Detection of solids accumulation in conduit using thermochromic material

Abstract

A system includes a conduit configured to transport fluid between a first location and a second location, and a thermochromic indicator disposed on an outer surface of the conduit. The thermochromic indicator covers at least a portion of the conduit. A color of the thermochromic indicator depends on a temperature of the outer surface of the conduit, and the temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator.

Description

DETECTION OF SOLIDS ACCUMULATION IN CONDUIT USING THERMOCHROMIC MATERIALFIELD OF THE INVENTION

[0001] The present disclosure is directed generally to methods and devices for detecting material deposition in conduits, and more particularly, to the use of thermochromic materials for monitoring and detecting the extent of material deposition inside conduits.BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] In the activity of transporting produced oil and gas via a pipeline, deposits may accumulate on the internal surfaces of the pipeline. Over time, the deposition of materials (e.g., wax, gel, sand, inorganic scale, asphaltene, and / or hydrate) may hinder flow or completely block the flow path through the pipeline. In addition, solids accumulation can result in corrosion at the pipe interface, risk of under-deposit corrosion and / or microbiologically induced corrosion. Deposits may develop over a short period (e.g., unintended production of sand could impact production within hours) or over a longer period (e.g., the impact of gradual wax deposition may be undetectable for months). Early identification and mitigation of the accumulation of wax (or solids) improves production and ensures pipeline integrity.

[0004] Monitoring the internal state of the pipeline involves the measurement of key parameters (e.g., pressures, temperatures, flow rates) and observing the progression of measured values in time. Monitoring is performed to identify conditions that may hinder production. Detection involves determining the location of a deposit that is hindering production or detecting early solids deposition that can result in localized corrosion as mentioned above.

[0005] Few methods exist for monitoring and detecting the extent of deposition within offshore oil and gas production lines. Of the conventional methods of interrogating the internal state of a pipeline, pigging operations are the most used method for purging, cleaning, and inspectingpipelines. In a typical pigging operation, a physical device is placed within the pipe of interest. The mechanical device is designed to maintain a seal with the pipe wall and is forced through the pipe by a difference in fluid pressure. Unfortunately, in pigging operations, mechanical devices can stop moving or become stuck in the pipeline. Stopped or stuck devices will block the flow path and must be removed from the pipeline before flow may resume.

[0006] Alternatively, external devices may be used to detect the internal state of the pipeline. For example, computed tomographic (CT) imaging has been used to detect deposits in pipelines in cases where the density differences between deposit and surrounding materials (e.g., various phases of fluid or pipe wall) are significant enough to enable the detection of these differences in pipeline. However, CT devices are normally transported to a location where deposition is suspected, and images of pipeline cross-sections are created by moving the CT device from one location to another. This is a time intensive and costly process.SUMMARY

[0007] In accordance with an aspect of the present disclosure, a system includes: a conduit configured to transport fluid between a first location and a second location; and a thermochromic indicator disposed on an outer surface of the conduit, wherein the thermochromic indicator covers at least a portion of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit, and wherein the temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator.

[0008] In accordance with another aspect of the present disclosure, a deposition detection device configured to be installed on a conduit includes: a thermochromic indicator configured to be disposed on an outer surface of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit; and a conduit attachment structure coupled to the thermochromic indicator and configured to position and maintain the thermochromic indicator on the outer surface of the conduit such that the thermochromic indicator is thermally coupled with the outer surface of the conduit and is visible from outside the deposition detection device

[0009] In accordance with another aspect of the present disclosure, a method includes: disposing a thermochromic indicator on an outer surface of the conduit configured to transport fluid between a first location and a second location, wherein the thermochromic indicatorcovers at least a portion of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit, and wherein the temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator; and inspecting visually the color of the thermochromic indicator to estimate an amount of material deposition in the conduit.BRIEF DESCRIPTION OF DRAWINGS

[0010] The drawings illustrate only example embodiments and are therefore not to be considered limiting in scope, as the example embodiments may admit to other equally effective embodiments. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or positions may be exaggerated to help visually convey such principles. In the drawings, reference numerals designate like or corresponding, but not necessarily identical, elements.

[0011] FIG. 1 is a schematic top view of an example system in which deposition detection devices are installed along a subsea conduit, in accordance with an embodiment of the present disclosure.

[0012] FIG. 2 is a plot illustrating temperature vs. thickness through various layers separating production fluid from subsea ambient fluid, in accordance with an embodiment of the present disclosure.

[0013] FIG. 3 is a schematic side view of an example system in which deposition detection devices are installed along a conduit, in accordance with an embodiment of the present disclosure.

[0014] FIG. 4 is a schematic cross-sectional view of an example system having a deposition detection device in the form of a clamp, in accordance with an embodiment of the present disclosure.

[0015] FIG. 5 is a schematic side view of an example system in which deposition detection devices are installed along a conduit, in accordance with an embodiment of the present disclosure.

[0016] FIG. 6 is a schematic cross-sectional view of an example system having a multi-piece deposition detection device surrounding a conduit, in accordance with an embodiment of the present disclosure.

[0017] FIG. 7 is a perspective view of an example arrangement of housing pieces for use in the multi-piece deposition detection device of FIG. 6, in accordance with an embodiment of the present disclosure.

[0018] FIG. 8 is a photograph of an example arrangement of temperature strips positioned in housing pieces for use in the multi-piece deposition detection device of FIG. 6, in accordance with an embodiment of the present disclosure.

[0019] FIG. 9 is a schematic side view of an example system in which deposition detection devices are installed along a conduit, in accordance with an embodiment of the present disclosure.

[0020] FIG. 10 is a schematic cross-sectional view of an example system having a deposition detection device in the form of a clamp, in accordance with an embodiment of the present disclosure.

[0021] FIG. 11 is a schematic cross-sectional view of a conduit surrounded by a thermochromic indicator, in accordance with an embodiment of the present disclosure.

[0022] FIG. 12 is a schematic side view of an example system in which thermochromic paint is disposed along a conduit, in accordance with an embodiment of the present disclosure.

[0023] FIG. 13 is a schematic side view of an example system in which thermochromic filament components are installed along a conduit, in accordance with an embodiment of the present disclosure.

[0024] FIG. 14 is a photograph showing an example cylindrical thermochromic filament being tested for use as a deposition detection device, in accordance with an embodiment of the present disclosure.

[0025] FIG. 15 is a schematic side view of an example system in which thermochromic filament components are installed along a conduit, in accordance with an embodiment of the present disclosure.

[0026] FIGS. 16A and 16B are photographs showing an example cone-shaped thermochromic filament being tested for use as a deposition detection device, in accordance with an embodiment of the present disclosure.

[0027] FIG. 17 is a process flow diagram illustrating an example method of detecting material deposition within a conduit, in accordance with an embodiment of the present disclosure.DETAILED DESCRIPTION OF THE INVENTION

[0028] The example embodiments discussed herein are directed to systems, apparatus, and methods related to monitoring and detecting depositions (e.g., wax or other materials) insideconduits (e.g., pipelines). In particular, the disclosed systems, apparatus, and methods provide a low-cost method of detecting wax or other material deposition using thermochromic material placed external to a conduit. The thermochromic material is visible from outside of the conduit, and a visual recording of the thermochromic material (e.g., taken by an ROV, AUV, or other recording device) may be analyzed to monitor and detect the internal state of the conduit. In some instances, the thermochromic material may be visually inspected directly by a person viewing the thermochromic material. The disclosed systems, apparatus, and methods enable both monitoring (i.e., observing the progression of deposition) and detection (i.e., determining the location of a deposit) of the internal state of the conduit.

[0029] The accumulation of wax or other solids inside a conduit (e.g., a pipeline or jumper) can be detected by monitoring temperature on the external surface of the conduit. The fluid being transported inside the conduit typically exhibits significantly higher temperatures compared to the surrounding seawater or ambient air. This temperature differential is particularly pronounced in deepwater applications, where the seawater temperature remains relatively constant near the pipeline or jumper. Additionally, the accumulation of solids, such as wax, acts as an insulator and affects the surface temperature of the conduit.

