new TECHNOLOGIES FOR NATURAL GAS OPERATIONS.
* Guided Mole Provides Simple, `Trenchless' Pipe Installations
GTI-sponsored research to reduce the need for trenching has resulted in the introduction of the Guided Mole, a low-cast, steerable, horizontal ground-piercing device used for new pipe installations.
Early in 2000, TT Technologies, Inc. (Aurora, Ill.)--a major manufacturer of ground-boring equipment--introduced commercial units under the Grundosteer[TM] tradename to join its line of Grundomat piercing tools. Digital Control Inc. (Renton, Wash.), a leader in location and tracking technology, produces the tool's guidance system.
The tool was developed as part of GTI's program to introduce "trenchless" technologies for natural gas distribution operations. With the Guided Mole, utility crews create precise underground pathways for pipe installations, thus avoiding major ground-breaking, trenching, excavation, and restoration activities required with more traditional installation methods. (The cost of restoring landscapes and pavements alone can account for up to 75 percent of the cost of a typical open-trench installation.)
The Guided Mole is priced competitively with the typical guided drilling machine. GTI estimates that even if the product has a market impact of only one percent in the year 2000, it could provide savings to the utility industry of up to $1 million.
"Obviously, considerable savings result from only having to dig a few holes, rather than trenching," explains Renny Norman, GTI Principal Product Development Manager. "However, underground boring is a much more sophisticated procedure than simple trenching. With the advanced technologies developed specifically for the Guided Mole, researchers were able to make the tool both steerable and simple to operate."
In operation, entrance and exit pits are usually created for the launch and retrieval of the pneumatically powered impact tool. (However, the tool has added flexibility in that surface launch and retrieval can also be used.) Onboard sensors providing pitch and roll information, and a handheld, aboveground locating device tracks the position and movement of the tool. Operators, noting when the tool begins to move off the planned course, correct its path by rotating the pneumatic hose tethered to the tool to provide the proper alignment of the tool body with the device's specially designed off-center steering head.
The three-inch-diameter tool was developed under GTI sponsorship by Foster-Miller, Inc., to address the need to improve operations related to installing residential service lines and small distribution mains (less than four inches in diameter), which account for the majority of most utilities' pipe installations.
Depending on soil conditions and borehole size, the Guided Mole has demonstrated the ability to bore on-course up to 150 feet.
"For our company, this tool is an absolute necessity," says George Ragula, Distribution Technology Manager for Public Service Electric & Gas Company (PSE&G) in New Jersey. "No one tool can be used for every pipe installation situation; we need a variety of tools and technologies. However, in PSE&G's highly urban service area, the Guided Mole serves us well due to its simplicity and ease of operation."
PSE&G was one of several utilities to test the Guided Mole for GTI. However, since receiving a prototype in 1997, use of the tool has become part of the company's common practice. PSE&G has used the Guided Mole for more than 5,000 feet of pipe in more than 50 installations under streets and highways, parking lots, stream crossings, and landscaped areas. In 10 jobs alone, the company saved more than $32,000 in labor and restoration costs.
Adds Ragula: "The use of this tool has proven to be effective in safely and reliably reducing costs while enhancing customer satisfaction."
* Companies Finding Leaks Faster with OMD
In Minneapolis, Chicago, Philadelphia, Brooklyn, San Francisco, Toronto, and other areas of North America, crews are speeding up the process of natural gas leak detection with the advanced technology built into the Optical Methane Detector[TM] (OMD), a product from the GTI program that entered the market in 1908.
With the (OMD) mounted on the front of utility vehicles, crews are accurately detecting methane leaks while traveling at normal traffic speeds. Field demonstrations--and, now, studies of real-life practice--show that mobile leak surveys using the OMD can be conducted up to four times faster than surveys using traditional methods (e.g., flame ionization detection, which limits speeds to 3 to 7 mph). The results are overall productivity improvements of 20 to 50 percent or more. Even at higher speeds, the OMD has shown the ability to respond to one-part-per-million (ppm) of methane or less.
Development of the OMD began at GTI in 1988, and, over the years, has involved the expertise of Westinghouse Science & Technology Center, Carnegie-Mellon Research Institute, and a host of utility participants. The product is now under license to Heath Consultants Incorporated, which manufactures and markets the (OMD) throughout the world.
Although the OMD is a relatively new product, GTI's post-commercialization research indicates that utilities are already reaping significant benefits by adding the OMD to leak survey fleets.
