四川盆地蓬莱气区近地表Q场求取及应用
Calculation and application of near-surface Q field in Penglai Gas Area,Sichuan Basin
韩嵩 1陈康 1汤聪 1王静 2张茜 3彭浩天1
作者信息
- 1. 中国石油西南油气田公司,四川成都 610041
- 2. 东方地球物理公司,河北涿州 072750;中油奥博(成都)科技有限公司,四川成都 610051
- 3. 东方地球物理公司,河北涿州 072750
- 折叠
摘要
近地表吸收衰减会严重降低地震资料的分辨率,利用微测井资料对近地表吸收结构进行估算,获得表层介质品质因子Q值,再进行反Q滤波补偿,可实现高保真、高分辨率的"双高"处理目的.为此,提出一种改进的谱比法对单井微测井数据进行Q值求取,然后通过拟合表层速度与Q值关系,将近地表速度(V)场转换成近地表Q场.四川盆地的表层较薄,层析反演的近地表速度场深度采样间隔为10 m,难以反映近地表厚度为几米的表层变化.为此,首先结合双井微测井数据的多炮拟合算法,求取浅层比较薄的表层等效Q值;其次结合地面地震的振幅及旅行时信息求取表层的相对Q场;然后用双井微测井求得的绝对Q值对相对Q场进行标定;最后将该表层平面Q场镶嵌在用Q-V拟合关系转换的近地表Q场的浅层,得到该工区优化的近地表Q场,用于地震资料的近地表Q补偿,从而达到拓宽频带、提高地震资料的分辨率的目的.
Abstract
Near-surface absorption attenuation can seriously reduce the resolution of seismic data.Using micro logging data to estimate the near-surface absorption structure,obtain quality factor Q value of surface layer me-dium,and then perform inverse Q filtering compensation can achieve high fidelity and high resolution proces-sing.This paper proposed an improved spectral ratio method for obtaining Q values from micro logging data of a single well and then fitted the relationship between surface layer velocity and Q values to convert the near-sur-face velocity field into a near-surface Q field.Because the surface layer of the Sichuan Basin is thin,the depth sampling interval of the near-surface velocity field by tomographic inversion is 10 meters,which makes it diffi-cult to reflect the surface layer changes that are several meters.Therefore,combined with the multi-shot fitting algorithm for micro logging data of two wells,the equivalent Q value of the shallow surface layer was obtained.Then,the relative Q field of the surface layer was obtained using the amplitude and travel time information of the seismic data.In addition,the absolute Q value obtained from the micro logging data of two wellswas used to calibrate the relative Q field.Finally,the plane Q field of the surface layer was embedded in the shallow layer of the near-surface Q field converted according to the Q-V fitting relationship,and the optimized near-sur-face Q field of the work area was obtained and used for near-surface Q compensation of seismic data,so as to broaden the frequency band and improve the resolution of seismic data.
关键词
近地表/品质因子Q/Q值估算/表层Q场/四川盆地Key words
near surface/quality factor Q/Q value estimation/near-surface Q field/Sichuan Basin引用本文复制引用
基金项目
中国石油西南油气田分公司勘探开发研究院项目(2022-N/G-62191)
出版年
2024
国家科技期刊平台
NSTL
万方数据