摘要:
针对羌塘盆地复杂的地震地质条件,从提高资料信噪比入手,近几年在羌塘盆地开展了数百千米二维地震采集与处理技术试验,初步总结出一套适合羌塘盆地地震采集与处理方法技术。试验结果证明:单井(18 m以上井深)、16~20 kg炸药药量、50 m以下道距、120次以上覆盖次数、“X”型检波器组合图形为较好的激发接收参数。处理获得的地震叠加剖面反射信息丰富,揭示出盆地古生界基底、三叠系、侏罗系中上部、侏罗系顶界各构造层以及断裂的空间展布特征,为查明地层埋深、构造圈闭和构造界面等提供了高质量数据。另外,穿过中央隆起带的地震剖面清楚显示该隆起带不是一个古老构造,而是一个现今构造。
Abstract:
It is difficult to acquire high-quality seismic sections in Qiangtang basin because of its complex seismic geological condition and low signal-noise ratio. In order to find out suitable technique for this basin, the authors conducted tests along a seismic profile more than several hundred kilometers long on the basis of increasing signal-noise ratio. The results indicate that a single hole with the depth of at least 18 meters, 16~20 kilogram charge sizes, 20~40 meters trace group interval, more than 120 folds and“X”type geophone array map constitute the optimum shooting and receiving parameters suitable for the feature of Qiangtang basin. And the quality of 2D seismic profiles obtained by using these parameters and techniques can be increased greatly and is obviously superior to that of the profiles obtained in the past. The processed stacking profiles show informative reflection and reveal the features of spatial distribution of Palaeozoic basement, Triassic, middle-upper Jurassic, upper Jurassic strata and faults, thus providing high-quality data for ascertaining the layer thickness and the structural traps and boundaries. In addition, the processed stacking profile across the central uplifting belt clearly shows that this uplifting belt is an anticline structure formed recently instead of an ancient dome.
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