or more first and second transmission paths spaced at every 30 degrees, 45 degrees, around a conduit, and/or 0.1 m, 0.2 m, etc. along a conduit, or the like. The intervals may be regular or irregular, or combination of regular and irregular intervals.

One, some or all of the interface signals may comprise a reflected signal (e.g. a signal transmitted across a particular transmission path and reflected at a target, or object, or the like).

The known distance of the first and second transmission paths may be measured known distances, estimated known distances, evaluated known distances, approximated known distances, or the like. The distances may include configured known distances.

That is to say that, in some instances a particular distance may have been measured prior, during, or after transmitting of the interface signal, or may have been estimated, evaluated, or approximated. In further instances, the first and second transmission paths may be provided so as to differ by a configured known distance, which may be able to be altered.

The medium may comprise a single phase or multiple phases. The medium may comprise any one or combination of: solid, liquid and/or gas component phase. The first layer may comprise any one, or more, of solid, liquid or gas component phases.

The first layer may comprise a single component phase. The first layer may comprise multiple component phases. The first layer may comprise different or the same component phases. The first layer may comprise water, oil, hydrocarbon gas, hydrates, asphaltenes, salts, etc. The second layer may comprise any one, or more, of solid, liquid or gas component phases. The second layer may comprise a single component phase. The second layer may comprise multiple component phases. The second layer may comprise different or the same component phases. The second layer may comprise water, oil, hydrocarbon gas, hydrates, asphaltenes, etc. The first layer and the second layer may comprise different or the same component phases.

At least one of the first and second layers may comprise two or more sub-layers, such as three, four, five, ten, twenty sub-layers, or any number therebetween. Each sub-layer may be adjacent, such as being adjacently stratified, or the like.

Each sub-layer may serve to define a sub-interface region between respective sub-layers. The sub-interface region may be provided as an interface layer, boundary layer, region of emulsion, foam, etc. The method may allow for determining the presence, and/or change in deposition in a conduit, pipeline, etc. For example, the interface region may be the region provided between material flowing in a pipeline and hydrates, asphaltenes, salts, etc. deposited in a pipeline. The method may be for allowing for determining the presence, and/or change in corrosion in a conduit, pipeline, etc. For example, the interface region may be the region provided between material flowing in a conduit and a wall of a conduit.

The method may comprise determining deposition and/or corrosion in a conduit, pipeline, etc. The method may comprise receiving one or more interface signals. The method may comprise transmitting one or more interface signals. The method may comprise using one or more transmitter/receivers, such as acoustic transducers, for transmitting and/or receiving interface signals. The method may comprise using one or more transducers. The method may comprise using one or more common transmitters/receivers (e.g. for transmitting/receiving two or more interface signals).

The method may comprise using one or more transceivers for transmitting and receiving.

The method may comprise using four transmitter-receiver pairs to provide twenty-four transmission paths (e.g. twenty-four transmission paths in a conduit). The method may comprise using movable/adjustable apparatus to provide configured known distances of transmission paths. The method may comprise using moveable/adjustable transmitters/receivers/transceivers.

The presence or lack of an interface region may be used to provide for determining the location of the interface region. For example, a determined presence or lack of an interface region may allow for determining that there is no location of an interface region associated with one or more particular transmission paths, and/or that a determined location is spurious.

The method may comprise not using, or discarding, a determined location of an interface region associated with having a lack of interface region (or a determined lack of interface region).

The interface signals may comprise one or more of acoustic signals, such as ultrasonic signals, electromagnetic signals, such as radio frequency signals, optical signals, or the like.

One or more of the interface signals may be communicated simultaneously.

According to a second aspect of the invention, there is a method for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, the method comprising: receiving a first interface signal having been transmitted across a first transmission path in a medium and determining a time of flight; receiving a second interface signal having been transmitted across a second transmission path in a medium and determining a time of flight, the first and second transmission paths being of different known distances; using the time of flight of the first interface signal together with the known distance of the first transmission path to provide a first flight characteristic and the time of flight of the second interface signal together with the known distance of the second interface signal to provide a second flight characteristic; determining the presence of an interface region by using the first flight characteristic and the second flight characteristic.

The first and second flight characteristic may be compared in order to determine the presence of an interface region. Determination of the presence of an interface region in a medium may be the determination of an interface region along one or more transmission paths in the medium.

The method may additionally comprise transmitting one or both of the first and second interface signals.

According to a third aspect of the invention there is provided a computer program stored, or storable, on a computer readable medium, the computer program configured to provide the method of any of the features of the first and second aspect.

According to a fourth aspect of the invention, there is provided apparatus for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, the apparatus configured to use a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a second transmission path in the medium in order to determine the presence of an interface region in the medium, the first and second transmission paths being of different known distances.

