GB2475039A

GB2475039A - Communicating information by transmitting chirps in a structure

Info

Publication number: GB2475039A
Application number: GB0919028A
Authority: GB
Inventors: Laurie Linnett
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-10-30
Filing date: 2009-10-30
Publication date: 2011-05-11
Anticipated expiration: 2029-10-30
Also published as: GB0919028D0; GB2475039B

Abstract

Method and apparatus for communicating information using a structure 100 comprising; transmitting 610 in a structure a chirp which is associated with particular information and receiving 620 and identifying a partial chirp and associating it with a transmitted chirp. The chirp has an identifiable change in frequency varying over the time period associated with particular information being communicated. The structure may be a structural support and/or a passage for fluid. The structure may be a pipeline, tubular, drillstring or casing in an oil and/or gas structure. The information may be digital or communicated as words. The information may be media data, images, pictures, video or control data to control a down hole assembly. The transmitted signal may be an acoustic signal including ultrasonic signals. The information may be communicated in a medium in the structure such as liquid or gas.

Description

Methods for communicating and associated apparatus

Technical Field

The invention relates to methods for communicating and associated apparatus. In particular but not exclusively, a method for communicating information using a structure, such as a pipeline, tubular, drill string, casing, or the like.

Background

In the field of oil and gas exploration, transportation and/or production it can be useful to communicate information with a well, or with some further section or portion of the production/transportation structure. For example, information can be retrieved from a well to help with logging the condition of that well. Similarly, information can be communicated to a drill bit to modify drilling conditions, etc. Exploration and production sites often use oil and gas structures, including conduits such as pipelines, tubulars, drill strings, casings, etc. to assist with the exploration and production of oil and gas.

Summary

According to a first aspect of the invention there is provided a method for communicating information using a structure, the method comprising: identifying a received partial chirp in a received signal, the received signal having been communicated using a structure, the received partial chirp being identified by observing an identifiable change of frequency of the received signal over at least a portion of a time period, and associating the received partial chirp with a transmitted chirp having been communicated in the structure in order to provide for determining information being communicated using the structure, such a transmitted chirp having the identifiable change of frequency varying over the time period and being associated with particular information being communicated.

The structure may be considered to have further functionality. The further functionality may provide structural support, and/or provide passage for a fluid, etc. The further functionality may be a primary, or main, functionality of the structure.

The structure may provide mechanical functionality in addition to being used for communicating information. The structure may be an oil and gas structure. The structure may be a conduit, such as a pipeline, tubular, drill string, casing (e.g. completion casing, temporary casing, etc.), or the like. The structure may be a downhole structure. The structure may be a subterranean structure. The structure may be a transportation structure. The structure may be a utility structure (e.g. water supply, waste transportation, etc). The structure may define a particular flow path.

The method may comprise determining information being communicated by using the associated chirp.

The method may comprise identifying the received partial chirp by observing the change of frequency of the received signal over two or more portions of the time period. The received partial chirp may be considered to be the transmitted chirp and signal noise and/or signal loss.

The method may comprise identifying a plurality of received partial chirps in a received signal. Each received partial chirp may be associated with different transmitted chirps.

Some or all of the plurality of received partial chirps may be identified by observing the change in frequency of the received signal over at least a portion of different time periods, such as sequential time periods.

Some or all of the plurality of received partial chirps may be identified by observing the change in frequency of the received signal over at least a portion of the same time period.

The method may comprise de-convolving the received signal to identify the plurality of received partial chirp over at least a portion of the same time period. Some or all of the plurality of received partial chirps may be identified by observing the change in frequencies of the de-convolved received signal.

That is to say that some or all of the of the received partial chirps may be associated with transmitted chirps having been communicated in the structure over the same time period. In such cases, such transmitted chirps may still be uniquely identifiable and to be associated with particular information. For example, the transmitted chirps may have been communicated as a transmitted signal. The transmitted signal may comprise a plurality of transmitted chirps. The transmitted signal may be convolved from a plurality of transmitted chirps.

