Thermally insulated duct for crude oil outflow
The use of hollow glass microbeads and fumed silica in a thermally insulated duct addresses the challenges of maintaining thermal insulation and durability, enhancing oil outflow speed and reducing costs by preventing heat conduction and paraffin formation.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MRP PARTICIPACOES EIRELI
- Filing Date
- 2025-12-19
- Publication Date
- 2026-07-23
AI Technical Summary
Existing thermally insulated ducts for crude oil outflow face challenges in maintaining effective thermal insulation, durability, and cost efficiency, particularly in underwater and onshore applications, due to static insulation materials that promote heat conduction and are costly to produce.
A thermally insulated duct using a dynamic combination of hollow glass microbeads and fumed silica, which move within the annular space, preventing direct contact and maintaining thermal insulation by swirling, thus reducing heat conduction and extending insulation effectiveness for over 50 years.
The duct maintains consistent thermal insulation, preventing paraffin formation and increasing oil outflow speed, while reducing costs and maintaining thermal efficiency over decades.
Smart Images
Figure 00000020_0000 
Figure 00000021_0000 
Figure 00000022_0000
Abstract
Description
[0001] THERMALLY INSULATED DUCT FOR CRUDE OIL OUTFLOW
[0002] Field of Invention
[0003]
[0001] The present invention refers to technical and functional improvements especially introduced in a particular type of thermally insulated duct used as a main duct during the outflow of crude oil in underwater regions or on the surface . Such type of duct is traditionally formed by two concentrically assembled tubes, so that a space is configured between them for filling a thermal insulation layer with an appropriate material . This layer is encapsulated by closing the ends of both concentric tubes .
[0004] State of the Art
[0005]
[0002] It is known that the production of thermally insulated ducts adds fundamental characteristics to meet different reguirements during the crude oil outflow, especially regarding thermal insulation means . Therefore, there is the need to obtain good thermal insulation between the internal tube and the external tube, configuring an insulating barrier from the external environment, where the temperature may vary between 0 °C and 50 °C .
[0006]
[0003] Therefore, crude oil is usually at its normal temperature in nature, varying between 30 °C and 120 °C, and this temperature should be preserved for a sufficient period from its origin (the underwater region) to the surface or to the final location for its delivery, storage and processing .
[0007]
[0004] The underwater pipelines used to transportoil products are, in fact, submitted to low temperatures at seabed level (usually between 0 °C and 20 °C) , while the transported fluids need to be frequently under relatively high temperatures (within the range between 70 °C and 200 °C) . While the temperature may decrease to a production field over the time, the fluid temperature should not fall below a minimum value before reaching its final delivery location at the end of the pipeline, so to avoid the formation of solid deposits or paraffin inside its outflow pipeline . Furthermore, the covered distances are significantly high and expressed in tens of kilometers . Considerable efficiency of the thermal insulation capacity is thus essential, lasting while the pipeline is in service, which may take decades . Among other requirements from a practical point of view, it may be emphasized that the thermal insulation capacity should not be negatively affected by the assembling operations on the pipeline, during which the underwater tubes are sequentially linked end to end, or during the settlement process of the resulting pipeline, which is gradually lowered into the sea, or even by the transport between a tube production line or site and the location where the pipeline is really installed.
[0008]
[0005] Other limitations arise from the tube production process, unavoidable dimensional tolerances which are inherent to the tubes, depending on their nature (usually steel ) , their diameter (generally between 80 and 700 mm) , and sealing treatments . A proposal considered by the oil industry to avoid the above problem consists of generatinghigh vacuum inside the annular space located between both coaxial tubes of a double coating tube . In this case, reaching good sealing is clearly critical and the reguired vacuum and the compatible thickness result in undesirable tube cost increase .
[0009]
[0006] Similar thermal insulation and durability reguirements are valid for other applications, primarily for conditions wherein a temperature difference in the same range is found between the internal part and the external part of the tube along the opposite direction .