The apparatus may be configured to determine the time of flight of the first and second interface signals from the time of receipt of the first and second interface signals. The time of receipt of the first and second interface signals may be considered to be the time of flight of the first and second interface signals.

The apparatus may be configured to compare the first flight characteristic and the second flight characteristic in order to provide for determining the presence of an interface region.

The apparatus may be configured to determine the presence of an interface region when the first flight characteristic and second flight characteristic are compared to be the same, substantially the same, similar, etc. The apparatus may be configured to determine the lack (or absence) of an interface region when the first and second flight characteristics are compared to be different, substantially different, etc. The apparatus may be configured to determine the lack (or absence) of an interface region when the first and second flight characteristics are compared to be different beyond a threshold (e.g. a predetermined threshold).

The first flight characteristic may be related to the average speed of the first interface signal having been communicated across the first transmission path. The second flight characteristic may be related to the average speed of the second interface signal having been communicated across the second transmission path. The first/second may be the average speed of the first/second interface signal having been communicated across the first/second transmission path.

A determined absence of an interface region may be used to determine that the medium through which the first and second transmission paths are communicated is homogenous (e.g. an emulsion, the same material, the same density, etc.).

The determined presence of an interface region may provide for determining, or distinguishing, a laminar or stratified arrangement in the medium, for example, a laminar or stratified arrangement of a multi-layered medium. A non-laminar or non-stratified arrangement may be determined as being an emulsion, such as a fine emulsion. The determined presence or absence of an interface region may provide for characterising the medium. For example, characterising the medium as one particular material or substance, rather than another. The apparatus may be configured to determine non-laminar flow. The apparatus may be configured to characterise a medium.

Determination of the presence of an interface region in a medium may be the determination of an interface region along one or more transmission paths in the medium.

The apparatus may be configured to use the flight characteristics associated with more than two interface signals. The apparatus may be configured to use the flight characteristics associated with more than two interface signals having been communicated across more than two transmission paths. Each further first and second interface signal may have further respective first and second transmission paths being of different known distances.

The apparatus may comprise one or more transmitters configured to transmit interface signals. The apparatus may comprise one or more receivers configured to receive interface signals. The transmitters/receivers may be configured to provide the transmission path. The transmitters/receivers may be configured to provide the known distance of the transmission paths.

The apparatus may comprise one or more common transmitters for transmitting two or more interface signals. The apparatus may comprise one or more common receivers for receiving two or more interface signals. The apparatus may be configured such that one, some or all of the transmission paths intersect. The apparatus may comprise one or more transceivers configured to transmit and receive interface signals.

The apparatus may be configured use a determined interface region, or determined lack of interface region with further apparatus for measurements of the medium. The apparatus may be configured to use a determined interface region, or determined lack of interface region to determine a profile of a medium.

The determined interface region may provide for determining the location (or relative location) of the interface region at different regions in the medium, for example, different regions of a medium in a conduit, container, reservoir, or the like. The determined interface region may provide for determining a profile of the interface region of a multi-layer medium, such as a profile of the interface region provided in a conduit, etc. The profile may be a cross-sectional profile. The profile may be a two-dimensional profile, or may be a three dimensional profile. The profile may be time variant. That is to say, the profile may change as the medium/interface region changes.

The apparatus may further comprise a user interface, such an output user interface (e.g. Liquid Crystal Display, Organic Light Emitting Diodes, etc.). The apparatus may be configured to provide visualisation of the medium. (e.g. visualisation of the presence of an interface region, such as real time visualisation). The apparatus may be configured to provide a visual representation of a change in presence of an interface region. The apparatus may be configured to provide a visual representation of a change in profile of an interface region.

The apparatus may be configured for use with a conduit. The apparatus may comprise a conduit, such as a conduit configured for use with a multilayered medium (i.e. a medium having two or more layers). The apparatus may be configured to communicate two or more first and second interface signals across the conduit. The conduit may comprise a pipeline, such as an oil and gas pipeline. The apparatus may be configured to communicate the two or more first and second interface signals at different interval orientations with respect to the conduit, such as spaced at every 30 degrees, 45 degrees, around a conduit, and/or 0.1 m, 0.2 m, 0.5 m, etc. along the conduit, or the like. The intervals may be regular or irregular, or combination of regular and irregular intervals.

The apparatus may be configured to use the time of flight of four interface signals having been communicated across four transmission paths through a medium to determine the presence of the interface region (e.g. medium in a conduit).

The known distance of the first and second transmission paths may be measured, estimated, evaluated distances, approximated, or the like. The known distances may be a configured known distances.

That is to say that, in some instances a particular distance may be measured prior, during, or after transmitting of the interface signal, or may be estimated, evaluated, or approximated. In further instances, the apparatus may be configured/configurable to transmit/receive an interface signal a configured distance. For example, the apparatus may be movable/adjustable to provide a configured known distance, such as providing movable/adjustable transmitters, and/or receivers.

