EL PASO NATURAL GAS NEARING COMPLETION OF SYSTEM'S LARGEST EXPANSION

El Paso Natural Gas Co.'s largest expansion program in its 64-year history will be completed along its northern system this spring or early summer.

According to the company, the three-tiered, $241.5 million expansion program will increase El Paso's gas-transport capacity by 835 MMcfd to 2.5 bcfd of conventional and coal-seam gas from the San Juan basin in northwestern New Mexico. That's enough natural gas, says the company, to supply the needs of a city of more than 800,000 residents.

The expansion involves the San Juan Triangle system, the company's northern main line, and the Permian-San Juan crossover line (Fig. 1).

The company also filed with the Federal Energy Regulatory Commission (FERC) in October 1991 to construct a new $15.2 million compressor station, Rio Vista, south of Bloomfield, N.M. The station would be used to move additional gas to the main line.

SERVES NEW GAS SOURCES

A major part of the expansion lies in the San Juan Triangle system where El Paso Natural Gas Co. (EPNG) will increase its takeaway capacity from the gas-rich San Juan basin in northwest New Mexico. This will help to eliminate the curtailments El Paso's producers have suffered as a result of limited pipeline capacity the company says.

The need for increased pipeline capacity in the San Juan basin arises because of the development of major new sources of gas, particularly coal-seam gas. The proposed expansion in the basin is designed to accommodate this increased production capability.

Recently, says Ronald H. Merrett, director of the New Mexico office of Interstate Natural Gas Markets, gas production in the San Juan basin has been restricted for lack of pipeline capacity to transport it to market. But completion of the expansion will greatly relieve this problem.

EPNG's pipeline expansion is particularly important because the increased ability to produce coal-seam gas in the San Juan basin has resulted in a doubling of production, Merrett says.

He says that producers hope to increase production in the basin by at least another 50% over the next 3-4 years. This should result in proportionate increases in state revenues.

According to EPNG, the amount of additional domestically produced natural gas can displace as much as 138,000 b/d of imported oil.

THREE PHASES

Construction work has consisted of more than 53 miles of pipeline loops along the main transmission line in the Four Corners area of New Mexico, extending from Blanco Plant to Valve City,

The looping utilizes 42-in. diameter pipe-the largest ever put into service on the EPNG system.

Along with the pipeline looping, a 12,000-hp, gas-turbine compressor set will be added to White Rock compressor station, approximately 30 miles south of Farmington, N.M. (Fig. 2).

In the second part of the expansion, El Paso will increase the capacity of the San Juan main line to California to allow it to handle most of the 400 MMcfd of gas subscribed on Mojave Pipeline in which El Paso is a partner.

Mojave forms much of the California portion connecting the recently commissioned Kern River Pipeline from Wyoming to near Bakersfield (OGJ, Mar. 9, p. 32, Mar. 16, p. 28). From Daggett, Calif., Mojave and Kern River jointly own the 1.1 bcfd line which Mojave operates from its Bakersfield headquarters.

Mojave and Kern River have begun supplying natural gas for enhanced oil recovery and cogeneration operations in central California. EPNG's expansion will also permit increased deliveries to existing utility systems in California, says the company.

From Valve City to Topock measuring station on the east bank of the Colorado River in Arizona, 178 miles of 34 and 36-in. pipeline loops have been installed along the existing system (Fig. 1).

Turbine upgrading, compressor modifications, and horsepower additions to existing compressor stations will provide an additional 23,516 hp of compression along this portion of the pipeline system.

The third part of the expansion, which was completed in 1991, made the present crossover line from the Permian basin to the San Juan basin bidirectional.

The line currently transports gas only from east to west but was expected to begin eastward flow by the first of this month. By modifying the line to transport natural gas in the opposite direction, the company will be able to move San Juan basin gas east for delivery to markets in the U.S. Midwest and East Coast.

Additional new metering facilities, together with certain changes to compressor piping at the Caprock, Lincoln, and Belen compressor stations, will allow 429 MMcfd of gas to move east to El Paso's Plains, Tex., compressor station for further transportation to eastern and Midwestern markets.

Construction of the expansion project began after the program was authorized by the FERC.

Approval to begin construction of the Rio Vista station should be obtained by the company later this year, and the station should be operational by mid-1993.

As of this spring, El Paso will be transporting more natural gas than ever before and will be flowing gas eastward as well as westward.

ENVIRONMENTAL EFFORTS

According to the company, 18 months and a mile of paperwork were required before EPNG received preliminary approval from the FERC in September 1991 to begin work on the expansion.

Federal legislation applicable to the expansion project includes the Native American Grave Protection and Repatriation Act, the Endangered Species Act, the National Historic Preservation Act, the Clean Air Act, and the Clean Water Act.

EPNG also conducted studies and designed mitigations to satisfy four land-managing entities: the Bureau of Land Management, the U.S. Forest Service, the Navajo Nation, and the Arizona State Land Department.

In general, says the company, most state requirements are met by fulfilling federal requirements.

To satisfy emissions control standards on the upgraded compressor stations, an evaluation of emission rates was required. Greg Odegard, EPNG director of environmental affairs, says that there was evidence that some of the new engines would not meet the U.S. Environmental Protection Agency's New Source Performance Standards.

EPNG agreed, therefore, to install emission controls that meet the requirements on some of the new ones. He says that air-monitoring stations also were installed to collect data on ozone and NOx levels in the area.

Because certain sensitive, threatened, or endangered plants and animals were suspected to be in specific areas along the project right-of-way, El Paso conducted surveys for these species.

Desert tortoise surveys were conducted on state, private, and federal lands in western Arizona. Populations were discovered along the western part of the proposed route. Trained biologists were present during construction in these areas to rescue any tortoises that were found.

A field survey for blackfooted ferrets was performed at the request of the Navajo Indians. Additional surveys were conducted on Forest Service lands for goshawks and spotted owls, which the service considers sensitive species.

To comply with the National Historic Preservation Act, EPNG conducted a cultural-impact assessment. The results generated a six- volume, 1,600-page report, says the company, which describes how excavation will be handled to preserve more than 100 historic, prehistoric, and sacred sites identified along the proposed pipeline route within the Navajo Indian Reservation.

These sites included ancient dwellings, campsites, and burial grounds, as well as areas used for gathering herbs and plants for religious and medicinal purposes. Where necessary, the pipeline route has been shifted to avoid a major site altogether.

Special agreements were reached with Indian tribes to determine what measures would be followed to protect any burial remains that might be discovered during construction. The arrangements set forth 1-2 day periods for notice to Indian tribes to collect burial remains and sacred items should any be uncovered during excavation.

Without these special arrangements, says El Paso, federal law would require the company to halt construction for up to 30 days at the site of a burial discovery.

To ensure compliance with environmental mitigations, a trained team of environmental inspectors will be present on the site during construction. Working in pairs, these inspectors will observe activities along each 15-mile spread. Their responsibilities will include ensuring that archaeological sites are undisturbed, that no damage occurs to areas outside the right-of-way, and that trash is removed from the site.

Once the pipeline is completed, crews will return to replant vegetation along the right-of-way.

When construction is complete, the environmental work for the current project will add more than $3 million to its cost, says El Paso, amounting to about 2% of the $241.5-million total cost.

BI-DIRECTIONAL CAPABILITY

Natural gas traveling through the EPNG pipeline system traditionally has made a one-way trip west. But the ability to sell gas in Midwestern and eastern markets has become a desirable alternative for producers.

Modifications to existing pipelines in the San Juan basin-Permian basin crossover have made the eastward flow of gas possible. Demand will determine whether gas flows east or west.

Carroll Crawford, EPNG director for measurement technical operations, says bidirectional capability through the existing line has been accomplished by the repiping of facilities at several compressor stations and installing bidirectional flow orifice meters and secondary electronic flow measurement (EFM) units.

He says the changes to accomplish operational control of the pipeline are innovative and cost-effective.