[0030] The present disclosure relates to making the surface temperature of the conduit visible to a recording device or a person by leveraging thermochromic materials. This visibility allows for the identification of solids accumulation inside the conduit. The term “thermochromic” refers to the property of substances to change color due to a change in temperature. This phenomenon is known as thermochromism. Thermochromic materials have previously been used in precision applications, where the color change needs to be accurately defined.

[0031] The terms “conduit,” “pipeline” and “pipe” are used herein interchangeably and may refer to a pipeline. The “conduit” is configured to communicate fluids (e.g., production fluid) from a first location to a second location. The disclosed systems and methods may be applied to subsea conduits located and / or configured to be positioned subsea, or land-based conduits located and / or configured to be positioned on land. A “subsea conduit” may refer to a subsea pipeline or a subsea jumper. The term “subsea conduit” refers to any conduit (e.g., pipeline, pipe, or jumper) that is either located subsea or configured to be positioned subsea. The “subsea conduit” is configured to communicate fluids (e.g., production fluid) from a subsea location to another location (e.g., another subsea location or a surface location). While certain parts of the following description may describe the deposition detection device(s) as being used with subsea conduits, it should be noted that the same deposition detection device(s) or similar device(s) may be used similarly with land-based conduits.

[0032] Turning now to the drawings, FIG. 1 is a top view (i.e., viewed from an overhead perspective) of a system in which at least one thermochromic indicator 100 is disposed on a conduit 102. In the embodiment illustrated in FIG. 1, the conduit 102 is a subsea conduit. However, as mentioned above, the thermochromic indicator(s) 100 may be similarly installed on a conduit located on land, rather than subsea. In a subsea context, the conduit 102 may include a subsea pipeline, a subsea jumper, or a combination thereof. In a subsea context, the conduit 102 may be located on the seabed or above the seabed. Three thermochromic indicators 100 are installed on the system shown. The system illustrated further includes a pipeline end termination (PLET) 104. Each thermochromic indicator 100 is attached to the outer surface of a conduit wall 106, as shown.

[0033] The thermochromic indicators 100 may each use thermochromic material to provide an indication of the amount of material deposition inside the conduit 102 at the location of the detection device. Each thermochromic indicator 100 is disposed on an outer surface of the conduit 102 and covers at least a portion of the conduit 102. A color of the thermochromic indicator 100 depends on a temperature of the outer surface of the conduit 102. The temperature of the outer surface of the conduit 102 depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator 100. The thermochromic indicator 100 (which may include a thermochromic liquid crystal, thermochromic paint, and / or thermochromic filament) may provide a visual indication of the temperature at the outer surface of the conduit 102, as the color of the thermochromic indicator 100 may be indicative of the temperature at the external conduit wall 106. In some embodiments, the color of the thermochromic indicator 100 may be a first color if the temperature of the conduit 102 at the location of the thermochromic indicator 100 is below a threshold temperature, and the color of the thermochromic indicator 100 may be a second color that is different from the first color if the temperature of the conduit 102 at the location of the thermochromic indicator 100 is above the threshold temperature.

[0034] In one embodiment, the color of the thermochromic indicator 100 can be detected by a passing remotely operated vehicle (ROV) 110 or autonomous underwater vehicle (AUV), though other embodiments could enable detection by other external devices. For example, the color of the thermochromic indicator 100 could be detected by a stationary, permanently installed subsea receiver 112. The ROV 110, AUV, and / or receiver 112 may be equipped with a camera to detect the color of the thermochromic indicator(s) 100. The color of the thermochromic indicator 100 at a certain location serves as an indication of the temperature at the outer wall 106 of the conduit 102. A passing ROV 110, passing AUV, or stationary receiver112 may record the wavelength of visible color of the thermochromic indicator 100 on the outside of the conduit 102, and an analysis may be performed based on the recorded wavelength to determine the local temperature at the measured conduit wall location.

[0035] The heat flow through the thermochromic indicator 100 may be impacted by an internal deposit layer (e.g., wax or scale deposit inside the conduit 102). Deposits will hinder the heat flow due to their insulating properties, and the hindered heat flow would thereby reduce the available heat flow to the thermochromic indicator 100. A passing ROV 110, passing AUV, or stationary receiver 112 would detect the color(s) of the thermochromic indicator 100, and thereby, changes in heat flow may be monitored over time and over a span of locations (e.g., circumferential and / or axial locations) along the conduit 102 to detect the extent of deposition in the conduit 102 or an indication of deposit absence or presence. Further, this method may be used to measure deposit characteristics (e.g., position in axial direction, position in circumferential direction, relative shape of deposit, estimated thickness of deposit, etc.). The measurements may enable quantitative or qualitative analysis of deposit characteristics.

[0036] A single thermochromic indicator 100 or multiple thermochromic indicators 100 may be placed on a conduit wall 106. The thermochromic indicator(s) 100 may be placed at different axial locations along the conduit 102 in a manner to enable axial detection of a deposit, as shown in FIG. 1. Additionally, or alternatively, the thermochromic indicator(s) 100 may be placed at different circumferential locations along the pipeline 102 in a manner to enable circumferential detection of a deposit. Multiple thermochromic indicators 100 may be combined as part of a single deposition detection device without departing from the scope of the present disclosure. A color change of the thermochromic indicator 100 may be detected by a passing device (e.g., a detector placed on an ROV 110 or AUV) or to a permanently installed receiver 112. A change in color of the thermochromic indicator 100 from an expected color at a single position can be translated to a relative thickness of deposit at that position. The expected wavelength value may be obtained from an analysis of historical data, simulation, or analogs.

[0037] While the seawater temperature remains somewhat constant in deepwater applications, it can be valuable for the ROV 110, AUV, or receiver 112 to also record and monitor the seawater temperature. Existing flow assurance analysis can provide a reasonably accurate estimation of the flow temperature inside the conduit 102. When both the flow temperature and the conduit surface temperature are known, it becomes possible to calculate deposition thickness inside of the conduit 102. This method of collecting and processing generated signals enables the construction of a model for the deposit-effected region of the conduit 102. Thecolor or change in color of the thermochromic indicator(s) 100 is correlated to deposit characteristics.

[0038] In some embodiments, the thermochromic indicator(s) 100 may be standalone components that are coupled to the outer surface of the conduit 102. In other embodiments, one or more thermochromic indicators 100 may be incorporated into a deposition detection device that is configured to be installed on the conduit 102. The deposition detection device may include a conduit attachment structure coupled to the thermochromic indicator 100 and configured to position and maintain the thermochromic indicator 100 on the outer surface of the conduit 102 such that the thermochromic indicator 100 is thermally coupled with the outer surface of the conduit 102 and is visible from outside the deposition detection device. Examples of such deposition detection devices will be provided in greater detail below. Such deposition detection device(s) can be installed temporarily or permanently on the conduit 102, and methods of installation may enable the deposition detection device(s) to be placed circumferentially, placed axially, and / or incorporated into a clamp.

[0039] The thermochromic indicator(s) 100 may be positioned at certain predetermined locations along the conduit 102. These locations may include locations along conduits where low liquid velocities are expected thus solids (e.g., sand, wax, scale, etc.) can accumulate at the bottom of the conduit. For example, for given sand characteristics (e.g., particle size, concentration), it is possible to estimate the critical velocity for sand transport. If predicted velocities are below that critical velocity, then sand will start accumulating and creating a sand bed which will grow until reaching equilibrium. Similar analysis can be performed for other flow assurance risks, such as scale, wax to determine locations prone to those solids deposition.

