Co-authors:

 Ernest D. Casey - President StarTrak Pigging Technologies, Inc.
 Thomas Cooney - National Account Manager - ORBCOMM Global L.P.

Abstract:

Vast changes have been made to worldwide communications during the final decade of this millennium. It is an every day event to use telephone and television communication systems that are derived via satellite transmissions. Recently such companies as ORBCOMM, a subsidiary of Orbital Sciences, has deployed Low Earth Orbital Satellites (LEOs) which orbit the earth at a distance of approximately 500 miles, traditional satellite systems orbit many thousands of miles above the earth.  Low Earth orbiting (LEO) satellite systems offer the ability to communicate with assets and personnel beyond the reach of terrestrial systems. This paper outlines LEO technology in general and focuses on pipeline applications based on the little LEO systems. The intention is to give communications professionals in the utility and energy industries, a primer that enables them to better understand where they can best apply LEO technology to derive benefit for their company's operations. This paper is intent to focus especially on the international pipeline operations companies where important data can be gathered from the operations field and utilized to its fullest extent in order to gain both maximum safety and efficiency.

History of Wireless Communications:

In 1887 Heinrich Hertz demonstrated that electromagnetic waves existed, but no-one thought of a practical means of using these waves until a young Italian, Guglielmo Marconi, conceived the idea of applying them to telegraphic communications. In 1896 he applied for the world's first patent for wireless telegraphy.

A wireless telegraph service between Clifden, Ireland and Glace Bay, Canada was established in 1907. This was the first ever transfer of data and voice communication between two continents. Long wave transmitted messages with large and expensive antennae systems also using high-powered transmitters (see fig i.). This method was found to be both expensive and unreliable and was replaced by Short Wave transmission. The utilization of short wave transmission became a strong competitor to transmission by cable links.

"What hath God Wrought" were the famous words which Samuel Morse telegraphed 1844. The Morse code evolved utilizing a series of dots and dashes as a means of transmitting data. However, it was not until 1837 that a patent was submitted by Charles Wheatstone for the "Electric Telegraph".
 
 

A further means of communication was developed by Graham Alexander Bell 1876 one which is now commonplace throughout the world known as the telephone. Bell's patent was filed on 14th February 1876 just two hours before a similar patent was filed by Elisha Gray. Alex Reeves known as Pulse Code Modulation (PCM) first conceived digitization of telephone transmissions in 1937. This method was deployed in the United States by the Public Switched Telephone Network in 1962.

The foregoing information is presented as a means of comparison between the Marconi era and the transmission of data in this modern age that covers the entire world and even carries deeply into outer space.
 

Satellite Technology:

GEO, MEO, and LEO are all industry jargon used to describe the different types of satellite orbit. fig. ii. shows the different orbits utilized by the Orbcomm system.

For many years, the dominant platform for space-based communications has been the GEO satellite. Due to the distance between the Earth's surface and the GEO satellite, highly specialized end user terminals are required. For example, accurate alignment of the user terminal antenna is critical to the performance of the product. In addition, the distance also requires significant Radio Frequency (RF) energy to overcome the path loss.  This has size implications for both battery life and product packaging.

GEO satellites are typically used for fixed-site and bandwidth intensive applications such as leased lines, international PSTN connections, television programming, and video feeds. Other applications, such as mobile telephony, are also used but they are often expensive and typically used by a small number of specialized users.

The drawbacks of using a GEO satellite include the terminal cost, service price, regional coverage, and line of sight from the terminal to the satellite. Each terminal must have a clear south-facing view in the Northern Hemisphere and a north-facing view in the Southern Hemisphere.

Additionally, for two-way voice communications, the propagation delay is significant and this has restricted widespread use of GEO satellites for this application.
Some examples of GEO-based satellite systems include those operated by Inmarsat, AMSC, PanAmSat, and GE Spacenet, (as illustrated in  fig iii.)
 
 

MEO satellite technology can best be described as a hybrid version of GEO and LEO technology.  It combines the advantages of both to provide a system with fewer satellites than a LEO system, but more than a GEO.  The higher altitude of a MEO satellite provides a bigger footprint than a LEO, but requires less power than a GEO. There are no commercially deployed systems of this type at this time; however, the system to be operated by ICO plans to deploy this technology for voice and data service over the next several years.

