川东高陡构造灰岩出露区地震资料品质主控因素分析  

Analysis of main controlling factors for seismic data quality of limestone exposed areas in high-steep structures in eastern Sichuan

作　　者：梁顺军 窝聿楷 刁永波 胡善政 胡峰 王中海 王晓阳 敬龙江 吴增友 高怀军 LIANG Shunjun;WO Yukai;DIAO Yongbo;HU Shanzheng;HU Feng;WANG Zhonghai;WANG Xiaoyang;JING Longjiang;WU Zengyou;GAO Huaijun(Southwest Geophysical Exploration Branch of BGP,CNPC,Chengdu 610213,China;Southwest Geophysical Research Institute of BGP,CNPC,Chengdu 610213,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]中国石油东方地球物理勘探公司西南物探分公司,四川成都610213 [2]中国石油东方地球物理勘探公司西南物探研究院,四川成都610213 [3]西南石油大学地球科学与技术学院,四川成都610500

出　　处：《复杂油气藏》2024年第3期271-280,295,共11页Complex Hydrocarbon Reservoirs

摘　　要：川东构造地震地质条件可概括为“恶地形、石灰岩、陡构造”,一直是地震攻关的重点和难点。随着物探技术装备、采集处理技术发展,高陡构造顶部灰岩出露区(简称灰岩区)地震资料品质有较大提高,但信噪比仍然远低于构造两翼砂泥岩出露区。如何看待灰岩区低信噪资料比这一客观的地震现象,是地震攻关力度不够,还是受限于地震多次覆盖的假设条件,亟需解答。基于最新川东高密度三维和束线三维地震资料分析,从地震勘探基本原理出发,结合模型正演技术和地震资料处理解释,认为灰岩区低信噪比地震资料是客观存在的,根本原因是灰岩区地震地质条件不满足多次覆盖的假设条件。影响灰岩区低信噪比资料的主控因素有3点,1)灰岩区0~500 m表层岩溶地貌引起地震波散射,产生各类复杂噪声,向下传播能量快速吸收衰减,有效反射能量弱;2)受不同构造几何形态影响,灰岩区低信噪比资料特征有所不同;3)受灰岩区内外炮检距的影响,纵向上灰岩区地震成像质量存在浅、中、深层分带现象,由浅至深资料品质变好。文章指出,面对高陡构造灰岩区特殊的地震地质条件,地震攻关重点应放在提高中深层地震资料信噪比上。The seismic and geological conditions of Eastern Sichuan structure can be summarized as“adverse terrain,limestone,and steep structures”,which has always been the focus and difficulty of earthquake research.With the development of physical exploration equipment,and acquisition and processing technology,the quality of seismic data in the limestone outcrop area at the top of steep structures(referred to as the limestone area)has been greatly improved.However,the signal-to-noise ratio is still much lower than that in the sandstone outcrop areas on both sides of the structure.The question of how to view the objective seismic phenomenon of low signal-to-noise ratio data in the limestone areas,whether due to insufficient earthquake research efforts or limited by the assumption of multiple earthquake coverage,must be answered urgently.Based on the analysis of the latest high-density 3D and bundle line 3D seismic data in Eastern Sichuan,starting from the basic principles of seismic exploration,combined with the model forward modeling technology and seismic data processing interpretation,we believe that the low signal-to-noise ratio seismic data in the limestone areas objectively exists,and the fundamental reason is that the seismic geological conditions in the limestone areas do not meet the assumption of multiple coverages.Three main controlling factors affect low signal-to-noise ratio data in limestone areas:1)The surface karst landforms in the limestone area from 0 to 500 m cause seismic wave scattering,generating various complex noises that rapidly absorb and attenuate downward propagating energy,resulting in weak effective reflected energy;2)The characteristics of low signal-to-noise ratio data in limestone areas are different due to the influence of different structural geometric shapes;3)Affected by the offset between inside and outside the limestone area,the seismic image quality in the upper limestone area is divided into shallow,middle and deep zones,and the data quality becomes better from shallow to deep.T

关 键 词：高陡构造 灰岩区 多次覆盖 假设条件 地震资料 低信噪比 

分 类 号：P631[天文地球—地质矿产勘探]