Abstract:

The Xujiaweizi faulting depression lies in the central part of the Songliao Basin. It is controlled by Songxi and Xuxi faults. Based on the geologic interpretations of the seismic reflection data，we have investigated the growth rate and the evolution of the master faults forming basin boundaries by applying the method of analyzing the relationship of displacementlength along strike of normal faults and the approaches for analyzing growth rate along dip direction. It is revealed that the faults formed mainly in the Shahezi Period. The average growth rate of fault is estimated to be 35 m/Ma and 71 m/Ma for Xuxi and Songxi respectively and larger than 60 m/Ma for the boundary fault system as a whole. During the Shahezi Period, Songxi and Xuxi faults were developed independently with a little soft link around their overlapping part. The Yingcheng Period was another important stage with much more intensive activities of Songxi fault, leading to a larger and deeper faulting depression with thicker sediments infilling. The average growth rate of fault was 18 m/Ma for Xuxi, and 85 m/Ma for Songxi. Hard link occurred between them. Only weak and local faulting activity occurred around some linking areas after the Yingcheng Period. The oil and gas fields are mainly located in the areas where secondary tectonic element developed. This finding bears important implications for the further oil and gas exploration in Xujiaweizi Area.

Key words:

Key words: Xujiaweizi faulting depression; fault linkage; growth rate; quantitative; development