In LEO systems, the low orbit reduces the RF power requirements, but decreases the amount of time the satellite is directly overhead a particular location. Consequently, many more satellites are deployed in a constellation, which provides global coverage.  The lower RF power requirement translates into smaller user terminals and both battery and antenna performance requirements are reduced. LEO systems can further be segmented into so-called "Big-LEO" and Little-LEO" categories.
 Current commercial or near commercial examples of Big-LEOs are Iridium and Globalstar, current commercial and near term commercial examples of Little-LEOs are ORBCOMM and Final Analysis.

For the purpose of transmitting data from pipeline field operations to pipeline control centers the ORBCOMM Little-LEO system has been selected.
 
 

Pipeline Industry Requirements:
The pipeline industry, as a whole, is an industry that is, and has to be, extremely safety conscious due to many factors, which can lead to total disaster if not carefully monitored. Many oil and gas pipelines are operated under extremely high pressures and although they may look quite innocent, on the exterior, can be hazardous if not operated and maintained correctly. To ensure safety and efficiency, the industry does take extreme caution to monitor all factors of pipeline operations. Data requirements include:
 

Safety Factors:
 

1. Pipeline Pressures and Temperatures.
2. Cathodic data including rectifier current and voltage. Protection against corrosion and possible pipe failure.
3. Pipe to soil potentials at frequent intervals. This ensures that the pipe is protected, cathodically.
4. Leak detection and immediate ability to isolate leakage.
5. Valve status and immediate ability to close off in emergency.
6. Monitoring of pipeline travelers including inspection devices.
7. Monitoring of flow conditions.
8. Pipeline wrapping integrity - monitoring

1.  Monitoring of flow rate and line pressures
2.  Monitoring of batched products.
3.  Monitoring of Compressor and Pumping Equipment
4.  Automating pigs and sphere launching
5.  Regular cleaning operations – pigging

Offshore pipelines transport crude oil and gas from well heads to land bases for onward transportation. In the case of crude oil, this is transported to the nearest refinery for processing.

Other oil pipeline systems such as Colonial, Explorer and Plantation, which are known as Common Carriers, transport refined products to end users throughout the United States which are far removed from the refining plants

The batched products, may be transported for more than one company, are carefully monitored throughout their travel to their various locations. In some cases the batched are separated by mechanical means, pipeline pigs or spheres, and in other cases the products are lapped, the interface being accepted. In both instances the products are monitored, pigs by mechanical or magnetic methods, the lapped products by gravitometers or other similar instrumentation.

Offshore monitoring of pigs especially instrumentation tools is not only necessary but also vital to inspection reporting. Inspection pigs are utilized to locate defects in the pipeline either in the metallurgy or mechanical defects such as intrusions normally caused by ships' anchors. Inspection pigs are normally equipped with two methods of measuring footage traveled the first being an odometer the second system being an internal time clock.  These are used in order to provide accurate timing against known points such as a valve or erected benchmark. By this method, any defects can accurately be pinned down.  Errors in actual location can be extremely costly to both the pipeline operating company and the contractor.

It is therefore a vital factor of pipeline operations that communications take an extremely large part in pipeline systems.  The Startrak Pigging System has developed methods of communicating valuable data utilizing the ORBCOMM Satellite System. This method provides efficiency for both land and offshore operations coupled with a great financial saving to the pipeline operator over the present day SCADA systems.

StarTrak Monitoring System:

In order that both safety and efficiency factors are provided to the pipeline industry, the StarTrak Pigging System transmits all data from the field of operations, which is made readily available to pipeline operators. The system, although developed originally as a pigging process, is not in any way limited to pigging operations. However, the basic system may be described, as follows:

Permanent monitoring stations are positioned along the route of the pipeline at intervals to be determined but typically five (5) miles apart. Between these stations, there are normally cathodic test stations usually at road and river crossings where access is available. In order that pipe to soil measurements may be monitored. Frequently, these sub-stations are tied into the "Master" station either by radio communication, electromagnetic communication utilizing the pipe as conductor, hard wired, or linked directly to Pipeline Control (PLC) through satellite communication network.

"Master" stations contain instrumentation to perform the following functions:

1. Monitor Pig passage, providing station identification, accurate time by     atomic clock and speed of pig at that station.
2. Provide flow based on speed of pig over previous section including calculation of slippage factor.
3. E.T.A at next Master station based on flow conditions as item ii.
4. Rectifier current and voltage of nearest rectifier also provide rectifier     identification.
5. Pipe to soil potential at master station.
6. Valve status from nearest valve station, and the ability to close valve in     emergency situations.
7. Leak detection and monitoring over a typical 30-mile section per EFA     Technologies System.
8. Pressure, Temperature at any given station along the pipeline.
9. Evaluation of pipeline protective wrapping at any section.

