HK1252769B - Real time integrity monitoring of on-shore pipes - Google Patents

Description

Real-time integrity monitoring of onshore pipelines

Background Art

Pipelines for recovering and transporting fluids or gases typically include many pipe segments joined together in an end-to-end configuration to extend the transport distance. For example, pipe segments may be joined together to extend to tens or hundreds or thousands of miles.

Pipelines in the oil and gas industry can be used to transport recovered hydrocarbons, such as crude oil, natural gas, produced water, fracturing fluids, flowback fluids or other types of gases (such as CO2), which can be pumped through the pipeline at a selected flow rate. During the crude oil transportation process, when the temperature is lower than or equal to the temperature called "waxing temperature" (WAT) or "cloud point", the dissolved wax found in the crude oil will precipitate and aggregate. The cloud point is specific to each crude oil composition and is a function of the concentration of wax, nucleating agents (such as asphaltenes and formation fines) and pressure. When enough wax accumulates in the pipeline, it may restrict the flow of oil, thereby reducing efficiency and production. Offshore pipelines are typically exposed to colder temperatures, and therefore, technologies such as pipeline insulation are implemented to inhibit the aggregation of wax found in crude oil. In order to monitor the integrity of offshore pipelines and the clean deposits accumulated in the pipelines, a device called a "pig" is usually sent through the pipeline. For example, some pigs can be used to detect pipeline damage, such as dents, corrosion or cracks.

Onshore pipelines can also be inspected for mechanical damage using pigs. However, because onshore pipelines run above ground and are more commonly buried several feet below the surface, the integrity of the pipeline can also be monitored by following the path of the pipe or tubular conduit with various sensing devices, such as acoustic emission tools, to detect any faults.

Summary of the Invention

This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

In one aspect, embodiments disclosed herein relate to a method comprising providing a length of pipeline having a space formed within a thickness of a pipeline casing and extending the length of the pipeline, and continuously monitoring at least one condition within the space to detect in real time whether a change occurs in the casing.

In another aspect, embodiments disclosed herein are directed to a method that includes providing a length of tubing having a signal transmitting material disposed within a thickness of a tubing casing, and continuously receiving a signal from the signal transmitting material to detect a condition of the casing.

In yet another aspect, embodiments disclosed herein relate to a method that includes continuously monitoring temperature along a length of a pipeline having a conductive material disposed within a thickness of a pipeline casing, and when a preselected temperature is detected, applying an electric current to the conductive material to heat the conductive material.

Other aspects and advantages of the invention will become apparent from the following description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 shows a portion of a pipeline according to an embodiment of the present disclosure.

FIG2 shows a diagram of a system according to an embodiment of the present disclosure.

FIG3 shows a diagram of pipe segments and pipe joints according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments disclosed herein may generally relate to methods for real-time monitoring of pipelines. The pipeline may be operated on land and/or through shallow water and may extend over long distances, such as tens, hundreds, or thousands of miles, above ground or buried a few feet (e.g., in the range of about 3 feet to about 6 feet) underground. Shallow water bodies may include, for example, rivers, lakes, or other bodies of water having depths of up to 50 meters, up to 100 meters, or up to 150 meters. In yet other embodiments, the pipeline may be operated offshore, such as through depths greater than 150 meters, such as greater than 500 meters or greater than 1000 meters.

Methods according to embodiments of the present disclosure may include providing a length of conduit that can be used to transport a fluid or gas. The conduit may include a shell defining a central bore extending the length of the conduit, through which the fluid being transported can be pumped. The shell may further have a continuous conduit formed between the thickness of the shell and extending the length of the conduit. As referred to herein, a conduit disposed "between" or "within" the thickness of the shell is a conduit that is not exposed to the inner surface or outermost surface of the shell, but is instead covered by or located below the inner surface and outermost surface of the shell. Further, the conduit may include a plurality of pipe segments connected together with pipe joints, wherein the pipe segments and pipe joints are alternately connected in an end-to-end configuration.

