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Thermal and burial history modelling of the Tuzluk and Soh Permit areas, southern Fergana Basin, Kyrgyzstan

Honours Degree 2007

Borrett, Jessica

University of Adelaide

Abstract

The Fergana Basin, located in the western part of central Asia has had a long exploration history. However, there is relatively little western literature available compared to Russian literature. Due to this, a comprehensive review of the regional geology of the Fergana Basin and its petroleum systems was compiled prior to petroleum system modelling. 

Burial and thermal histories calibrated to vitrinite reflectance data in the Santos Tuzluk and Soh permits of the south west Fergana Basin, Kyrgyzstan, indicate that the Palaeozoic source rocks passed through the hydrocarbon generative windows almost 300 million years ago, whilst the younger Mesozoic and Palaeogene source rocks are thermally immature for hydrocarbon expulsion.

Estimation of missing section incurred during the Hercynian Orogeny (late Carboniferous) and the Permo-Triassic peneplain phase in the study area is about 6,500m and increases towards the Fergana Basin southern margin. Results indicate an increase in exhumation during the Alpine Orogeny along strike in the study area, ranging from 400m in the west to 1,900m in the east.

The Alpine Orogeny has considerable syn-orogenic sedimentation (up to 4,311m of Mesozoic through to recent sediment section has been deposited in the Tuzluk and Soh permit). The Neogene burial associated with the Alpine Orogeny has not taken the Palaeozoic section to the maximum palaeo-temperatures and maturity from samples taken, which they experienced prior to the Hercynian exhumation.

The locally non-productive nature of the Mesozoic and Cenozoic source rocks in these permit areas suggests the likelihood of migration from a mature basinward source as there are multiple oil and gas fields in the Tuzluk and Soh permits that are producing from Mesozoic through to Recent reservoirs in Alpine structures. Palaeozoic accumulations derived from Palaeozoic source rocks in the study area appear most unlikely.

Australian School of Petroleum
THE UNIVERSITY OF ADELAIDE

SA 5005 AUSTRALIA

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