companies. Such analyses identify sedimentary basins and aid in the 

 ranking of frontier areas according to their potential for petroleum. 



Once it is determined that a frontier area has hydrocarbon potential 

 it may be necessary, especially in remote areas such as Alaska, to 

 establish survey control networks onshore and to perform hydrographic 

 surveys updating navigation charts. Good surveying control and charts 

 are a prerequisite to reduce the risks to seismic vessels in the search 

 for offshore oil and gas resources. Increased efforts to establish and 

 update horizontal control networks, as well as the operation of hydro- 

 graphic vessels, are therefore a signal of future OCS oil and gas 

 activities, often followed closely by geophysical vessels searching for 

 petroleum. 



Another aspect of the pre-exploration phase that has often been 

 troublesome is resolving ownership disputes between the states and the 

 Federal government. Until the appropriate boundary has been agreed 

 (outer territorial limit off each state involved) and ownership is 

 resolved, it is impossible for the industry to obtain development rights 

 and impossible for the governing body to collect royalties. Often this 

 will require precise tidal boundary surveys at the shoreline correlated 

 with tide state data to determine the low tide line, from which 3-mile 

 (3-league in Texas and Florida Gulf Coast) boundaries can be located. 



It is unlikely that the pre-exploration phase would include any 

 major onshore impacts. Indeed, the public is often indifferent to 

 exploration activities and other than company employees and involved 

 Federal workers the only persons who might know that these activities are 

 occurring are fishermen and other maritime interests. 



2. Geological and Geophysical Exploration : This phase, like the 

 previous phase, does not usually involve major permanent facilities or 

 major environmental disruption. Work during this phase is based on the 

 current proposed lease schedule worked out between government and 

 industry. From industry recommendations developed in the pre- 

 exploration phase, using regional surveys, the Bureau of Land Management 

 develops an overall leasing schedule which indicates the order in which 

 frontier areas will be offered for lease. Once the schedule is set 

 industry moves its program beyond pre-exploration into detailed geological 

 and geophysical exploration. The companies individually or collectively 

 conduct extensive geophysical surveys and shallow rock coring programs 

 in promising areas to locate and identify geologic structures capable of 

 trapping and holding hydrocarbons. 



Where there are large structures, deep test wells (COST) may be 

 drilled by a consortium of comnanies "off-structure" (away from where 

 hydrocarbons collect) to determine the characteristics of reservoir 

 rocks. The oil and gas companies involved in the effort share the 

 information gained and the multi -mil lion dollar costs involved. 



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