Equipment placement. The first pieces of equipment to enter a newly 

 prepared site are the main components of the drilling rig. Even though a new 

 upland or marsh fill road may be used for transport to the site, older roads 

 are often used part of the way. Since some of the pieces of equipment are wery 

 heavy (a portable drilling rig may weigh 45 metric tons), repairing, strength- 

 ening, or shoring up of older roadways may be necessary. In upland areas, 

 holes must be filled with sand, shell, and/or crushed gravel. Bridges or 

 culverts need strengthening. After the vehicles have passed, repairs may be 

 required on the roadway or conduits. 



Over marsh fill roads, particularly leveed areas with board runs, soft 

 spots must be filled with shell. Layers of board need to be respiked. 



The pieces of equipment entering the site include the portable rig, power 

 plants, power train and rotary table, drill pipe, well casing, conductor pipe, 

 steel settling and sump pits, pumps, shaker tables, sand separators, water-well 

 drilling equipment, dry mud, hoppers, miscellaneous tanks, storage sheds, 

 trailers for crew, and the blowout preventer. All equipment is placed at 

 preplanned locations. 



For dredged (marine) sites, the rig, power plants, rotary table, crew 

 facilities, and other equipment are all located on one barge, which is pushed 

 by a tug up the channel and aligned over the planned wellhead location. The 

 barge hull is flooded with water so that it settles to the bottom, and spuds 

 are driven to secure it. Other equipment such as drill pipe and mud are moved 

 by barge to the site, and the barges are made fast adjacent to the drilling 

 rig. 



Drilling activities. The actual drilling of a well generally takes one to 

 three months. Depths drilled may range from 1,300 to 8,300 m (4,000 to 25,000 ft), 

 though most of the shallower deposits have already been tapped in coastal 

 areas. The formations drilled are largely Cenozoic sedimentary delta deposits - 

 sand, silts, and clays - derived from upland drainage, intermixed with marine 

 shales and clays. Thus, the usual drilling equipment is the rotary rig. In 

 drilling, many of the processes are repetitive in nature. There is no clearcut 

 progression of activities beyond the drilling, bringing a well into production, 

 testing, and leaving of a site. Often the repetitive activities singly do not 

 offer many actual or potential environmental effects. It is their repetitive 

 nature and the incremental effects that may be important. 



In nearly all coastal areas accessible by road, the crews change every 

 eight hr. Thus, there is a flow of traffic back and forth along the roads 

 during day and night. These are generally light-duty vehicles. Much heavier 

 trucks move in and out of the site during daylight hours. These include trucks 

 bearing drill pipe, casing, mud, and other supplies. Special service vehicles 

 may occasionally traverse the roads. These include vacuum trucks, well-logging 



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