Says Paul Beckendorf, GTI Principal Product Development Manager: "Every once in a while a technology comes along that yields a huge gain in productivity. The OMD is one of these. It is literally changing the way utilities conduct their leak survey activities. GTI's involvement in the entire process, from concept development through commercialization, helped assure the success of this radically different technology."
As of December 1999, nearly 60 OMDs had been shipped to utilities. Interviews with users confirm the predicted productivity increases.
"Post-commercialization research shows the capability for companies to eliminate one out of every three leak survey vehicles," asserts Beckendorf. "In addition, users are reporting a potential 90 percent decrease in maintenance costs by using the OMD over flame ionization units."
"One of the unit's characteristics that stands out is the reduced maintenance requirement," notes Anton Kacicnik, Project Supervisor, Enbridge Consumers Gas. "The OMD does not have any parts that would require daily maintenance and calibration. There are no parts to clean, filters to clean and/or replace, fuels to replenish, or batteries to change. The field use showed that the only consumable item for the OMD is an occasional tissue to clean the lenses. No other field leak detection equipment comes to mind that would require that little maintenance."
Most of the companies indicated that they are changing business practices when switching from flame ionization to OMD mobile units. However, some of the companies are making significant improvements to take advantage of the OMD's capabilities:
* One company is reducing the number of surveyors in the vehicle from two to one.
* Other utilities are considering using OMDs in areas not now "mobile surveyed." One company that previously had to do walking surveys because of high traffic speeds estimates its use of the mobile OMD yields a productivity increase of 2,000 percent.
* Chevron Production is attaching the OMD to all-terrain vehicles to survey gathering lines not accessible with conventional survey vehicles. "Typical leak detection surveys of our gathering lines require a man and a track, plus a field guide--and the survey is usually conducted on foot," explains Chevron's Ron Drymon, Head Oilfield Operator. "With our OMD, it requires only the vehicle and driver."
* Overtime work on special surveys conducted by northern utilities during the winter when frost is in the ground is being eliminated or reduced due to the increased productivity of the OMD units.
"We liked the concept from the beginning," reports Jerry Freeman, Leak Survey Technician with Reliant Energy Minnegasco. "We were impressed by how small of a leak the OMD could find compared to flame ionization equipment. We also like the idea of no maintenance except for the calibration and the light bulb. There isn't any noise from a pump pulling in an air sample and the worries of a tubing line not being connected."
Reliant Energy Minnegasco is taking the initiative to advance the OMD technology by developing an automated leak detection system using an onboard computer linked with a Geographic Information System (GIS). Leak survey area maps from the GIS are loaded in the truck computer to track the survey area. Information is then imported back to the GIS and stored as a permanent record.
"The Office of Pipeline Safety from the state of Minnesota is very excited about our moving ahead with this part of the project," Freeman adds. "This will eliminate the possibility of missed surveys or incomplete data. We believe combining the OMD with the automatic leak detection system will make us better at serving our customers safely, along with our responsibility to the general public."
* New Device Provides Real-Time Energy Data at Low Cost
Ametek, Inc., is introducing a new microprocessor-based instrument that measures the energy content (heating value) of natural gas at a lower cost than conventional measurement equipment.
Developed through the GTI program originally as a microcalorimeter called the "Therm Factor Transmitter," Ametek's GEC 100 Gas Energy Content Meter is designed to provide data in real time, expressed as therms/scf (standard cubic foot), for large-volume customer metering applications. At a cost of about $4,000 per unit, the GEC 100 can do the job of two common devices--a standard calorimeter or a gas chromatograph--at a savings of about $10,000 to $25,000 per application.
"Originally, this was a basic research project at GTI," explains Renny Norman, GTI Principal Product Manager, "where the feasibility of the concept was proven. It has since gone through a series of prototype phases and rigorous field testing to bring it to market."
Tests were conducted by Nicer Gas, NW Natural, Cinergy Corp., Pacific Gas and Electric Company, Public Service Electric and Gas Company, and Southern California Gas Company. Demonstrations showed an average measurement repeatability within the goal of 1 Btu.
Notes Norman: "In today's gas industry, the need for lower-cost, real-time, more-accurate metering is being driven by increased competition and the varying quality of gas supplies. Large-volume customers, especially, require real-time precise measurements for accurate billing. The GEC 100 was developed specifically for this type of application. We estimate that through the use of the GEC 100, the industry could realize savings of up to $10 million a year upon full industry usage."