[0010]
[0007] Currently, the state of the art offers various solutions for the production of a thermally insulated duct, such as taught by the following documents : FR2721681, FR3106183, US3040760, US4371197 , US4824705, US5307842 , US6058979, US6145547 , US7011115, US10995588 , US2003007522 6, US20210310332 and US202200907 08 . These documents teach different methods for thermal insulation, some of them including heating sources and others adding different materials which, generally speaking, are combined to form an intermediary layer for thermal insulation between the internal tube and the external tube .
[0011]
[0008] We can observe in the state of the art and in the very use of a thermally insulated duct that the thermal insulation layer settled in said annular space is "static", presenting many restrictions over the used materials . It is clear that such restrictions are related to different final production characteristics of the set, starting from the cost and thermal efficiency thus obtained .Therefore, new solutions would be desirable to obtain different advantages, not only concerning cost, but also regarding thermal efficiency and durability.
[0012] Objects of the Invention
[0013]
[0009] In view of the above state of the art, the present invention is based on the use of a new compound which, unlike the usual ones, "is not static", and also contains only two different materials : glass microbeads and fumed silica . The balanced combination between them has culminated in an advantageous thermal insulation in different aspects : lower cost, thermal efficiency and durability .
[0014]
[0010] On the other hand, the preferably hollow glass microbeads have higher density and grain size than fumed silica, and said materials "are not static", i . e . they move among themselves, providing advantageous effects for thermal insulation .
[0015] [ Oil] Therefore, as previously stated, the first obj ect of the present invention is a compound formed by only two "non-static" materials, i . e . hollow glass microbeads and fumed silica . The former has higher density and grain size than the latter, which has allowed a dynamic effect between the two components . The glass microbead particles, when moved by the natural vibration of the oil outflow inside the duct forming the crude oil outflow column, act by accelerating the detachment process of the fumed silica particles from the external surface of the internal tube, making both microbead particles and the fumed silica particles remain continuously moving within the annular space . Therefore, when themicrobead particles and the fumed silica particles are no longer next to the external surface of the internal tube and move towards the internal surface of the external tube, they are no longer conditioned to the crude oil temperature outflowing into the internal tube, which varies between 70 and 150 °C, and will be conditioned to the internal temperature of the external tube, i . e . the external local temperature, which is close to 0 °C . This movement cools the microbead particles and the fumed silica particles .
[0016]
[0012] We should also highlight that, in the opposite direction, when the microbead particles and the silica particles are no longer next to the internal surface of the external tube and move towards the external surface of the internal tube, they are no longer conditioned to the local external temperature of the external tube, which is close to 0 °C, and will be conditioned to the internal temperature of the external tube, i . e . the temperature of the outflowing oil within the insulated column, which varies between 70 and 150 °C . This movement promotes heating of the microbead particles and the fumed silica particles . With this movement, the thermal ductility coefficient of the annular space is kept constant .
[0017]
[0013] If the particles are maintained static inside the annular space, they may promote heat conduction between themselves, through their surfaces, which would change the thermal efficiency of the thermal space . This is why it is important to use a nonstatic insulating material which is heavier inrelation to others, so to allow its movement to internally swirl all particles, so that both the microbead particles and the silica particles are never in permanent contact with each other and, thus, they will never act as heat conductors .
[0018]
[0014] The non-stabilization of particles inside the annular space will avoid heat conduction between them. Since the annular space will be thermally insulated, there will be less heat exchange with the crude oil coming from the well up to its delivery point, thus increasing its outflow speed and, conseguently , the daily production gain, avoiding the creation of paraffin and keeping itself constant for years, since both insulation materials keep their characteristics for more than 50 years .
[0019]
[0015] With this material combination and their dynamic effect, homogenous and constant thermal insulation is kept for years during the operation, and conseguently, the present duct presents all characteristics for crude oil conduction in different offshore and onshore sites, i . e . on sea platforms between the oil well and the Christmas tree (offshore) and / or between the crude oil well and a surface pump on the ground (onshore) . It is also used with the same advantages in onshore crude oil pipelines, where the tubular segments have a considerably large diameter and are bipartite, by keeping the same configuration, i . e . an internal and an external tube, forming between them a spacing to be filled in with the present thermal insulation material . In this use, the present duct presents adeguate thermal insulation, adding significantadvantages over the same conventional ducts which use an insulating external coating, such as glass wool, stabilized with an aluminum sheet coating and straps of the same material . All this is eliminated by the present thermal insulation compound, considerably reducing the final cost of the pipeline .
