南方复杂山地碳酸盐岩出露区地震采集技术分析

摘要

The quality of seismic data collected in complicated southern area with mountains and bare carbon-ates,is hard to reach the desired effect.This paper does a series of comparative analyses about technologies and methods for seismic data acquisition based on thorough understanding of the geological characteristics and the key exploration technical difficulties of seismic.(1)Using various surface survey techniques to fulfill fine sur-face structure survey,and to set up relative accurate near-surface structure model and velocity model for compu-ting statics,choosing the best well site and designing well depth.(2)Dynamic observation system is used wide-ly in the southern complex terrain.For example,long arrangement and wide shot distance is utilized to deal with imaging of high and steep structure,observation system with increased density is employed in limestone district, and wide-line observation system is adopted in the special region with caverns and fissures.(3)The conditions of excitation and reception are improved to meet the sophisticated exploration needs of multilayer lithology with naked rocks.The position of shot is optimized to adapt the lithology changing and to avoid caverns and thick pure limestone district.Double well combined excitation is often used in the limestone district,and large com-bined reception need more than two strings of detectors per channel.Of course,the reception effect of detector in the well is better than those on the ground.Applying the above techniques and methods to processing and analyzing the collected seismic data,the quality of the seismic profiles and single shot records are improved, and both seismic reflection wave energy and SNR are all heightened.%在受山地和碳酸盐岩裸露双重复杂条件影响的南方地区开展地震勘探工作，采集的地震数据质量很难达到理想效果。基于对南方复杂地形山区的地震地质特征及勘探技术难点深入分析的基础上，对地震数据采集技术与方法进行了一系列的技术攻关和对比分析：（1）综合应用多种表层调查技术进行精细表层结构调查，建立相对准确的近地表结构模型和速度模型，求准静校正量，指导井位优选和井深设计。（2）采用动态观测系统，高陡构造成像方面采用长排列大炮检距，灰岩区采用加密炮观测系统，溶洞裂隙发育地区采用宽线观测系统；（3）针对复杂多变出露多地层岩性，改善激发接收条件，根据岩性变化优选炮点点位，尽量避开溶洞和厚层纯灰岩区。灰岩区采用双深井组合激发，每道至少要两串以上检波器面积大组合接收，检波器井下接收比地面接收效果好。采用以上技术方法，对采集的地震资料进行处理和分析，地震剖面和单炮记录品质有所改善，地震反射波能量及信噪比均有所提高。