containing the sample is extracted in the same apparatus, or in a Soxhlet, until 

 all oil is removed. The weight of the sample converted to volume, and the 

 volumes of water and oil obtained are calculated to percentage of pore space. 



Titration Method 



The water content of a weighed, crushed sample can be measured by ex- 

 tracting the sample with anhydrous alcohol and titrating with Fischer's reagent. 

 The oil content is determined by weighing before and after extraction and sub- 

 tracting the weight of the water. 



Critical Solution Temperature Method 



The water present in the sample is extracted with anhydrous alcohol, and 

 the temperature at which a mixture of equal volumes of kerosene and the 

 alcohol solution becomes clear on heating, or turbid on cooling, is measured. 

 The method is calibrated for the particular brine and crude oil present in the 

 sample, and the volume of alcohol used for extraction is adjusted so that the 

 critical solution temperature falls within a convenient range. 



Other less desirable methods include the vaporization of water and absorp- 

 tion with phosphorous pentoxide, and the extraction of oil from a weighed 

 sample of the core by volatile solvents such as pentane and subsequent recovery 

 of the oil by distillation. 



Saturation methods most in use are the retort and Stark-Dean distillation 

 procedures. The retort method appears the most popular because of its simplicity 

 and speed and the fact that both oil and water are being measured simultaneously. 

 The Stark-Dean distillation is used when the water content of the sample is of 

 prime importance. All saturation methods now in use are unreliable, even 

 though it is widely acknowledged that the water content may be accurately de- 

 termined. Their unreliability is no particular detriment in core-analysis inter- 

 pretation, however, as they are in no sense a measure of actual reservoir con- 

 ditions. 



BULK OR FULL- Since 1947 apparatus and methods have been 



DIAMETER METHODS developed in which the entire core, cut or 



broken to convenient lengths, is used for the 

 test specimen. This type of analysis, called full diameter, special, or bulk 

 analysis, claims greater accuracy and reliability by avoiding the pitfalls of the 

 small test specimen. It is not limited by the diameter of the core and is limited 

 in length only by the type of apparatus; specimens from 8 to 18 inches in 

 length are conveniently handled by this comparatively new technique. The 

 small-plug method is still in universal use for the analysis of sandstones and 



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