FIG1 illustrates an example of a pipeline according to an embodiment of the present disclosure. Pipeline 100 includes pipe segments 110 and pipe connectors 120 that are alternately connected together in an end-to-end configuration. The housings of the connected pipe segments 110 and pipe connectors 120 define a central bore 105 that extends longitudinally through the length of pipeline 100, through which fluid and/or gas can flow. The housing 112 of pipe segment 110 includes an inner layer 114 having an inner surface 115 that defines central bore 105. Pipe segment housing 112 further includes an outer shield 116 layer. Outer shield 116 can provide protection from contaminants and damage from environmental factors. The housing thickness is measured between the inner surface 115 and the outermost surface of the housing.

One or more conduits may be formed between inner layer 114 and outer shield 116. The conduits formed between inner layer 114 and outer shield 116 may extend continuously through the length of tube segment 110 from one end to the outer end. For example, as shown in FIG1 , the conduit may be a space 130 that may have air or other gas flowing therethrough or held therein. In some embodiments, for example, the conduit may be made of a physical material capable of flowing data, light, sound, electrical current, or other signals.

The space 130 formed between the inner layer 114 and the outer shield 116 can be formed by one or more intermediate layers 118 disposed between the inner layer 114 and the outer shield 116. For example, as shown in FIG1 , the intermediate layer 118 can have two longitudinally extending grooves that, when disposed between the inner layer 114 and the outer shield 116, form the space 130. In some embodiments, more than one intermediate layer can be disposed between the inner layer and the outer shield, wherein the intermediate layers can individually or collectively form one or more spaces. For example, two or more intermediate layers having corresponding portions in shape can be concentrically disposed between the inner layer and the outer shield, wherein portions of non-corresponding shapes can form a space between the intermediate layers. Further, in some embodiments, the intermediate layer can be provided by one or more wound strips that are spirally disposed between the inner layer and the outer shield of the housing, wherein a space can be formed between the wound strips.

The intermediate layer can have a substantially flat cross-section, or it can have a non-flat predetermined cross-sectional shape, such as a rounded, roughened, convex, or other non-planar shape. In embodiments where the intermediate layer has a non-flat cross-sectional shape, the non-planar portion of the intermediate layer can be used to create spaces extending the length of the pipe segment. The intermediate layer, including one or more strips, can interlock to some extent or not.

Pipe segments can be joined in an end-to-end configuration using a pipe joint, wherein the conduit formed by the pipe segment housing can be fluidly connected via the conduit formed by the pipe joint. For example, as shown in FIG1 , a pipe joint 120 can have a pipe joint housing 122 having a first annular space 131 located at a first end of the pipe joint, a second annular space 132 located at a second end of the pipe joint, and one or more spaces 133 extending longitudinally from the first annular space 131 to the second annular space 132. Each pipe segment 110 can be connected to the end of the pipe joint 120 such that the opening of the space 130 in each pipe segment 110 opens into the annular spaces 131, 132, thereby continuously connecting the spaces 130 in each pipe segment 110. In some embodiments, the pipe joint can have a space extending longitudinally through the pipe joint housing, wherein the opening of the pipe joint space can be aligned with the opening of the adjacent pipe segment space, thereby forming a connected and continuously extending space through the entire length of the pipeline. Other means of fluidly connecting the pipe segment spaces through one or more spaces formed in the pipe joint housing can be used to provide a continuous spatial conduit through the entire length of the pipeline.

Further, although the pipe segment space 130 and the pipe joint space 133 are shown as extending linearly along the length of the shell 112, 122, other continuously extending spatial paths can be formed through the shell of the pipe segment and the pipe joint. For example, in some embodiments, the material strips forming the first intermediate layer can be spirally wrapped around the inner layer so that a relatively small gap or space (e.g., 5-10% of the width of the strip) is formed between adjacent strips. One or more additional intermediate layers can be arranged around the first intermediate layer (overlapping with the first intermediate layer) so that the gap formed between adjacent strips can be partially closed to form one or more spatial openings at both ends of the pipe segment. In such an embodiment, the space formed can extend along the length of the shell in a spiral path. In some embodiments, spaces of different shapes can be connected to each other to form an irregularly shaped but continuous conduit that passes through the entire length of the pipeline.