The received partial chirps may be associated with transmitted chips that vary with an increasing frequency over the time period. The received partial chirps may be associated with transmitted chips that vary with a decreasing frequency over the time period. The identifiable change in frequency may be one or more of: linear, exponential, logarithmic, polynomial, or the like.

The information may be associated with particular data.

The information may be digital information (e.g. is and Os). The identification of a received partial chirp over a particular time period may be associated with a i, or vice versa. The absence of identification of a received partial chirp over a particular time period may be associated with a 0, or vice versa.

The identification of a particular received partial chirp may be associated with particular indices, such as binary indices (e.g. 21, or 22, etc.). In such cases, information may be received as words (e.g. a group of bits communicated as a unit).

That is to say that information may be communicated in words over a particular time period.

The identification of a received partial chirp over a particular time period associated with a transmitted chirp having an increasing frequency may be associated with particular information (e.g. i, 0, a particular indices, or the like), while identification of a received partial chirp over a particular time period associated with a transmitted chirp having a decreasing frequency may be associated with different particular information, such as opposite information.

For example, identification of a received partial chirp associated with a transmitted chirp having an increasing frequency may be associated with a i, while identification of a received partial chirp associated with a transmitted chirp having a decreasing frequency may be associated with a 0. Similarly, identification of a received partial chirp associated with a transmitted chirp having an increasing frequency may be associated with a 1 at particular indices location in a word (e.g. 22 in a word), while identification of a received partial chirp associated with a transmitted chirp having a decreasing frequency may be associated with a 0 that at particular indices location in a word (e.g. 0 at 22 in a word). Such transmitted chirps may be considered to be complementary chirps.

The modulus rate of change of frequency of complementary transmitted chirps may be similar, or the same.

The information may be associated with media data, such as multimedia data. The information may be associated with images, such as pictures and/or video. The information may be associated with control data, such as control data used to control drill bits, or the like. The information may comprise control signals.

The method may comprise receiving the received signal.

The method may comprise transmitting the transmitted chirp using the structure for subsequent receipt as the received partial chirp.

The transmitted and received signal may comprise an acoustic signal, such as an ultrasonic signal.

The method may comprise communicating information bi-directionally, such as full duplex or half duplex communication.

The bandwidth of the transmitted chirp may be commensurate with the bandwidth permitted by the structure and/or a receiver for receiving the received signal at the structure. That is to say the bandwidth of the transmitted chirp may be similar to, or the same as (e.g. matched with), the bandwidth of the structure and/or receiver.

The method may comprise communicating information in a medium in the structure, such as in a liquid or gas (e.g. in water, oil, etc.) According to a second aspect of the invention there is provided a method for communicating information using a structure, the method comprising: providing a transmitted chirp for transmitting using a structure, the transmitted chirp having an identifiable change of frequency varying over a time period and being associated with particular information to be communicated using the structure, the transmitted chirp for subsequent identification as a received partial chirp in a received signal, such a received partial chirp being associatable with the transmitted chirp by observing the change in frequency of the received signal over at least a portion of the time period in order to determine the information to be communicated.

The structure may provide mechanical functionality in addition to being used for communicating information. The structure may be an oil and gas structure. The structure may be a conduit, such as a pipeline, tubular, drill string, casing (e.g. completion casing, temporary casing, etc.), or the like. The structure may be a downhole structure. The structure may be a subterranean structure. The structure may be a transportation structure. The structure may be a utility structure (e.g. water supply, waste transportation, etc.). The structure may define a particular flow path.

The method may comprise providing a transmitted signal comprising a plurality of transmitted chirps. The plurality of transmitted chirps may be convoluted to provide the transmitted signal.

The method may comprise transmitting the transmitted chirp(s).

The bandwidth of the transmitted chirp(s) may be commensurate with the bandwidth permitted by the structure and/or a receiver for receiving the received signal at the structure.

According to a third aspect of the invention there is provided a method for communicating information using a structure, the method comprising: transmitting a transmitted signal using a structure, the transmitted signal comprising a transmitted chirp having an identifiable change of frequency varying over a time period and being associated with particular information to be communicated in the structure; receiving a received signal and identifying a received partial chirp in the received signal, the received partial chirp being identified by observing an identifiable change of frequency of the received signal over at least a portion of the time period; and determining information being communicated using the structure by associating the received partial chirp with the transmitted chirp.