[0040] Importance of Clear Layer on Thermochromic Materials in Subsea Applications

[0041] Given that the rate of conduction heat transfer in water is greater than the rate of convection heat transfer in air and considering that deepwater temperatures are significantly lower than air temperatures, a clear layer should be used over the thermochromic material when used in subsea applications. This clear layer helps regulate the surface temperature of the thermochromic material, ensuring it remains within a desired thermochromic color range. The thickness of the thermochromic material and thickness of the clear layer should be optimized according to thermochromic color range as well as the minimum and maximum temperature range expected for the subsea application.

[0042] FIG. 2 shows an example of the temperature change with respect to thickness of different layers of a system (e.g., the system shown in FIG. 1) including a thermochromic indicator (e.g., 100) disposed over a conduit (e.g., 102). The system includes a coating of clearmaterial disposed over the thermochromic indicator. The thermochromic indicator is visible through the clear coating. The coating may provide thermal insulation between the seawater or ambient air surrounding the conduit and the thermochromic indicator so that the thermochromic indicator can retain enough heat for an accurate detection of temperature changes due to deposits inside the conduit. The plot in FIG. 2 illustrates a temperature reduction 200 from production temperature 202 at a location inside the conduit, across a subsea conduit wall thickness 204, a thermochromic material thickness 206, and a clear layer thickness 208 to seawater temperature 210 at a location outside the conduit. The thermochromic material thickness 206 and the clear layer thickness 208 may be tailored to maintain an expected temperature along the thermochromic indicator to be within the thermochromic sensitive range of the indicator. The thickness of any material deposit (e.g., wax) inside the subsea conduit will change the temperature shown visually via the thermochromic indicator.

[0043] One or more thermochromic indicators may be chosen with one or more specific thermochromic sensitive ranges to be targeted based on the location(s) where the thermochromic indicator(s) are to be positioned along a conduit (e.g., near a subsea manifold vs. 10 km away from the subsea manifold), as well as the expected production and / or ambient temperatures (202, 210) of the application. For example, in subsea applications, the seawater temperature 210 may be less than 5 degrees Celsius, less than 25 degrees Celsius, less than 20 degrees Celsius, less than 15 degrees Celsius, or less than 10 degrees Celsius. In some embodiments, the production temperature 202 may be greater than 150 degrees Fahrenheit, greater than 175 degrees Fahrenheit, or greater than 200 degrees Fahrenheit.

[0044] There are several forms of thermochromic materials that may be used for the disclosed thermochromic indicator to detect conduit surface temperature including, but not limited to, thermochromic liquid crystal, thermochromic paint, and thermochromic filament (to construct a 3D surface layer). Examples of each of these types of thermochromic indicators are described below with reference to FIGS. 3-16B.

[0045] Thermochromic liquid crystal strips

[0046] Thermochromic liquid crystal strips are materials that may change color in response to temperature variations. These strips contain liquid crystals that exhibit a total color spectrum response when the temperature changes. The crystals are dispersed within a polymer matrix, and as the temperature shifts, the molecular structure of the liquid crystals changes, resulting in a visible color change. These sheets are highly sensitive to temperature and have previously been used for applications such as thermal mapping, detecting insulation voids, and locating electrical shorts on circuit boards. Thermochromic liquid crystal strips are durable and can becut to size, making them versatile for different testing and evaluation purposes. In practical applications, thermochromic liquid crystal strips are often used in precision settings where accurate temperature readings are crucial. Thermochromic liquid crystal strips can be attached or adhered on to the surface of a conduit to provide a color-change based indication of internal solids accumulation within the producing conduit via temperature visualization. Although thermochromic liquid crystal strips can be used underwater, an additional clear layer may be applied to the strips to regulate the heat flux experienced by the thermochromic material to be within the thermochromic sensitive range. Examples of thermochromic indicators using thermochromic liquid crystal strips are described below with reference to FIGS. 3-7.

[0047] As shown in FIG. 3, the thermochromic indicator used for detecting solids accumulation in a conduit 102 may include a temperature strip 300 of one or more thermochromic materials. This temperature strip 300 may be a thermochromic liquid crystal strip. The temperature strip 300 may be attached to the conduit 102 on the outer surface 106 of the conduit 102, thereby covering a portion of the conduit 102. The temperature strip 300 may be attached to the conduit 102 magnetically or using an adhesive. The temperature of the conduit 102 at a particular location on the outside of the conduit 102 may depend on whether the conduit 102 contains accumulated solids at a corresponding inside location of the conduit 102 that is at least partially aligned with the particular location of the conduit 102. For example, the temperature of the conduit 102 at the location of the temperature strip 300 on the outer surface 106 of the conduit 102 may depend on whether the conduit 102 contains solids at an inside location of the conduit 102 that is at least partially aligned with the location of the temperature strip 300 on the outside of the conduit 102. The color(s) of the temperature strip 300 may depend on the temperature of the conduit 102 at the location of the temperature strip 300 on the conduit 102.

[0048] Different portions of the temperature strip 300 that are in contact with different areas of the conduit 102 having different temperatures may have different colors. For example, the temperature strip 300 may include a thermochromic material, such as a liquid crystal material, which can be formulated to have different colors corresponding to different ranges of temperatures. The temperature strip 300, entirely or a portion thereof, may have a first color (e.g., black or alternatively red) when being exposed to a temperature below a threshold temperature or in a particular range below the threshold temperature. The temperature strip 300, entirely or a portion thereof, may have a second color (e.g., red or alternatively black) when being exposed to a temperature above the threshold temperature or in a particular range above the threshold temperature. For example, a portion of the temperature strip 300 that isaligned with the location of material deposition inside the conduit 102 may have a first color (e.g., a dark color or alternatively a light color) and another portion of the temperature strip 300 that is not aligned with the location of material deposition inside the conduit 102 may have a second color (e.g., a light color or alternatively a dark color). To be clear, a first color of the temperature strip 300 or a portion thereof that is relatively lighter or darker color may be used to indicate a temperature of the conduit 102 that is below the threshold temperature, and a second color that is different from the first color and that is a relatively lighter or darker color may be used to indicate a temperature of the conduit 102 that is above the threshold temperature.

[0049] In some embodiments, the same temperature strip 300 may include multiple different thermochromic materials, such as thermochromic liquid crystal materials, which can be formulated to have colors that change at temperatures corresponding to different temperature ranges. For example, a single temperature strip 300 may include one thermochromic liquid crystal material formulated to change colors when the temperature at its location crosses a first temperature threshold, and another thermochromic liquid crystal material formulated to change colors when the temperature at its location crosses a second temperature threshold different than the first temperature threshold. A single temperature strip 300 may include multiple liquid crystal materials that change colors over a range of threshold temperatures.

[0050] By using the temperature strip 122, which is made from one or more thermochromic materials, the presence and amount of the deposition within the conduit 102 can be visually and non-invasively estimated. For example, by estimating the amount of the solid deposition in the conduit 102, maintenance operations such as removing at least a portion of the solid deposition may be performed before the deposition restricts the flow of fluid through the conduit 102. Also, unnecessary disruptions of normal operations of the conduit 102 may be avoided if the level of the deposition is estimated to be low.

[0051] In some embodiments, one or more temperature strips 300 may be coupled to the outer surface 106 of the conduit 102 as shown, for example, in FIGS. 3, 5, and 9. In some embodiments (e.g., as shown in FIGS. 3, 5, and 9), one or more arrays 302A, 302B of multiple temperature strips 300 may be coupled to the outer surface 106 of the conduit 102 at one or more longitudinal locations along the conduit 102. In some embodiments (e.g., as shown in FIGS. 3 and 5), an array 302A / B of temperature strips 300 may be coupled to the outer surface 106 of the conduit 102, each temperature strip 300 having multiple liquid crystal components 306 that are aligned with each other in a linear direction, this linear direction being parallel to a longitudinal axis of the conduit 102. In such cases, the array 302A / B of temperature strips300 are themselves arranged / spaced from each other circumferentially around the circumference of the conduit 102. In other embodiments (e.g., as shown in FIG. 9), an array 302A / B of temperature strips 300 may be coupled to the outer surface 106 of the conduit 102, each temperature strip 300 having multiple liquid crystal components 306 that are aligned with each other in a circumferential direction around the circumference of the conduit 102. In such cases, the array 302A / B of temperature strips 300 are themselves arranged / spaced from each other longitudinally along the length of the conduit 102. As described above, the multiple liquid crystal components 306 of any given temperature strip 300 may have the same or a different temperature detection range than the other liquid crystal components 306 of the same temperature strip 300.