For example, pipe segments may be connected together via pipe fittings in an end-to-end configuration, such as by interlocking end shapes (between the end of the pipe fitting and the end of the pipe segment), interference fit, bolts, gluing, welding, by fastening sleeves or sleeves to the adjoining ends, and other fastening techniques.

1 shows a pipeline 100 having two pipe segments joined together in an end-to-end configuration via a pipe joint 120. However, it will be understood that a pipeline may be formed from two or more pipe segments, each joined to one or two adjacent sections of pipe by corresponding connections. The pipe segments may be rigid or flexible.

According to an embodiment of the present disclosure, one or more layers of a pipe section may be formed from a flexible material. For example, as shown in FIG1 , an inner layer 114 and an outer shield 116 may be formed from a flexible material extruded into a tubular shape. A pipe section having one or more layers formed from a flexible material may be referred to as a flexible pipe. A flexible pipe may have an inner layer defining a central hole or overflow channel extruded from a flexible material. One or more intermediate layers (e.g., strips, tapes, wraps) may be applied around the inner extruded layer so that at least one conduit extends the length of the pipe. An outer layer of flexible material may then be extruded over the intermediate layer to form an outer shield. In some embodiments, more than one flexible material may be extruded around the inner layer and/or outer shield. The flexible material may include, for example, polymers and fibers embedded in the polymer (e.g., steel, aluminum, beryllium, or copper alloy fibers embedded in the polymer). Suitable polymers may include, for example, olefin polymers blended with at least one thermosetting elastomer or polyolefin.

The middle layer may be formed, for example, from a steel, carbon steel, or other metal composite layer; a plurality of relatively narrow strips of material arranged in a side-by-side relationship; a high-strength tape having oriented polymer chains; a tape reinforced with fibers; a composite material of a strength-enhancing polymer or other metal strip; a polymer reinforced with metal fibers, such as polyethylene or polypropylene; or other tapes containing metal reinforcements, including steel, aluminum, or copper alloys. The middle layer may be formed from a stronger material than the material forming the inner layer, for example to provide pressure reinforcement to prevent the inner layer from bursting and to prevent the pipe from collapsing due to external pressure.

According to an embodiment of the present disclosure, a method for monitoring a pipeline may include monitoring a conduit formed within a housing of the pipeline and extending the length of the pipeline. For example, a length of pipeline may be provided having a housing defining a central bore extending the length of the pipeline and a void formed within the housing and extending the length of the pipeline. The pipeline may be formed from a plurality of pipe segments connected together in an end-to-end configuration via pipe joints, wherein the pipe segment housings and the pipe joint housings together form a pipeline housing having the void extending continuously therethrough.

At least one condition within the space of the pipeline housing can be continuously monitored to detect in real time whether changes have occurred in the housing. For example, in some embodiments, the pressure within the space extending through the pipeline housing can be continuously monitored. The space can include multiple pressure transducers disposed within the space along the length of the space. The pressure transducers can include, for example, thin-film pressure transducers, piezoelectric pressure transducers, or any other pressure sensing element capable of generating a signal based on the sensed pressure. The pressure transducers can continuously monitor the pressure within the space and send a signal to a user, a storage device, an alarm system, or other end component that relays the detected pressure. Changes in the pressure within the space can indicate, in real time, a rupture in the housing or changes in the environment surrounding the pipeline housing that could damage the housing, for example.

In some embodiments, the space extending the length of the pipeline can be pre-pressurized to a preset pressure. For example, the space can be filled with a predetermined amount of an inert gas, such as nitrogen. A pressure transducer can be positioned within the space to monitor the pressure within the space. Detecting a drop in pressure can provide a real-time indication that damage to the housing has occurred.