The method may be communicating information comprising video information in a structure.

According to a fourth aspect of the invention there is provided apparatus for communicating information using a structure, the apparatus configured to identify a received partial chirp in a received signal, such a received signal having been communicated using a structure, a received partial chirp being identifiable by observing an identifiable change of frequency of a received signal over at least a portion of a time period, the apparatus further configured to associate an identified received partial chirp with a transmitted chirp in order to provide for determining information being communicated using a structure, such a transmitted chirp having the identifiable change of frequency varying over the time period and being associated with particular information being communicated using a structure.

The apparatus may be configured to determine information being communicated from associated chirps.

The apparatus may comprise a receiver for receiving a received signal. The apparatus may be attached or attachable with a structure.

The apparatus may comprise a user interface, which may be a graphical user interface. The user interface may be a display, such as a liquid crystal display, light emitting diode display, or the like. The display may be configured to displaying video images.

According to a fifth aspect of the invention there is provided apparatus for communicating information using a structure, the apparatus configured to provide a transmitted chirp having an identifiable change of frequency varying over a time period and associated with particular information to be communicated using a structure, such a transmitted chirp for communication using a structure and for subsequent identification as a received partial chirp in a received signal, such a received partial chirp being associatable with a transmitted chirp by observing the change in frequency of a received signal over at least a portion of the time period in order to determine the information to be communicated.

The apparatus may comprise a transmitter for transmitting a transmitted chirp. The apparatus may be attached or attachable with a structure.

According to a sixth aspect of the invention there is provided apparatus for communicating information using a structure, the apparatus comprising: a transmitter configured to transmit a transmitted chirp using a structure, the apparatus configured to provide a transmitted chirp having an identifiable change of frequency varying over a time period and associated with particular information to be communicated using a structure, a receiver for receiving a received signal using a structure, the received signal comprising a received partial chirp associated with a transmitted chirp communicated using a structure; wherein the apparatus is configured to identify a received partial chirp in a received signal by observing an identifiable change of frequency of a received signal over at least a portion of a time period, the apparatus further configured to associate an identified received partial chirp with a transmitted chirp in order to provide for communicating particular information using a structure.

The apparatus may further comprise a structure.

The apparatus may be configured to be one or more of: mountable, demountable, attachable, detachable, fixably attachable, retrofit with a structure.

According to a seventh aspect of the invention there is provided a method for communicating information, the method comprising: identifying a received partial chirp in a received signal, the received signal having been communicated, the received partial chirp being identified by observing an identifiable change of frequency of the received signal over at least a portion of a time period, and determining information being communicated by associating the received partial chirp with a transmitted chirp having been communicated, such a transmitted chirp having the identifiable change of frequency varying over the time period and being associated with particular information being communicated.

The method may be for communicating using a structure, which may be an oil and gas structure (e.g. a pipeline, completion casing, drill string, etc.) According to a eighth aspect of the invention there is provided a method for communicating comprising: identifying a chirp within a received signal by observing an identifiable change in the frequency of the received signal over a time period, the received signal having been communicated in a structure; and associating information with the identified chirp.

The structure may be considered to have further functionality. The further functionality may provide structural support, and/or provide passage for a fluid, etc. The functionality may be a primary, or main, functionality of the structure.

According to a ninth aspect there is provided a computer program product, provided on a computer readable medium, the computer program product configured to provide the method according any of the features of the first, second, third, sixth, or eighth aspect.

The invention includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. For example, it will readily be appreciated that features of the first aspect may be used with features of the second, third, fourth, fifth, sixth, seventh, or eighth aspect, without the need to recite again every possible permutation here.

Corresponding means for performing one or more of the discussed functions are also within the present disclosure. It will be appreciated that one or more embodiments/aspects may be useful in communicating information, such as communicating information in an oil and gas structure.

