Robert L. Sluder
Kern River Gas Transmission Co.
Salt Lake City
Kern River pipeline, the largest natural-gas pipeline built in the U.S. in more than a decade, commenced operations in February (OGJ, Mar. 9, p. 32).
Following 6 years of market, supply, engineering, and regulatory development, an intense 1-year construction period brought the pipeline to its current operation moving as much as 680 MMcfd of gas to points throughout the western U.S.
Engineering played a significant role throughout the entire process from early flow studies and route mapping, to support of the application during U.S. Federal Energy Regulatory Commission (FERC) hearings, to providing design support during construction.
In fact, of the 5.5 million man-hr spent on the project, more than 500,000 man-hr were dedicated to engineering. Engineering also finalized design details, prepared and awarded construction contracts, and assisted in the start-up and commissioning of the system.
SYSTEM
The Kern River pipeline consists of approximately 685 miles of heavy wall (0.429, 0.515, and 0.618 in. W.T.) steel pipe. This amount equates to more than 360,000 tons of material which required nearly 4,500 railroad cars for delivery.
The total cost of materials for compression, measurement, and supervisory control and data acquisition (scada) and telecommunications equipment exceeded $300 million.
The exclusive Kern River facilities extend from a point of interconnection with Northwest Pipeline Corp.'s transmission facilities near Opal, Wyo., southwestward across Utah and Nevada to a point near Daggett, Calif. (Fig. 1).
At this point, Kern River jointly owns with Mojave Pipeline Co., Bakersfield, approximately 221 miles of common facilities consisting of varying diameter pipelines and delivery measurement and pressure-regulation stations.
These facilities include 140 miles of 42-in. OD pipeline which extends from Daggett to the southeastern side of the San Joaquin Valley in California. Near this point, the pipeline divides into two 30-in. laterals, one extending 38 miles into the heart of the Kern River field and the other extending 43 miles into the oil fields on the west side of the San Joaquin Valley.
The Kern River pipeline is the largest grassroots transmission system to be built in the past 10 years. It features multiple electronic measurement facilities and a fully real-time scada system.
The pipeline is designed to operate at pressures up to 1,200 psig and utilizes three main line compressor stations: one at Muddy Creek, Wyo., one at Fillmore, Utah, and the third at Goodsprings, Nev.
These three compressor stations provide 39,500 hp (site-rated) of main line turbine-driven compression for the system.
An additional 8,500 hp (site-rated) of compression is provided at two supply stations located in the Overthrust Belt of southwest Wyoming. The operating capacity of the pipeline, as currently configured, is 700 MMcfd; that volume is totally subscribed.
In addition, the pipeline can readily be expanded to between 1.2 and 1.35 bcfd by installation of additional compressor stations. Kern River has recently filed an expansion application with FERC to go to the 1.2 bcfd capacity.
EARLY CONSIDERATIONS
The first major engineering challenge for the pipeline was overcome when the Williams Cos., Tulsa, and Tenneco Inc., Houston, decided to merge competing projects and two large engineering groups along with marketing, legal, and administrative departments to form the Kern River Gas Transmission Co.
This task demanded that two large, diverse corporations come to a consensus on design philosophies, organizational structures, and commitment of resources.
An engineering team from both companies settled on an engineering philosophy that would take the most restrictive and conservative approach when blending the varying design and construction philosophies of the two companies.
Besides the normal hydraulic parameters, the team had to consider such other factors as emission limits and sound restrictions as well as topographic, geologic, and hydrologic conditions. These parameters dictated early on that Kern River needed geotechnical expertise to assist with slope stability and fault crossings.
Also, as the several preliminary routing studies were reduced to the most viable routes, more detailed engineering analysis was necessary to confirm ultimate constructability and operational reliability.
With route locators acting as guides, teams of geologists scoured the routes evaluating slope stability, earthquake fault crossings, and erosion potential.
Ultimately, a primary route and several alternatives were presented to the FERC for consideration in issuance of a certificate to construct and operate.
Subsequently, the FERC ordered an environmental impact study in preparation of which FERC and the California State Lands Commission would jointly participate.
Based on market demands and reserve life studies in Wyoming's Overthrust Belt, the initial capacity for the pipeline was set at 700 MMcfd.
EOR ROLE
The idea to build a natural-gas pipeline in this region had been discussed by various companies for at least 30 years but was generally considered uneconomic. The project moved forward because of the forces of market supply and demand and because Kern River had consistently focused on California's enhanced oil recovery (EOR) market.