FIG2 illustrates an example of a system 200 for continuously monitoring the pressure within a space 210 extending the entire length of a pipeline 220. The pipeline 220 may be an onshore pipeline that may extend a distance across land (e.g., in a direction substantially parallel to the land surface), be partially or completely buried at a shallow depth 230 underground, and/or extend through shallow water. For example, in some embodiments, a majority of the pipeline's length (e.g., greater than 50%, greater than 75%, or greater than 90%) may be buried underground at depths ranging from, for example, less than 10 feet, less than 7 feet, or less than 5 feet. The pipeline 220 may have a casing 240 defining a central bore 245 through which a fluid or gas may flow or be stored, wherein at least one enclosed space 210 may be formed within the thickness of the casing 240 and extend fluidly or continuously along the entire length of the pipeline 220. At least one pressure transducer 260 may be disposed within the space 210 or along the length of the pipeline 220. The pressure transducer(s) 260 may detect the pressure within the space 210 and generate a signal indicative thereof. The pressure signal 265 can be sent wirelessly or through an additional conduit disposed within the thickness of the tubing housing that is capable of transmitting data or signals (discussed in more detail below). The pressure signal can be transmitted to a receiver. The receiver can be part of the computing device 270 or a storage device accessible to the computing device.

For example, computing device 270 may include a computer processor and a memory having instructions (e.g., one or more software programs) executed on the computer processor, the computer processor having the function of receiving the pressure signal transmitted from the pressure transducer. The computing device may continuously process the received signal and may display the results on a graphical user interface 275 (e.g., a screen) in various formats (e.g., graphs, charts, etc.). Further, in some embodiments, computing device 270 may have an alarm program that can generate an alarm when a preselected pressure condition is detected. For example, if a change in pressure exceeding a predetermined amount (e.g., a 5% change, a 10% change, a 15% change) is detected, an alarm may be generated.

In some embodiments, a gas having a predetermined composition can be disposed within a space formed by the pipeline housing, wherein the gas composition can be continuously monitored. In some embodiments, the gas composition can be continuously monitored by continuously flowing gas having a predetermined composition through the space. The gas can flow through the space, for example, by pumping gas into the space and exhausting the gas through at least one exhaust port formed in the housing. The gas composition can be tested after the gas leaves the at least one exhaust port formed in the housing. In some embodiments, the gas composition can be continuously monitored by extracting gas from the at least one exhaust port formed in the pipeline housing at intervals and testing the gas composition of the gas after extraction. For example, gas can be extracted from the space formed within the pipeline housing twice a day, once a day, twice a week, once a week, or at other selected intervals and tested to determine whether the tested composition has changed compared to the predetermined composition. For example, a change in gas composition can indicate corrosion or cracks in the pipeline housing.

The temperature within the space formed by the entire length of the pipeline can be continuously monitored, either alone or in combination with monitoring other conditions in the space. For example, temperature and pressure can be continuously monitored through one or more conduits formed between the thickness of the pipeline casing, where the temperature measurements can be compared with the pressure measurements, for example to determine whether the measured pressure changes are due to temperature changes in the external environment. The temperature within the conduit (e.g., the space) formed by the pipeline casing can be continuously monitored using one or more temperature sensors. Suitable temperature sensors can include, for example, thermistors, thermocouples, or other sensors capable of generating an electrical signal in response to temperature changes. The signal indicative of the temperature measurement can be transmitted, for example, wirelessly or through a conduit disposed within the thickness of the pipeline casing capable of transmitting the signal.