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 example of communicating a signal using a structure; Figures 2a and 2c show examples of a transmitted chirp and Figure 2b shows an example of a received signal comprising a partial chirp; Figure 3 shows a further example of transmitted chirps; Figure 4 shows an example of a signal being communicated using a structure comprising packets of chirps; Figure 5 shows apparatus for communicating information using a structure; and Figure 6 shows a further embodiment of communicating information using a structure.

Detailed description of the figures

Figure 1 shows a structure 100, such as an oil and gas pipeline, tubular, drill string, casing (e.g. completion casing, temporary casing, etc.), or the like. The structure 100 has a primary, or main, functionality such as providing a passage for fluid flow, or providing a structural support.

In this example, the structure 100 is a hollow oil and gas conduit 100, which allows passage of fluid and has a wall portion 110. However, this is exemplary only. The oil and gas structure may be form of structure configured for oil and gas conditions.

As is shown in Figure la, a frequency based transmitted signal, f, is communicated into the wall 110 of the conduit 100 at a first end region 120. In this example, the amplitude of the transmitted signal is modulated so as to allow communication of information using the conduit 100. Here, the transmitted signal is an acoustic signal, such as an ultrasonic signal. The transmitted signal f is communicated thought the wall 110 of the conduit 100 and is received as a received signal f01 at a second end region 130 of the conduit 100.

This can be considered to be an ideal scenario, in which no signal loss occurs and no noise occurs (i.e. f = f01). Of course, in real world applications that need not always be the case. Consider the example shown in Figure 1 b.

Here, the wall 110 of the conduit 100 is in mechanical communication with the formation 140. The formation 140 may be part of an underground formation, strata, or the like. Similarly, the formation 140 may be a further piece of apparatus, deposit, corrosion, or the like. For example, the formation 140 may be a casing, and the conduit 100 may be a drill string that is touching the casing.

In this example, consider that the impedance of the formation 140 and the conduit are similar at the point of contact for the particular frequency of the transmitted signal, f. As such, when the transmitted signal f is communicated in the wall 110 of the conduit 100 some of the transmitted signal f leaks out of the conduit 100 before it is received at the second end region 130. This can be considered to be signal loss f. Of course, signal loss may occur (additionally or alternatively) due to attenuation of the transmitted signal in the conduit 100.

This has the effect that the received signal f01 at the second end region 130 is reduced in amplitude. Therefore, information provided in the transmitted signal is less derivable. In some cases, the information in the received signal (or even the received signal itself) is lost irrevocably.

In addition, in some further examples (as is shown in Figure ib), signal noise fnoise at or around the frequency of transmitted signal f1 is injected into the conduit 100. This noise is unwanted. An example of such noise may be from the communication of frequencies within the sub-terrain due to drilling, or the like. The effect of the signal noise fnoise is that the received signal f01 at the second end region 130 comprises spurious information that may have been cumulatively and/or differentially combined with the transmitted signal f.

Of course, it may be possible to try to identify when such signal losses f0 or signal noise fnoise occurs by communicating transmitted signals using some form of checking (e.g. cyclic redundancy). Otherwise, the information determined from the received signal f01 may be taken as being accurate. However, if such checking is used, retransmission can use up valuable time and bandwidth, especially when considering transmitting large amounts of information, such as that required by media (e.g. video, streaming audio and/or video, or the like).

Consider now the example of a transmitted signal 210 shown in Figure 2a. The transmitted signal 210 is for communicating using the structure of Figure ib, which by example is a conduit 100. Here, the transmitted signal 210 comprises a chirp.

That is to say that the transmitted signal 210 has a frequency that varies over a particular time period (shown here as tchirp). In this example, the transmitted signal 210 can also be considered to have a particular bandwidth (shown here as fchirp).

The bandwidth is the range of frequency that the chirp signal occupies from a lower frequency f1 to an upper frequency f2. Although f1 is shown in Figure 2a as emanating from the origin, that need not mean that the bandwidth starts at DC, as will be appreciated.