[0052] As illustrated in FIGS. 3-6, one or more thermochromic indicators (e.g., in the form of multiple temperature strips 300) may be positioned circumferentially around the outer surface 106 of the conduit 102 from a vertically lower end of the conduit 102 to a vertically upper end of the conduit 102. As illustrated in FIGS. 9 and 10, one or more thermochromic indicators (e.g., in the form of multiple liquid crystal components 306 of the same temperature strip 300) may be positioned circumferentially around the outer surface 106 of the conduit 102 from a vertically lower end of the conduit 102 to a vertically upper end of the conduit 102. In either case, this circumferential arrangement provides temperature readings indicative of the temperature of the outer surface 106 of the conduit 102 at multiple circumferential positions around the conduit 102.

[0053] In some embodiments, one or more thermochromic indicators (in the form of temperature strips 300) may form part of a deposition detection device 308 configured to be installed on a conduit 102. The deposition detection device 308 also includes a conduit attachment structure 310 coupled to the thermochromic indicator(s) and configured to position and maintain the thermochromic indicator(s) on the outer surface 106 of the conduit 102 such that the thermochromic indicator(s) are thermally coupled with the outer surface 106 of the conduit 102 while being visible from outside the deposition detection device 308. As discussed above, when used for subsea applications, the deposition detection device 308 may include a clear coating or layer disposed over the thermochromic indicator(s) to enable visibility of the indicator(s) while providing desired temperature insulation from the ambient environment. The clear coating or layer may be incorporated into the conduit attachment structure 310 of the deposition detection device 308. FIGS. 3-10 illustrate multiple different types and arrangements of example deposition detection devices 308. It should be noted that in other embodiments thermochromic indicators (in the form of temperature strips 300) may beindividually coupled to the outer surface 106 of the conduit 102 via adhesive or magnetically without departing from the scope of the present disclosure.

[0054] FIG. 3 shows two deposition detection devices 308 installed on the conduit 102. Each deposition detection device 308 includes thermochromic indicators (in the form of temperature strips 300) disposed on the outer surface 106 of the conduit 102. In the embodiment of FIG. 3, each deposition detection device 308 also includes a conduit attachment structure 310 in the form of a housing 312, with the temperature strips 300 embedded in the housing 312. In some embodiments, the housing 312 may be made from epoxy or another visibly transparent material. In other embodiments, the housing 312 may include a first housing material that is not transparent and that has multiple windows formed therein, where each temperature strip 300 is embedded in epoxy or another clear material in the window. This is similar to the embodiments shown in FIGS. 7 and 8, except that the housing 312 is a continuous housing in FIG. 3, rather than multiple discrete housings. The embodiment of FIG. 9 has a similar structure to that described above with reference to FIG. 3, except that the temperature strips 300 extend along the conduit 102 circumferentially instead of longitudinally.

[0055] In some embodiments, as shown in FIG. 4, the conduit attachment structure 310 may include a clamp (e.g., formed by the clear housing 312 extending partially around the circumference of the conduit 102). In some embodiments, the clamp may include multiple clear housings 312 that each extend partially around the circumference of the conduit 102 and that are rotatably connected to each other to allow for tightening of the clamp around the outer surface 106 of a conduit 102 of any desired size. As illustrated in FIG. 4, the deposition detection device 308 may include an ROV / AUV engagement feature 400 coupled to the conduit attachment structure 310 to aid in the placement of the deposition detection device 308 around the conduit 102 and / or securing the clamp to the conduit 102. The deposition detection device 308 of FIG. 4 may be removably attached to the conduit 102 via the ROV / AUV engagement feature 400. In FIG. 4, the ROV / AUV engagement features 400 are handles. In other embodiments, the ROV / AUV engagement feature 400 may include a rotatable pin configured to tighten the clamp around the conduit 102. The embodiment of FIG. 10 has a similar structure to that described above with reference to FIG. 4, except that the temperature strips 300 extend along the conduit 102 circumferentially instead of longitudinally.

[0056] As illustrated in FIG. 4 (and similarly in FIG. 10), each of the temperature strips 300 may be disposed directly against (or nearly directly against) the outer surface 106 of the conduit 102. In some embodiments, the deposition detection device 308 may further include one or more magnets coupled between the housing 312 and the conduit 102 or between thetemperature strips 300 and the conduit 102 to connect the temperature strips 300 to the conduit 102 and / or to conduct temperature to the thermochromic material. In some embodiments, the deposition detection device 308 may further include thermally conductive materials (e.g., thermally conductive bars) coupled between the temperature strips 300 and the conduit 102 to conduct temperature to the thermochromic material.

[0057] FIGS. 5-8 illustrate embodiments of the deposition detection device 308 having multiple housings that are attached to each other to enable positioning of the deposition detection device 308 around any size of conduit 102.

[0058] FIG. 5 shows two deposition detection devices 308 installed on the conduit 102. FIG. 6 illustrates a cross-sectional view of one of the deposition detection devices 308 of FIG. 5 installed on the conduit 102. Each deposition detection device 308 includes thermochromic indicators (in the form of temperature strips 300) disposed on the outer surface 106 of the conduit 102. FIG. 5 shows two deposition detection devices 308 installed on the conduit 102. In the embodiment of FIG. 5, each deposition detection device 308 also includes a conduit attachment structure 310 in the form of multiple housings 500, with each temperature strip 300 embedded in one of the housings 500. As illustrated, the housings 500 may be connected end to end and configured to be wrapped around the conduit 102. In some embodiments, the housings 500 may be made from epoxy or another visibly transparent material. In other embodiments, each housing 500 may include a first housing material that is not transparent and that has a window formed therein, where each temperature strip 300 is embedded in epoxy or another clear material in the window. An example of this layout is shown in FIGS. 7 and 8.

[0059] As illustrated in FIG. 6, each of the temperature strips 300 may be disposed directly against (or nearly directly against) the outer surface 106 of the conduit 102. In some embodiments, the deposition detection device 308 may further include one or more magnets coupled between the housings 500 and the conduit 102 or between the temperature strips 300 and the conduit 102 to connect the temperature strips 300 to the conduit 102 and / or to conduct temperature to the thermochromic material. In some embodiments, the deposition detection device 308 may further include thermally conductive materials (e.g., thermally conductive bars) coupled between the temperature strips 300 and the conduit 102 to conduct temperature to the thermochromic material.

[0060] FIGS. 7 and 8 illustrate example housings 700 and 800 that may be used for the housings (e.g., 500) in the system layout described above with reference to FIGS. 5 and 6. In FIG. 7, each housing 700 may be constructed of epoxy or another clear material. Each housing 700 may include an indentation 702 formed therein to receive a temperature strip (not shown).Although not shown, a temperature strip may be positioned in the indentation 702 and coupled to the housing 700 via adhesive. In addition, each housing 700 may include two passageways 704 drilled therethrough at opposing ends of the housing 700. The passageways 704 are configured to receive pins therethrough for connecting the housing 700 to other housings 700. Adjacent housings 700 may have complementary shaped ends that overlap where the passageways 704 are located so that one pin can be inserted through the passageways 704 of two adjacent housings 700 to rotatably connect the housings 700 end to end.