According to an embodiment of the present disclosure, a method for real-time monitoring of a pipeline may include providing a length of pipeline having a housing defining a central bore extending the length of the pipeline and at least one conduit formed within the thickness of the housing and extending the entire length of the pipeline. The conduit may be a signal-transmitting material or other physical material capable of flowing data, light, sound, or electrical current, disposed between at least two layers forming the inner and outer surfaces of the pipeline housing. For example, the conduit of the signal-transmitting material may be disposed between an inner layer of a flexible pipe and an outer shield. One or more conditions within the thickness of the pipeline housing may be measured and continuously monitored. For example, a signal-transmitting material forming one or more conduits through the thickness of the pipeline housing may continuously detect a condition of the housing and generate a signal representative of the condition. The signal may be transmitted through the signal-transmitting material to monitor the condition of the housing in real time.

According to embodiments of the present disclosure, the conduit formed by the signal transmission material (disposed between the thickness of the housing and extending the entire length of the pipeline) may include a conductive material. The conductive material can be used to transmit signals from one or more sensors, as disclosed herein. In some embodiments, the conductive material can be both a sensor and a transmitter, wherein an electric current can be applied through the conductive material and a change in one or more states of the pipeline housing can be detected by a voltage drop across the conductive material. For example, a crack in the housing or corrosion in the housing may change the environment in which the conductive material is disposed, which may change the flow of current applied thereto. In some embodiments, the signal transmitted by the conductive material may include a voltage drop across the conductive material caused by a change in the housing (e.g., a crack or dent in the housing). The resistivity of the conductive material can be used to reversely calculate the location of the change that caused the measured voltage drop.

The conductive material can be provided in the form of a strip applied to at least one intermediate layer disposed between the inner surface defining the central bore of the pipe and the outer surface of the pipe. For example, one or more strips of conductive material can be provided linearly along the length of the pipe or at an angle relative to the length of the pipe such that the strip(s) extend helically along the length of the pipe. The strips of conductive material can have a width ranging, for example, from less than 50% of the outer circumference of the pipe, less than 20% of the outer circumference of the pipe, less than 10% of the outer circumference of the pipe, or less than 5% of the outer circumference of the pipe. In some embodiments, the conductive material can be in the form of one or more wires. The wires can have a diameter ranging, for example, from less than 15% of the thickness of the casing (measured from the inner surface to the outer surface of the pipe), less than 10% of the thickness of the casing, or less than 5% of the thickness of the casing.

For example, a conductive material can be provided in the form of at least two conductors as a signal transmission conduit through a pipeline casing. A voltage can be applied to a first conductor of the at least two conductors, and a voltage along a second conductor (spaced apart from the first conductor) can be measured to detect the resistivity between the first and second conductors. For example, this configuration of a pair of conductors positioned within the thickness of a pipeline casing can be used to detect moisture within the pipeline casing, where an increase in moisture can indicate a crack in the casing. In such an embodiment, moisture collected between the spaced conductors can provide a path for current flow (reducing the resistivity between the spaced conductors), and when a voltage is applied to the first conductor, the measured voltage from the second spaced conductor can indicate the resistivity between the two conductors. Two spaced conductors can be provided within the pipeline casing (as a conduit between the inner and outer layers of the pipeline casing), or more than two spaced conductors can be provided. In some embodiments, multiple pairs of conductors can be provided in a grid configuration (e.g., as a Faraday grid) to detect moisture within the thickness of the pipeline casing across a large area (e.g., up to the entire circumference and extending throughout the entire length).

In some embodiments, the signal transmission material may be provided in a mesh outside the thickness of the conduit housing, such as an outer shield surrounding the conduit. Insulating tape or a layer of insulating material may then be applied over the outer mesh to insulate the outer mesh communication lines.

Embodiments having conductive material extending along the length of a pipe segment and within the thickness of a pipe casing can include a pipe joint capable of connecting pipe segments together and transmitting signals carried by the conductive material between adjacent pipe segments. The pipe joint can be configured to connect the conductive material extending through adjacent pipe segments by having the conductive material extending between two openings formed at opposing axial ends of the pipe interface, wherein the axial ends of the adjacent pipe segments are inserted into the openings of the pipe joint, and the exposed conductive material at the axial ends of the pipe segments contacts the conductive material in the pipe joint. The conductive material in the pipe segments and the pipe joint can be insulated from the external environment in which the pipeline is installed.

