Operations 



Day-to-day operations of pipelines are highly automated and require 

 work forces only for regular monitoring and maintenance. 



After installation, pipelines must be monitored periodically. The 

 techniques include monitoring pressure gauges, metering pipeline flow, 

 and surface and air patrols of the routes. Timely leak detection and 

 control of a pipeline necessitate the use of monitoring systems which 

 are "redundant." The main focus of pipeline surveillance is a central 

 control station where the flow rates of the transmission line and of its 

 tributary gathering lines are monitored on a continuous 24-hour basis. 

 Pipelines are currently controlled by radio-activated equipment that can 

 cut off the flow of any part of a line which exhibits low pressures 

 indicative of leaking. 



There are two important direct measurement tools that are used for 

 leak detection. One is a pressure sensor that measures pressure 

 reductions. If oil and gas are shipped in the same pipeline, the system 

 will only respond to leaks that cause a pressure decline of at least 30 

 psi. The second technique measures the volume of flow at two different 

 points on a line and can be used to verify that there has been no loss 

 of oil. If accurate and calibrated instrumentation is used and maintained, 

 this technique is extremely reliable. 



A third method for detecting leaks requires the periodic patrolling 

 of the line by surface vessels and aircraft. This surveillance is 

 mandated every two weeks by government regulations. Although this 

 procedure is not an immediate response approach to a major leak, it does 

 provide a means of spotting leaks that may be too insignificant to be 

 picked up by direct measurement sensors. 



Community Effects 



A pipeline has attributes that may potentially affect a community, 

 depending upon corridor selection. However, with proper planning, such 

 as occurred in Scotland, these effects can be insignificant in onshore 

 communities. 



Employment : Offshore, main pipelines are constructed from pipe- 

 laying barges, which employ about 160 to 175 people. Approximately 50 

 workers would be recruited locally [28]. This operation would lay 

 approximately one mile of pipe per day, and the longest lines would not 

 exceed 200 miles. Gathering lines are usually of much less total length 

 in a field, requiring fewer construction personnel. The length of time 

 required to construct a line depends on factors such as climate and 

 bottom conditions. Pipeline construction offshore will only provide 

 temporary employment in specific skills, such as welding, and is not a 

 likely attractor of new residents. 



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