A SUGGESTED METHOD OF APPROACH FOR THE 
DETERMINATION OF SALT DOME OVERHANG 
By O. C. LESTER JR., Houston, Texas 
The purpose of this paper is to present for consideration and 
discussion a method of seismic attack on the problem of salt deme, 
or associated caprock, overhang such as has been indicated by 
recent developments at Barber’s Hill and Allen domes. 
The original Gulf Coast geophysical problem was one of re- 
connaissance—the search for a salt plug of relatively shallow depth 
which might lie anywhere within a few hundred thousand acres. 
Next came the slightly more detailed problem of searching for 
deeper and deeper domes within the same large areas in which the 
shallow domes had been found. 
As the location of more and more of these domes became an 
established fact, further and far more intricate problems were 
presented in the detailing of them, with primary attention paid 
to contouring the top (either caprock or salt), and outlining the 
boundary of the steep plunge from top to flanks. The varying 
degrees of success with which each of these problems has been met 
by geophysics, in numerous instances, is well known to all con- 
nected with the oil business. However, the significant point is, 
that each successive problem has been met, and a reasonable 
solution offered. 
The problem now presented is one of salt dome detail under 
the surface of the dome; and the attack must be made through 
the top of the dome, or by approach on its flank, under the top. 
A method of approach is suggested here, which involves the 
reflection type of seismic shooting, and will be submitted in a 
general way for your consideration. 
In attempting to obtain detailed subsurface information by 
geophysical means we are confined to physical operations at the 
surface of the ground. This fact, coupled with the necessity of 
obtaining information at depths of several thousand feet requires, 
in refraction work, that shot and recording points be placed at 
distances several miles apart, so that energy (or seismic waves) 
may attain the depth desired. For investigating in detail the ver- 
tical changes in a roughly horizontal bed, the refiection method, 
which requires the seismic waves to contact the bed in question 
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