A determined interface region may allow for determining the presence of at least a first and second layer. The first and second layers may comprise adjacent layers.

The first and second layers may be stratified, or substantially stratified. The interface region may comprise an interface layer, boundary layer, or the like. The interface region may comprise a region of emulsion. The interface region may comprise a region of gas and liquid foam.

At least one of the first and second layer may comprise two or more sub-layers, such as three, four, five, ten, twenty sub-layers, or any number therebetween. Each sub-layer may be adjacent, such as being adjacently stratified, or the like.

Each sub-layer may serve to define a sub-interface region between respective sub-layers. The sub-interface region may be provided as an interface layer, boundary layer, region of emulsion, foam, etc. The apparatus may be configured to allow for determining the presence, and/or change in deposition in a conduit, pipeline, etc. For example, the interface region may be the region provided between material flowing in a pipeline and hydrates, asphaltenes, salts, etc. deposited in a pipeline. The apparatus may be configured to allow for determining the presence, and/or change in corrosion in a conduit, pipeline, etc. For example, the interface region may be the region provided between material flowing in a conduit and a wall of a conduit.

The apparatus may be configured to determine the presence or lack of an interface region to provide for determining the location of the interface region. For example, a determined presence or lack of an interface region may allow for determining that there is no location of an interface region along a particular transmission path, and/or that a determined location is spurious.

The apparatus may be configured not to use, or discard, a determined location of an interface region associated with an interface signal having been communicated across a transmission path having a lack of interface region (or a determined lack of interface region).

The apparatus may be comprised with a conduit, container, pipeline, or the like. The apparatus may be attachable/detachable with a conduit, container, pipeline, etc. The apparatus may be mountable/demountable with a conduit, container, pipeline, etc. The apparatus may be configured for attachment/mounting with the outer side of a conduit, container, pipeline, and/or the inner side of a conduit, pipeline, container, etc. The apparatus may be configured to be retro-fit to a conduit, container, pipeline, etc. The apparatus may be provided with a conduit for use as a modular component of a pipeline, and/or further conduit. For example, the apparatus may be comprised with a portion of pipeline, conduit, flow circuit, or the like, for use with other modular parts of a pipeline, conduit, etc. Such other modular parts may not comprise apparatus, but merely act to complete a flow circuit, or the like.

The apparatus may be configured such that one or more interface signals may be transmitted from transmitters implanted, or embedded, in a medium, which may be a medium in a conduit, reservoir, pipeline, etc. That is to say that the apparatus may be configured such that one or more signals might be transmitted and received (and/or reflected and received) from regions within a medium, such as a medium in a conduit, pipeline, reservoir, or the like. The apparatus may comprise one or more locators to allow location of the apparatus within a medium.

According to a fifth aspect of the invention there is provided apparatus for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, the apparatus comprising: a first receiver configured to receive a first interface signal having been transmitted across a first transmission path in a medium and to provide for determining a time of flight; a second receiver configured to receive a second interface signal having been transmitted across a second transmission path in a medium and to provide for determining a time of flight, the first and second transmission paths being of different known distances; the apparatus configured to use a determined time of flight of a first interface signal together with the known distance of the first transmission path to provide a first flight characteristic and a determined time of flight of a second interface signal together with the known distance of the second interface signal to provide a second flight characteristic; the apparatus further configured to determine the presence of an interface region by using the first flight characteristic and the second flight characteristic.

According to a sixth aspect of the invention there is provided a measurement device comprising an apparatus of the fourth or fifth aspect. The measurement device may be a flow meter. The measurement device may be an oil and gas flowmeter. The measurement device may be comprised with a conduit (e.g. a pipeline).

According to a seventh aspect of the invention there is provided a pipeline, such as an oil and gas pipeline, comprising an apparatus of the fourth or fifth aspect, or a device of the sixth aspect.

According to an eighth aspect of the invention, there is provided a device for determining the presence of an interface region, the device comprising: one or more conduits for permitting passage of a medium, such as a multi-layered medium; and apparatus according to any of the features of the fourth or fifth aspects.

According to a ninth aspect of the invention, there is a method for characterising a medium, the method comprising: using a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a second transmission path in the medium in order to characterise the medium, the first and second transmission paths being of different known distances.

According to a tenth aspect of the invention, there is a method for determining a laminar arrangement in a multi-layered medium, the method comprising: using a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a second transmission path in the medium in order to determine a laminar arrangement in the medium, the first and second transmission paths being of different known distances.

According to an eleventh aspect of the invention, there is a method for determining the presence of an interface region in a medium, such an interface region being defined between a first and second layer of a medium, the method comprising: using a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a second transmission path in the medium in order to determine the presence of an interface region in the medium, the first and second transmission paths differing by a known distance.