[0020] Description of the Figures
[0021]
[0016] So to better understand the present invention, we offer below a detailed description, with reference to the attached figures as listed below .
[0022]
[0017] Figure 1 represents a schematic view of an offshore crude oil extraction platform.
[0023]
[0018] Figure 2 shows a schematic view of an onshore crude oil extraction site .
[0024]
[0019] Figure 3 shows a side view and a detail of a thermally insulated duct of the present invention .
[0025]
[0020] Figure 4 is a side sectional view with two enlarged details of two thermally insulated ducts interconnected by a glove .
[0026]
[0021] Figure 5 shows a complementary view schematically exemplifying a pipeline with the improvement of the present invention .
[0027] Detailed Description of the Invention
[0028]
[0022] According to these illustrations and their details, more particularly figures 1 and 2, the present invention, THERMALLY INSULATED DUCT FOR CRUDE OIL OUTFLOW, was particularly developed to configure production columns with improved thermal insulation, so to transport crude oil and gas in different production sites, be them offshore or onshore .
[0029]
[0023] Figures 1 and 2 are schematic examples ofdifferent crude oil production installations, both offshore and onshore .
[0030]
[0024] On figure 1, (A) shows the sea level and (B) denotes the sea bed. This figure schematically shows an (offshore) oil platform ( 1A) , which well (2A) has a production column (3A) formed by various THERMALLY INSULATED DUCTS of the present invention and this point is the first CRUDE OIL OUTFLOW extending to the Christmas tree ( 4 ) , from which the crude oil outflow continues by means of another production column (5A) , ending on the platform ( 1A) . From there, the crude oil is adeguately transported to refineries or ground reservoirs .
[0031]
[0025] As previously stated, going below the Christmas tree ( 4 ) and the sea bed (B) , there are the production columns (3A) reaching up to the oil well (2A) . This column (3A) varies in diameter and length, and may reach kilometers . We may also consider several production columns (3A) reaching the same Christmas tree ( 4 ) , according to many variants, of course, which will determinate the best arrangement on the sea bed.
[0032]
[0026] In most cases, the oil contained in the oil well (2A) will be at a temperature within the range between 70 and 150 °C. Considering the sea bed water as being close to 0 °C, and the earth below the sea bed being kept at a very low temperature, by the oil outflow from the crude well (2A) up to the Christmas tree ( 4 ) , the oil cools off with this heat exchange . If this temperature reaches a minimum level of 35 °C, the oil starts a crystallization process inside the production columns (3A) and (5A) and the formation ofparaffin over its internal surface , causing internal diameter restrictions and the consequent decrease of the daily oil production .
[0033]
[0027] On figure 2 , ( C ) indicates the soil level . This figure schematically shows an onshore oil extraction site ( IB ) , also with one or more production columns ( 3B ) formed by various THERMALLY INSULATED DUCTS of the present invention . This point is the first CRUDE OIL OUTFLOW extending from the crude oil well ( 2B ) to the surface pumping unit ( 6 ) , from which at least one pipeline ( 7 ) transports the crude oil to its destination point ( 8 ) , which may be a static storage location, such as a tank, or a naval or ground transport unit .
[0034]
[0028] As previously stated, the pipelines ( 7 ) are usually tubes with considerably large diameters and use an insulating external coating, such as glass wool , stabili zed with an aluminum sheet coating and straps of the same material .
[0035]
[0029] Figures 3 and 4 exempli fy in more detail the thermally insulated duct , configuring the production columns ( 3A) and ( 3B ) , by which we can veri fy that each segment is formed by two concentric tubes , an internal tube ( 9A) and an external tube ( 10A) , between which spacers ( 11 ) are located, while their ends are sealed by optional compensator rings ( 12 ) , j ointly with weld beads ( 13 ) . Said ends also have reversed external threads ( 14 ) for interconnection between the segments through a glove ( 15 ) .
[0036]
[0030] Between the internal tube ( 9A) and an external tube ( 10A) , an annular space ( 16 ) is formed and filled with thermal insulation ( 17 ) .