[0061] In FIG. 8, each housing 800 may be constructed from a first housing material 802 that has a window 804 formed therein. Each window 804 may receive a corresponding temperature strip 300, which is embedded in epoxy 806 inside the window 804 as shown. In addition, each housing 800 may include two passageways drilled therethrough at opposing ends of the housing 800. The passageways (not visible in FIG. 8) are configured to receive pins 808 therethrough for connecting the housing 800 to other housings 800. Adjacent housings 800 may have complementary shaped ends that overlap where the passageways are located so that one pin 808 can be inserted through the passageways of two adjacent housings 800 to rotatably connect the housings 800 end to end.

[0062] The configuration of multiple housings connected end to end described above with reference to FIGS. 5-8 may be beneficial since it provides a deposition detection device 308 that is easily configurable to conduits of different diameters. Fewer housings and temperature strips may be connected end to end to wrap around smaller diameter conduits, while a greater number of housings and temperature strips may be connected end to end to wrap around larger diameter conduits.

[0063] FIG. 11 is a schematic diagram illustrating certain components of a system including a thermochromic indicator 100 disposed on an outer surface 106 of a conduit 102 (e.g., a subsea conduit). As illustrated, the thermochromic indicator 100 may be disposed around the conduit 102. The thermochromic indicator 100 may be disposed partially around or entirely around (as shown) the conduit 102. In some embodiments, the system may include an additional clear layer 1102 disposed around the thermochromic indicator 100. The layout shown in the cross section of FIG. 11 can be used when the thermochromic indicator includes thermochromic paint (1100) or thermochromic filament (1300), as described below with further reference to FIGS. 12-16B.

[0064] Thermochromic paint

[0065] Thermochromic paint, also known as heat-sensitive paint, contains pigments that change color based on temperature variations. These pigments can be either leuco dyes orthermochromic liquid crystals. When the temperature changes, the molecular structure of these pigments alters, resulting in a visible color change. Thermochromic paint has previously been used in applications such as art projects, home decor, and scientific experiments. The paint can be customized to respond to specific temperature ranges, making it versatile for different uses.

[0066] As shown in FIG. 11, the thermochromic indicator may include a thermochromic paint 1100 that covers at least a portion of the conduit 102. The thermochromic paint 1100 can be applied on to the surface of the conduit 102 to provide a color-change based indication of internal solids accumulation within the conduit 102 via temperature visualization. Although thermochromic paint can be used underwater, an additional clear layer 1102 may be applied adjacent the thermochromic paint 1100 to regulate the heat flux experienced by the thermochromic paint to be within the thermochromic sensitive range, as shown in FIG. 11.

[0067] The temperature of the conduit 102 at the location of the thermochromic paint 1100 on the outer surface 106 of the conduit 102 may depend on whether the conduit 102 contains solids at an inside location of the conduit 102 that is at least partially aligned with the location of the thermochromic paint 1100 on the outside of the conduit 102. The color(s) of the thermochromic paint 1100 may depend on the temperature of the conduit 102 at the location of the thermochromic paint 1100 on the conduit 102.

[0068] Different portions of the thermochromic paint 1100 that are in contact with different areas of the conduit 102 having different temperatures may have different colors. For example, the thermochromic paint 1100 can be formulated to have different colors corresponding to different ranges of temperatures. The thermochromic paint 1100, entirely or a portion thereof, may have a first color (e.g., black or alternatively red) when being exposed to a temperature below a threshold temperature or in a particular range below the threshold temperature. The thermochromic paint 1100, entirely or a portion thereof, may have a second color (e.g., red or alternatively black) when being exposed to a temperature above the threshold temperature or in a particular range above the threshold temperature. For example, a portion of the thermochromic paint 1100 that is aligned with the location of material deposition inside the conduit 102 may have a first color (e.g., a dark color or alternatively a light color) and another portion of the thermochromic paint 1100 that is not aligned with the location of material deposition inside the conduit 102, or that is aligned with a location of a different relative amount of material deposition inside the conduit 102, may have a second color (e.g., a light color or alternatively a dark color). To be clear, a first color of the thermochromic paint 1100 or a portion thereof that is relatively lighter or darker color may be used to indicate a temperature of the conduit 102 that is below the threshold temperature, and a second color thatis different from the first color and that is a relatively lighter or darker color may be used to indicate a temperature of the conduit 102 that is above the threshold temperature.

[0069] By using the thermochromic paint 1100, which is made from a thermochromic material, the presence and amount of the deposition within the conduit 102 can be visually and non- invasively estimated. For example, by estimating the amount of the solid deposition in the conduit 102, maintenance operations such as removing at least a portion of the solid deposition may be performed before the deposition restricts the flow of fluid through the conduit 102. Also, unnecessary disruptions of normal operations of the conduit 102 may be avoided if the level of the deposition is estimated to be low.

[0070] In some embodiments, one or more thermochromic paints 1100 may be applied to the outer surface 106 of the conduit 102. As shown in FIG. 12, for example, one or more arrays 1200A, 1200B of multiple thermochromic paints 1100 may disposed on the outer surface 106 of the conduit 102 at one or more longitudinal locations along the conduit 102. In some embodiments, an array 1200A / B of thermochromic paints 1100 may be disposed on the outer surface 106 of the conduit 102, each thermochromic paint 1100 being applied as a strip in a circumferential direction around the circumference of the conduit 102. In such cases, the array 1200A / B of thermochromic paints 1100 are themselves arranged / spaced from each other longitudinally along the length of the conduit 102.

[0071] The thermochromic material of any given strip of thermochromic paint 1100 in the array 1200A / B may have the same or a different temperature detection range than one or more of the other strips of thermochromic paint 1100 in the same array 1200A / B. For example, an array 1200A / B of thermochromic paints 1100 may include a first thermochromic paint 1100 A as one paint strip and a second thermochromic paint 1100B as another paint strip. The second thermochromic paint 1100B covers a portion of the conduit 102 adjacent to the portion of the conduit 102 covered by the first thermochromic paint 1100 A. The second thermochromic paint 1100B has a different composition of its thermochromic material than the first thermochromic paint 1100 A. As such, the different rings of thermochromic paint 1100 may be able to detect different temperatures of the outer surface 106 of the conduit 102 in the same general area along the length of the conduit 102, thus increasing the temperature range for detection. As the production fluid temperature is expected to be consistent over relatively short distances (e.g., distances less than 10 feet) along the length of the conduit 102, the multiple rings of thermochromic paint 1100 need not be covering the exact same portion of the conduit 102 to give a reasonable estimate of the temperature in that region of the conduit 102.

[0072] As illustrated in FIGS. 11 and 12, one or more thermochromic indicators (e.g., in the form of thermochromic paint 1100) may be positioned circumferentially around the outer surface 106 of the conduit 102 from a vertically lower end of the conduit 102 to a vertically upper end of the conduit 102. This circumferential arrangement provides temperature readings indicative of the temperature of the outer surface 106 of the conduit 102 at multiple circumferential positions around the conduit 102. Different arrangements of thermochromic paint(s) 1100 (e.g., horizontal strips, etc.) along the conduit 102 may be used without departing from the scope of the present disclosure.

[0073] Another type of thermochromic indicator 100 (i.e., using thermochromic filament 1300) will now be described with reference to FIGS. 11 and 13-16B.

[0074] Thermochromic filament

[0075] Thermochromic filament is a type of 3D printing material that changes color based on temperature variations. This filament is typically made by blending a base polymer, such as polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS), with thermochromic pigments. When the temperature of the printed object changes, the pigments alter their molecular structure, resulting in a visible color change.

[0076] As shown in FIG. 11, the thermochromic indicator 100 may include a thermochromic filament 1300 that covers at least a portion of the conduit 102. The thermochromic filament 1300 may be 3D printed to fit on the outer surface 106 of the conduit 102 to provide a colorchange based indication of internal solids accumulation within the conduit 102 via temperature visualization. Although thermochromic filament can be used underwater, an additional clear layer 1102 may be applied adjacent the thermochromic filament 1300 to regulate the heat flux experienced by the thermochromic filament 1300 to be within the thermochromic sensitive range, as shown in FIG. 11. ABS-based thermochromic filament may be more appropriate for use in subsea applications, since PLA material is biodegradable.

