discovery should be much longer than in 

 Alaska. (The Atlantic OCS, for this reason, 

 could be considered unattractive as a 

 potential oil and/or gas province except for 

 offsetting favorable conditions of location 

 and weather. 



4. In the intensively explored Gulf of Mexico, 

 the original development was an extension 

 of both onshore fields and the geologic 

 sequence. It has been estimated that 

 significant production from the deeper 

 tracts leased in the last three years will 

 take up to 4 or 5 years. 



The decisions on the location, timing and scale of development 

 described above are translated into activities on the offshore and 

 facilities on the onshore. Part 2 identifies and describes these 

 activities and facilities in detail. 



1.3.2 Phases of Development 



It is convenient to divide the OCS development process into six 

 major sequential phases. Each phase is characterized by the intro- 

 duction or development of specific industrial projects and activities. 



The six phases are (1) pre-exploration, (2) geological and geo- 

 physical exploration, (3) exploratory drilling, (4) field development, 

 (5) production, and (6) shut-in of facilities. The development process 

 is analyzed by these phases not only because they are physically 

 different, but also because laws and administrative regulations require 

 that one precede the next. In a mature petroleum province such as the 

 Gulf of Mexico, all of these activities may be occurring simultaneously. 



A wide variety of activities, equipment, facilities and projects 

 are required to explore, develop, and place into production oil 

 and gas fields offshore (see Plate 1, following References, for an 

 idealized diagrammatic version of the OCS process). 



A flow chart of the major activities involved in the exploration 

 and development of an offshore oil or gas field is shown in Figure 6 

 along with the six phases of this long and complex process. 



1. Pre-exploration : Prior to the initiation of oil and gas 

 prospecting in a frontier area, significant effort is devoted to care- 

 fully analyzing available geological and geophysical surveys. The 

 analyses are done by seismic companies under contract to oil and gas 



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