The GEC 100 uses catalytic technology to measure energy content by reacting a sample from a natural gas stream with a carrier gas, and then measuring the heat given off by the reaction.
The device is AC powered and can cover a range of 800 to 1,500 Btu and operates in -4 [degrees] to 122 [degrees] F. The calibration gas is rugged and has a dewpoint below -20 [degrees] F.
Says Ametek Project Manager Steve Maselli: "More widespread use of therm measurement in the industry can result in new marketing strategies, improved customer relations, and increased profitability when it is applied on a real-time energy measurement basis. The timely identification of supply costs and distribution system loading can also make it possible to serve new markets in the gas industry, such as seasonal loads, and lead to the introduction of new rate structures."
* Report Looks at Cast-Iron Bell Joints
The number, methods, and costs of repairing leaks in cast-iron bell joints are available in a GTI report based on a survey of 24 natural gas companies.
Among the findings are that the weighted average cost of sealing bell joints--including excavation, repair, back-fill-ing, and restoration--was $986 (average repair costs ranged from $200 to $2,433). The survey also showed that most companies (76 percent) use their own crews for repair work, while 24 percent use contractor crews.
According to U.S. Department of Transportation reports, as of 1996, the industry had about 49,000 miles of cast-iron pipe in the ground, about 42 percent of which was owned by survey respondents. While the amount of east-iron gas lines has been decreasing (a 7 percent reduction from 1993-1996), repairing leaking joints is a prevalent industry concern. It is estimated that about 91,000 such repairs were made in 1996 alone.
As described in the report, several programs at GTI have investigated new methods for sealing cast-iron joints, including a technique for applying sprayable sealants from inside the pipe while gas is flowing. Other research identified the need for tighter requirements for expansion/contraction at joints and resulted in requests to sealant manufacturers to modify existing materials.
* CEESI-Iowa Addresses Industry Need for High-Volume Meter Calibration
Gas meters are the cash registers of the natural gas industry--the devices used to ensure that the gas company and its customers receive the right amount of energy, at the right time, for the right price. Inaccurate meters can result in gas-exchange inequities that could mean millions of dollars in lost revenues for the company, and over- or under-delivery to customers.
With today's highly competitive gas industry, the proper maintenance and calibration of measurement equipment has become a prime concern. However, there are few U.S. sources for advanced measurement services outside of the expertise of specific meter manufacturers.
Recognizing the need for a facility for large-diameter gas pipeline meter calibration, in 1999 GTI began supporting the development of the High-Flow Test Facility in Ventura, Iowa--operated by the Colorado Engineering Experiment Station, Inc. (CEESI)--to address the special needs of large-volume meters.
Prior to its opening in mid-1999, an extensive inter-laboratory comparison with European facilities was made. Tests of meters ranging in sizes from 20 to 30 inches in diameter confirmed that the venture facility duplicated results from the established European facilities.
"Our research has shown that ultrasonic flowmeters hold a lot of promise for more accurate and lower-cost means of measurement," explains GTI Program Manager Stephen Foh. "However, the lack of a facility for calibrating these meters has hindered their use in the United States. Prior to CEESI-Iowa, the only large-volume calibration facilities were in Europe. Now meter manufacturers and users have a domestic source."
GTI viewed the Iowa facility as a strategic complement to the GTI Metering Research Facility (MRF) in San Antonio.
"While the GTI MRF mainly focuses on lower flow rates, CEESI-Iowa addresses the higher flow ranges and pipeline pressure," says Foh. "This provides the U.S. gas industry with a full-range of calibration and development testing capabilities."
The CEESI-Iowa facility provides ultrasonic flowmeter calibration using actual flowing conditions with sizes up to 36 inches in diameter and a daily throughput in excess of two billion standard cubic feet. In addition to ultrasonic meters, the facility offers services for extended-range turbine meters and other meters that require calibration at high Reynolds numbers. The facility is also well suited for studying the effects of flow conditioners on meter performance and measurement.
"The bulk of our calibrations so far have been ultrasonics," notes Steve Caldwell, CEESI Vice President. "However, we can calibrate any meters ranging in line sizes from 4 to 30 inches. A particularly attractive feature of the facility is our quick turnaround time, usually one to two days."
* Using Satellites for Pipeline Protection
GTI researchers, investigating the use of satellite-based technology for pipeline protection, have identified the potential for satellite imagery to detect slope motion and ground movements that could threaten nearby pipelines.
