497 
ing to allow core drilling in 600 meters of water, a normal rotary 
drill, and vibrating core drilling equipment. Cores up to 200 meters 
can be taken.®” 
The Soviets have announced plans to build their largest crane ship 
to permit construction of fixed Caspian drilling and production plat- 
forms in over 90 meters of water. Tentative completion date for 
this ship is 1976. The self-propelled catamaran will be equipped to 
lift 600 metric ton loads more than 40 meters above the sea. Deck 
load capacity will be around 1,500 metric tons. The largest crane 
ship now operating in the Caspian Sea has a lifting capacity of about 
250 metric tons. The new crane ship should permit wildcatting in 
several very promising Caspian areas that have been inaccessible 
because of water depth. 
The Soviets are experimenting with two new methods of drilling, 
termed branching and horizontal drilling. Soviet petroleum engineers 
feel that branching and horizontal drilling should be especially valuable 
in offshore operations or in tapping subsea sectors of coastal reservoirs 
by drilling from shore. The Soviets are already producing oil from 
beneath the Sea of Okhotsk by conventional directional drilling from 
Sakhalin Island and partially offshore fields are thought to exist in 
many Soviet shelf areas. The branching well system consists of a 
vertical bore extending to a point just above a known hydrocarbon 
zone. At this point, five or six turbodrilled or electrodrilled branches 
slant away from the vertical bore like roots of a tree, each branch 
extending for 80 to 300 meters in different directions into the produc- 
ing horizon. The horizontal well consists of a vertical bore that 
gradually curves to the horizontal as it reaches the producing horizon 
and is then continued horizontally for as much as 1,000 meters. Both 
the branching and horizontal wells greatly increase the area of 
drainage and thus the productivity of the well, according to Soviet 
geologists. Soviet experience with the two techniques, however, has 
usually been associated with oil and gas deposits having producing 
horizons 80 meters or more in thickness at a maximum depth of 
1,500 meters. 
The Soviets, who drill 90 percent of their wells with turbodrills, 
appear to be turning away from downhole drilling motors and are 
becoming interested in U.S. rotary drilling bits. They are in the process 
of considering proposals from American firms for the construction 
of a $200 million facility to make rotary bits.© 
SOVIET POLICY REGARDING OFFSHORE OIL AND GAS EXPLOITATION 
In recent years the Soviets have attempted to revive their long- 
neglected offshore petroleum industry. Professor A Geodekian, Dep- 
uty Director of the U.S.S.R. Academy of Scienses’ Oceanographic In- 
stitute, called for increased basic research in the fields of offshore 
petroleum geology and geochemistry in an article published in Pravda 
last year.®* . 
The article warns that these areas have been given too little atten- 
tion, possibly because of the country’s large proven reserves of oil 
and gas onshore. While the Soviet Union can obtain large increases 
87 Serete Wins Russian Survey Order. Offshore. May 1975. p. 153. 
_ 88 Newsletter. The Oil and Gas Journal, August 4, 1975. 
69 Basic Ocean Research is Pushed Faster in Russia. Offshore, December 1974, p. 19. 