[0031] Therefore , each segment i s formed by an internal tube ( 9A) inserted within an external tube ( 10A) and welded at their ends . In case of an eventual need, compensator rings ( 12 ) are used, being welded at their ends between said tubes ( 9A) and ( 10A) . This compensator ring ( 12 ) may be considered as being of the same material as the internal and external tubes , or di fferent materials .
[0037]
[0032] The external tube ( 10A) has reversed external threads ( 14 ) to allow the segments to be interconnected by a glove ( 15 ) , but the coupling of segments may vary, especially concerning the threads . This means that , in this first case , the internal tube ( 9A) has shorter length than the external tube ( 11 ) , but this si zing could be inverted and, therefore , said glove may be coupled to the internal tube ( 9A) instead of being coupled to the external tube ( 10A) . However , such variant does not change the functionality of the set .
[0038]
[0033] The production process of the insulated tube follows some basic criteria , i . e . :
[0039] the internal tube ( 9A) and the external tube ( 10A) are cut within an appropriate si ze for coupling by means of the glove ( 15 ) ;
[0040] fastening by means of welding of the spacers ( 11 ) as appropriately distributed, so that , after mounting the insulated tube , both the internal tube ( 9A) and the external tube ( 10A) are positioned in a way to avoid contacting each other , other than the welds at the ends ;
[0041] insertion of the internal tube ( 9A) inside the external tube ( 10A) with pre-establishedlengths in the proj ect ;
[0042] insertion of compensator rings ( 12 ) , when applicable ;
[0043] welding of an end so to j oin the internal tube ( 9A) , the external tube ( 10A) and the compensator ring ( 12 ) , leaving the other end open to the annular space ( 16 ) ;
[0044] hot air inj ection inside the internal tube ( 9A) , allowing its expansion to a new position inside the external tube ( 10A) , taking into account that the expansion is variable and depends on the temperature to which the tube will be submitted during the operation inside the well , usually within the range between 1 and 15 mm for each 12-meter insulated tube ;
[0045] welding of the second end, similarly to the first one for complete weld;
[0046] thermal treatment of the welded ends of the insulated tube to relieve tension;
[0047] insertion of the thermal insulation ( 17 ) within the annular space ( 16 ) through a hole ( 18 ) . This process may use small vacuum pumping to facilitate the thermal insulation penetration inside the annular space ;
[0048] closing the hole ( 18 ) by means of welded buffering;
[0049] manufacturing of external threads ( 14 ) at the respective internal tube ( 9A) or external tube ( 10A) , following the coupling to be carried out by the glove ( 15 ) ; and
[0050] placement of the glove ( 15 ) at one of the ends of the insulated tube , thus concluding a fullunit to be coupled to another identical one , until the production columns ( 3A) and ( 3B ) reach the desired length .
[0051]
[0034] Concerning figure 5 , we highlight that a pipeline ( 7 ) also reguires thermal insulation ( 17 ) . In this case , as previously mentioned, tubes with extremely large diameters are included . Under these conditions , a preferred construction is the one where the internal ( 9B ) and external tubes ( 10B ) are lengthwise bipartite and j oined by their tabs according to a more convenient solution . The interconnection between them is also carried out appropriately . However , ignoring said details , one preponderant detail about this type of pipeline would be the existence of the annular space ( 16 ) to fill in the thermal material ( 17 ) . For these bipartite sets in pipelines , we may consider several materials to produce the chutes , from the group of glass fiber , polyethylene , carbon fiber and others .
[0052]
[0035] The international oil scenario , broadly speaking, looks intensely for an alternative for the execution of THERMAL INSULATION ( 17 ) appropriate to oil at the production columns ( 3A) and ( 3B ) , from its exit from the oil well ( 2A) and ( 2B ) up to the tree ( 4 ) or pumping unit ( 6 ) , as previously stated .