It will be appreciated that based on the material properties of the conduit 100 shown in Figure 1, the conduit 100 will allow a particular range of frequencies to be communicated using the conduit 100. That is to say that based on the construction of the conduit 1 00 some frequencies will pass freely through the conduit, will others will be attenuated. This may be considered to be the bandwidth of the conduit 100.

Similarly, a receiver (not shown) used to receive a received signal will have a bandwidth of frequencies that it can detect. Frequencies beyond that bandwidth will not be detected, or not be detected well.

In the example of the transmitted signal 210 shown in Figure 2a, the transmitted signal 210 has a bandwidth fh1 that is commensurate with the bandwidth of the conduit 100 and/or a receiver. Here, the transmitted signal 210 has a bandwidth that fills, or at least substantially fills, the bandwidth of the conduit 100 and/or a receiver.

Figure 2b shows a received signal 220 having been received at the second end region 130 of Figure 1 b. The received signal 220 has been received as a result of the transmission of the transmitted signal 210 shown in Figure 2a being transmitted in the conduit 100.

As can be seen, the received signal 220 comprises a received partial chirp 230, along with a noise portion 240a and a lost portion 240b. The noise portion 240a comprises spurious frequencies due to signal noise fnoise, while the lost portion 240b has no signal (or no detectable signal) due to the signal loss f10 of the signal through the formation 140 at those specific frequencies.

Of course, the skilled reader will appreciate that this is exemplary only. In some examples, the lost portion 240b may comprise a signal. However, it may be that the signal is too weak to detect or too weak to determine sufficiently that that frequency is part of the received signal. Similarly, noise portion 240a and lost portion 240b may overlap, or be combined. Some received signals 220 may comprise only a lost portion 240b, or only a noise portion 240a. Similarly, received signals may comprise a plurality of lost portions and/or noise portions 240a, 240b.

Here, it is possible to identify the received partial chirp 230 in the received signal 220 by observing a change in frequency of the received signal over at least a portion of the particular time period. In this particular example, the received partial chirp 230 can be identified at the beginning of the time period, or at the end of the time period, or both. The variation in frequency of the received partial chirp 230 can then be associating with the transmitted chirp 210 in order to communicate information.

Although the frequency of the chirp shown in Figures 2a and 2b might be considered to vary linearly over a time period, that need not always be the case. Figure 2c shows a further example in which the chirp varies in a non-linear manner.

It will readily be appreciated that the communication of digital or binary information may be communicated using a conduit 100 by using such transmitted chirps 210 and identifying received partial chirps 230 in a received signal 220. For example, the presence of a received partial chirp 230 over a particular time period may indicate a transmitted 1', while the absence may indicate a transmitted 0', or vice versa.

Consider a transmitted signal 310 shown in Figure 3a. Here, the transmitted signal 310 comprises a first, second and third chirp 310a, 310b, 320c. Each chirp 310a, 310b, 310c, is uniquely identifiable. In this example, each chirp 310a, 310b, 310c is uniquely identifiable because the frequency of each chirp 310a, 310b, 310c varies differently over a particular time period tchjrp. In other words, the change of frequency, or rate of change of frequency, is identifiably different between different chirps.

Here, the first, second and third chirps 310a, 310b, 310c are assigned to represent particular data, which in this embodiment are binary indices 0, 1, and 2. That is to say that the first chirp 310a is associated with the binary indices of 2°. Transmission of the first chirp means the communicating of 1'. Similarly, communication of the second chirp 310b means the communicating of 2', and communicating of the third chirp means the communicating of 4'.

All of the chirps 310a, 310b, 310c are communicated in the transmitted signal 310 in the conduit 100 in a particular time period. That is to say that the transmitted signal 310 is a cumulative signal comprising those three chirps 310a, 320b, 330c. This can be achieved using convolution, or the like.

In this example, the identified presence of a received partial chirp in a received signal assigned to a particular indices means that that indices is counted, or attributed as being 1, while, the absence means that that indices is not counted. In such a manner, a word of data can be communicated over a time period. It will be appreciated that a received signal may be de-convolved in order to identify received partial chirps associated with the transmitted chirps 310a, 310b, 310c.

