复杂地形地震剖面上的陷阱及物探解释方法

Trap of Seismic Section and Geophysical Interpretation Method for Complex Terrain

为了准确解释地下构造形态,基于正演模型研究在地形起伏、固定基准面与浮动基准面之间填充速度不同等情况下,地下构造产生畸变或产生假构造的现象。结果表明,填充速度与目的层平均速度一致时地震剖面与模型一致,反映真实构造形态;当填充速度小于目的层平均速度时,地震剖面产状畸变与浮动基准面形态相同;当填充速度大于目的层平均速度时,地震剖面产状畸变与浮动基准面形态相反。用固定基准面制作构造图的方法来消除假构造的影响,反映了地下真实构造形态,解决了复杂地区构造保真问题,提高了勘探精度,保证了勘探质量。

Using the building forward model,the distortion of structures and false structure caused by topographic variation and the difference of filling speed between floating datum and fixed datum is studied.Seismic section is consistent with model,and real structural shape is reflected when filling speed is similar to average velocity of target layer.The attitude distortion of seismic section is consistent with the shape of floating datum if filling speed is less than average velocity of target layer.The attitude distortion of seismic section is consistent with the shape of floating datum if fillingspeed is less than average velocity of target layer. The attitude distortion of seismic section is opposite to the shape of floating datum if filling speed is more than average velocity of target layer. The false structure can be eliminated through the structural map with fixed datum, thus reflecting the real structural shape, solving the problem of structural fidelity, improving exploration precision and success rate of drilling, and ensuring the quality of exploration.