VSP地震干涉成像及应用研究  

The study of VSP seismic interferometric imaging method and its application

作　　者：陈国金[1] 陈占国[1] 雷朝阳 张亚红[1] 张洁[1] 孙振涛[1] 张卫红 吴永栓[1] CHEN GuoJin;CHEN ZhanGuo;LEI ChaoYang;ZHANG YaHong;ZHANG Jie;SUN ZhenTao;ZHANG WeiHong;WU YongShuan(Sinopec Geophysical Research Institute,Nanjing 211103,China)

机构地区：[1]中国石化石油物探技术研究院,南京211103

出　　处：《地球物理学报》2020年第6期2357-2374,共18页Chinese Journal of Geophysics

基　　金：中国石化科技部基础性前瞻性研究项目(P18077-3)资助.

摘　　要：受井中检波器串级数局限,垂直地震剖面(VSP)反射波成像范围窄,且不能对井中最浅接收点上方区域有效成像.虽然多次波成像能扩大成像范围,但在实际应用中尚有诸多困难和挑战.本文根据Wapenaar的地震干涉理论,基于上下行波场分离技术,研发了VSP地震干涉成像方法.该方法将VSP自由表面多次波重建为在地表震源位置激发(虚震源)接收的拟地面地震反射波,然后偏移成像,以达到对多次波间接成像的目的.通过数值模型实验,测试了VSP干涉成像的极限分辨率,并讨论了主要采集参数的影响,结果表明:该方法的垂向和水平极限分辨率分别达约10m和20m,且能分辨深度达6500m处的50m×100m溶洞;采用12至24道井中检波器串采集的VSP资料,其干涉成像结果显著优于VSP反射波成像,与相应的地面地震成像效果相当.将本文方法应用于新疆地区采集的VSP资料,结果表明:与VSP反射波成像相比,成像同相轴更加连续,成像范围显著扩大;与地面地震成像相比,成像结果相当,尤其在浅中部甚至更好.新方法不仅无需进行井中接收点静校正,且能显著增大成像范围,有利于成像同相轴的追踪对比、地震属性提取和地质解释,尤其对中国新疆地区深部缝洞型储层的成像,具有广泛的实际应用前景.Limited by the number of geophones in the well,the VSP reflection imaging has a narrow imaging range and cannot effectively image the area above the shallowest receiving point in the well.Although multiple imaging can expand the imaging range,there are still many difficulties and challenges in practical applications.Based on the seismic interferometry of Wapenaar and wave field separation technology,a VSP seismic interferometric imaging method is developed.This method reconstructs the free surface multiples of the VSP into virtual-surface seismic reflection waves that are shot(virtual source)at the surface source location and then be migrated to achieve the purpose of indirectly imaging of multiples.Numerical simulation is used to demonstrate the limitation resolution of VSP interferometric imaging,the results show that the method has a vertical and horizontal resolution up to about 10m and 20m respectively and can resolve 50 m×100 m karst caves with depths up to 6500 m;the interferometric imaging results of VSP data acquired by 12 to 24 geophones are significantly better than its reflection imaging,and comparable to the corresponding surface seismic imaging results.Applying the method of this paper to VSP dataset acquired in Xinjiang,the results show that the seismic events in interferometric imaging results are more continuous than VSP reflection imaging results,and the imaging range is significantly expanded;compared with surface seismic imaging the results are comparable,and even better in the shallow middle area.The new method not only eliminates the need for static correction of receiving points in the well,but also significantly increases the imaging range,which is beneficial to seismic event tracking,seismic attribute extraction and geological interpretation,especially for the imaging of deep fracture-cavity reservoirs in Xinjiang,China.Therefore,the method proposed in this paper has a bright future in practical applications.

关 键 词：上下行波场分离 地震干涉法 VSP地震干涉成像 自由表面多次波 拟地面地震反射波 

分 类 号：P631[天文地球—地质矿产勘探]