[0077] The temperature of the conduit 102 at the location of the thermochromic filament 1300 on the outer surface 106 of the conduit 102 may depend on whether the conduit 102 contains solids at an inside location of the conduit 102 that is at least partially aligned with the location of the thermochromic filament 1300 on the outside of the conduit 102. The color(s) of the thermochromic filament 1300 may depend on the temperature of the conduit 102 at the location of the thermochromic filament 1300 on the conduit 102.

[0078] Different portions of the thermochromic filament 1300 that are in contact with different areas of the conduit 102 having different temperatures may have different colors. For example, the thermochromic filament 1300 can be formulated to have different colors corresponding todifferent ranges of temperatures. The therm ochromic filament 1300, entirely or a portion thereof, may have a first color (e.g., blue or alternatively white) when being exposed to a temperature below a threshold temperature or in a particular range below the threshold temperature. The thermochromic filament 1300, entirely or a portion thereof, may have a second color (e.g., white or alternatively blue) when being exposed to a temperature above the threshold temperature or in a particular range above the threshold temperature. For example, a portion of the thermochromic filament 1300 that is aligned with the location of material deposition inside the conduit 102 may have a first color (e.g., a dark color or alternatively a light color) and another portion of the thermochromic filament 1300 that is not aligned with the location of material deposition inside the conduit 102, or that is aligned with a location of a different relative amount of material deposition inside the conduit 102, may have a second color (e.g., a light color or alternatively a dark color). To be clear, a first color of the thermochromic filament 1300 or a portion thereof that is a relatively darker or lighter color may be used to indicate a temperature of the conduit 102 that is below the threshold temperature, and a second color that is different from the first color and that is a relatively lighter or darker color may be used to indicate a temperature of the conduit 102 that is above the threshold temperature.

[0079] By using the thermochromic filament 1300, which is made from a thermochromic material, the presence and amount of the deposition within the conduit 102 can be visually and non-invasively estimated. For example, by estimating the amount of the solid deposition in the conduit 102, maintenance operations such as removing at least a portion of the solid deposition may be performed before the deposition restricts the flow of fluid through the conduit 102. Also, unnecessary disruptions of normal operations of the conduit 102 may be avoided if the level of the deposition is estimated to be low.

[0080] As illustrated in FIGS. 11 and 13-16B, one or more thermochromic indicators (e.g., in the form of thermochromic filament components 1300) may be positioned circumferentially around the outer surface 106 of the conduit 102 from a vertically lower end of the conduit 102 to a vertically upper end of the conduit 102. This circumferential arrangement provides temperature readings indicative of the temperature of the outer surface 106 of the conduit 102 at multiple circumferential positions around the conduit 102. Different arrangements of thermochromic filament components 1300 along the conduit 102 may be used without departing from the scope of the present disclosure.

[0081] In some embodiments, one or more components made from thermochromic filament 1300 may be applied to the outer surface 106 of the conduit 102. As shown in FIG. 13, forexample, one or more thermochromic filament components 1300A, 1300B may disposed on the outer surface 106 of the conduit 102 at one or more longitudinal locations along the conduit 102. As illustrated, the thermochromic filament components 1300A / B may be 3D printed around the entire circumference of the conduit 102. As shown in FIG. 13, the thermochromic filament components 1300 may be cylindrical in shape as printed around the conduit 102.

[0082] FIG. 14 is a photograph of a prototype that was used to demonstrate operation of a cylindrical shaped thermochromic filament component 1400 for detection of material deposition inside a conduit. The prototype is an experimental setup where material was deposited in the lower half of a PVC pipe (representing the conduit), and a cylindrical thermochromic filament sleeve 1400 was printed and placed around the PVC pipe. Then, hot water (representing production fluid) was flowed through the interior of the PVC pipe. The thermochromic filament sleeve 1400 is constructed from thermochromic material that has a lighter color at temperatures above a certain temperature threshold and a darker color at temperatures below the temperature threshold. The water flowing through the PVC pipe has a higher temperature than the temperature threshold. As illustrated, the thermochromic filament sleeve 1400 has a lighter color at its upper half, which corresponds to a location in the PVC pipe where no deposition is present. The thermochromic filament sleeve 1400 has a darker color at its lower half, which corresponds to the location in the PVC pipe where deposition is present. As such, the thermochromic filament sleeve 1400 can be used to detect the presence of material deposition within the internal pipe. This is similar to how a cylindrical thermochromic filament component disposed around a conduit would operate. That is, the system may show a temperature change visibly on the outside of the thermochromic filament component in response to different temperatures within the conduit.

[0083] As shown in FIG. 15, in some embodiments, the thermochromic filament 1300 may be disposed on the outer surface 106 of the conduit 102 with a thickness that varies along a length dimension of the conduit 102. As a result, the thermochromic filament component 1300 may be cone-shaped rather than cylindrical. This cone shape of the thermochromic filament component 1300 may enable visualization of a wider range of temperatures from outside the thermochromic filament 1300 than is possible using a cylindrical filament component (e.g., as in FIG. 13). Essentially, a single cone-shaped thermochromic filament component 1300 acts like multiple cylindrical thermochromic filament components each having different thicknesses placed side by side on the conduit 102. When different thicknesses of the thermochromic filament 1300 are applied, even though the filament composition is the same,the thermal insulation available through the filament component 1300 changes such that a thicker portion offers greater insulation than a thinner portion.

[0084] The cone-shaped thermochromic filament components 1300 (e.g., 1300A and 1300B), as shown in FIG. 15, may be beneficial for detecting the shape of material deposits in the conduit 102 when the deposits are not uniform. In such instances, a slope of the color boundary visible on the thermochromic filament 1300 along the length dimension of the conduit 102 may be indicative of the amount and / or shape of material deposition inside the conduit 102. For example, the change in color of the thermochromic filament between a first color of the filament (above a temperature threshold) and a second color of the filament (below the temperature threshold) visible on the outside of the filament component 1300 may have a slope that indicates irregular deposition of material (in a circumferential direction) within the conduit 102.

[0085] FIGS. 16A and 16B are photographs of a prototype that was used to demonstrate operation of a cone-shaped thermochromic filament component for detection of material deposition inside a conduit. The prototype is an experimental setup where material 1602 was deposited in the upper half of a PVC pipe 1604 (representing the conduit) with variable thickness of the deposit along the circumference of the pipe bore (greatest thickness at the top of the pipe). A cone-shaped thermochromic filament component 1600 was printed and placed around the PVC pipe 1604. Then, hot air (representing production fluid) was flowed through the interior of the PVC pipe 1604. The thermochromic filament component 1600 is constructed from thermochromic material that has a lighter color at temperatures above a certain temperature threshold and a darker color at temperatures below the temperature threshold. The air flowing through the PVC pipe 1604 has a higher temperature than the temperature threshold. As illustrated, the thermochromic filament component 1600 has a lighter color at its lower half proximate the end of the cone-shaped filament component 1600 having the smallest thickness. This corresponds to a location in the PVC pipe 1604 where no deposition is present. The thermochromic filament component 1600 has a darker color at its upper half, which corresponds to the location in the PVC pipe 1604 where material deposition 1602 is present. The thermochromic filament component 1600 has a slightly darker color at its lower half proximate the end of the cone-shaped filament component 1600 having the greatest thickness. This is due to the insulating properties of the filament itself at this thicker region. The darker color portion of the filament takes up more of the cone-shaped filament component 1600 as it moves from the smaller thickness end to the larger thickness end. Near the end of the filament component 1600 having the smaller thickness, there is a well-defined slope visible between thedarker color portion of the filament at the top and the lighter color portion of the filament at the bottom. This downward slope indicates a change in thickness of material 1602 deposited in the PVC pipe 1604 in the circumferential direction. If there were no change in thickness of the deposit, the line between darker and lighter portions of the cone-shaped filament component 1600 would be straight, aligned with the length direction of the PVC pipe 1604.

