论文详情
陆地双检采集系统在地表和地下一定深度设置两层同类型检波器同时接收地下反射波场信息,可为波动方程偏移提供充分的边界条件而无须做近似处理,因而,基于该采集系统的双检偏移算法具有更高的构造成像和保幅计算能力。为满足实际资料的保幅成像需求,通过分析层间延迟时差对双检构造成像和保幅性的影响,提出了基于互相关的层间延迟时差定量计算方法,并建立了以层间延迟时差为主要指标,以道间延迟时差、层间和道间振幅差、层间和道间正常延迟时差占比为参考指标的评价函数,为双检数据的采集和处理提供了一定的参考。模型数据的成像测试结果表明,成像输入数据的信噪比高于3.0时可得到较好的真振幅计算效果。实际资料成像结果表明,该评价函数可有效区分双检地震数据的质量,评价结果低于0.6的数据不能达到保幅成像要求,应予以校正。
In dual-sensor seismic acquisition systems,two layers of geophones of the same type are installed—one on the surface and one underground—to record the reflected wave field simultaneously.This technique can provide sufficient information for solving the second-order partial derivative wave equation without the need of approximations,thus offering superior structural imaging and amplitude preservation.By analyzing how these are influenced by the delay time difference,a quantitative method for calculating this time difference based on cross-correlation was constructed.An evaluation function was also established,which takes the delay time difference between layers as the main index,and the delay time difference,the amplitude difference,and the proportion of normal delay time difference between layers and traces as the reference indices.The imaging results of simulated data showed that the evaluation function is sensitive to changes in the signal-to-noise ratio (SNR).When the SNR of the imaging input data is higher than 3,an improved evaluation of the true amplitude can be obtained.Results on actual data showed that the evaluation function can effectively distinguish the quality of dual-sensor data.However,data with SNRs lower than 0.6 should be corrected because they cannot guarantee amplitude-preserving imaging.