134 



Fig. 2 — Estimated World Petroleum Reserves 



behind the rapid expansion of offshore petroleum ex- 

 ploration and production. 



With these incentives in mind, let's briefly review the 

 major oflfshore drilling developments that have occurred 

 during this century: 



The first offshore drilling was carried out from 

 wooden piers along the coast of Cahfornia at the turn 

 of the century. This was a natural extension of land 

 fields into the sea. 



During the 1920s the same thing occurred in Lake 

 Maracaibo, Venezuela. More than 5,000 wells have now 

 been drilled in the lake in water depths up to 120 ft. 



During the next decade, there was extensive drilling 

 in the marshes of Louisiana. Several hundred drilling 

 rigs designed for this purpose were built during a 20- 

 year period. 



In the 1940s, drilling moved into the open water of 

 the Gulf of Mexico. By 1948, platforms were being 



built in 50 ft. of water off Louisiana. Due to low success 

 ratios encountered when exploring for commercial oil 

 reservoirs, the industry soon found it necessary to de- 

 velop a lower-cost technique for locating such reservoirs. 



Thus, during the 1950s the offshore mobile unit 

 underwent a rapid period of development. Mobile rigs 

 made it possible to move on a location quickly, drill a 

 well, and move to another location. With the advent of 

 mobile drilling units, operations moved rapidly into 

 deeper waters. 



A full-scale exploratory well was drilled in 632 ft. of 

 water off the coast of California several years ago. Right 

 now there is a rig operating in approximately 640 ft. of 

 water in the Santa Barbara Channel. Humble recently 

 announced that the company would be drilling a well 

 in that area in 1,300 ft. of water by year-end. 



Fig. 4 — Water Depth Records — Producing Wells 



As indicated above, the present producing depth record 

 is 340 ft. in a field located off the coast of Louisiana. It 

 is anticipated that new producing depth records will be 

 established in the Santa Barbara Channel during the 

 next few years. 



Related Statistics 



The statistics which follow provide an insight into 

 the magnitude of past and current offshore operations: 



Fig. 3 — ^Water Depth Records — Exploratory Wells 



'58 '59 '60 '61 '62 '63 '64 '65 '66 '67 '68 

 YEARS (EST.) (EST.) 



Fig. 5 — Seismic Surveys (Land and Marine) — Crew 

 Months 