[0086] As such, the thermochromic filament component 1600 can be used to detect the presence of material deposition within the internal pipe 1604 and the relative amount of material 1602 deposited at different circumferential locations along the bore of the pipe. This is similar to how a cone-shaped thermochromic filament component disposed around a conduit would operate. That is, the system may show a temperature change visibly on the outside of the thermochromic filament component in response to different temperatures within the conduit.

[0087] FIG. 17 illustrates a method 1700 for detecting material deposition within a conduit in accordance with presently disclosed embodiments. At block 1702, the method 1700 includes disposing a thermochromic indicator on an outer surface of the conduit configured to transport fluid between a first location and a second location. The thermochromic indicator covers at least a portion of the conduit, and a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit. The temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator. At block 1704, the method 1700 includes inspecting visually the color of the thermochromic indicator to estimate an amount of material deposition in the conduit. The color of the thermochromic indicator may be a first color if the temperature of the conduit at the location of the thermochromic indicator is below a threshold temperature, and the color of the thermochromic indicator may be a second color that is different from the first color if the temperature of the conduit at the location of the thermochromic indicator is above the threshold temperature.

[0088] In some embodiments, the conduit may be a subsea conduit, and inspecting (1704) the color of the thermochromic indicator may include recording an image of the thermochromic indicator using a subsea recorder. The subsea recorder may include an ROV camera, an AUV camera, or a stationary subsea recorder. In some embodiments, inspecting (1704) the color of the thermochromic indicator may include processing the image of the thermochromic indicator via an image processing system to determine an estimated temperature of the outer surface of the conduit.

[0089] Certain illustrative embodiments are described below:

[0090] Embodiment 1 : A system, including: a conduit configured to transport fluid between a first location and a second location; and a therm ochromic indicator disposed on an outer surface of the conduit, wherein the thermochromic indicator covers at least a portion of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit, and wherein the temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator.

[0091] Embodiment 2: The system of Embodiment 1, wherein the color of the thermochromic indicator is a first color if the temperature of the conduit at the location of the thermochromic indicator is below a threshold temperature and wherein the color of the thermochromic indicator is a second color that is different from the first color if the temperature of the conduit at the location of the thermochromic indicator is above the threshold temperature.

[0092] Embodiment 3: The system of Embodiment 1, wherein the conduit is located subsea.

[0093] Embodiment 4: The system of Embodiment 1, further including a coating of clear material disposed over the thermochromic indicator, wherein the thermochromic indicator is visible through the coating.

[0094] Embodiment 5: The system of Embodiment 1, wherein the thermochromic indicator includes a temperature strip of thermochromic material.

[0095] Embodiment 6: The system of Embodiment 5, wherein the thermochromic indicator is attached to the outer surface of the conduit magnetically.

[0096] Embodiment 7: The system of Embodiment 5, wherein the temperature strip is embedded in a housing that is at least partially clear.

[0097] Embodiment 8: The system of Embodiment 7, including: a plurality of housings connected end to end and configured to be wrapped around the conduit, wherein each housing is at least partially clear; and a plurality of thermochromic indicators including temperature strips each embedded in one of the housings.

[0098] Embodiment 9: The system of Embodiment 1, wherein the thermochromic indicator includes a thermochromic paint that covers the portion of the conduit.

[0099] Embodiment 10: The system of Embodiment 9, further including at least a second thermochromic indicator including a second thermochromic paint that covers at least another portion of the conduit adjacent to the portion of the conduit, wherein the second thermochromic paint has a different composition than the thermochromic paint.

[0100] Embodiment 11 : The system of Embodiment 1, wherein the thermochromic indicator includes a thermochromic filament formed on the outer surface of the conduit.

[0101] Embodiment 12: The system of Embodiment 11, wherein the thermochromic filament has a thickness that varies along a length dimension of the conduit.

[0102] Embodiment 13: The system of Embodiment 12, wherein a slope of a change in color of the thermochromic filament along the length dimension of the conduit is indicative of the amount of material deposition inside the conduit.

[0103] Embodiment 14: The system of Embodiment 11, wherein the thermochromic filament includes polylactic acid (PLA).

[0104] Embodiment 15: The system of Embodiment 11, wherein the thermochromic filament includes acrylonitrile butadiene styrene (ABS).

[0105] Embodiment 16: The system of Embodiment 1, wherein one or more thermochromic indicators are positioned circumferentially around the outer surface of the conduit from a vertically lower end of the conduit to a vertically upper end of the conduit.

[0106] Embodiment 17: A deposition detection device configured to be installed on a conduit, the deposition detection device including: a thermochromic indicator configured to be disposed on an outer surface of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit; and a conduit attachment structure coupled to the thermochromic indicator and configured to position and maintain the thermochromic indicator on the outer surface of the conduit such that the thermochromic indicator is thermally coupled with the outer surface of the conduit and is visible from outside the deposition detection device.

[0107] Embodiment 18: The device of Embodiment 17, wherein the color of the thermochromic indicator is a first color if the temperature of the conduit at the location of the thermochromic indicator is below a threshold temperature and wherein the color of the thermochromic indicator is a second color that is different from the first color if the temperature of the conduit at the location of the thermochromic indicator is above the threshold temperature.

[0108] Embodiment 19: The device of Embodiment 17, further including a coating of clear material disposed over the thermochromic indicator, wherein the thermochromic indicator is visible through the coating.

[0109] Embodiment 20: The device of Embodiment 17, wherein the thermochromic indicator includes a temperature strip of thermochromic material.

[0110] Embodiment 21 : The device of Embodiment 20, wherein the thermochromic indicator is attached to the outer surface of the conduit magnetically.

[0111] Embodiment 22: The device of Embodiment 20, wherein the conduit attachment structure includes a housing that is at least partially clear, wherein the temperature strip is embedded in the housing.

[0112] Embodiment 23: The device of Embodiment 22, wherein the conduit attachment structure includes a plurality of housings connected end to end and configured to be wrapped around the conduit, wherein each housing is at least partially clear, and the device including a plurality of thermochromic indicators including temperature strips each embedded in one of the housings.

[0113] Embodiment 24: The device of Embodiment 17, wherein the conduit attachment structure includes a clamp.

[0114] Embodiment 25: The device of Embodiment 17, further including an ROV / AUV engagement feature coupled to the conduit attachment structure.

[0115] Embodiment 26: A method, including: disposing a thermochromic indicator on an outer surface of the conduit configured to transport fluid between a first location and a second location, wherein the thermochromic indicator covers at least a portion of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit, and wherein the temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator; and inspecting visually the color of the thermochromic indicator to estimate an amount of material deposition in the conduit.

[0116] Embodiment 27: The method of Embodiment 26, wherein the conduit is a subsea conduit, and wherein inspecting visually the color of the thermochromic indicator includes recording an image of the thermochromic indicator using a subsea recorder.

[0117] Embodiment 28: The method of Embodiment 27, wherein the subsea recorder includes an ROV camera, an AUV camera, or a stationary subsea recorder.

[0118] Embodiment 29: The method of Embodiment 27, wherein inspecting visually the color of the thermochromic indicator includes processing the image of the thermochromic indicator via an image processing system to determine an estimated temperature of the outer surface of the conduit.

[0119] Embodiment 30: The method of Embodiment 26, wherein the color of the thermochromic indicator is a first color if the temperature of the conduit at the location of the thermochromic indicator is below a threshold temperature and wherein the color of the thermochromic indicator is a second color that is different from the first color if the temperature of the conduit at the location of the thermochromic indicator is above the threshold temperature.