Each station is designed to transmit this information either by the passage of a "Pathfinder" Magnetic Pig, on Command or on a Timed Basis. Items i & ii would be excluded from command or timed basis.

Pigging Operations:

Each "Master" station is equipped with a specially designed intelligent magnetometer in order to detect the passage of a magnetic pig and cause data to be transmitted on a VHF frequency to the ORBCOMM Satellite Network. This specially designed magnetometer consists of a dual sensor array that is required to be buried close to the pipeline.

The sensors are positioned at seven (7) meters apart in order to provide two distinct applications. The first of these obtain speed of the pig at that station, the second to provide system security in the event of becoming activated by lightening. The intelligence is provided by a micro processor contained on the mother board, together with electronics for other various applications, located in a weatherproof housing and mounted, as shown in fig iv.

The sensor assembly is designed to be programmed for sensitivity and reset time after it has become activated. The latter function allows the pig clear passage from the station so avoiding the possibility of becoming re-activated by the pig's passage at low flow rates.

The magnetometer detects the crossover of polarity and causes the entire system to become active thus transmitting the required data. In the case of magnetic spheres, there is a single magnetic pole therefore the magnetometer becomes active at maximum field strength in order to detect the sphere directly under the sensor. This method may be used to activate valve systems.
 

Offshore Operations:

Offshore requirements certainly include pigging operations but may differ from land requirements in as much as leak detection over larger sections of 30 miles may not prove practical. Further, pipe to soil measurements cannot be accomplished in the same manner as those on land sections. Valve monitoring and E-stop facilities can be accomplished.

Due to potential paraffin wax problems in crude oil systems, it is necessary that on line temperature be monitored in order to recognize possible problem areas where wax build-up may occur. Therefore, especially in deep waters, all data may be transferred from sub-sea locations to the surface by acoustic transmission. Such data to be received by instrumentation housed on a permanent positioned buoy. The digitized data is transmitted through the ORBCOMM system back to a central operating control station that may be either on land or at the offshore platform.

For pigging operations such as on-line inspection programs, a temporary station is positioned inside of a surface buoy. (See fig iv).  The sensor is located directly on the pipeline and connected by cable to the surface electronic package.

DGPS coordinates are taken at that station which has its own internal reference. At the passage of a magnetic tool, the station becomes active and causes a transmission to take place that provides time of the event together with station identification.

For deep-water applications, it is not practical to use cable connection from sensor to the surface; therefore an acoustic system is utilized. At the passage of a magnetic pig, or on command, a train of acoustic pulses is transmitted to the surface where it is received and re-transmitted to the satellite system. Dependant on the water depth at selected locations; one surface station may be capable of handling several sub-surface monitors. It would also be practical to have a two-way communication system in order to command the activation of sub-surface units such as valves.

Conclusion:

Presently, many of the functions, as described in this paper, are carried out by extremely expensive methods such as pig monitoring.  In one particular case it was witnessed that thirty-two pipeline technicians using five vehicles attempted to track one pig through a pipeline section. In that particular instance, they missed the pig's passage at three out of the four stations. The use of permanent stations would have provided a much higher degree of efficiency with lower labor intensive requirements. Other operations include the use of helicopters to transport technicians to remote areas in order to either monitor pigs or obtain critical data such as pipe to soil potentials.

Monitoring of instrumentation pigs to one-tenth of a second at known GPS locations provides inspection companies with a higher degree of accuracy for their final interpretation of defective areas after pipeline inspection surveys have been carried out.

For companies transporting different grades of products for various customers, the system would provide an efficient method of monitoring batches of product so allowing greater overall control of the possible contamination between products. Greater versatility can be achieved by use of satellite monitoring systems while providing operations personnel with critical data.
 

In addition to the benefits as previously described, which are derived from satellite communication technology, which is directed to the pipeline industry, further benefits are now available to the utilities industries. To examine one single case alone, one finds that every month meter readers appear to read electric meters, gas meters and water meters. Coping with this monitoring system, especially in large cities, can be both expensive and not always reliable especially during winter periods. One satellite monitoring system per household could easily accommodate electric, gas and water companies. This would be conducted on a timed basis and the costs shared between the respective organizations.

The systems described in this paper will enhance future pipeline operations to ensure a higher level of technology at vastly reduced costs for both installation and operations. The key words being: