Warren R. True
Pipeline/Gas Processing Editor
Gas-movement patterns for the U.S. west of the Rocky Mountains are in the middle of historic changes.
Last month, Questar Pipeline Co. commissioned its north-south crossover. In July, Questar Pipeline and two partners proposed the TransColorado pipeline, also oriented north and south.
This latter is specifically intended to move curtailed volumes of western Colorado gas south to Blanco, N.M.
Or, gas could move north over Questar's new crossover, then west over one of the proposed Wyoming-California pipelines or east into the Trailblazer system, soon to benefit from full open-access status.
At the same time, two existing gas-pipeline hubs west of the Rocky Mountains are evolving into major gas-transportation centers.
All this activity derives largely from growing gas demand in California and the rest of the U.S. Installation of at least one major gas-transportation system from Wyoming to California is certain.
The activity also derives from the presence of much curtailed gas supply along the western Rockies in Wyoming and Colorado and the rapid pace of gas drilling, especially coalbed, in those areas and New Mexico.
This first of two articles focuses on Questar's north-south pipeline and on the proposed TransColorado pipeline.
The concluding article will discuss the development of major gas-pipeline hubs in southwestern Wyoming and northeastern New Mexico in anticipation of greater supply availability in those areas.
WHAT'S HAPPENING
Activity is occurring in three areas:
- Questar Pipeline Co. has commissioned a $22 million, 81.5-mile, 20-in. link between its formerly separate southern and northern systems (OGJ, Feb. 26, p. 38; Fig. 1).
In addition, the TransColorado project, a planned 31 1 mile system from Rio Blanco County, Colo., to Blanco, N.M. (Fig. 1), was proposed to the Federal Energy Regulatory Commission (FERC) in July. The project would connect Questar Pipeline's southern system in Colorado with east-west systems taking gas near Blanco.
- North of these locations, in the southwest corner of Wyoming along the Moxa Arch and clustered around Northwest Pipeline Corp.'s Opal, Wyo., gas plant, several recent projects have reconfigured gas transportation in the area, making it more flexible.
In addition, the Trailblazer pipeline segments which run eastward from this corner and which have been operating below capacity are in the process of obtaining full open-access status. This system can therefore be expected to move more gas eastward, especially to Midwest markets.
This activity in Wyoming is in advance of the start later this fall or early next year of construction on at least one of the major pipeline systems to California. Each would run between Wyoming's gas-producing regions, across Utah, and into California south of Nevada for EOR, residential, commercial, and power-generation markets (box).
Another proposed major system, Altamont, would bring gas into this corner of Wyoming from Canada and, depending on volumes, would be available to tap into shut-in gas production along its route.
- South of Questar Pipeline and the proposed TransColorado system, in the northwestern corner of New Mexico, another batch of pipeline projects has been redefining that gas-transportation scene.
This activity is driven partially by the volumes of shutin gas in the Piceance basin of central western Colorado and by the eruption of coalbed methane exploration in the San Juan and Piceance areas.
Northwest Pipeline, Transwestern Pipeline Co., and El Paso Natural Gas Co. (EPNG) have proposed or are currently building extensions and expansions of their systems in the adjacent Colorado and New Mexico counties as well as along main lines westward to California.
MAJOR SYSTEMS
With the exception of Northwest Pipeline's system between the Pacific Northwest and New Mexico, gas networks in Wyoming, Utah, Colorado, and New Mexico have been oriented eastwest. Completion of Questar's crossover between its two segments and the prospect of TransColorado looming for western Colorado producers, however, significantly change that historical pattern of gas movement.
The presence of both these large systems, especially if linked as planned, will facilitate gas movement between and among the major east-west systems in Wyoming and New Mexico.
SEGMENTS' CONNECTION
Questar Pipeline's north-south crossover links its two systems with a line from near the company's Kastler compressor station at its Clay basin storage field in Daggett County, Utah, to its Fidlar station in Uintah County (Fig. 1).
Maximum working pressure for the line is 936 psig, says G. W. DeBernardi, Questar Pipeline's vice-president of engineering and transmission services. Capacity is 86 MMcfd from south to north.
Planning started in the summer of 1987.
Application to the FERC was in February 1988. Commission approval came in December 1989.
Although most of the construction was accomplished this summer, some occurred in February across croplands near the Green River east of Vernal, Utah. The purpose was to get through the croplands while the ground was frozen and before planting season, says DeBernardi.
Remaining construction commenced the first week of June. The line was placed in service Aug. 30.
Contractor for the line was Gregory & Cook Inc., Houston. Gregory & Cook had constructed the CO2 and phosphate-slurry lines for Chevron Chemical Co. in 1985 through a portion of the same pipeline corridor, DeBernardi says. And therefore the contractor had experience dealing with the construction terrain and government agencies.
The line was conceived as a means better to balance receipts and deliveries into the southern system, says A. J. Marushack, president and CEO of Questar Pipeline.
For balancing receipts and deliveries on the southern system, Questar Pipeline had depended upon Northwest's 26-in. pipeline to take gas in excess of demand up to Questar Pipeline's northern system.
Or, if demand on the southern system exceeded supply, again Northwest's line was needed to bring supplies by displacement into Questar's southern system.
Movement on Northwest's system was on an interruptible basis. Changes in Northwest Pipeline's volumes as a result of its open-access status further threatened Questar Pipeline's ability to balance volumes, says Marushack.
In its filing with the FERC, Questar Pipeline called this dependence on Northwest Pipeline for transportation between its northern and southern systems its "Achilles heel."
Complicating the interruptible transportation arrangement with Northwest was the fact that 85% of peak-day deliverability of the largest producing field on Questar's southern system, Natural Buttes, is owned by Colorado Interstate Gas Co. (CIG) and is transported on Questar on a firm basis.