[0120] The use of the terms "about", “approximately”, and similar terms applies to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of ordinary skill in the art would consider as a reasonable amount of deviation to the recited numeric values (i.e., having the equivalent function or result). For example, this term may be construed as including a deviation of ±10 percent of the given numeric value provided such a deviation does not alter the end function or result of the value. Therefore, a value of about 1% may be construed to be a range from 0.9% to 1.1%. Furthermore, a range may be construed to include the start and the end of the range. For example, a range of 10% to 20% (i.e., range of 10%-20%) includes 10% and also includes 20%, and includes percentages in between 10% and 20%, unless explicitly stated otherwise herein. Similarly, a range of between 10% and 20% (i.e., range between 10% - 20%) includes 10% and also includes 20%, and includes percentages in between 10% and 20%, unless explicitly stated otherwise herein.

[0121] It is understood that when combinations, subsets, groups, etc. of elements are disclosed (e.g., combinations of components in a composition, or combinations of steps in a method), that while specific reference of each of the various individual and collective combinations and permutations of these elements may not be explicitly disclosed, each is specifically contemplated and described herein. By way of example, if an item is described herein as including a component of type A, a component of type B, a component of type C, or any combination thereof, it is understood that this phrase describes all of the various individual and collective combinations and permutations of these components. For example, in some embodiments, the item described by this phrase could include only a component of type A. In some embodiments, the item described by this phrase could include only a component of type B. In some embodiments, the item described by this phrase could include only a component of type C. In some embodiments, the item described by this phrase could include a component of type A and a component of type B. In some embodiments, the item described by this phrase could include a component of type A and a component of type C. In some embodiments, the item described by this phrase could include a component of type B and a component of type C. In some embodiments, the item described by this phrase could include a component of type A, a component of type B, and a component of type C. In some embodiments, the item described by this phrase could include two or more components of type A (e.g., Al and A2). In some embodiments, the item described by this phrase could include two or more components of type B (e.g., Bl and B2). In some embodiments, the item described by this phrase could include two or more components of type C (e.g., C 1 and C2). In some embodiments, the item described by this phrase could include two or more of a first component (e.g., two or more componentsof type A (Al and A2)), optionally one or more of a second component (e.g., optionally one or more components of type B), and optionally one or more of a third component (e.g., optionally one or more components of type C). In some embodiments, the item described by this phrase could include two or more of a first component (e.g., two or more components of type B (Bl and B2)), optionally one or more of a second component (e.g., optionally one or more components of type A), and optionally one or more of a third component (e.g., optionally one or more components of type C). In some embodiments, the item described by this phrase could include two or more of a first component (e.g., two or more components of type C (Cl and C2)), optionally one or more of a second component (e.g., optionally one or more components of type A), and optionally one or more of a third component (e.g., optionally one or more components of type B).

[0122] If a component of a figure is described but not expressly shown or labeled in that figure, the label used for a corresponding component in another figure may be inferred to that component. Conversely, if a component in a figure is labeled but not described, the description for such component may be substantially the same as the description for the corresponding component in another figure. For any figure shown and described herein, one or more of the components may be omitted, added, repeated, and / or substituted. Accordingly, embodiments shown in a particular figure should not be considered limited to the specific arrangements of components shown in such figure.

[0123] Further, a statement that a particular embodiment (e.g., as shown in a figure herein) does not have a particular feature or component does not mean, unless expressly stated, that such embodiment is not capable of having such feature or component. For example, for purposes of present or future claims herein, a feature or component that is described as not being included in an example embodiment shown in one or more particular drawings is capable of being included in one or more claims that correspond to such one or more particular drawings herein.

[0124] Terms such as “first”, “second”, “primary,” “secondary,” “above”, “below”, “inner”, “outer”, “distal”, “proximal”, “end”, “top”, “bottom”, “upper”, “lower”, “side”, “left”, “right”, “front”, “rear”, and “within”, when present, are used merely to distinguish one component (or part of a component or state of a component) from another. This list of terms is not exclusive. Such terms are not meant to denote a preference or a particular orientation, and they are not meant to limit embodiments of earth penetrating tools. In the following detailed description of the example embodiments, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skillin the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0125] It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of example embodiments. For example, the functions described above and implemented as the best mode for operating the present invention are for illustration purposes only. Other arrangements and methods may be implemented by those skilled in the art without departing from the scope and spirit of this invention. Moreover, those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

CLAIMSWhat is claimed is:

1. A system, comprising: a conduit configured to transport fluid between a first location and a second location; and a thermochromic indicator disposed on an outer surface of the conduit, wherein the thermochromic indicator covers at least a portion of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit, and wherein the temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator.

2. The system of claim 1, wherein the color of the thermochromic indicator is a first color if the temperature of the container at the location of the thermochromic indicator is below a threshold temperature and wherein the color of the thermochromic indicator is a second color that is different from the first color if the temperature of the container at the location of the thermochromic indicator is above the threshold temperature.

3. The system of claim 1, further comprising a coating of clear material disposed over the thermochromic indicator, wherein the thermochromic indicator is visible through the coating.

4. The system of claim 1, wherein the thermochromic indicator comprises a temperature strip of thermochromic material.

5. The system of claim 4, wherein the thermochromic indicator is attached to the outer surface of the conduit magnetically.

6. The system of claim 4, wherein the temperature strip is embedded in a housing that is at least partially clear.

7. The system of claim 6, comprising:a plurality of housings connected end to end and configured to be wrapped around the conduit, wherein each housing is at least partially clear; and a plurality of thermochromic indicators comprising temperature strips each embedded in one of the housings.

8. The system of claim 1, wherein the thermochromic indicator comprises a thermochromic paint that covers the portion of the conduit.

9. The system of claim 1, wherein the thermochromic indicator comprises a thermochromic filament formed on the outer surface of the conduit.

10. The system of claim 9, wherein the thermochromic filament has a thickness that varies along a length dimension of the conduit.

11. The system of claim 1, wherein one or more thermochromic indicators are positioned circumferentially around the outer surface of the conduit from a vertically lower end of the conduit to a vertically upper end of the conduit.

12. A deposition detection device configured to be installed on a conduit, the deposition detection device comprising: a thermochromic indicator configured to be disposed on an outer surface of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit; and a conduit attachment structure coupled to the thermochromic indicator and configured to position and maintain the thermochromic indicator on the outer surface of the conduit such that the thermochromic indicator is thermally coupled with the outer surface of the conduit and is visible from outside the deposition detection device.

13. The device of claim 12, further comprising a coating of clear material disposed over the thermochromic indicator, wherein the thermochromic indicator is visible through the coating.

14. The device of claim 12, wherein the thermochromic indicator comprises a temperature strip of thermochromic material.

15. The device of claim 14, wherein the thermochromic indicator is attached to the outer surface of the conduit magnetically.

16. The device of claim 14, wherein the conduit attachment structure comprises a housing that is at least partially clear, wherein the temperature strip is embedded in the housing.

17. The device of claim 16, wherein the conduit attachment structure comprises a plurality of housings connected end to end and configured to be wrapped around the conduit, wherein each housing is at least partially clear, and the device comprising a plurality of thermochromic indicators comprising temperature strips each embedded in one of the housings.

18. The device of claim 12, wherein the conduit attachment structure comprises a clamp.

19. A method, comprising: disposing a thermochromic indicator on an outer surface of the conduit configured to transport fluid between a first location and a second location, wherein the thermochromic indicator covers at least a portion of the conduit, wherein a color of the thermochromic indicator depends on a temperature of the outer surface of the conduit, and wherein the temperature of the outer surface of the conduit depends on an amount of material deposition inside the conduit that is at least partially aligned with a location of the thermochromic indicator; and inspecting visually the color of the thermochromic indicator to estimate an amount of material deposition in the conduit.

20. The method of claim 19, wherein the conduit is a subsea conduit, and wherein inspecting visually the color of the thermochromic indicator comprises recording an image of the thermochromic indicator using a subsea recorder.

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