The invention includes one or more corresponding aspects, embodiments or features in isolation or in various combinations with of aspects whether or not specifically stated (including claimed) in that combination or in isolation. It will be appreciated that one or more embodiments/features/aspects may be useful in characterising a medium, such as determining the presence or absence of an interface region.

The above summary is intended to be merely exemplary and non-limiting.

Brief description of the figures

These and other aspects of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows an exemplary embodiment, comprising a conduit, and apparatus for determining the presence of an interface region; Figure 2 shows further embodiments of the invention for determining the presence of an interface; Figure 3 shows a further embodiment of apparatus for determining the presence of an interface region comprising a common transmitter; Figure 4 shows an embodiment of exemplary apparatus with a cross-section of a pipeline; Figure 5 shows an embodiment of exemplary apparatus with a pipeline; Figure 6 shows an exemplary embodiment of apparatus for use in flow visualisation; Figure 7 shows a further exemplary embodiment of apparatus comprising locators; and Figure 8 is a diagrammatic representation of an arrangement of layers within a conduit.

Detailed description of the figures

Figure Ia shows a section of an exemplary conduit 100 comprising a medium 130 having a first layer 110 and a second layer 120. Here, the first layer 110 is adjacent the second layer 120 by means of an interface region 115.

The conduit 100 is provided in a horizontal configuration, such that the first layer 110 rests on the second layer 120. Here, the first layer 110 is a liquid hydrocarbon, such as oil, while the second layer 120 is water. Alternatively, the first and/or second layer may be any liquid, gas or solid (e.g. the first layer 110 may be a mixture water and oil in an emulsion, while the second layer may be asphaltene, such as an asphaltene deposit, or the like).

In the example shown in relation to Figure Ia, the first layer 110 and the second layer each have a flow rate in a particular direction. Because the first layer 110 and the second layer 120 are separated by an interface region 115, the medium 130 can be considered to define a laminar or stratified arrangement (as opposed to non-laminar or non-stratified arrangement, which may be an emulsion arrangement, particularly a fine emulsion arrangement).

The conduit 100 shown in Figure la is provided with a first transmission path of known distance, D'. Here, the conduit 100 comprises a recess 150 having an effective known distance, d', so as to provide a second transmission path, D2. That is to say that the difference in distance between the first and second transmission paths is the known distance, d. Here, d' is provided in communication with the first layer 110.

Figure Ia further shows apparatus 200 according to an embodiment of the invention.

The apparatus 200 comprises a first transmitter 210a and a first receiver 210b. The first transmitter 210a and first receiver 210b are configured to transmit and receive respectively a first interface signal across the first transmission path, D1. The apparatus 200 is configured such that the first interface signal passes initially through the first layer 110, and then through the second layer 120 in order to reach the first receiver 210b.

The apparatus 200 further comprises a second transmitter 220a and a second receiver 220b. The second transmitter 220a and second receiver 220b are configured to transmit and receive respectively a second interface signal across the second transmission path, D2. Here, the second transmitter 220a is in communication with the recess 150 so as to communicate the second signal initially through the first layer 110, then through the second layer 120 so as to reach the second receiver 220b. Of course, in alternative configurations the recess 150 (or functionally similar, such as a protrusion) may be provided with the apparatus 200, rather then the conduit 100.

Each transmitter 210a, 220a and receiver 220a, 220b is configured to transmit and receiver ultrasonic signal species. Here, the apparatus 200 is configured to emit and receive uniquely identifiable ultrasonic signals so that there is a reduced chance of crosstalk between non-corresponding transmitters/receivers. The identifiable signals have a unique modulation so as to be uniquely identifiable, such as a unique amplitude modulation.

The apparatus 200 is configured to evaluate the time of flight of a first and second interface signal travelling across the first and second known distances (see later exemplary discussion in relation to Figure 6). In the present embodiment, the first and second interface signals are transmitted simultaneously.

Here, the apparatus 200 is configured to be mountable/demountable with the conduit 100, but in alternative configurations the apparatus 200 may be comprised with the conduit 100, or portion of the conduit, or the like. For example, the apparatus may be comprised with a portion of pipeline, or the like, for comprising with a conduit.

In use, the apparatus 200 is configured to use the time of flight of the first interface signal and the distance, D1, of the first transmission path in order to provide a first flight characteristic. The first flight characteristic can be considered to be the ratio of the time of flight of the first interface signal with the distance D1. That is to say that the first flight characteristic relates to the average speed of the interface signal.

Algebraically, the first flight characteristic can be consider to be: (1) tl where f1 is the first flight characteristic, and t1 is the time of flight of a first interface signal having been communicated across the first transmission path, D1.

In a similar manner the apparatus 200, in use, is configured to use the time of flight of the second interface signal and the distance, 02, of the second transmission path in order to provide a second flight characteristic. The second flight characteristic can be considered to be the ratio of the time of flight of the second interface signal with the distance D2.

f2cc-(2a) t2 or alternatively d+D (2b) where f2 is the second flight characteristic, t2 is the time of flight of a second interface signal having been communicated across the second transmission path, 02, and d is the known differing distance between D and 02.

