BULLETIN OF THE AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS 
VOL. 18. NO. 1 (JANUARY. 1934). PP. 119-132). 5 FIGS. 
APPLICATIONS AND LIMITATIONS OF DIP SHOOTING! 
E. E. ROSAIRE? and JOSEPH L. ADLER? 
Houston, Texas, and Houghton, Michigan 
ABSTRACT 
The history and methods of dip-shooting are outlined and the degree of accuracy 
obtainable by the method is investigated. Plotting of the misclosures on 151 dip- 
shooting traverses in the Gulf Coast to yield a frequency curve shows a probable error 
of about 87 feet, in traverses averaging 27,500 feet in length. This error is apparently 
independent of the length of the traverse, and within the range of spreads commonly 
used, that is, from 1,400 to 2,400 feet, independent of the spacing of the dip determina- 
tions. The smoothness of the frequency curve is broken by an excessive number of mis- 
closures greater than 250 feet. These may be due to unusual structural conditions on 
the traverses concerned, such as terracing between dip points or faulting, or to gross 
personal errors. The principal common errors appear to lie in the drafting of the pro- 
files, the determination of the time step-out, and the weathering correction. These er- 
rors on individual dips may considerably exceed the probable error, but on traverses of 
average length will tend to compensate one another. Other sources of error are dis- 
cussed, but aré believed to be of minor importance. 
The purpose of this paper is to present an outline of the methods 
used in the determination of the dip of sound-reflecting strata in the 
Coastal Plain series of Louisiana and Texas by the reflection seismo- 
graph, and an analysis of the errors involved. Many data accumulated 
by Rosaire and Kannenstine and the Independent Exploration Com- 
pany, of Houston, were available for this purpose. Especial acknowl- 
edgement must be made to J. D. Marr and C. B. Bazzoni for sugges- 
tions bearing on the research. 
CONDITIONS GOVERNING CHOICE OF METHOD 
The fundamental limitation on the use of reflections is that in 
themselves they tell little or nothing with regard to the nature of the 
reflector. Even in the “hard rock” areas, where definite lithological 
breaks occur, reflections must be identified by some auxiliary method, 
such as checking against the log of a well already drilled, or prefer- 
ably, determining arrival half time by recording or shooting down a 
well. 
In the upper portion of the Coastal Plain series no laterally per- 
sistent lithologic horizons have yet been determined, and so, a priori, 
1 Read before the Geophysics Division of the Association at the Houston meeting 
March 24, 1933. Manuscript received, September 30, 1933. 
2 Rosaire and Kannenstine, consulting geophysicists, Houston, Texas. 
3 Assistant professor of geology, Michigan College of Mining and Technology, 
Houghton, Michigan. 
£19 641 - 
