School of Studies in Earth Science, Vikram University, Ujjain-456010 M.P. (INDIA)
Email: ashutodixit@gmail.com, singhkn_vikram@yahoo.com,

The ratios of di-benzo-thiophene to phenanthrene and pristane to phytane joined together suggests the easiest way to know the crude oil source rock depositional environments of the particular area. This type of studies signify identification of the source formation(s) in a basin thereby providing valuable guidance for further exploration of oil wells. The ability to interpret this information from the data analyzed of a crude oil is much valuable during drill stem test of the samples collected from exploratory wells which are characteristically drilled on structural heights, stratigraphically remote from the source formation(s). The ratio of these two compounds is usually interpreted to be an indicator of the oxicity of the environment of deposition3,4. Recent advances in organic geochemistry in combination with geological constraints lead us to suggest that the Pr/Ph ratio cannot be used as an indicator for oxygen levels. However, in hypersaline environments of deposition the rationale behind a low Pr/Ph ratio is easier to understand, and in these environments application of the Pr/Ph ratio can be expected to be successful.

In the present endeavor the ratio of pristane and phytane of Ankaleswar oilfield has been evaluated to know the relationship of other parameters. The Ankaleswar oilfield is one of the promising field of Gujarat state and contributing 10% of the total production of the Indian oilfields.