In this paper, the question, "What are tar sands?" is addressed. In an effort to categorize the tar sand deposit at Raven Ridge near Vernal, Utah, the coordinated and combined activities with corresponding disciplines such as the following were considered:

  • recognizing the potential of the heavy oil impregnated rock,

  • characterizing the deposit based on the composition of the oil,

  • developing reserves,

  • characterizing the material,

  • establishing possible reservoir characteristics,

  • defining conventional oil production potential.

Some fourteen shallow holes were drilled and cored. Tar sand samples were taken from the lean, medium, and rich bitumen content rock. These samples were analyzed chemically.

The results of the coring, logging and chemical analysis are as follows:

  • There is a definite correlation between the results that were computed from electric logs and with those obtained from chemical analysis of some 268 tar sand samples.

  • Asphaltene, polar molecule and hydrocarbon content of the bitumen from Raven Ridge was compared to similar analyses of other tar sand deposits of the world using SARA (Saturates, Aromatics, Resins, and Asphal-tenes) analyses. The results indicate that the petroleum (oil sand) deposit is a thermally mature oil.

  • A reservoir engineering analysis was carried out to determine the potential rate of oil production, from a well drilled at a suitable location downdip based on the available geologic data from the near outcrop core data. The results indicate a good possibility of conventional oil production.

Conclusions are that chemical analysis (SARA) of tar sand samples obtained from various depths, near surface up to 50 feet deep, could provide a positive indication of oil production from a well drilled down-dip from the outcrop.

You can access this article if you purchase or spend a download.