As detailed in a GTI report (GRI-99/0096), interpretations of satellite radar data of three sites along a Northwest Pipeline Corporation natural gas line showed that the technique--called satellite radar inferometry --could provide a less expensive means of determining significant slope motion risks.
"Currently, slope motion is usually measured, if at all, with techniques like laser range finding using reflectors," explains GTI Project Manager Keith Leewis. "And pipe strains can be measured by strain-gauge systems. However, these are all relatively expensive and require pre-positioning of equipment. Today's satellite-based technology offers a cost-effective alternative."
For the study, researchers combined images (to form "interferograms") taken before and after suspected land motion at sites of historical ground movement near transmission pipelines.
* At one site, results indicated an area of land motion uphill from, and moving toward, an adjacent pipeline--a significant finding because the land motion had not been previously known to the pipeline operator.
* A second site was initially misidentified, and investigators examined an area north of an actual point of known previous ground motion. No motion was discovered; and while not the original study's intent, the research showed that the technique does not readily generate "false positives."
* Images were limited at a third site due to wet snow. However, this served to test the limitations of the satellite technique and indicated that radar images must be timed to avoid new snow on the subject areas.
"It is hoped that further research will better establish this technique for application to gas pipelines," says Leewis. "But even by itself, this study shows good promise for the technique in detecting large area motions hazardous to pipelines."
* DOT Approves Use of Clock Springs Pipe Repair System
In January 2000, the U.S. Department of Transportation (DOT) formally approved the use of the Clock Spring[R] technology for specific repairs on all natural gas pipelines in the United States.
Clock Spring was developed by NCF Industries Inc. and Clock Spring Company of North America, LP, with support from GTI and the former Panhandle Eastern Corporation, to provide pipeline companies with an effective alternative to more costly methods for repairing gouged, dented, or corroded pipe. With Clock Spring, repairs are made by wrapping a pipe defect with a fiberglass composite-reinforced coil held in place with a specially designed adhesive.
When Clock Spring was initially developed in the early 1990s, pipe repair regulations for the type of defects Clock Spring can repair outlined only two methods: covering the damaged pipe with a welded metal split sleeve or replacing the damaged section--both of which require shutting down the line.
Explains GTI Principal Project Manager Keith Leewis: "With Clock Spring, not only can repairs be made more economically than conventional methods, but all repairs are made while the line is in service without a loss in revenues."
GTI estimates that use of composite repairs could provide annual savings of $8.5-$11.5 million to the gas transmission industry. Labor and material savings using Clock Spring have been estimated at up to 40 percent over the metal sleeve repair method and 65 percent over section replacement. Importantly, repairs restore the strength of the line pipe sufficiently to permit it to operate at its original allowable operating pressure. Additional GTI research has shown that Clock Spring repairs will maintain the integrity of the pipe for more than 50 years.
Prior to January's full DOT approval, pipelines were using the technology under special waivers from DOT and state authorities. (Worldwide, more than 45,000 Clock Spring repairs have been made on high-pressure pipelines.)
"As the authority responsible for pipeline safety, before granting approval of any product, the DOT has to be fully convinced of the safety, as well as the economic benefits, of using the technology in the field," Leewis notes. "We expect the results of this blanket approval will be a considerable expansion in the use of Clock Spring on gas and oil pipelines in the United States."
Leewis cites significant R&D activities for helping to prove the validity of Clock Spring technology. Efforts involved hydrostatic testing, accelerated corrosion testing, and the development of companion software for identifying the severity of defects (GRIWrap[TM]). In addition, to further verify its permanence, Clock Spring-repaired sections that were buried for up to seven years in actual operating conditions were uncovered and tested, showing that none of the repairs exhibited any deterioration.
Clock Spring is manufactured and marketed by Clock Spring Company of North America, LP (Houston).
* Stray Current Mapper Protects Piping System Ability to Inhibit Corrosion
Most steel natural gas piping networks are equipped with cathodic protection (CP) systems that impress low-voltage currents on the pipe to inhibit corrosion. However, in the increasingly complex underground environment, stray currents from other sources (such as parallel or crossing pipelines, industrial plants, or electrified rail systems) can reduce the CP system's effectiveness and, in some cases, accelerate pipe corrosion.
In response, GTI and an international consortium of natural gas companies are supporting Radiodetection Corp. in the development of a Stray Current Mapper--an aboveground, one-person-operated system that can detect the source, identify the discharge point, and assess stray current amplitudes. The system is expected to be commercially available in 2000.