Consider the example when: D = 100 mm 02 = 105 mm d=5mm t1 = 20 ps t2 = 21.5 ps The first flight characteristic is determined to be 5 (or 0.2). The second flight characteristic is determined to be 4.884 (or 0.205). In this case, because the first flight characteristic is determined to be different from the second flight characteristic, then the apparatus 200 determines that an interface region 115 is present in the medium 100. In other words, because the flight characteristic of the first and second interface signal has been determined to be different, then the apparatus 200 determines the presence of an interface region 115.

Of course, even though the first and second layers 110, 120 are considered to be fluids, in alternative configurations the determined presence of an interface region 115 may relate to a layer of deposition being formed on the inside of the conduit 100.

The embodiment shown in Figure lb is the same as that shown in relation to Figure la, but that the medium is a homogenous medium 135. That is to say that no interface region 115 exists. In this example, when the apparatus 200 is used in a similar manner to above, the following times of flight for the first and second interface signals are observed: t1 = 40 ps t2 = 42 p5 In this case, the time of flight of the first and second interface signals differs from the example above, because the medium 135 is different.

As before, the first and second flight characteristics can be determined. In this case the first flight characteristic and the second flight characteristic can be determined to be 2.5 (or 0.4). That is to say that the first and second flight characteristics are determined to be the same. Therefore, the apparatus determines that the homogenous medium 135 does not have an interface region 115 present.

It will be appreciated that in some embodiments, the apparatus 200 may be configured so as to determine the lack or absence of an interface region even when the first and second flight characteristics are determined to be different. For example, when they are different to within a particular (predetermined) threshold.

The determined lack of an interface region 115 can be used to determine that the arrangement of the medium in the conduit 100 is non-laminar or non-stratified. In such cases, a property of the medium, such as a flow property may be altered until laminar or stratified conditions return (e.g. flow regime change). This may be beneficial in, for example, the oil and gas production and transportation industry, where it may be difficult to process/transport emulsions.

It will readily be appreciated that in the above example, the interface signals of the apparatus 200 mounted, for example to the outer side of a conduit 100, will additionally pass through the wall of the conduit 100. However, in embodiments when the wall thickness might not be considered to negligible, the apparatus 200 compensates for the wall thickness because both the first and second interface signal both have to pass through the same thickness of wall.

For example, if it is known that the wall thickness is 10 mm of steel, the time taken for the first interface signal to pass into the medium 130, 135 through the conduit 100, and for it to pass from the medium 130, 135 through the wall to the receiver 210b is the same as that for the second interface signal. Therefore, when the first flight characteristic is compared with the second flight characteristic, the time taken to travel through the wall is effectively cancelled (i.e. because it is common to both time of flights).

Figures 2a and 2b show further embodiments of the invention. In Figure 2a shows a configuration of apparatus 300 using reflected first and second interface signals.

Here, the apparatus 300 comprises a first transceiver 310a configured to transmit a first interface signal across the first transmission path, D1 and receive respectively, a reflected first interface signal. Here, D1 is twice the cross-section of the conduit 100.

In a similar manner, the apparatus 300 comprises a second transceiver 320a associated with the second transmission path, D2.

Figure 2b shows a configuration of apparatus 400, similar to that described in relation to Figure 1, in which the conduit 100 comprises a first and second recess 1 50a, 1 50b having a combined effective known distance, d', so as to provide a second transmission path, D2.

Of course, it will be appreciated that the difference in distance of the first and second transmission paths may be provided by any suitable functional configuration. For example, the first and second transmission paths may traverse the conduit 100 at different angles so as to provide different effective distances (see Figure 3).

Figure 3 shows a further embodiment of apparatus 500 in which a common transmitter 510e is configured to transmit a first and second interface signal along two transmission paths 350c, 350d for receipt by two receivers 510b, 510d. In this example, there is no provision of a recess with the conduit 100. Rather, the apparatus 500 is configured with the conduit (e.g. the exterior of the conduit 100) such that the first transmission path passes across the conduit 100 is at an angle a and the second transmission path passes across the conduit 100 is at an angle ft Here, angle a and angle 13 differ so as to provide the different distances of transmission paths. Of course, in alternative configurations, there may additionally or alternatively be provided with one or more recesses (or similar).

While the apparatus 500 shown in Figure 3 has a common transmitter 310e, and two receivers 3 lOb, 310d, in alternative embodiments, the apparatus 500 may comprise any number of transmitters/receivers, one, some or all of which may act as common transmitterslreceivers. Similarly, there is no need to provide a common transmitter or receiver in order to provided the first transmission path at an angle a and the second transmission path at an angle 13; this could be provided by two transmitters and two receivers in a similar manner to Figures 1 or 2.