[0053]
[0036] As for the thermal insulation of the production columns ( 5A) and ( 7 ) , there are several applicable technologies , since , in these cases , we can imagine a comprehensive external coating for this segment , i . e . there i s no external dimensional limitation for that . Even more so when dealing with thermal coating for the production columns ( 3A) and(3B) , there are three important points :
[0054]
[0037] A - the insulation will be subject to high pressure and will need to remain constant for over 30 years (the average period of a production well ) ;
[0055]
[0038] B - the insulation should have high thermal efficiency, so to make sense to use it to contain the drastic temperature decrease when the oil outflows from the well (2 ) to the Christmas tree ( 4 ) ; and
[0039] C - the insulation is restricted to very limited thickness dimensions , since the dimensions of the production column (3 ) are already very limited, so to be inserted between the Christmas tree ( 4 ) and the well (2A) or (2B) .
[0056]
[0040] Based on these three main points, vacuum insulation tubes, known as VIT (Vacuum Insulation Systems ) , cannot be used, since, when submitted to high pressures, the gases contained within their tubes (when forming laminates ) migrate to the space containing vacuum, thus drastically reducing its thermal efficiency by the first 3-4 years of use .
[0057]
[0041] For this reason, the thermal insulation of the present invention contains all the necessary characteristics for the operational demands of a production well and, by keeping the oil outflow at a temperature which is closer to its original temperature, an increase in daily production is obtained for each well (2 ) , besides avoiding the formation of paraffin inside it .
[0058]
[0042] As previously stated, operational restrictions do not leave much room to use many materials in the annular space ( 16) for the formation of the thermal layer .
[0043] For this reason, the present invention is a definitive solution to meet the above requirements , wherein the thermal insulation ( 17 ) is a new compound with two di fferent materials which, unlike the usual ones , "are not static" , one of them being glas s microbeads ( 19 ) and the other being fumed silica ( 20 ) . The balanced combination between them resulted in an advantageous thermal insulation in di fferent aspects : reduced cost , thermal e fficiency and durability .
[0059]
[0044] Therefore , as previously stated, the present invention is a thermal insulation ( 17 ) constituted by two "non-static" materials , i . e . glass microbeads ( 19 ) and fumed silica ( 20 ) .
[0060]
[0045] Considering the annular space ( 16 ) volume , a preferred filling formula is between 1 and 4 % glass microbeads ( 19 ) and between 96 and 99% fumed silica ( 20 ) .
[0061]
[0046] Glass microbeads ( 19 ) are preferably hollow .
[0062]
[0047] Glass microbeads ( 19 ) have a diameter between 3 and 6 , 000 pm (micrometers ) .
[0063]
[0048] Fumed silica ( 20 ) has grain si ze between 5 and 18 nm ( nanometers ) .
[0064]
[0049] Glass microbeads ( 19 ) have higher density and grain size than fumed silica ( 20 ) , which allowed a dynamic effect between both components . The glass microbead ( 19 ) particles , when moved by the natural vibration of oil outflow inside the duct forming the crude oil outflow column, work by accelerating the detachment process of fumed silica ( 20 ) particles from the external surface of the internal tube ( 9A) , making both microbead ( 19 ) particles and fumed silica(20 ) particles remain in continuous movement inside the annular space . Therefore, when the microbead ( 19) particles and the fumed silica (20 ) particles are no longer next to the external surface of the internal tube ( 9A) and move themselves towards the internal surface of the external tube ( 10A) , they will be no longer conditioned to the temperature of the crude oil outflowing in the internal tube, which varies between 70 and 150 °C, and will be conditioned instead to the internal temperature of the external tube ( 10A) , i . e . the external local temperature, which is close to 0 °C . This movement promotes cooling of both the microbead and silica particles .
[0065]
[0050] We also highlight that, in the opposite way, when the microbead ( 19) particles and the fumed silica (20) particles are no longer next to the internal surface of the external tube ( 10A) and move themselves towards the external surface of the internal tube ( 9A) , they will be no longer conditioned to the external local temperature of the external tube ( 9A) , which is close to 0 °C, and will be conditioned instead to the internal temperature of the external tube ( 10A) , i . e . , the temperature of oil outflowing in the insulated column, varying between 70 and 150 °C . This movement promotes heating of both microbead ( 19) particles and fumed silica (20 ) particles . With this movement, the thermal conductivity coefficient of the annular space is kept constant .
