【摘要】 镇巴地区属于典型的复杂山前带探区,其非常复杂的地表地质条件及地下地质构造特征("双复杂")给地震勘探带来了严峻的挑战。区内已开展了从二维到三维的多轮地震采集攻关研究,全面尝试了从叠前时间偏移到叠前深度偏移,再到逆时偏移的地震资料成像处理,但获得的成果资料均表现为低信噪比特征。区内地震单炮记录及叠加资料的波场特征主要表现为绕射波和半支绕射,且波组不稳定、不完整、不健全,主要目的层基本没有稳定的水平反射同相轴。理论计算和模型正演分析表明,目前地震资料的低信噪比特征应该是地下地质结构的客观反映,预示镇巴地区地下稳定地质体的尺度、规模偏小,已接近甚至小于地震可观测的最小尺度。在提出地震采集、处理进一步攻关研究具体建议的同时,为切实加快镇巴地区油气勘探进程,建议尽早实施风险钻探。更多还原

【Abstract】 Zhenba area is a typical complex piedmont zone because of complex surface and subsurface geological conditions("dual complex").The seismic exploration technology faces severe challenges.Through repeated 2D and 3Dseismic exploration,prestack time migration,prestack depth migration and reverse time migration,the available data shows still low signal-to-noise ratio.The seismic wavefield in single-shot records and stack sections mainly displays some diffraction or half diffraction and their reflection events are instable,incomplete and imperfect,and no continuous horizontal reflection in general.Theoretical calculation and analysis on forward modeling show that current low signal-to-noise ratio of seismic data should be the objective reflection of subsurface structures,which indicates that the sub-structure scale in Zhenba area is small,even less than the observable minimum standards of seismic survey.Therefore,we should carry out further research on the seismic acquisition and processing in Zhenba area.Meanwhile,in order to speed up the exploration procedure in Zhenba area,risk drilling should be determined to proceed as soon as possible.更多还原