Figure 3 shows an example of a pipe joint and pipe segments having conductive materials connected together. The lengths of the pipe segments 310 and pipe joint 320 are not shown to scale. Further, the pipe joint 320 is shown partially transparent to illustrate the internal parts and components disposed therein.

Pipe segment 310 has a shell 312 defining a central bore 305, wherein shell 312 includes an inner layer 314, an outer layer 316, and at least one intermediate layer 318 disposed between inner layer 314 and outer layer 316. Intermediate layer 318 may include at least one layer, strip, or wire made of a conductive material that extends the length of the pipe segment and is exposed at each axial end of pipe segment 310. The conductive material disposed between the thickness of pipe segment 310 may be insulated from the environment in which the pipeline is disposed, for example by forming outer layer 314 and inner layer 316 from an electrically insulating material or by providing an electrically insulating material around all surfaces of the conductive material except for portions exposed at the axial ends for connection to other conductive material. For example, the insulating material may be coated or layered around the conductive layer(s), strip(s), or wire(s), wherein all portions of the conductive layer(s), strip(s), or wire(s) except those exposed at the axial ends of the pipe segment are covered by the electrically insulating material. By exposing the conductive material at the axial end of the pipe segment 310 , the conductive material may come into contact with the conductive material disposed through the pipe joint 320 .

As shown, pipe fitting 320 includes a pipe fitting housing 322 having a first annular space 331 at a first axial end of the pipe fitting and a second annular space 332 at a second axial end of the pipe fitting. The axial ends of pipe segments can be inserted into the first annular space 331 and the second annular space 332 of the pipe fitting to connect the pipe segments. The axial end of pipe segment 310 can be inserted into either the first annular space 331 or the second annular space 332 and secured therein, for example, via an interference fit between the axial end of pipe segment 310 and the annular space within pipe fitting 320. In some embodiments, the axial end of pipe segment 310 can be inserted into either the first annular space 331 or the second annular space 332 formed in pipe fitting 320, and the outer surfaces surrounding the annular spaces can be radially compressed inward to secure the inserted axial end of the pipe segment. An inner portion 324 of pipe fitting 320 (disposed between first annular space 331 and second annular space 332) can have a thickness less than (as shown), greater than, or equal to, the thickness measured between the inner and outer surfaces of first annular space 331 and second annular space 332.

Conductive material 333 (e.g., in the form of a layer, strip, or wire) can be disposed within the thickness of the pipe joint 320, defining a central bore 305 extending therethrough between the outermost surface of the pipe joint and the inner surface of the pipe joint. For example, by forming the outermost and inner surfaces with an electrically insulating material or by coating the conductive material 333 with an electrically insulating material, the pipe joint conductive material 333 can be electrically insulated from the environment in which the pipe joint is disposed, such that end portions of the conductive material 333 remain uncoated to electrically communicate with the conductive material in the adjacent pipe segment. In some embodiments, a conductive ring 335 can be disposed at the base of each annular space 331, 332, with the conductive material 333 extending from a first conductive ring 335 in the first annular space 331 to a second conductive ring 335 in the second annular space 332. The conductive material 333 can contact and transmit electrical signals between the first and second conductive rings 335 while also being electrically insulated across the thickness of the pipe joint. When the axial ends of the pipe segments are inserted into annular spaces 331, 332, the conductive material exposed at the axial ends of the pipe segments can contact the electrical signal and pass the electrical signal to conductive ring 335. In this way, pipe segments and pipe joints connected together with conductive material extending therethrough can have the electrical signal passed through a first conductive material in a first pipe segment connected to the pipe joint, through a first conductive ring in the pipe joint, through the pipe joint conductive material, through a second conductive ring in the pipe joint, through a second conductive material in a second pipe segment connected to the pipe joint, and so on, for the length of the signal transfer line.

