利用重磁资料研究Vøring盆地断裂构造与油气远景

    Fault structure and the oil and gas prospect of the Vøring Basin using gravity and magnetic data

    • 摘要: 挪威中部近海的Vøring盆地有着良好的油气地质条件,为了深入了解该区的断裂构造特征和油气勘探潜力,系统整理了现有的重磁数据。使用变纬度化极技术消除跨纬度变化对于磁力数据的影响,并运用位场边缘识别技术提取本区位场边缘识别信息。综合了已有的地质和地球物理认识,对研究区的重磁异常特征进行了系统分析,确定了Vøring盆地的断裂构造特征,划分了油气勘探有利区。研究表明Vøring盆地内次级断裂走向复杂,有NE向、近SN向2组主要断裂,同时沿NW向和近EW向发育2组断裂往往切断前2组断裂。盆地还发育有4条大的边界断裂(F1~F4),这些断裂控制了本区次级构造的发育。在Vøring盆地内圈定了油气勘探有利区,在重力垂向二阶导数异常图上反映为异常幅值高、异常梯度变化大、有断裂控制的异常带及其侧翼。

       

      Abstract: The Vøring Basin, in the Norwegian midland near the sea has favorable geological conditions for hydrocarbon accumulation. To gain a deeper understanding on the fault structure and hydrocarbon exploration potential in the basin, available gravity and magnetic data have been analyzed systematically. The Varimax transformation technique was applied to eliminate the influence of latitude changes on the magnetic data. Additionally, the edge detection technique for potential fields was utilized to delineate the edge of the local field in this area. By integrating existing geological and geophysical knowledge, a systematic analysis on the gravity and magnetic anomalies in the study area was conducted, and ultimately the fault structure features of the Vøring Basin were identified and the outlining favorable areas for hydrocarbon exploration were defined. Result indicates that the secondary faults in the Vøring Basin exhibit complex orientations, including mainly two sets of major faults in northeast and nearly north-south directions respectively. Additionally, there are other two sets of faults trending northwest and nearly east-west, and they often cut across the first two sets of faults. The basin is surrounded by four major boundary faults (F1~F4), which control the development of secondary structures in the area. Favorable hydrocarbon exploration areas in the Vøring Basin were delineated, represented by high-amplitude anomalies with clear gradients in the second-order vertical derivative anomalies, as well as anomalous bands controlled by faults and their flanks, as evidenced on the gravity gradient map.

       

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