Placement of equipment - dredged sites. Many fields in areas with dredged 

 sites have centralized production facilities located on upland areas. Construc- 

 tion of these production facilities proceeds as described above. Centralized 

 production facilities, however, are sometimes located on large barges or on 

 pile foundation platforms in marsh areas or in shallow coastal waters. Wellhead 

 production equipment such as mechanical pumps and heaters are placed on pile 

 foundation platforms and are located either immediately over or adjacent to the 

 well. 



For barge-mounted facilities, a channel or special slip may be dug to moor 

 the equipment. Spoil is often placed immediately adjacent to the site. Since 

 the barge will be sunk to the bottom, there is no problem with the spoil reen- 

 tering the slip. The barge is brought in under tug power and positioned. The 

 ballast tanks are filled and the barge settles on the bottom. Often a pile 

 driver will place piles around the edges of the barge so that it cannot move, 

 and the barge may be anchored securely to the piles with cable or steel. 

 Flowlines, output oil gathering lines, and gas lines are connected to the 

 production equipment. 



For equipment mounted on a pile foundation, the extent of the activities 

 depends on the extent and permanence of the production equipment. For well 

 pumps and heaters, piles (often concrete) are driven into the sediment, and a 

 structure of heavy timbers or steel is fastened to the piles. Barges transport 

 the production equipment, which is placed on the structure and connected. 



Large production platforms may require extensive strengthening in soft or 

 unstable substrate. Often pile drivers will place many piles into the sediments 

 to serve as a foundation. The platform will be either steel or a combination 

 of steel and concrete, poured on site. The production equipment will be trans- 

 ported by barge, placed, and connected. 



In a few instances, production equipment is built on land made from dredge 

 spoil. In these cases marsh areas, perhaps up to several hectares, are covered 

 with spoil, and the land elevation is raised considerably above high water. 

 The spoil is leveled and must undergo a lengthy drying process, depending upon 

 its characteristics. Often levees are placed around the perimeter of the made- 

 land to aid in protecting the facilities from flooding or releasing petroleum 

 or wastes to adjoining lands in case of accidents. After the fill has dried, 

 placement of production equipment follows the same sequence as on upland produc- 

 tion sites. 



Saltwater Jisposal facilities. Brine associated with coastal oil and gas 

 production may range from 5.5 ppt (Mackin, 1971) to over 400 ppt (Collins, 

 1967). It has a highly variable character, ranging greatly in total concentra- 

 tion and relative ionic makeup. In upland areas, disposal is nearly always by 

 injection well into the original formation or compatible formations. In coastal 

 areas, disposal may be into marine waters or disposal wells. 



104 