By providing a conductive ring between the conductive material extending through the adjacent pipe segments and the pipe joint, the conductive material of the pipe joint does not need to be aligned with the conductive material of the pipe segment. However, according to some embodiments of the present disclosure, the conductive material in the pipe segment can be aligned with the conductive material in the pipe joint (without using a conductive ring). Further, in some embodiments, the conductive material can be configured into a shape other than a ring to electrically connect the conductive material of the pipe joint with the conductive material of the pipe segment. For example, one or more clips (e.g., T-shaped clips) can extend at the connection between the pipe segment and the pipe joint to electrically connect the conductive material of the pipe joint with the conductive material of the pipe segment. In some embodiments, a clip or other connecting component formed of a conductive material can be inserted into the axial end of the pipe segment and contact the conductive material provided in the pipe segment, wherein when the axial end of the pipe segment is fixed to the pipe joint, the exposed portion of the connecting component can contact the conductive material of the pipe joint.

Furthermore, in some embodiments, the pipe joint may be partially or completely formed of a conductive material, wherein the conductive material exposed at the axial end of the pipe segment may contact the conductive material of the pipe joint when the pipe segment is secured to the pipe joint. An electrically insulating material may be disposed around the pipe joint, for example by wrapping the pipe joint with electrically insulating tape or spraying a coating with electrically insulating material, to electrically insulate signals transmitted through the conductive material.

Other configurations of connected conductive material through the pipe segments and pipe joints may be used, wherein the conductive material extending through the length of the pipe segment and through the connection in the pipe joint may be electrically insulated from the environment in which the pipe is disposed. For example, the exterior and/or interior surfaces of the pipeline casing may have electrically insulating material applied thereto, for example, with electrical insulating tape or by spraying the electrically insulating material thereon.

According to an embodiment of the present disclosure, a method of monitoring a pipeline may include changing at least one condition of the pipeline in response to the monitoring. For example, in some embodiments, the temperature along the length of the pipeline can be continuously monitored, wherein the pipeline has a housing defining a central bore extending the length of the pipeline, and the housing has a conductive material disposed between two layers: an inner layer forming an inner surface of the housing and an outer layer forming an outer surface of the housing. For example, a preselected temperature or temperature range may be selected depending on the environment in which the pipeline is disposed and/or the fluid or gas disposed within the pipeline. In some embodiments, the preselected temperature may be a minimum temperature for maintaining one or more conditions of the fluid or gas disposed within the pipeline. When the preselected temperature is detected, an electric current may be applied to the conductive material to heat the conductive material.

For example, in some embodiments of monitoring a pipeline carrying crude oil, the preselected temperature can be the wax precipitation temperature or "cloud point" of the crude oil. The temperature can be continuously monitored by one or more conductive conduits disposed within the thickness of the pipeline casing and extending the entire length of the pipeline. When a temperature less than or equal to the cloud point is detected, an electric current can be applied to the conductive material and short-circuited to heat the area where the preselected temperature is detected. By heating the area of the pipeline where the temperature is detected to be less than or equal to the cloud point, the nucleation and aggregation of wax in the crude oil can be prevented or suppressed. These embodiments can be used when the pipeline transporting crude oil extends through a colder environment, such as across land in the northern regions of North America, Asia, or Europe, or the southern regions of South America.

The temperature of the conductive material disposed within the thickness of the housing may be continuously monitored, such as with a temperature sensor or other sensing types disclosed herein.

By providing a pipeline having a continuous conduit path through the entire length of the pipeline and monitoring the conduit, one or more conditions of the pipeline housing can be continuously monitored, and changes in one or more conditions can be detected in real time. For example, rather than periodically sending a sensing device along the pipeline to measure one or more conditions of the pipeline, a conduit extending through the pipeline of the present disclosure can be continuously monitored without affecting the operation of the pipeline.

