基于地质模型的定向组合激发-接收技术  

A directional combined excitation-receiving technology based on geological model

作　　者：李亚林[1] 徐峰[2] 彭更新[1] 刘福烈[2] 郭念民[1] 徐凯驰 LI YaLin;XU Feng;PENG GengXin;LIU FuLie;GUO NianMin;XU KaiChi(Petrochina Tarim Oilfield Company,Korla Xinjiang 841000,China;Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]中国石油塔里木油田公司,新疆库尔勒841000 [2]西南石油大学,成都610500

出　　处：《地球物理学报》2021年第10期3742-3755,共14页Chinese Journal of Geophysics

基　　金：中国石油重大科技专项课题(2018E-1807);国家自然科学基金项目(41804137)资助.

摘　　要：定向设计的震源、检波器组合可增强特定方向传播的地震波能量,同时压制其他方向噪声,从而改善低信噪比数据的资料品质.本文提出了一种基于地质模型的定向组合激发-接收技术方法,该技术方法包含三个步骤:定向方向计算、定向组合参数设计、定向组合数据处理.首先对地质模型做波动方程正演并统计地震波出射到地表的能量和角度(方向),然后优化设计组合参数将波场能量定向聚焦到该方向,在进行激发-接收定向组合处理后,最终实现提升地下弱照明地区成像质量的目的.基于此思路,本文首先分析了地震波场产生方向性的原因,以模型照明结果为例展示了地质结构与波场传播方向的相关性;然后定义了表征波场传播方向和能量大小的能流密度矢量,在此基础上推导出声学介质条件下地表出射波场的角度和能量计算方法;最后给出了组合叠加波场的表达式和求解各组合参数的目标函数.经理论模型和实际资料验证,本文提出的定向组合方法能显著改善资料信噪比,在低信噪比地区应用前景广阔.The combination of seismic source and geophone with directional design can enhance the energy of seismic wave propagating in specific direction,while suppressing noises in other directions,thereby improving the data quality of low signal-to-noise ratio data.This paper proposes a directional combined excitation-receiving technology method based on a geological model.The technical method includes three steps:directional angle calculation,directional combined parameter design,and directional combined data processing.Firstly,we carry out wave equation forward modeling on the geological model,count the energy and angle(direction)of seismic wave emitted to the surface,and then optimize the design combination parameters to focus the wave field energy in this direction.After the excitation-receiving combination processing,we finally achieve the purpose of improving the imaging quality of underground weakly illuminated areas.Based on this idea,this paper first analyzes the reasons for the directivity of seismic wave field,and takes the model illumination results as an example to show the correlation between geological structure and wave field propagation direction;Then,the energy flux density vector representing the propagation direction and energy of the wave field is defined,and the calculation method of the angle and energy of the surface emitted wave field under the condition of acoustic medium is derived;Finally,the expression of combined superposition wave field and the objective function for solving each combined parameter are given.Verified by theoretical model and actual data,the directional combination method proposed in this paper can significantly improve the signal-to-noise ratio of data,and has broad application prospects in areas with low signal-to-noise ratio.

关 键 词：基于地质模型 定向组合 能流密度矢量 信噪比 

分 类 号：P631[天文地球—地质矿产勘探]