<p>A comprehensive approach has been proposed for the physicochemical study of samples of unknown composition. Analytical methods relevant to each step of the study are described. Various analytical procedures are examined along with the advantages and disadvantages of each method. The research algorithm permits determination of the nature of the samples as well as their qualitative and quantitative composition using modern analytical methods to solve practical problems related to the operation of equipment for the extraction of petroleum and natural gas and also to scientific questions concerning the origin and transformation of specific substances. This approach is quite universal and was developed taking account of the advantages and disadvantages of each method.</p>