Placement and operation of production facilities . 



1. Activity sequence 



Production aspects occur both at the wellsite and at a central treatment 

 complex. Normally at a wellsite only slight structural modifications of 

 the existing drilling barge site are necessary to convert the well to 

 production status. Placement of gathering flowlines from the well to the 

 treatment facilitiees requires activities as described for the installa- 

 tion and maintenance of lines; these include line survey, limited 

 vegetation clearing, line installation, and necessary site restoration. 

 If drilling was conducted from a floating barge, which is typically the 

 case, the barge is removed and replaced by a small elevated platform 

 supporting the wellhead. Small-scale digging and pile driving are 

 required. 



Centralized treatment facilities are typically located on firm, elevated 

 sites, if they are available nearby. Otherwise, the complex is construc- 

 ted in the marsh using the same construction techniques and processes 

 employed in preparing a wellsite. Treatment and processing equipment may 

 be supported on (1) a leveed pad dredged from the marsh; (2) a platform 

 complex elevated on pilings and supplemented by stationary barges; or (3) 

 a combination of the above. Brine-disposal lines are installed to tran- 

 sport brine to disposal wells or discharge sites. Routine operation, 

 maintenance, and repair of treatment, pumping, and storage equipment are 

 frequently conducted within the confines of the pad site or on the 

 platform/barge structures. Processing wastes are stored within the 

 complex area, disposed of via flowlines, or transported off the site 

 immediately. Routine maintenance and operational trips are conducted 

 primarily by boat, barge, or float plane. Typical areal extent of a 

 newly constructed production faility is approximately 4 ha (10 acres). 

 Dredging and spoil placement for barge-mounted production equipment 

 location or channel maintenance is occasionally required. 



2. Primary ecological alterations 



2.1 Trampling and crushing of vegetation due to construction machinery 



2.2 Complete loss of vegetation within the pad site or platform complex 



2.3 Permanent displacement and/or loss of consumer groups within the 

 facility site 



2.4 Increases in concentrations of suspended sediments and dissolved 

 nutrients 



284 