Figure 4a shows a cross-section of a conduit 100 comprising apparatus 450 having a plurality of pairs of transceivers 50a-50f for determining the presence of an interface region. Figure 4b shows a section of one pair of transceivers 50a, which is similar to the upper portion of the embodiment shown in Figure 2b. Of course, the transceivers (and/or transmitters/receivers) may be configured in a similar manner to any of the embodiments described in relation to Figure 1, or 2.

In this example, the medium a is multi-layered medium 135. That is to say that the medium 130 comprises an interface region 115 defined between a first layer 110 and second layer 120.

In this example, each pair of transceivers 50a-50f is configured to transmit and receive interface signals across the medium 130 at different regions in order to determine the presence of the interface region 115.

The presence of an interface region 115 is determined with respect to the region of the medium 130 through which the associated interface signals are communicated.

Exemplified in Figure 4a are the transmission paths for interface signals being transmitted from one pair of transceivers 50a to every other pair of transceivers 50b-50f.

For example, in relation to the transceiver 50a communicating a first and second interface signal to transceiver 50b, it will be appreciated that the transceivers 50a, 50b are configured to provide a first and second transmission path, each of a different distance so as to provide for determining the presence of an interface region. However, for clarity the first and second transmission paths are not explicitly shown in Figure 4a.

In this example, each pair of transceivers 50a-50f is located at a regular interval around the conduit 100 (e.g. 30 degrees, 45 degrees, etc). However, the pairs of transceivers 50a-50f may be configured at irregular intervals. It will be appreciated that one or more transmitters/receivers may be used rather than transceivers.

In this case only some of the interface signals pass through the interface region 115.

Other interface signals only pass through the first layer 110 or second layer 120. The apparatus 450 is configured to determine the presence of an interface region 115 for interface signals passing through the interface region (e.g. 50a to 50e, 50a to 50c, etc.). The apparatus 450 is further configured to determine the lack of an interface region 115 for those interface signals passing only through the first layer 110 or second layer 120 (e.g. 50a to 50f, 50a to 50b, etc.).

Such an apparatus 450 can allow for a cross-sectional, or two-dimensional, profile of the interface region 115 to be provided. It will readily be appreciated that, for example, the apparatus 450 may be configured to discard (or not use) the determined absence of an interface region 115 provided by transceiver 50a and SOb, or 50a and 50f, in order to provide a profile.

In a similar manner to Figure 4, Figure 5 shows a conduit comprising apparatus 550 for determining the presence of an interface region 115, in which the apparatus 550 is provided with a plurality of pairs of transceivers 50a-50f, 60a-60f, 70a-70f, spaced not only around a conduit 100, but also along the conduit 100 (some of the transceivers are not shown for clarity). As is shown by example, each particular pair of transceivers 60a is configured to communicate interface signals to not only further transceivers 60d across the conduit, but to transceivers 70d along the conduit. Of course, in certain circumstances, the apparatus 550 may be configured to communicate interface signals only across, or only along the conduit 100. This configuration provides for the determination of the presence (or absence) of interface regions 115 associated with regions of the medium 130, 135 through which the first and second transmission paths pass.

Figure 6 shows an exemplary apparatus 900 similar to the apparatus 550 described above, comprising a plurality of transmitters/receivers 910a-910n, 920a-920n for use with the conduit 100. Again, each of the transmitters/receivers are configured to transmit/receive interface signals across a medium. It will be appreciated that the apparatus 900 may be configured with 2, 3, 4, 5, 10, 20 or more transmitters/receivers (or transceivers), or any number therebetween.

Here, the apparatus 900 further comprises a remote controller 930 comprising a processor 940 and a memory 950, the processor 940 and memory 950 being configured in a known manner. The processor/memory 940, 950 may be provided by a microcontroller, such as provided by a field programmable gate array, application specific integrated circuit, programmable intelligent computer, or the like. Here, the controller 930 is configured to operate the transmitters/receivers so as to provide the interface signals. The controller 930 is further configured to determine the time of flight of respective signals, and determine the presence of an interface region (i.e. associated with respective transmission paths) by using the first and second flight characteristics.

By being remote, the controller 930 is configured to communicate with the transmitterslreceivers from a distance (i.e. not located at a multi-layer medium). In this embodiment, the controller 930 is configured to communicate with the respective transmitterslreceivers by wired communication, but in alternative embodiments, the controller 930 may be configured to communicate with the transmitters/receivers by wireless, optical, acoustic (i.e. using the layer in the conduit as a vehicle for signals) or any combination thereof.

The controller 930 is configured to provide an output 960. The output 960 is in communication with a user interface 965, such as a Liquid Crystal Display output.

The profile (or data associated with the profile) of the interface region 115 is provided from the controller to the user interface 965 so as to provide a display of the profile of the interface region 115 (e.g. flow visualisation). Such a configuration allows for a three-dimensional profile to be displayed. Of course, two dimensional (or cross-sectional) profiles would be equally possible.

