Flowlines - dredged locations. In dredged locations, production facilities 

 are centrally located on dry land, barges, or piles. From the wellhead, the 

 flowline leads to the marsh surface at the edge of the dredged slip. In order 

 to reach the marsh from the wellhead (often a distance of 10 to 20 m or 33 to 

 66 ft), flowlines may be buried in the bottom of the slip, or they may be 

 elevated on pilings. Once they reach the marsh proper, flowlines nearly always 

 run on the marsh surface or are elevated slightly above it. They cross naviga- 

 ble canals by being buried under the canal. 



A survey crew travels by boat or marsh buggy, stakes the proposed flowline 

 route, and clears some vegetation. Since the flowline is not too unwieldy, the 

 marsh buggy may travel along the surface carrying pipe, allowing a section-by- 

 section connection of flowline. Supports can be placed by hand if necessary. 

 If the situation is convenient, the pipe may be joined on the barge and pulled 

 by the buggy. 



Crossing canals that do not accommodate crewboats and supply vessels often 

 requires the driving of piles for pipe supports. The pipe may be raised in 

 these areas for passage of small outboard-powered boats. For larger canals, 

 however, it is necessary to bury the pipe. A dragline digs a trench in the 

 bottom of the canal into which the flowline is placed. Then sediment is replaced 

 in the ditch. The ditch is usually 3 to 4 m (9 to 13 ft) deep so the flowline 

 will be below the level usually maintained by dredges for navigation. An 

 alternative method involves placing the flowline on the bottom initially. Then 

 a large pump mounted on a barge pumps water under high pressure to the end of a 

 hose. The hose is pointed at the sediment just below the pipe. The water 

 movement suspends the sediment and creates a depression. The pipe drops into 

 the hole, and as the hose moves away, the sediment falls out of suspension, 

 partially filling the hole. In older canals it was the practice to bring the 

 flowline from the marsh surface and bend it 90 o down to cross a canal. However 

 if canal banks eroded significantly, a long horizontal length of pipe hung over 

 the water without support, potentially causing leak and obstruction problems. 

 Now, in some areas, flowlines are buried some distance from the channel edge 

 and gently slope down to cross beneath the canal. 



Placement of equipment - upland, diked marsh. Some equipment for produc- 

 tion must be placed very near the wellhead since it is involved in pumping 

 fluids in or out or controlling the formation of hydrates in the flowlines. 



Gas wells flow under their own pressure to the surface. Often oil will 

 flow to the surface because of the formation of gas pressure associated with 

 the petroleum strata. When this pressure drops, the oil must be pumped to the 

 surface by artificial lifts. These may be mechanical, hydraulic, electric, or 

 gas actuated. The equipment at the surface is minimal and in some cases is 

 located wholly in the casing (electric pumps). Other production equipment is 

 located right at the wellhead. 



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