[0066]
[0051] If the particles of both materials are kept static inside the annular space ( 16) , they may promote heat conduction between each other, throughtheir surfaces , which would change the thermal efficiency of the annular space ( 16) . This is why the use of a heavier "non-static" insulating material than others is important, so to allow its movement to promote internal swirling of every particle, so that microbead particles ( 19) and fumed silica (20 ) particles may never be in permanent contact to each other and, thus , they will never act as heat conductors .
[0067]
[0052] The non-stabilization of particles inside the annular space ( 16) will avoid heat conduction between each other . Since the annular space will be thermally insulated, there will conseguently be less heat exchange between crude oil coming out of the well up to its delivery point, thus increasing its outflow speed and, conseguently, the daily production gain, avoiding the creation of paraffin and keeping itself constant for years, since both insulation materials keep their characteristics for more than 50 years .
[0068]
[0053] With this material combination and their dynamic effect, an even and constant thermal insulation is kept for years during the operation . Therefore, the present duct presents all characteristics for crude oil conduction on different offshore and onshore installations, i . e . on sea platforms ( 1A) between the oil well (2A) and the Christmas tree ( 4 ) (offshore) and / or between the crude oil well (2B) and a (C) surface pump ( 6) on the ground (C) (onshore ) . It is also used with the same advantages for onshore crude oil pipelines (7 ) , where the tubular segments present a considerably large diameter and are bipartite, keeping the sameconfiguration, i . e . an internal tube and an external tube forming between them a space to be filled in with the present thermal insulation material . In this use, the present duct has adeguate thermal insulation, adding a significant advantage over the same conventional ducts using an external insulating coating, such as glass wool, stabilized as an aluminum sheet coating and straps of the same material . All this is eliminated with the present thermal insulation compound, which ultimately reduces considerably the final cost of the pipeline .
[0069]
[0054] It will be understood that specific characteristics and construction combinations of the production columns on offshore and onshore crude oil production sites may vary considerably, while maintaining the same inventive concept of the set . Therefore, it should be noted that the construction described in detail by way of example is clearly subj ect to constructive variations, but always within the scope of the inventive concept thus disclosed of a thermal insulation constituted by two non-static materials, hollow glass beads and fumed silica . Therefore, several modifications may be done to the configuration as detailed herewithin, according to the descriptive reguirements of the law, thus being understood that the present details should be interpreted in a non-limiting and illustrative way.
Claims
CLAIMS1 ) THERMALLY INSULATED DUCT FOR CRUDE OIL OUTFLOW, comprising equal segments , each of them formed by two concentric tubes , an internal tube ( 9A) and an external tube ( IDA) , between which spacers ( 11 ) are located, while their ends are sealed by optional compensator rings ( 12 ) together with weld beads ( 13 ) and said ends al so have reversed external threads ( 14 ) for interconnection between the segments through a glove ( 15 ) ; between the internal tube ( 9A) and an external tube ( 10A) , an annular space ( 16 ) is formed and filled in with thermal insulation ( 17 ) , which repeats itsel f in the pipeline ( 7 ) ; characteri zed by the thermal insulation ( 17 ) being constituted by two non-static materials , glas s microbeads ( 19 ) and fumed silica microbeads ( 20 ) , following an annular space ( 16 ) filling formulation comprising :- between 1 and 4 % glass microbeads ( 19 ) ; and- between 96 and 99% fumed silica ( 20 ) .2 ) THERMALLY INSULATED DUCT FOR CRUDE OIL OUTFLOW of claim 1 , characteri zed by the glas s microbead ( 19 ) being preferably hollow .3 ) THERMALLY INSULATED DUCT FOR CRUDE OIL OUTFLOW of claim 1 , characteri zed by the glas s microbead ( 19 ) having a diameter between 3 and 6 , 000 pm .4 ) THERMALLY INSULATED DUCT FOR CRUDE OIL OUTFLOW of claim 1 , characteri zed by the fumed silica ( 20 ) having grain si ze between 5 and 18 nm .5) THERMALLY INSULATED DUCT FOR CRUDE OIL OUTFLOW of claim 1, characterized by the glass microbeads ( 19) having higher density and grain size than fumed silica (20) .