基于锤击和多级井中检波器接收微测井的近地表Q值调查方法  

Near-surface Q-value survey method based on uphole with hammer excitation and receiving using multi-stage geophones in wells

作　　者：郭念民[1] 周旭 徐凯驰 王彦峰 吕景峰 段孟川 GUO Nianmin;ZHOU Xu;XU Kaichi;WANG Yanfeng;LYU Jingfeng;DUAN Mengchuan(Research Institute of Exploration&Exploitation,Tarim Oilfield Company,PetroChina,Korla,Xinjiang 841000,China;Tarim Geophysical Division,BGP Inc,CNPC,Korla,Xinjiang 841000,China)

机构地区：[1]中国石油塔里木油田公司,新疆库尔勒841000 [2]东方地球物理公司塔里木物探处,新疆库尔勒841000

出　　处：《石油地球物理勘探》2023年第2期295-304,共10页Oil Geophysical Prospecting

基　　金：中国石油股份重大专项“塔里木盆地大油气田增储上产关键技术研究与应用”之课题“复杂山地、黄土塬及大沙漠区地震关键技术研究与应用”(2018E-1807)资助。

摘　　要：基于锤击和多级井中检波器接收的微测井是一种安全、经济的表层结构调查方法,已在表层结构速度调查方面得到了规模化应用。但由于存在记录延迟时差、激发子波非一致性及干扰波等影响因素,它难以直接应用于近地表Q值调查。为此,在目前常用锤击和多级井中检波器接收微测井观测系统基础上,在井口位置增设延迟校正检波器,用于校正不同炮次记录延迟时差,在相邻炮次接收范围的交界处设置一个重复接收点,用于消除激发子波的非一致性;而且基于质心频率偏移Q值估算方法,通过不同深度点接收初至波质心频率及方差随深度变化的多项式拟合,消除干扰波对初至波质心频率及方差随深度变化规律的影响,提高Q值估算精度。模型正演模拟结果分析和塔里木沙漠区实际资料应用结果均表明:用上述方法求取的Q值与模型和经验公式所得结果接近;同时,利用由该方法求得的Q值对实际资料做近地表吸收补偿,可显著提高地震剖面的分辨率。Uphole based on hammer excitation and receiving with multi-stage geophones in a well is a safe and economical method of surface structure investigation,which has been widely used in the surface structure velocity survey.However,due to the factors of time difference of excitation delay,inconsistency of excitation wavelet,and influence of surface excitation noise,it cannot be directly used in near-surface Q-value survey.In this paper,on the basis of the commonly used uphole observation system using hammer excitation and receiving signals with multi-stage geophones in a well,a delay correction geophone is arranged on wellhead to correct the delay time difference of different shot records,and a pair of repeating geophones are set at the junction of receiving ranges of adjacent shots to eliminate excitation wavelet inconsistency.The Q-value estimation method based on centroid frequency shift can eliminate the impact of noise on the variations of centroid frequency of the first arrival wave and variance with depth through the polynomial fitting reflecting the variations of centroid frequency of the first arrival waves received at different depths and variance with depth,which improves Q-value calculation accuracy.The result analysis of forward modeling and the application to the real data of the Tarim desert area show that the results of the proposed method are close to the Q-values from modeling and calculation with the empirical formula.The near-surface absorption compensation is carried out,which effectively improves the resolution of the seismic profile.

关 键 词：近地表 吸收衰减 Q值调查 井中接收微测井 多项式拟合 质心频率偏移法 

分 类 号：P631[天文地球—地质矿产勘探]