Figure 3b shows a further transmitted signal 410 comprising three up-chirps 410a, 410b, 410c and three down-chirps 410d, 410e, 410f. The up-chirps 410a, 410b, 410c have an increasing frequency over the time period, while the down-chirps 410c, 410e, 410f have a decreasing frequency over the time period. In this example, each up-chirp has a complementary down-chirp (i.e. having the same, or similar, modulus of rate of change of frequency). For example, up-chirp 410a is complementary with down-chirp 410d.

In this example, the identified presence of a received partial chirp in a received signal assigned to a particular up-chirp means that that chirp is counted, or attributed, while, the identified presence of a received partial chirp in a received signal assigned to a particular down-chirp means that that chirp is not counted.

Considering the example above comprising indices, it may be that the identification of a particular up-chirp means that 21 should be counted, while the identification of a corresponding down-chirp means that 21 should not be counted.

Of course, in some examples the up-chirps and down-chirps may not be corresponding. In fact, each may be for communicating unique information. For example, the transmitted signal 410 of Figure 3b may be for communicating a word comprising 2°, 21, 22, 2, 2, and 2.

While the example has been described with reference to binary indices, or binary data or the like, a skilled reader will readily appreciate that any information any be communicated using such chirps (e.g. each identifiable chirp may be associated with a colour, or the like).

Similarly, although by example, the up-chirps 410a-c and down-chirps 410d-410f have been shown to have the same starting frequency, this is exemplary only.

Consider, by way of an example, the further embodiment of a transmitted signal 415 shown in Figure 3c comprising chirps.

Figure 4 shows a signal 500 for being communicated comprising a plurality of packets 505. Each packet comprises a plurality of chirps, as exemplified by Figure 3.

Each packet spans a time period (e.g. tchirp). Even though signal loss and/or signal noise are detrimental to the communication of the signal, the information being communicated can still be determined by observing the received partial chirps in each packet 505, and associating them with transmitted chirps.

Figure 5 shows apparatus 600 comprised with the conduit 100 as the oil and gas structure. The apparatus 600 comprises a transmitter 610 in communication with the first end region 120 of the conduit 100. The transmitter 610 is further in communication with an image recorder 640, such as a video camera, and is configured to provide a transmitted signal for communication using the conduit 100 from data provided by recorder 640. In this example, the recorder 640 is located at a region within a well.

The apparatus 600 further comprises a receiver 620 in communication with the second end region 130 of the conduit 100. The receiver 610 is further in communication with a user interface 640, such as a user display, and is configured to provide a received signal and determine information being communicated in the conduit by identifying receive partial chips and associated them with transmitted chirps.

Here, the condition of a well may be observed by the image recorder 540 and communicated to the user interface 630 using the conduit 100.

Of course, it will be appreciated that the transmitter 610 may also act as a receiver and the receiver 620 may also act as a transmitter, such that information can be bi-directional. In some examples, information may be communicated in one direction using up-chirps, while information in the other direction may be communicated using down-chirps. This in one example in which full duplex communication can be provided.

Similarly, while the above example describes an image recorder 640, it will readily be appreciated that the conduit 100 may be used for communication with a drill bit, or the like.

It may be that the conduit is used to communicate control signals. For example, the structure may be used to communicate signals with a bottom hole assembly. Such a configuration may allow for directional and/or speed control, etc. Similarly, the structure may be used to communicate signals with other apparatus, such as values, or the like.

Although the above examples describe a conduit 110, and in particular a hollow conduit, a skilled reader will readily appreciate that the above embodiments may be provided with different structures, which, in some cases, may be solid (i.e. need not be hollow). Similarly, the above embodiments may be suitable for communicating in further oil and gas structures, such as transportation structures (e.g. transportation pipelines).

Other mediums may also be used, rather than an oil and gas structure. For example, the method described in relation to Figure 3 or 4 may be used to communicate signals, such as acoustic or electromagnetic signals, through air as a medium. In some examples, the method need not be limited to the use with oil and gas structures.

