基于多参数融合的弱弹性介质激发井深设计方法  

A multiparameter fusion methodology of well depth design for seismic excitation in weakly elastic media

作　　者：包洪刚 BAO Hong-Gang(R&D Center of Science and Technology,Sinopec Geophysical Corporation,Nanjing 211112,China)

机构地区：[1]中石化石油工程地球物理有限公司科技研发中心,江苏南京211112

出　　处：《物探与化探》2025年第2期330-339,共10页Geophysical and Geochemical Exploration

基　　金：中石化石油工程技术服务有限公司科研项目“江苏下扬子古潜山关键地震技术研究”(SG18-80X)。

摘　　要：弱弹性介质薄互层较多,激发的地震波能量衰减快、优势频带窄,造成地震资料分辨率低,如何选择较好的激发岩性是改善激发效果的关键。为此,以苏北探区为例,分析水网地区影响资料品质的主要因素,通过微测井调查测定高速层顶界面,采用静力触探方法和岩性取心优选优势岩性段,量化分析相关子波的倍频程、分辨率、主瓣与旁瓣能量比、子波清晰度等,建立地震子波属性与激发岩性的匹配关系,优选地震波传播速度高、岩土弹性属性好、子波频带宽的岩性面,建立工区表层岩性平面图,逐点设计激发井深,确保宽频激发。将以上技术应用于YA三维、SDX三维激发井深设计,所获得的单炮频率归一性较好,地震剖面目的层优势频带拓宽了10 Hz以上,提升了1.5个倍频程。这一结果表明,水网地区“弱中选优”的激发策略可以有效地改善在弱弹性介质中的激发效果,提高地震资料分辨率和成像精度。Due to numerous thin interbeds in weakly elastic media,seismic excitation typically yields rapidly attenuated seismic wave energy and a narrow dominant frequency band,resulting in low-resolution seismic data.Therefore,selecting a favorable lithology plays a crucial role in improving the seismic excitation effect.This study explored the dominant factors influencing the quality of seismic data obtained from the northern Jiangsu exploration area,a region with a dense river system.Specifically,this study determined the top boundary of the high-velocity layer based on microlog surveys and the dominant lithologic member using the cone penetration test and lithologic coring.It quantitatively analyzed seismic wavelet attributes,including octave band,resolution,main-to-side lobe energy ratio,and wavelet clarity,establishing their matching relationship with the lithology for seismic excitation.By selecting a lithologic surface featuring a high seismic wave propagation velocity,a favorable elastic property,and a wide frequency band in the study area,it plotted a surface lithology map for pointwise well depth design,ensuring wide-frequency excitation.The above techniques were applied to well depth design for seismic excitation in the YA and SDX areas,achieving well-normalized single-shot frequencies and widening the dominant frequency band of the target layer in the seismic profile by over 10 Hz,with an increase of 1.5 octave bands.The results show that the excitation strategy of"selecting the dominant lithology from weakly elastic media"in regions with dense river systems can effectively enhance the seismic excitation effect in weakly elastic media,thereby improving the imaging accuracy and resolution of seismic data.

关 键 词：水网地区 弱弹性介质 高分辨率 激发岩性 

分 类 号：P631.4[天文地球—地质矿产勘探]