Structural deformation and its implication for hydrocarbon accumulation in the Wuxia fault belt, northwestern Junggar basin, China

Abstract

With the great discovery of unconventional oil in the Fengcheng Formation in the Mahu sag, the Wuxia fault belt, which shows similar lithological characteristics and lithofacies, is considered the most favorable area for future petroleum exploration. However, the complicated structural patterns remain unclear and restrict the petroleum exploration and development. In this study, combined with new seismic data and some borehole data, we conclude the structural styles in the Wuxia fault belt and analyze their distribution characteristics, and further investigate their implications for tectonic evolution and hydrocarbon accumulation. Five typical seismic sections are captured from the west to the east of the fault belt. Decollement folds and fold accommodation faults superimpose on the underlying basement fault related folds. Structure patterns also show a zonation in S–N direction and a segmentation in E–W direction. The balanced section reveals that the present-day structure features were fundamentally formed by Late Permian. The structural deformation shows distinctive features of a foreland basin which may develop in Early Permian and continue until the Late Permian. The oil reservoirs in the Fengcheng Formation in deeper detachment fold and the autochthonous Fengcheng Formation in fault propagation folds are the most favorable regions for further unconventional petroleum exploration.