The U.S. Department of Energy and Texaco Inc., representing the 22-company DeepStar Project, have signed a research and development agreement to examine how oil and gas behave in subsea pipelines.
They will build a 41/2-mile, 6-in. "flow assurance" test loop at the Rocky Mountain Oilfield Testing Center (Rmotc) at Teapot Dome field near Casper, Wyo.
DOE said DeepStar partners are interested in how and why gas hydrates form in offshore pipelines. Hydrates exist naturally in deepwater environments and have long been viewed as a potential supply of nonconventional natural gas. But when a combination of low temperatures and elevated pressures causes them to form in pipelines, they can create blockages in the lines.
When completed in January, the flow loop will focus on hydrate formation, first with crude and then with a gas mist condensate.
DOE said, "The Wyoming climate, especially in winter, creates an appropriate setting for simulating the undersea conditions conducive to hydrate formation."
The testing facility will complement Texaco's large-scale flow assurance loop at Humble, Tex. which was primarily designed to study paraffin deposition and blockages in deep water.
Project details
DOE said the $1.6 million Wyoming test loop will have a 3,600 psi working pressure. A 2-mile water-jacketed cooling section will be capable of dropping crude oil temperatures to 40° F. from 75° F. Once cooled, the fluids will enter a 21/2-mile bare steel pipeline buried just below the freeze zone (about 40 in. deep at the Wyoming site).Researchers plan a concentrated test schedule to take advantage of the upcoming winter. During a 200-day test program for hydrates, tests will be run to determine the accuracy of computer software designed to predict hydrate formation.
Researchers intend to create hydrate plugs within the pipeline, then test software for locating and advising operators on the best techniques for removing blockages. Chemicals designed to inhibit formation of hydrates will be evaluated.
The loop will test sensors that monitor deposits building up in the pipeline, along with meters, separators, and pumping equipment, under field-like conditions.
When temperatures warm next spring, the hydrate test program will end, and 100 days of testing will focus on deposition of paraffin in crude oil operations.
The Wyoming test loop is designed for 10 years of life. It will become the property of DOE, and Rmotc will be field operator.
Under the R&D agreement, DOE and its partners will provide equipment, personnel, and funding, but no dollars will be exchanged. DeepStar participants and Rmotc will prepare a report on the testing, which will be available to industry.
DeepStar is an industry cooperative project aimed at developing economic, low-risk methods of producing hydrocarbons from the deepwater Gulf of Mexico.
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