In some embodiments, the output 960 is configured to be in communication with a different apparatus, such as a multiphase flow meter. Alternatively, the controller 930 and output 960 are comprised with a multiphase flow meter.

In further embodiments still the output 960 may provide the determined presence or absence of an interface region 115 to allow for further measurements or analysis of the medium 130, 135 (e.g. the location of the interface region 115). In such cases, the user interface may not be provided, or may be provided with further apparatus.

Although, the apparatus 900 is described as being provided with a remote controller 930, this need not always be the case. In some instances the controller 930 and/or user interface 965 may be provided locally (i.e. local to the medium 130, 135, conduit 100, etc.).

Figure 7 shows a further embodiment of the invention, comprising apparatus 800 in a similar configuration to that described in relation to Figure 1, whereby the apparatus 800 is immersed in a medium having the first layer 110, second layer 120, and interface region 115. Here, the apparatus 800 is provided such that it is not comprised with a conduit or the like, but is provided with locators 810, configured such that the apparatus 800 can be located in a medium 130, 135, so as to transmit interface signals through the first and second layers (or homogenous layer).

Here, the apparatus 800 is immersed in a reservoir comprising the medium, but in alternative configurations that apparatus may be for use in a conduit 100, or the like.

The locators 810 may be configured such that the apparatus 800 can be embedded in deposits, or located in liquid/gas, such as flowing liquid/gas, as will be appreciated.

The apparatus 800 may be configured such that the interface region 115 is maintained, or controlled, to be a particular distance between receiver/transmitter.

In the above described exemplary embodiments the first and second layers are shown to be continuously stratified. However, in alternative arrangements, as illustrated in Figure 8, a first layer llOa may be at least partially contained within a second layer 120 with an interface region 115a defined therebetween. Further, a first layer IlOb may be entirely contained within a second layer 120 with an interface region 115b defined therebetween. The present invention may permit individual masses of a first component which are suspended within a second component to be identified, and even characterised. In this way individual interface regions may be identified. This may be of use in identifying the structure or arrangement of an emulsion, for example.

While in the above embodiments, layers such as oil and water have been described, it will readily be appreciated that the apparatus/method may be applicable for any layer, which may be a solid, liquid or a gas. In alternative embodiments, the apparatus may be configured to determine the presence of an interface region in other layers in a conduit, such as coolants, or the like.

In addition, and in view of the foregoing description, it will be evident to a person skilled in the art that various modifications to any of the embodiments may be made within the scope of the invention. Similarly, the apparatus and/or methods disclosed may have other functions/steps, in addition to those described.

It will be appreciated to the skilled reader that the features of particular apparatus may be provided by apparatus arranged such that they become configured to carry out the desired operations only when enabled, e.g. switched on, or the like. In such cases, they may not necessarily have the appropriate software loaded into the active memory in the non-enabled state (e.g. switched off state) and only load the appropriate software in the enabled state (e.g. on state). The apparatus may comprise hardware circuitry and/or firmware. The apparatus may comprise software loaded onto memory. The apparatus may comprise a Field Programmable Gate Array, Application Specific Integrated Circuit, or the like. The apparatus may comprise electromagnetic transducers, acoustic transducers or the like.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

