Comparative Geological Study of Hydrocarbons Producing Barmer and Jaisalmer Basins in Rajasthan, Western India
Dandamudi, Subhakar *1; Misra, Kiran S.1
(1) Petroleum Engineering and Earth Sciences, University of Petroleum and Energy Studies, Dehradun, India.
Significant geological similarities and dissimilarities between hydrocarbon producing basins in western Rajasthan, Western India are enumerated. Satellite imagery is interpreted of these basins and it has been found that the major pattern of lineaments is orthogonal and related to basement tectonics. The basin forming tectonics in Jaisalmer basin is controlled by basement faults trending in NE-SW direction, while for Barmer basin the nearly vertical faults are tending in NW-SE direction. The lineaments mapped in this desert region have shown that the basement blocks have moved up or down. On surface these regions can also be recognized by the varying pattern of the dune complexes and several associated geomorphological features. Topographic highs and lows which kept on moving relatively were active during the pre-rift and the post-rifting stages, of the basin evolution. The evolution of both Jaisalmer and Barmer basins seems to have commenced almost with the beginning of the Proterozoic Era.
The stratigraphic sequence in Jaisalmer basin started with the Randha and Birmani Proterozoic formations. After a prolonged hiatus sedimentation commenced again during Cretaceous to continue up to middle Eocene. After second hiatus the Shumar formation of Quaternary Era was deposited. While in the case of Barmer the stratigraphy is marked with the Jodhpur formation of the Proterozoic to lower Cambrian besides the Cretaceous volcanics. However, the evolution of Barmer basin started with the eruption of Malani suite of volcanic rocks. The major difference found in the startigraphy of the two basins is the presence of the Cretaceous volcanics which underlie the Tertiary sequence only in Barmer basin. In Rageswari field these Cretaceous volcanics are the prolific producers of the hydrocarbons in the form of gas. Suggesting Mesozoic and older Paleozoic successions as source rocks.
The intersectional area of these two basins is of geological interest and needs detailed exploration of hydrocarbons because compounding effect of subsidence along both the Jaisalmer and Barmer basins might have given rise to exceptionally thick sedimentary sequence.
AAPG Search and Discovery Article #90141©2012, GEO-2012, 10th Middle East Geosciences Conference and Exhibition, 4-7 March 2012, Manama, Bahrain