Consider the example shown in Figure 6. Here, a medium 1000 is used to communicate signals. In this example, the medium 1000 is a structure, such as building structure (e.g. a rolled steel joist, etc). Information can be communicated in a similar manner to that described above. Again, in this case, the structure can be considered to have further functionality (e.g. provide structural support, provide passage for a fluid, etc.), in addition to ability to be used to communicate information.

In some further examples, a transmitted signal may be transmitted in a fluid or the like being transported or stored in a conduit. Similarly, a transmitted signal may be communicated using a conduit, by being received in a fluid being stored or transported in the conduit. That is to say that being communicating using a conduit need not be limited to using a wall of the conduit for communication.

It will be appreciated that any of the aforementioned methods or apparatus may have other steps or functions in addition to the described steps/functions, and that these steps/functions may be performed by the same apparatus.

The applicant 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 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 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

Claims 1. A method for communicating information using a structure, the method comprising: identifying a received partial chirp in a received signal, the received signal having been communicated using a structure, the received partial chirp being identified by observing an identifiable change of frequency of the received signal over at least a portion of a time period, and associating the received partial chirp with a transmitted chirp having been communicated in the structure in order to provide for determining information being communicated using the structure, such a transmitted chirp having the identifiable change of frequency varying over the time period and being associated with particular information being communicated.
2. The method according to claim 1, wherein the structure has a primary functionality, that primary functionality being structural support and/or passage for a fluid.
3. The method according to claim 1 or 2, wherein the structure is an oil and gas structure, comprising at least one of: a conduit, such as a pipeline; a tubular; a drill string; a casing.
4. The method according to any of the preceding claims further comprising determining information being communicated by using the associated received partial chirp.
5. The method according to any preceding claim comprising identifying the received partial chirp by observing the change of frequency of the received signal over two or more portions of the time period.
6. The method according to any preceding claim comprising identifying a plurality of received partial chirps in a received signal, each received partial chirp being associated with different transmitted chirps.
7. The method according to claim 6 wherein some or all of the plurality of received partial chirps are identified by observing the change in frequency of the received signal over at least a portion of different time periods.
8. The method according to claim 6 wherein some or all of the plurality of received partial chirps are identified by observing the change in frequency of the received signal over at least a portion of the same time period.
9. The method according to any preceding claim, wherein the information is associated with particular data.
10. The method according to claim 9, wherein the information is digital information, such as is and Os.
ii. The method according to claim 10, wherein identification of a received partial chirp over a particular time period is associated with a 1 and the absence of identification of a received partial chirp over a particular time period is associated with a 0, or vice versa.
12. The method according to claim 9 wherein the identification of a particular received partial chirp is associated with particular binary indices.
13. The method according to claim 12, wherein information is communicated as words.
14. The method according to claim 13, wherein identification of a received partial chirp associated with a particular transmitted chirp having an increasing frequency is associated with a 1 at particular indices location in a word, while identification of a received partial chirp associated with a particular transmitted chirp having a decreasing frequency is associated with a 0 at a particular indices location in a word, or vice versa, such transmitted chirps considered to be complementary chirps.
15. The method according to claim 14, wherein the modulus rate of change of frequency of complementary transmitted chirps is similar, or the same.
16. The method according to any preceding claim, wherein the information is associated with one or more of: media data, such as multimedia data; images, such as pictures and/or video; control data, such as control data used to control down hole assembly.
17. The method according to any preceding claim further comprising receiving the received signal.
18. The method according to any preceding claim further comprising transmitting the transmitted chirp using the structure for subsequent receipt as the received partial chirp.
19. The method according to any preceding claim, wherein the transmitted and received signal comprises an acoustic signal, such as an ultrasonic signal.
20. The method according to any preceding claim, wherein the bandwidth of the transmitted chirp is commensurate with the bandwidth permitted by the structure and/or a receiver for receiving the received signal at the structure.
21. The method according to any preceding claim wherein the method comprises communicating information in a medium in the structure, such as in a liquid or gas.