Crawford says that the seven compressor stations along the way will remain virtually unchanged with the exception of station piping modifications. Reversing the gas flow will be accomplished by installing new pipe and valve arrangements within the bi-directional compressor stations so the gas can enter through the existing station suction piping.

After compression, the gas then is discharged through another new line that ties into the main 30-in. crossover lines for the continued trip to the east.

This new piping compressor arrangement will be at the Belen station (40 miles south of Albuquerque), Lincoln station (75 miles northwest of Roswell, N.M.), and Caprock station (50 miles east of Roswell), with bypass capability at the other four stations.

Dual-directional, orifice-type meters and new electronic flow-metering devices will be installed at Wingate check meters, where gas enters the western end of the crossover, and at Plains station on the eastern end.

Bi-directional flow increases the flexibility of services the company offers, says EPNG, and will give producers and sellers new markets through EPNG pipelines.

PROCUREMENT PROCESS

Purchasing large-diameter pipe, compressors, turbine engines, valves, and hundreds of miscellaneous items associated with the $241.5 million expansion has been complicated.

EPNG contacted and evaluated manufacturers in Japan, Canada, France, and other countries before company agents purchased more than 230 miles of pipe for the expansion, says Charles C. Price, EPNGs director of purchasing.

Being lowest bidder, Price says, is not enough. A given company must manufacture according to EPNG's precise specifications and deliver the product on time to meet construction schedules.

Of 25 potential pipeline construction contractors, 8 were asked to submit bids. Two contractors-Great Plains Pipeline Construction Inc., Lubbock, Tex., and Gregory & Cook Inc., Houston-won construction contracts.

Similarly, bids were entertained from three domestic pipemakers and seven foreign manufacturers. Contracts were awarded to two American and one French pipe mill for 34, 36, and 42-in. pipe.

Receiving the contracts were the U.S. firms of Napa Pipe Corp., Napa, Calif., and Berg, Panama City, Fla., and the French firm, GTS (Fig. 3).

Finished pipe usually is transported by railroad flatcars in either 40 or 80-ft. lengths and then hauled to the job site by truck. Half of the French pipe, however, made a complicated trip that included a transatlantic trip by freighter to New Orleans, where it was barged to another destination for coating, and then shipped by rail to the company's pipe staging site in Arizona.

The other half was shipped to Los Angeles, coated, then trucked to two sites in Arizona for Storage.

Moving the domestically produced pipe required more than 1,000 railroad cars, with each holding eleven 80-ft joints.

To reduce costs, EPNG purchased two turbines that formerly had been used on drilling platforms in the North Sea.

After the company's turbine maintenance crews reconditioned the turbines, they were installed at White Rock and Dilkon compressor stations.

Solar Turbines Inc., San Diego, supplied two other turbines and compressors for Navajo and Window Rock compressor stations. It also is constructing a turbine for the proposed Rio Vista compressor station, which is part of another EPNG expansion (Fig. 4).

When flat steel plates arrive at Napa's facility, they are UOEed into tubular pipe for use in El Paso's huge expansion program now under way. "UOE," EPNG says, is steelworker slang that means bending the flat plates into a "U" shape, further bending into an "O", then hydraulically "E"xpanding it into its final shape.

Napa Pipe is the only manufacturer of straight-seam, DSAW (double-submerged, arc-welded) line pipe in the western U.S., according to EPNG. The company, a wholly owned subsidiary of Oregon Steel Mills Inc., produced 113 miles of 34-in. and 36-in. pipe for El Paso.

The facility can produce more than 6 miles of large-diameter pipe a day.

NEW TURBINES

Solar Turbines Inc.'s "Centaur" gas turbines will supply additional power to Florida, Wenden, Dumas, Bondad, Navajo, Window Rock, and Rio Vista compressor stations.

Solar, a subsidiary of the Caterpillar Co., Peoria, Ill., manufactures the turbines and compressors at two large plants in San Diego.

At EPNG's proposed Rio Vista compressor station, the company plans to operate a new Solar system that emits much lower levels of NO, without using increased amounts of industrial water. The turbine will utilize a newly developed combustor (similar to a carburetor in an automobile) developed by Solar which offers low exhaust emissions.