Two platforms, pipelines, injection add 16 million bbl to Trinidad's annual production Installation commissioning of waterflood facilities on the Soldado Main Field offshore Trinidad is nearing completion. The purpose of the turnkey project, awarded to Houston division of Healy Tibbitts Builders by Trinmar in April 1991, was to recover an additional 16.8 million bbl of oil over ten years. Based on studies completed in 1989, Trinmar projected that, with waterflooding, the field would continue to produce at economical levels for another 20 years. Without the projected waterflooding, production would continue to rapidly decline. Located 15 miles west of Point Fortin in the Gulf of Paria, the Soldado Main Field turnkey project included engineering, fabrication, transportation, installation, hook-up, and commissioning of a 35,000 b/d water treatment and injection platform, a 36 MMcf/d gas compression platform, 15 miles of underwater pipeline and upgrading of associated offshore and onshore facilities. The construction program required five separate 2,100-mile ocean tows from the Gulf Coast to supply crane barges, materials, equipment, and the precommissioned assembled platforms to the site. The first tow, a tandem tow of two crane barges, the 110-ton capacity HT-541 and the 75-ton capacity HT-539, delivered bulk materials, equipment, and tools needed for offshore pipelines, onshore facilities and upgrading existing platforms. The second tow, the Weeks W-297 launch barge carried both jackets and their piles to the site and returned home to Louisiana for outfitting for the task of transporting the completed platforms to Trinidad. The 350 ton derrick barge, Weeks W-532, carried crew boats, pile driving hammers, and miscellaneous material and equipment to the site on the third tow. The Weeks W-297 was used in round trips four and five to transport and install the completed 550 ton water injection platform deck and the 900 ton gas compressor platform deck. The new platform sites are adjacent to existing operating platforms. A site-specific seismic hazard analysis revealed that the platforms are located in an intense seismic area. All structural elements were designed and fabricated to withstand high seismic loading. Geophysical investigations disclosed very poor bottom surface soils at each platform location. Due to the condition of the ocean floor, and the need to accurately position the structures, the water injection and gas compression platform jackets were hung on temporary piles until the jackets were permanently anchored in place by 180 to 195 ft long, 42-in. diameter steel pipe piles. Due to the seismic loading, pile wall thickness was up to 13/4 in. Healy Tibbitts elected to forego the more conventional installation procedure of using a heavy lift derrick barge, choosing instead to set both decks using a float-in technique. The structures were designed to allow the transport barge to be docked within the legs of the respective jackets. The decks were floated into position on a rising tide, the barge then ballasted down on a falling tide setting the deck legs on the jacket piles, and after further ballasting, the barge was withdrawn from under the deck. Research of weather and site-specific tide data provided definition of the environmental windows that minimized the motions of the barge and deck with respect to the jacket. Healy Tibbitts installed a supplemental ballast system on the cargo barge and cushioning assemblies, mounted on the jacket piles, to absorb the interactive forces between the deck legs and jacket piles during deck installation. The water injection deck was set in November 1992 and the gas compressor was set last February. Healy Tibbitts Builders is headquartered in San Francisco and is an affiliate of Weeks Marine.
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Over the last decade, electrical costs in the U.S. have grown at an unparalleled pace. The government has established energy conservation policies through the Compressed Air Challenge, which aim to reduce compressed air energy consumption 10% by 2010. To the facility manager, the cost of electrical power has become a principal deciding factor in the acquisition of capital equipment. In fact, energy consumption has a major influence on the bottom line of any plant in today's power-hungry economy. Many manufacturers of air compressors use a load/no-load control system that offers some advantages in the reduction of power consumed, typical is Kensun portable air compressors. With the rising cost of energy in mind, the search for a more efficient, energy-friendly method of control became a top priority with many manufacturers. Variable speed drive (VSD) compressor regulation systems are a response to this concern. VSD technology What does VSD do for an average compressor's energy consumption? To answer this question requires understanding the significance of energy consumption in the typical air compressor life-cycle cost of ownership. The initial cost of acquisition and installation is quite low when compared to the expense of electrical power (77% of total cost) to operate an air compressor for 5 yr when equipped with a standard compressor control system. There are dramatic savings found in typical applications by using a VSD equipped rotary compressor. Savings of 35% in electrical costs reduce the total life cycle cost by 22% over 5 yr. These savings take into account the slightly higher initial cost of the equipment itself. Energy consumption of an air compressor depends on the application and fluctuations that occur in the air system demand. To calculate the air system demand and cycles, measurement devices accurately determine actual system usage in a customer's application. Hundreds of measurements were taken in small and