22. A method for communicating information using a structure, the method comprising: providing a transmitted chirp for transmitting using a structure, the transmitted chirp having an identifiable change of frequency varying over a time period and being associated with particular information to be communicated using the structure, the transmitted chirp for subsequent identification as a received partial chirp in a received signal, such a received partial chirp being associatable with the transmitted chirp by observing the change in frequency of the received signal over at least a portion of the time period in order to determine the information to be communicated.
23. The method according to claim 22, wherein the structure has a primary functionality, that primary functionality being structural support and/or passage for a fluid.
24. The method according to claim 22 or 23, wherein the structure is an oil and gas structure, comprising at least one of: a conduit, such as a pipeline; a tubular; a drill string; a casing.
25. The method according to any of the claims 22 to 24, wherein the method comprises transmitting the transmitted chirp.
26. The method according to claim 25, wherein the bandwidth of the transmitted chirp is commensurate with the bandwidth permitted by the structure and/or a receiver for receiving the received signal at the structure.
27. A method for communicating information using a structure, the method comprising: transmitting a transmitted signal using a structure, the transmitted signal comprising a transmitted chirp having an identifiable change of frequency varying over a time period and being associated with particular information to be communicated in the structure; receiving a received signal and identifying a received partial chirp in the received signal, the received partial chirp being identified by observing an identifiable change of frequency of the received signal over at least a portion of the time period; and determining information being communicated using the structure by associating the received partial chirp with the transmitted chirp.
28. The method according to claim 27, wherein the structure has a primary functionality, that primary functionality being structural support and/or passage for a fluid.
29. The method according to claim 27 or 28, wherein the structure is an oil and gas structure, comprising at least one of: a conduit, such as a pipeline; a tubular; a drill string; a casing.
30. The method according to any of the claims 27 to 28, comprising communicating information comprising video information in a structure.
31. Apparatus for communicating information using a structure, the apparatus configured to identify a received partial chirp in a received signal, such a received signal having been communicated using a structure, a received partial chirp being identifiable by observing an identifiable change of frequency of a received signal over at least a portion of a time period, the apparatus further configured to associate an identified received partial chirp with a transmitted chirp in order to provide for determining information being communicated using a structure, such a transmitted chirp having the identifiable change of frequency varying over the time period and being associated with particular information being communicated using a structure.
32. Apparatus for communicating information using a structure, the apparatus configured to provide a transmitted chirp having an identifiable change of frequency varying over a time period and associated with particular information to be communicated using a structure, such a transmitted chirp for communication using a structure and for subsequent identification as a received partial chirp in a received signal, such a received partial chirp being associatable with a transmitted chirp by observing the change in frequency of a received signal over at least a portion of the time period in order to determine the information to be communicated.
33. Apparatus for communicating information using a structure, the apparatus comprising: a transmitter configured to transmit a transmitted chirp using a structure, the apparatus configured to provide a transmitted chirp having an identifiable change of frequency varying over a time period and associated with particular information to be communicated using a structure, a receiver for receiving a received signal using a structure, the received signal comprising a received partial chirp associated with a transmitted chirp communicated using a structure; wherein the apparatus is configured to identify a received partial chirp in a received signal by observing an identifiable change of frequency of a received signal over at least a portion of a time period, the apparatus further configured to associate an identified received partial chirp with a transmitted chirp in order to provide for communicating particular information using a structure.
34. Apparatus according to any of the claims 31 to 33, wherein the structure has a primary functionality, that primary functionality being structural support and/or passage for a fluid.
35. Apparatus according to any of the claims 31 to 34, wherein the structure is an oil and gas structure, comprising at least one of: a conduit, such as a pipeline; a tubular; a drill string; a casing.
36. Apparatus according to any of the claims 31 to 35, wherein the apparatus comprises a structure.
37. Apparatus according to any of the claims 31 to 36, wherein the apparatus is configured to be one or more of: mountable, demountable, attachable, detachable, fixably attachable, retrofit with a structure.
38. Apparatus according to any of the claims 31 to 37, wherein the apparatus comprises a user interface.
39. A computer program product, provided on a computer readable medium, the computer program product configured to provide the method according any of the claims 1 to 30.
40. Apparatus substantially as described herein with reference to the figures.
41. Methods substantially as described herein with reference to the figures.