The Kern River pipeline now links California with the vast natural-gas reserves in the U.S. Rocky Mountain states and in Western Canada. The pipeline is the most accessible, competitive, and technologically advanced gas-transportation system to enter today's market.
California's EOR market was a significant market anchor for Kern River from early in the project. This market exists because most Kern County crude is too heavy to be extracted from the ground without help.
Although 3 billion bbl already have been produced from Kern River's three largest heavy-oil fields alone, an estimated 3.2 billion bbl--or one tenth of the lower 48 states known crude reserves--of recoverable proven reserves remain in Kern County.
However, producers must first inject steam into the producing formations to heat and thin the oil so that it can flow more easily.
Unfortunately, because EOR producers have not had an alternative fuel available to them, as much as I of every 3 bbl of oil pumped has been consumed to generate more steam. Replacing oil with natural gas to fuel steam generation means that all of the oil pumped can be refined.
If 1 additional bbl of every 3 of Kern County's heavy-oil production can be refined because of natural gas use, the amount of oil to be gained will equal more than 50% of that expected from proven offshore reserves. Obviously, with natural gas supplied by the Kern River pipeline to fuel the steam generators, the amount of domestic crude that can be refined for consumption will increase dramatically.
This not only reduces U.S. dependence on foreign oil but also will result in improved air quality. California's clean air legislative initiatives are expected to increase the state's demand for natural gas, especially in the EOR market in Kern County.
Approximately 30% of the Kern River pipeline's capacity is dedicated to the EOR operations in Kern County. The remaining capacity serves electrical generation and local distribution customers in Utah, Nevada, and California.
Customers, or users of the gas, include Chevron USA Inc., Union Pacific Fuels Inc., Shell Western E&P Inc., Los Angeles Department of Water & Power, Mobil Natural Gas Inc., Amoco Energy Trading Corp., PetroCanada Hydrocarbons Inc., Canadian Hydrocarbons Marketing (U.S.) Inc., CanWest Gas Supply U.S.A. Inc., Salmon Resources, Southwest Gas Corp., Mountain Fuel Supply Co., Nevada Cogeneration Associates, and M.H. Whittier Corp.
These customers have all supported Kern River's capacity by signing 15-year transportation agreements.
ROUTING, REGULATORY HURDLES
Using the PIPESYM flow model developed by Tenneco Gas Pipeline and the best estimates of supply and delivery volumes, Kern River's engineers set about to size and locate the required major compression facilities.
This process became difficult as route preferences were altered because what would work for the design team would not work for the team in the field, or vice versa.
As a result, more than 400 miles of alternate routes along with a variety of compressor station locations were physically examined before the final route was selected. Some routing alterations had virtually no impact on proposed compressor station locations while others resulted in significant shifting of the sites.
As the multitude of preliminary routing studies were pared down to the most viable ones, more detailed engineering analysis was necessary to confirm the ultimate constructability and operational reliability. With route locators acting as guides, teams of geologists from Golder Associates scoured the routes evaluating slope stability, earthquake fault crossings, and erosion potentials.
Kern River submitted its original application to the FERC on May 31, 1985. During the summer and fall of 1985 and starting again in spring of 1986, surveyors and field engineers determined the exact route.
At the same time, the company's environmental people were conducting studies on the proposed route.
From 1986 through 1989, Kern River representatives went through a series of hearings before the FERC to defend the proposed route and to discuss how the company would handle a variety of logistical problems ranging from landslides, to earthquakes, to stream crossings.
Engineers also attended several public meetings and delivered presentations on the project, routing and facility specifics, impact-mitigation measures, etc. In addition, data requests were received from a multitude of parties which had to be addressed.
These requests ranged from hydraulic studies and pipeline efficiencies to compressor sizing to mechanical stress analysis to wetlands considerations and plant and wildlife impact mitigation.
Originally, the Mojave Pipeline Co. was in competition with Kern River for the FERC's approval to build an interstate pipeline into California. Finally, in the late 1980s, following several years of regulatory battles before the FERC, Kern River and Mojave agreed that Kern River would build the Wyoming-to-California line, Mojave would construct a pipeline from Topock, Ariz., to Daggett, and they would jointly build common facilities from Daggett to Bakersfield large enough to handle both companies' volumes.
In 1990, 5 years after the original filing, the FERC granted Kern River approval to begin construction.
Kern River divided construction into eight spreads spanning four states--Wyoming, Utah, Nevada, and California--and the spreads ranged from 61 miles to 112 miles long.