"With this tool, the industry will have a device to help solve a complex problem," explains GTI NDE Program Manager Harvey Haines. "Removing stray currents from the pipe is much easier once the source of the stray current is located."
Traditional techniques to identify stray currents rely on time-consuming tests. The Stray Current Mapper provides a new, cost-effective method for routine examinations.
With the mapper system, multiple components (called "smart sensor bars") are positioned on the ground directly above the pipeline at suitable intervals. The sensors, each with a unique identification, log data to create a system profile that allows operators to identify stray current sources. Operators can quickly identify problems by using handheld receivers--walked along the pipeline and synchronized with the sensor bars--that interpret data, map the stray currents, display results in real time, and determine the current amplitude and direction.
The technology is built on the success of another product, Radiodetection's Pipeline Current Mapper--also supported by GTI, Southern California Gas Co. (SoCal), and Pacific Gas and Electric Co. (PG&E)--which can assess the effectiveness of CP systems and determine if and where the pipe is contacting other structures or experiencing coating defects.
The research consortium for the Stray Current Mapper project includes SoCal, PG&E, the New York Gas Group, Italy's SNAM S.p.A., and the Netherlands' Gasunie. Field tests will be conducted in cooperation with consortium members to determine costs, benefits, and final design changes.
"The Stray Current Mapper represents a quantum improvement in the methodology for dealing with stray current interference," notes William Boyd, Research Manager for SoCal and project manager for the consortium. "Interference test data that were previously limited in scope and costly to obtain--if available at all--will now be readily accessible and easily understood using the new technology."
PSE&G has used the Guided Mole for more than 5,000 feet of pipe in more than 50 installations under streets and highways, parking lots, stream crossings, and landscaped areas. In 10 jobs alone, the company saved more than $32,000 in labor and restoration costs.
* How It Works
The OMD is based on the ability of methane gas to absorb specific wavelengths of infrared (IR) light. An IR light source, mounted on one side of the vehicle's front bumper, directs a beam of light at an optical detector mounted at the other end of the bumper. If the vehicle encounters a gas leak plume that intrudes into the IR light beam, the detector responds to the presence of methane and sends a signal to a display panel inside the vehicle. The OMD performs 14,000 measurements per second, which provides an instant response to a gas leak over a wide range of vehicle speeds.
The OMD is simple to use, lightweight, and can be quickly mounted on a variety of vehicles.
* Calculating the benefits
Most of the benefits to be gained from using the OMD are hosed on the increase in speed at which the vehicle can be driven and, consequently, the increase in efficiency of surveying. This will be affected by the traffic conditions, general survey environment, and the number and nature of the leaks identified. In addition, benefits vary based on the use of the OMD and miles driven.
As shown in the chart, based on assumptions for 8,500 annual survey-miles and a 30 percent improvement in productivity, a company can expect $178,500 in annual savings.
* Average FI survey speed--5 mph
* Average cost of mobile survey--$70/mile
* Survey crew--2 crew-members
* Mobile survey productivity--12 miles/day --955 vehicle-miles/yr.
Stray Current Mapper Research Consortium
* Southern California Gas Co.
* Pacific Gas and Electric Co.
* New York Gas Group
* SNAM S.p.A. (Italy)
* Gasunie (Netherlands)
* Copies of the report--A Review of U.S. Cast Iron Bell-Joint Repair (GRI-99/0089)--are available through GTI's Document Fulfillment Center (firstname.lastname@example.org; FAX: 630/406-5995) and through www.gastechnology.org at no cost for GTI members and for $25 (plus shipping and handling) for nonmembers.
for MORE INFORMATION
* Jim Albrecht Principal Communications Specialist Gas Technology Institute 847/768/-0500 FAX: 847/768-0501 email@example.com
[C] 2000 by Gas Technology Institute. Subscriptions to GRID are free to the natural gas industry. Address subscription requests to:
Editor, GRID Gas Technology Institute 1700 South Mount Prospect Road Des Plaines, Illinois 60018 USA
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|Title Annotation:||Guided Mole drilling machine|
|Comment:||new TECHNOLOGIES FOR NATURAL GAS OPERATIONS.(Guided Mole drilling machine)|
|Publication:||Pipeline & Gas Journal|
|Article Type:||Product Announcement|
|Date:||Oct 1, 2000|
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