沙漠戈壁地区地震资料层析静校正研究与应用
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摘要
折射静校正对于地表结构复杂,砂砾层厚度变化剧烈的戈壁沙漠地区,很难取得比较好的效果。为此模拟类似地区的浅表地震地质条件,建立了一低速带横向变化大且基岩出露的数值模型进行模拟试验。模拟结果表明,由于横向速度的变化及地表起伏原因,导致单炮记录初至波与折射波前后炮差异较大,同时目的层的反射波严重扭曲。而通过层析反演速度场模型计算的静校正量,使得单炮记录目的层反射波呈标准的双曲线形态,且相同层位反射波的时间表现一致。在新疆某矿区,进行了常规折射静校正与层析静校正的对比,从地震时间剖面看,常规折射静校正的成像效果不很理想,存在小的扭曲,而层析静校正则表现为同相轴光滑、连续性好,构造形态清晰,避免了假构造的解释。
In regions with complex topographical and surface structures,sandy gravel thickness violently variable gobi and desert areas,the refraction statics is hardly to get preferable effects.By this,similar near-surface seismic-geologic conditions are simulated,and established a low velocity zone with large lateral variation and bedrock outcropped numerical model and carried out simulation test.The simulated result has demonstrated that,because of lateral velocity changes and surface relief caused first arrivals and refractions of front and back shots on single-shot record have greater differences,and seriously distorted target reflections.The tomographic inversion velocity field model computed statics values bring on target reflections presenting standard hyperbola pattern on single-shot record,and same horizon reflections time representation uniformed.In a Xinjiang mine area,contrast of conventional refraction statics and tomographic statics has been carried out;from seismic time sections,imaging effect of conventional refraction statics is not satisfactory,small distortion existed;while tomographic statics presents smooth phase axes,good continuity,clear structural forms,and false structural interpretation avoided.
In regions with complex topographical and surface structures,sandy gravel thickness violently variable gobi and desert areas,the refraction statics is hardly to get preferable effects.By this,similar near-surface seismic-geologic conditions are simulated,and established a low velocity zone with large lateral variation and bedrock outcropped numerical model and carried out simulation test.The simulated result has demonstrated that,because of lateral velocity changes and surface relief caused first arrivals and refractions of front and back shots on single-shot record have greater differences,and seriously distorted target reflections.The tomographic inversion velocity field model computed statics values bring on target reflections presenting standard hyperbola pattern on single-shot record,and same horizon reflections time representation uniformed.In a Xinjiang mine area,contrast of conventional refraction statics and tomographic statics has been carried out;from seismic time sections,imaging effect of conventional refraction statics is not satisfactory,small distortion existed;while tomographic statics presents smooth phase axes,good continuity,clear structural forms,and false structural interpretation avoided.
引文
[1]杨为民,张云岗,刘原英.层析静校正技术在山地复杂地区三维地震勘探中的应用[J].中国煤田地质,2007,19(2).
[2]刘伊克,常旭,王辉.三维复杂地形近地表速度估算及地震层析静校正[J].地球物理学报,2001,(2).
[3]林伯香,孙晶梅,徐颖,等.几种常用静校正方法的讨论[J].石油物探,2006,(4).
[4]赵艳平,宁俊瑞,高鸿,等.层析反演静校正技术在鄂尔多斯盆地中黄土塬区的应用[J].中国煤炭地质,2010,22(5).
[2]刘伊克,常旭,王辉.三维复杂地形近地表速度估算及地震层析静校正[J].地球物理学报,2001,(2).
[3]林伯香,孙晶梅,徐颖,等.几种常用静校正方法的讨论[J].石油物探,2006,(4).
[4]赵艳平,宁俊瑞,高鸿,等.层析反演静校正技术在鄂尔多斯盆地中黄土塬区的应用[J].中国煤炭地质,2010,22(5).
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