The contractors were: Hood Corp., Whittier, Calif. (Spread 1); Associated Pipeline Contractors, Houston (Spreads 2 and 5); Gregory & Cook, Houston, (Spread 3); Sheehan Pipeline Construction Co., Tulsa (Spreads 4 and 7); H. B. Zachry, San Antonio (Spread 6); and ARB Inc., Bakersfield (Spread 8).
During construction, crews moved over 13 million cu yd of dirt; poured 10,000 cu yd of concrete; completed more than 55,000 welds; used 83 miles of X-ray film to inspect 100% of the welds; and installed 40 miles of conduits.
From the inception of the project, Kern River's objective was to ensure that engineering, economic, and environmental considerations were taken into account in selection of the pipeline route. Kern River's philosophy was to locate the route, wherever practicable, to avoid environmentally sensitive areas, to run parallel to existing roads, railroads, highways, and other existing surface disturbances, and to utilize to the fullest extent possible existing utility corridors.
Kern River was committed to adhering to all applicable federal, state, and local environmental laws and regulations during construction of the pipeline and remains so during operations.
In addition to such U.S. agencies as the Forest Service, Bureau of Land Management, and Fish & Wildlife Service, consultations were made with state and local agencies such as planning departments, agricultural extension, and wildlife resource divisions.
During construction, crews were careful to preserve the environmental quality of the region along the pipeline. Kern River Gas Transmission spent more than $70 million protecting threatened or endangered plants and wildlife and restoring the construction area,
Approximately 200 biologists, archaeologists, and paleontologists hired during construction protected wildlife and preserved fossils and artifacts. Throughout construction, Kern River worked constantly with federal, state, and local agencies to ensure environmental compliance.
Kern River Gas Transmission will continue to monitor environmental reclamation for a 5-year period.
REMOTE CONTROL
The three main line compressor stations on the system generate 39,500 hp; seven meter stations in Wyoming and one at Daggett constantly measure the gas in the line; and the gas quality station near Coalville, Utah, makes a final check of the blended gas after the supply points to ensure pipeline quality.
Kern River designed all of these facilities to be remotely operated from the company's gas control center in Salt Lake City (Fig. 2).
Kern River pipeline is one of the first totally computerized and automated pipeline systems in the industry generating real-time information. Fig. 3 illustrates data communication along the system.
With the latest technology and metering equipment, Kern River's scada information is updated continuously for volumes, pressures, temperatures, and equipment operating parameters. It is updated every 15 min on chromatograph analyses, providing timely and accurate flow data.
To accomplish this, satellites, radio, fiber optics, and terrestrial communications technology merge with some of the fastest and most sophisticated computer technology available to form the nerve center for Kern River's operations.
This network integrates traditional gas-control systems with business and operations applications to produce a totally electronic, real-time operating environment. Through the gas control center in Salt Lake City, one operator can monitor and run the entire pipeline.
Controllers have precise flow control information and can remotely open or close valves along the line and operate each of the 19 meter stations.
CURRENT OPERATIONS, PLANS
Winter start-up of the pipeline (OGJ, Mar. 9, p. 32) presented several challenges.
Residual water remaining in ball valve cavities had frozen, hindering checkout and initial commissioning of the line. Methanol was injected to solve the problem.
Multiple pigging runs were made to dewater the pipeline segments following hydrostatic testing. But 1.5-3.0 mils of water film remaining on inner walls equates to as much as 90,000 lb of liquid. At saturation conditions, the pipeline would dry out in 4-6 weeks.
One major delivery point was unable to blend the wet gas, forcing delivery curtailments and a search for portable dehydration equipment.
Within 3 weeks, these facilities were in place at the delivery point to treat nearly 500 MMcfd.
Normal delivery was resumed, and in about 1-1/2 weeks the entire system was dried (less than 3 lb/MMcf water). The dehydration equipment was put on temporary standby, then shortly demobilized.
The pipeline is currently running full, with average volumes exceeding expected maximum capacity. System performance tests indicate increased capabilities.
A staff of 30 operations personnel and 10 engineering employees, along with 10 personnel in the gas-control department are responsible for daily operations. They are supported by the other Kern River departments located in Salt Lake City (ROW, environmental, compliance and administration), and work in concert with the business and regulatory side of Kern River located in Houston to implement the daily gas delivery plans.
Kern River's total complement is approximately 90 persons.
An application is currently before the FERC to expand the system up to 1.2 bcfd throughput. And Kern River is holding an open season to test market interest in this or other possible expansion scenarios.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
