Technology and application of distributed acoustic sensing 3D-VSP in desert areas

In the desert hinterland of the Junggar Basin, the seismic data fidelity and resolution are generally low, leading to an unclear understanding of the genesis and distribution patterns of volcanic reservoirs, and difficulties in reservoir prediction and detailed characterization of hydrocarbon accumulations. To accurately delineate the complex internal characteristics of Carboniferous volcanic reservoirs and enhance the resolution of target horizons in seismic data, China’s first onshore fiber-optic 3D-VSP seismic pilot test was conducted in the hinterland of the Junggar Basin. Techniques for acquisition, processing, and interpretation tailored for 3D-VSP data were proposed. First, a VSP data geometry was designed based on geological requirements and the characteristics of fiber-optic equipment, and high-quality VSP seismic data were obtained using efficient vibroseis sources and distributed fiber-optic receivers. Subsequently, by analyzing the characteristics of fiber-optic data and tackling key processing techniques, reliable borehole seismic data processing results were achieved. Finally, through high-resolution VSP imaging, joint comparison and interpretation of surface and borehole seismic data were conducted to analyze the spatial characteristics of the target reservoir. Methods for describing and characterizing deep Carboniferous volcanic reservoirs were discussed, thereby improving reservoir prediction accuracy and reducing the multiplicity of interpretations in seismic data analysis. Application results demonstrate that this method provides a more reliable data foundation for the detailed characterization of Carboniferous hydrocarbon reservoirs in the Junggar Basin, offering significant support and implications for efficient oilfield exploration and development.