TREASURE FROM THE SEA 



Actually, the first offshore production came from wells slant- 

 drilled from the beaches of California, out under the Pacific. As 

 the ocean floor of the Pacific falls away quite steeply from the 

 shoreline, this leaves only a narrow band offered for prospecting. 

 It is primarily due to this type of submarine relief that deepwater 

 drilling techniques have developed more rapidly on the west coast. 

 In fact, it was here that the first floating drilling vessels were used, 

 rather than in the Gulf of Mexico. 



The oil industry decision to build floating drilling rigs rather 

 than bottom supported units is based upon several factors, some of 

 which are: 



a. The ability to drill in deeper water. 



b. Mobility for foreign as well as domestic operations. 



c. Less expensive to operate than some bottom supported units. 



d. Those with a hull similar to a ship can head into the sea 

 during severe conditions, thus minimizing roll and pitch. 



Cuss III— a jloatiTig drilling vessel. Courtesy Union Oil Co. of Calif ornw 



The oil boom is not confined to the Gulf of Mexico, but is in 

 fact becoming world wide. To some extent, this has caused an 

 exodus of marine drilling rigs from the Gulf, to such places as Lake 

 Maracaibo (where there are approximately 4,000 offshore wells). 

 Cook Inlet, Alaska, the Gulf of Suez, the Persian Gulf, the Gulf of 

 Guinea, and many others. 



Concerning foreign oil prospecting, the majority of interest 

 is probably now directed to the North Sea, a sedimentary basin 

 almost as big as Texas. A major discovery on the threshold 

 of the world's thirstiest gas and oil market would be not only a 

 bonanza, but could also have a direct bearing on the European Com- 

 mon Market, as the holder of such a find would have a key to much 

 of Europe's energy. 



In 1960 Slochteren, Netherlands became the third largest gas field 

 in the world. And, these producing sands are the same ones that 

 have been discovered on the northeast coast of England. The ques- 

 tion as to whether these sands are also under the North Sea, is the 

 reason for great acceleration of oil prospecting in that area. 



The prospects are so great in the North Sea that it will take 

 approximately three years of drilling to check the prime geologic 

 structures already located. With the ratification by Great Britain, 

 the 1958 Geneva Convention on the continental shelf became effec- 

 tive on 10 June 1964. This convention proclaims that the sea-bed 

 and subsoil of the submarine areas adjacent to the coast belong to 

 the coastal state as far out as the "depth of the superjacent waters 

 admits of the exploitation of the natural resources of the said areas." 

 It contains also provisions for drawing of boundaries where the 

 claims of two or more countries overlap. Hence, the oil and gas 

 rights of the North Sea will be divided up among Belgium, Denmark, 

 England, France, Germany, the Netherlands, and Norway. 



The greatest portion by far, of all geophysical prospecting has 

 been in the search for oil and gas geologic structures, with but a 

 small fraction of expended effort directed to solid minerals. In 

 petroleum exploration, the seismic reflection method is the most 

 widely used, with gravity, seismic refraction, and magnetic survey 

 methods following in that order. With the data provided by this 



method it is possible to chart depths to subsurface interfaces with 

 accuracy exceeded only by measurements in wells. Similar to the 

 fathometer operation in many respects, the system depends on travel 

 times of elastic waves reflected back to the surface from different 

 earth formations. 



SURVEY BOAT 



RECOaOING BOAT 



SHOOTING BOAT 



Seismic reflection shooting offshxyre. 



The advantage of the reflection method is that it permits charting 

 of many horizons from each shot, with the precision approximately 

 the same for the deeper horizons as for the shallow ones. In the 

 other mentioned methods, reliability decreases with increasing 

 depth. 



With seismic reflection, depth determinations are not exact, 

 as sound velocity within various layers is not precisely known. This 

 inaccuracy, however, is not too important as it is the position of 

 local humps or domes in the rock layers that is sought by the 

 geophysicist. 



DIATOMS. — As oil is referred to as "black gold", so has diato- 

 mite, the lightweight remains of diatoms, been called "white gold." 

 Diatoms are members of the yellow-green group of algae and are 

 the most numerous plants of the phytoplankton, sometimes amounting 

 to ninety percent of the total. There are many different species 

 of diatoms, all of which are unicellular and microscopic, with an 

 above average one measuring perhaps l/200th of an inch. Although 

 they are a form of vegetation, diatoms possess no leaves, stalks or 

 roots. Rather, their most characteristic feature is a transparent 

 shell of silica, filled with the protoplasm of the cell. 



Like plants ashore, diatoms are seasonal, with their numbers 

 fluctuating accordingly. It is seldom that thay are completely 

 absent from any portion of the surface waters.- Ordinarily, they 

 are more numerous near land as their required nutrients are nor- 

 mally more abundant in coastal waters. With the extended hours of 

 sunlight in the spring, occasionally their numbers become so vast 

 that they tend to change the very color of the sea. During these 

 times the waters may become green, brownish-green or even red, 

 and a single cup of sea water may well contain hundreds of thousands 

 of diatoms. 



These silicified diatom skeletons, sinking to the ocean floors in 

 earlier eras, resulted in large deposits of packed diatomite. Today 

 these deposits are mined in places such as California, Nevada, 

 Oregon, Washington, Denmark, Finland, and France. 



Due to its light weight in relation to bulk, industry has found 

 many uses for diatomite. Albert Nobel created dynamite in 1870, 

 by soaking nitroglycerine into diatomaceous earth. When made 

 into strainers, it is porous enough to let liquid flow through it, while 

 its lacy particles strain out bacteria. It is for this quality, that 

 drug firms use the product. It has also been used as a cigarette 

 filter, to strengthen concrete and to produce a flat or semigloss 

 finish in paint. 



GOLD. — Concerning recovery from the sea, the only "trace 

 element" that has really attracted attention is gold. Just one of 

 our 300 million cubic miles of sea may contain as much as 25 tons 

 of this precious metal. But, it is in such minute particles that ex- 

 traction is not currently financially feasible. There have been a 

 few attempts, all of which met with failure. A minute amount was 

 extracted experimentally as a by-product of bromine production. 

 The final cost, however, amounted to approximately five times the 

 value of the gold recovered. Also, there was the unsuccessful at- 

 tempt in 1927 of the German METEOR expedition. This was the 

 German attempt to obtain sufficient gold from the mid- Atlantic 

 to pay off their war debt. 



Research on gold extraction will no doubt continue, to some 

 extent. If an economic method is not found, scientists will still gain 

 other useful information from their efforts. 



12 