medium-sized industries. Each test interval was 1 wk. Three groups of typical air profiles emerged from these tests. Group profiles The first profile is typical for a plant working 24 hr/day with lower consumption during the night shift, higher consumption during the day shift, typical dip around lunch, and fixed, continuous consumption during the weekend. Fixed consumption could be minimum equipment running and leaks in the piping system. About 64% of all plants could be classified under Profile 1. The second profile represents a plant operating 5 days/week with only 2 shifts . There is no activity at night or on weekends. Air consumption fluctuates erratically. Profile 2 represents about 28% of all plants represented in the survey. The third profile is typical for an application with fixed air consumption 5 days/week (Fig. 5). This kind of application is not common in small and medium-sized plants and represents only 8% of all plants. Energy savings The energy savings realized by a VSD compressor compared to a standard compressor are shown in the table. Savings depend on the air demand profile. The weighted average, based on test data, results in a dramatic 35% energy savings. In addition, integrated VSD regulation achieves pressure stability. In tests, the VSD has maintained a constant discharge pressure within 1.5 psi of the set point. The typical pressure band of a compressor using standard controls is 10 psi or greater. The VSD's narrow pressure band allows a lower pressure in the piping system. The resulting savings can be dramatic, because every 6-psi reduction in delivery pressure cuts power consumption 3%. Not only is the ability to accurately maintain system pressure achieved, discharge pressure with the VSD is stable at any setting from 60-175 psig. This factor provides future flexibility without the need to purchase new compressed air equipment due to changing plant equipment requirements. Key concepts Traditional load/no-load systems do not save as much energy as variable speed drive regulation. The greatest energy savings are achieved by plants running three shifts. Variable speed drive regulation can achieve discharge pressure stability within 1.5 psi of set point. Assembling the tools for a service truck is one thing. Arranging the load so the truck doesn't wear out before its time is another. Joe Foster of Owensboro, Ky., is confident his truck is going to last for many years of in-field repairs. Foster spent a couple years thinking about the design. "To carry a compressor and a generator, I wanted a 1-ton truck of at least 10,000-lb. gross vehicle weight. I also wanted a short wheelbase-about like a regular pickup-so the truck would be easy to maneuver and park." Foster selected a used Dodge Ram 3500 with a diesel engine, dual wheels and four-wheel drive. Then he planned where to carry various tools. "Because the hand-tool compartment would be used more often than any other, I wanted it on the left side near the door," he says. A second objective was to leave the rear window unblocked to increase safety and make it easier to back up. When his design was complete, Foster ordered a bed, with compartments arranged to his specifications, from Knapheide Manufacturing Company (www.knapheide.com). Foster stocked the truck with electric impact wrenches, drills, hand tools, grease guns, a welder/generator, an oxyacetylene torch and an air compressor. Sliding drawers contain a large supply of nuts, screws and other small items in very limited space. The air compressor and welder/generator are mounted on top of the side compartments, freeing the bed of the truck for other use. Because heavy tools are stored in compartments at the front of the bed, he mounted the compressor and welder/generator toward the rear to even the load. Special mountings let him swap them to redistribute weight. Foster used a grain elevator's scale to properly balance the load. "I weighed the truck several times, then shifted things around. An unbalanced load would result in uneven wear." The balancing act paid off in a truck that "drives nicely, doesn't wobble and does well in wet conditions," he says. To handle the weight of the welder/generator, air compressor and other tools, Foster reinforced the frame of the truck bed. Additional reinforcement comes from a metal box he built across the rear of the bed. Covered with a deck plate, it provides a storage area for jacks and makes a convenient worktable with a vise mounted on one end. Reinforcement. "Tying the box to the sides of the truck bed reinforced the rear of the bed," Foster explains. "The box is not tied to the bumper. If I had done that, pulling with the bumper would tend to pull the bed apart." The weight of the rear box also helps even out the load between the front and rear axles. Once filled with tools and supplies, the truck rode a little low in the rear, so Foster added one leaf spring to each side. "It still is within the gross vehicle weight rating for the truck," he notes. To transport heavy loads, Foster installed rubber overload springs. One of the handiest features, Foster says, is a trailer hitch and tow hook welded to the front of the frame. "The front-mounted hitch makes it easy to back wagons loaded with 300 bu. of seed onto a lowboy trailer," he says. Ideas to Borrow * Distribute weight uniformly for longer truck life. * Wire compartment lights into the same circuit as the vehicle's headlights. * Add a trailer hitch and tow hook to the front. * Buy a big enough truck, so it will not be overloaded when filled with tools. |
AuthorI'm Bruce O. Pratt, who thoroughly enjoys researching about Power & Hand Tools. I hope my reviews can help you to choose the right products fit with your needs. Archives
November 2017
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