Furthermore, rather than detecting one or more problems with a pipeline (e.g., by observing changes in the flow through the central bore of the pipeline) and then sending one or more devices along the pipeline to detect where the problem originates, the methods disclosed herein can allow for real-time detection of problem initiation and, in some embodiments, indication of where the problem initiation occurred. For example, the continuous monitoring methods disclosed herein can allow for early detection of corrosion initiation, pitting or cracking in the casing, or other problem initiation (e.g., through early detection of changes in gas composition, changes in current flowing through the conduit, or through other monitoring techniques disclosed herein) before a complete failure occurs in the pipeline casing (e.g., a crack in the casing leading to a leak), thereby providing an opportunity to repair or replace a portion of the pipeline before the portion fails.

Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications may be made in the example embodiments without materially departing from the scope of the present disclosure. Accordingly, all such modifications are intended to be included within the scope of the present disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover structures described herein that perform the stated function and include not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents because a nail employs a cylindrical surface to secure wood parts together and a screw employs a helical surface, a nail and a screw may be equivalent structures in the context of fastening wood parts. It is the express intention of the applicant not to invoke 35 U.S.C. § 112(f) for any limitation of any claim herein except those in which the claim expressly uses the phrase "means for..." and the associated function.

Claims (11)

1. A method for monitoring pipelines, comprising: A pipe of a certain length is provided, the pipe comprising: A housing defining a central hole extending the length of the conduit, the housing comprising: An inner layer with an inner surface; The outer layer having an outer surface; The distance measured between the inner surface of the housing and the outer surface of the housing; and A signal transmission material disposed between the inner surface and the outer surface of the housing; and Continuously receive signals from the signal transmission material to detect the condition of the housing. The pipe of the specified length comprises multiple pipe segments and at least one pipe joint, each of the at least one pipe joint comprising: An annular space formed at each axial end of the pipe joint; A conductive ring is provided at the base of each annular space; and The conductive material in contact with each conductive ring; and The signal transmission material in the casing of the pipe section contacts the conductive ring in each pipe joint. 2. The method according to claim 1, wherein the signal transmission material comprises a conductive material. 3. The method according to claim 2, wherein the conductive material of the signal transmission material is electrically insulated within the distance. 4. The method of claim 2, further comprising applying a current through the signal transmission material, wherein the detected condition is the voltage drop across the signal transmission material. 5. The method of claim 2, wherein the signal transmission material comprises at least two wires, and further comprises: Apply voltage to the first wire of the at least two wires; and The voltage is measured along the second of the at least two wires, and the signal includes the measured voltage; The condition detected by the measured voltage is moisture. 6. The method of claim 2, wherein the signal transmission material forms a Faraday cage around the housing. 7. The method of claim 2, wherein the signal includes a voltage drop from the change in the condition of the housing, further comprising determining an amount of resistivity through the voltage drop to calculate the location of the change. 8. The method of claim 1, wherein the at least one pipe joint connects adjacent pipe segments together in an end-to-end configuration, wherein the signal transmission material extends continuously through the pipe segments and the at least one pipe joint. 9. The method of claim 8, further comprising providing an electrically insulating material around at least one pipe joint in the pipe of the said length, wherein the signal transmission material is a conductive material, and wherein the at least one pipe joint is formed of the conductive material. 10. A method for monitoring pipelines, comprising: Continuous temperature monitoring along the length of a pipe, the pipe including a housing, the housing comprising: an inner layer including an inner surface defining a central hole extending the length of the pipe; an outer layer including an outer surface; and a conductive material disposed between the inner surface and the outer surface; and When a pre-selected temperature is detected, an electric current is applied to the conductive material to heat it. The pipe of the specified length comprises multiple pipe segments and at least one pipe joint, each of the at least one pipe joint comprising: An annular space formed at each axial end of the pipe joint; A conductive ring is provided at the base of each annular space; and The conductive material in contact with each conductive ring; and The conductive material in the casing of the pipe section contacts the conductive ring in each pipe joint. 11. The method of claim 10, wherein the temperature is continuously monitored using at least one temperature sensor, and wherein a signal from the at least one temperature sensor is transmitted through the conductive material.