FOR several years the Bureau of Mines has been engaged in a survey of typical crude oils from the producing fields of the United States. Results of these surveys have been published as Reports of Investigations. More recently, the Bureau has studied properties of crude oils from countries other than the United States, typical of the producing districts of Canada, Mexico, Trinidad, Venezuela, Argentina, Colombia, and Peru.
The Bureau of Mines undertook a study of foreign crude oils for two reasons: First, foreign fields are potential sources of supply for the United States; in fact, considerable quantities of some foreign crudes have already been imported. Second, these oils are very similar in physical and chemical properties to oils found in the United States and a study of these resemblances has scientific value.
Most of the samples were collected during the summer of 1922, although some samples date back to I9I 9 and 192o. The samples were placed in cans that were tightly soldered at once and there is no evidence that the ,oils had weathered before they were analyzed. All the samples are thought to be fairlv representative of the districts under consideration.
The details of the methods used in this survey in collecting samples, making laboratory tests, and interpreting results, have been discussed in the reports on domestic crudes. For a de.tailed description of the tabulated results, the reader is referred to Technical Paper 346.