CLAIMS1. A method for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, the method comprising: using a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a second transmission path in the medium in order to determine the presence of an interface region in the medium, the first and second transmission paths being of different known distances. a)
2. The method according to claim 1, wherein the first flight characteristic isQassociated with the ratio of the time of flight of the first interface signal and the distance of the first transmission path, and the second flight characteristic is associated with the ratio of the time of flight of the second interface signal and the distance of the second transmission path.
3. The method according to claim 1 or 2, wherein the first flight characteristic and the second flight characteristic are compared in order to determine the presence of an interface region.
4. The method according to claim 3, comprising determining the presence of an interface region when the first flight characteristic and second flight characteristic are compared to be substantially the same and determining the lack of an interface region when the first and second flight characteristics are compared to be substantially different.
5. The method according to claim 3, comprising determining the lack of an interface region when the first and second flight characteristics are compared to be different beyond a particular threshold.
6. The method according to any preceding claim, wherein the first flight characteristic is related to the average speed of the first interface signal having been communicated across the first transmission path and the second flight characteristic is related to the average speed of the second interface signal having been communicated across the second transmission path.
7. The method according to any of the preceding claims in which a determined 0) absence of an interface region provides for determining that the medium through which the first and second transmission paths pass has a non-laminar or non-stratified arrangement. 0)
8. The method according to any of the preceding claims, wherein a determined absence of an interface region provides for determining that the medium through which the first and second transmission paths pass is substantially homogenous
9. The method according to claim 8, wherein a determined absence of an interface region provides for determining that the medium through which the first and second transmission paths pass is an emulsion.
10. The method according to any preceding claim, wherein a determined presence of an interface region provides for determining a laminar or substantially stratified arrangement in the medium.
11. The method according to any of the claims 1 to 10, wherein the first and second transmission paths pass across similar regions of the medium.
12. The method according to any preceding claim comprising using the flight characteristics associated with more than two interface signals, the more than two interface signals having been communicated across more than two transmission paths.
13. The method according to claim 12, wherein each further first and second interface signal has further respective first and second transmission paths being of different known distances.
14. The method according to claim 12 or 13, wherein at least two of the interface signals have been transmitted from a common transmitter and/or at least two of theQinterface signals have been received at a common receiver. a)15. The method may comprise using a determined interface region to provide for determining the location of the interface region at regions in the medium.16. The method according to claim 15, wherein determining an interface region may provide for determining a profile of the interface region of the medium.17. The method according to claim 16, wherein the profile is time variant.18. The method according to claim 16 or 17, wherein a determined presence of an interface region allows for a visual representation of the profile or change in profile to be provided.19. The method according to any preceding claims, wherein the method is for determining the presence of an interface region in a conduit.20. The method according to claim 19, comprising using the time of flight of two or more first and second interface signals having been communicated across two or more first and second transmission paths of a conduit at different interval orientations.21. The method according to any preceding claim, comprising receiving one or more interface signals and transmitting one or more interface signals.22. The method according to any preceding claim, wherein the interlace signals 0) comprise acoustic signals.23. The method according to any preceding claim, wherein the method is for use 0) with a hydrocarbon flow in a production/transportation pipeline.24. A method for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, the method comprising: receiving a first interface signal having been transmitted across a first transmission path in a medium and determining a time of flight; receiving a second interface signal having been transmitted across a second transmission path in a medium and determining a time of flight, the first and second transmission paths being of different known distances; using the time of flight of the first interface signal together with the known distance of the first transmission path to provide a first flight characteristic and the time of flight of the second interface signal together with the known distance of the second interface signal to provide a second flight characteristic; determining the presence of an interface region by using the first flight characteristic and the second flight characteristic.25. A computer program stored on a computer readable medium, the computer program configured to provide the method of any of the claims 1 to 24.26. Apparatus for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, the apparatus configured to use a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission 0) path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a secondQi transmission path in the medium in order to determine the presence of an interface region in the medium, the first and second transmission paths being of different known distances.27. The apparatus according to claim 26, wherein the apparatus is configured to use the flight characteristics associated with more than two interface signals, having been communicated across more than two transmission paths, each further first and second interface signal having further respective first and second transmission paths being of different known distances.28. The apparatus according to claim 26 or 27 comprising one or more transmitters configured to transmit interface signals and one or more receivers configured to receive interface signals, the transmitters/receivers configured to provide the transmission path.29. The apparatus according to any of the claims 26 to 28, wherein the apparatus further comprises a user interface, the user configured to provide visualisation of the presence of an interface region in a medium.30. The apparatus according to any of the claims 26 to 29, wherein the apparatus is configured for use with a conduit.31. The apparatus according to claim 21, wherein the conduit comprises an oil and gas pipeline.32. Apparatus for determining the presence of an interface region in a medium, such an interface region being defined between first and second layers of a medium, 0) the apparatus comprising: a first receiver configured to receive a first interface signal having been i transmitted across a first transmission path in a medium and to provide for 0) determining a time of flight; a second receiver configured to receive a second interface signal having been transmitted across a second transmission path in a medium and to provide for determining a time of flight, the first and second transmission paths being of different known distances; the apparatus configured to use a determined time of flight of a first interface signal together with the known distance of the first transmission path to provide a first flight characteristic and a determined time of flight of a second interface signal together with the known distance of the second interface signal to provide a second flight characteristic; the apparatus further configured to determine the presence of an interface region by using the first flight characteristic and the second flight characteristic.33. A measurement device comprising apparatus according to any of the claim 26 to 32.34. The measurement device according to claim 33, wherein the device is an oil and gas flowmeter.35. A pipeline comprising an apparatus according to any of the claims 26 to 32.36. A device for determining the presence of an interface region, the device comprising: one or more conduits for permitting passage of a medium, such as a multi-layered medium; and 0) apparatus according to any of the claims 26 to 32.i 37. A method for determining a laminar arrangement in a multi-layered medium, the method comprising: using a first flight characteristic associated with the time of flight of a first interface signal having been communicated across a first transmission path in a medium together with a second flight characteristic associated with the time of flight of a second interface signal having been communicated across a second transmission path in the medium in order to determine a laminar arrangement in the medium, the first and second transmission paths being of different known distances.38. A method substantially as described with reference to the description and/or the figures.39. Apparatus substantially as described with reference to the description and/or the figures.