FLUOROANALYSIS Liquid petroleum will fluoresce under ultra- 



violet light of wave lengths down to 2000 

 angstrom units (DeMent, 1947). This property of fluorescence has led to the 

 development of analytical techniques which were applied to exploration by 

 Blau (1943), Squires (1948), and others. Although sands, soils, shales, and 

 drill cuttings may be analyzed rapidly for petroleum content, experience is 

 necessary for interpretation of results. 



Reconnaissance surveys are conducted on a grid pattern in much the same 

 way that soil surveys are conducted. Samples of about 1 ounce are collected 

 near surface, or at about 2 feet in depth, after which they are dried, crushed, 

 and sieved prior to analysis. The fluorescence is recorded on a sensitive film 

 from which differences of intensity are read by means of a densitometer. A 

 sensitivity in the order of 1 part-per-billion is claimed, and many samples may 

 be processed simultaneously. 



Samples collected over barren areas would not be expected to fluoresce, 

 whereas those that do would be related to gas seepage. Anomalous values are 

 found over the accumulation as well as around the edges (Campbell, 1946). 

 Satisfactory results are reported from surveys conducted in a variety of ter- 

 ranes, including swamps and sand dunes. The cost of a fluorographic survey, 

 according to Turner (1943), is about $3.50 for each sample collected and 

 analyzed. 



FLUOROLOGS Well cuttings can be screened for fluorescence 



in much the same manner as cuttings are 

 analyzed by other geochemical procedures. Fluorologs, as they are called, make 

 use of a photographic method for recording fluorescence. The data are plotted 

 on standard log forms that show the depth at which the sample was collected. 



The fluorolog of a producing well usually shows values that are relatively 

 high at the surface and that progressively increase with depth. Dry holes 

 generally have low readings throughout their entire length. Fluorologs, like 

 geochemical well logs, provide a direct measurement of petroleum derivatives 

 and can supplement electric-log data. 



MICROBIOLOGICAL Hydrocarbon gases from underlying oil and 



METHODS gas pools have been shown to sustain and 



stimulate the growth of certain micro- 

 organisms in surface soils. Some techniques are based upon the effects of gas- 

 eous hydrocarbons on certain bacteria, while others measure the effects of the 

 bacteria upon these gases. Bacteria may be implanted in the soil and their 

 development studied, or the soil can be analyzed for specific strains of bacteria. 



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