Marushack says that the northern system moves about 70% of the gas that is moved on the combined 2,400-mile Questar system. For 1989, Questar Pipeline moved approximately 179 bcf over its entire transportation system.
But the transportation and purchase receipts on the southern system can run as high as 120 MMcfd during periods of low utilization. "That gas must be taken into the system," Marushack says.
With total system capacity on the southern system at 135 MMcfd, seasonal fluctuations in demand could severely constrain system flexibility.
Questar summarized the situation in its application by saying it had "no direct control over Northwest's pipeline system" through which Questar Pipeline's excess southern-system supplies "can be off-loaded or southern system deficiencies received."
Questar Pipeline's ability to balance northern and southern system receipts and deliveries, that is, stood "at the mercy of" Northwest and CIG.
Marushack says the "point is that we haven't had control over those volumes and yet we need to deliver to Mountain Fuel Supply [on the southern segment] up to 125-130 MMcfd on a peak day. So one of those things we've anticipated is the ability to take gas from the northern system or from Clay basin down to the center of the [southern] system to ensure that we have the volumes available" there.
Another advantage for Questar in the direct connection between its two systems lies in the route taken by that connection. The northern terminus for the new line is the Kastler compressor station atop Questar Pipeline's Clay basin storage facility.
This depleted gas reservoir (OGJ, July 31, 1978, p. 177) looms more and more important for Questar Pipeline as well as for Northwest, which has contractual access to a large part of the reservoir.
Marushack says that current storage capacity of Clay basin is 100 bcf with approximately 50 bcf of the total available for working (cycle) volumes. Currently, 80 bcf of gas is in storage, of which 35 bcf is working.
Storage as a tool for ensuring flexibility of receipts and deliveries on all U.S. systems is growing in importance. And DeBernardi says Questar Pipeline is seeing increased interest in storage especially among marketers.
To a large extent, it can be said that the role formerly played by take-or-pay contracts-that of cushioning transporters from the vagaries of demand-has been taken over by storage.
Transmission companies can use storage to hold gas taken under firm-transportation agreements but having no markets or gas held in storage to be used to fulfill delivery contracts when demand outstrips what the physical pipeline system itself can supply.
TRANSCOLORADO
The third advantage for Questar of its north-south connection became evident in July when the TransColorado Gas Transmission Co. filed with the FERC to build a system along the western slope of the Colorado Rocky Mountains.
The northern end of TransColorado would be anchored on the eastern end of Questar Pipeline's southern segment (Fig. 1).
The routing could hardly have been accidental: Questar Pipeline became a one-third partner (with KN Energy Inc.'s Rocky Mountain Natural Gas Co. and Western Gas Supply Co.'s Public Service Co. of Colorado) in the project earlier this year (OGJ, Feb. 26, p. 38).
Conceivably, gas could move down Questar Pipeline's system from Wyoming producers or Clay basin storage into TransColorado and thence into major east-west systems at Blanco.
Alternatively, production from the San Juan and Piceance areas could move up TransColorado into Questar Pipeline and Clay basin and out into Questar Pipeline's northern system. From there gas could move through interconnects either east over Trailblazer or west over either Kern River or WyCal into California markets.
The system will consist of 270 miles of 22 in. pipeline from the Big Hole area of Rio Blanco County, to Ignacio, La Plata County, Colo., and 41 miles of 24 in. pipeline from Ignacio to Blanco, N.M.
There it will interconnect with EPNG and Transwestern primarily allowing gas to move west into California markets but also with eastward movement an option over Transwestern and interconnects to the U.S. Midwest or Northeast.
The system plans 4,750 hp of turbine compressor near Olathe, Colo., and two 2,700-hp reciprocating compressors near Dolores, Colo.
Estimated cost of the project is slightly less than $151 million.
TransColorado's application asserts a capacity of up to 300 MMcfd primarily out of Piceance basin production, both conventional and coal seam. Maximum operating pressure would be about 1,250 psi.
Much of this production, according to TransColorado, comes from tight sand formations characterized by low permeabilities and high water content. As a result of these conditions, typical monthly production rates for western Colorado natural-gas wells reflect only 15-22 days per month of actual production.
Coalbed-methane production from the Piceance area, the company states, requires extensive dewatering, and at present these volumes are only being modestly produced.
Further, TransColorado says a conglomerate of small producing fields characterizes the western Colorado natural-gas supply profile. The small gathering system and gas-cleaning plants associated with these fields do not have "sufficient facility redundancies to guarantee high delivery reliabilities."
Colorado Interstate Gas Co. (CIG), another major transporter of Colorado gas besides Northwest Pipeline, is not idle while Colorado volumes stand to be moved by another company.
In August, CIG filed as an intervenor in the project. And CIG says it is actively discussing transportation contingencies with producers in the region. Contrary to rumors of a Piceance basin lateral, it denies having any active plans for a line south from its main line to begin taking volumes from the Piceance.
Northwest Pipeline also filed as an intervenor last month. Northwest's Ed England, vice-president for processing, says he sees no need for that system: "We can move the gas from those areas." That opinion is hardly surprising, given the layout of its system (Fig. 1).
Even though Northwest Pipeline's current system in western Colorado is operating at its 280-MMcfd capacity moving gas south, England says that when Kern River is built from southwest Wyoming, much of the current volume on Northwest in Colorado can move north to the Opal region and into Kern River to California or into Northwest Pipeline's main system to the U.S. Northwest.
When that happens, he says, existing capacity will be available on the Colorado segment for movement north, as well, from Ignacio or south over Northwest's 33-mile connection (currently under construction and discussed in the conclusion to this series) to the Blanco hub, then either east or west.
Copyright 1990 Oil & Gas Journal. All Rights Reserved.