镇巴地区地震勘探效果分析与认识.pdf

第53卷第6期
石油物探
Vol 53, No 6
2014年11月
GEOPHYSICAL PROSPECTING FOR PETROLEUM
Nov,,2014
文章编号:1000-141(2014)06-0744-08
镇巴地区地震勘探效果分析与认识
敬朋贵
(中国石油化工股份有限公司勘探分公司,四川成都610041)
摘要;鎮巴地区属于典型的复杂山前带探区,其非常复杂的地表地质条件及地下地质构造特征(“双复杂”)给地
震勘探带来了严峻的挑战。区内已开展了从二维到三维的多轮地震采集攻关研究,全面尝试了从叠前时间偏移
到叠前深度偏移,再到逆时偏移的地震资料成像处理,但获得的成果资料均表现为低信噪比特征。区内地震单
炮记录及叠加资料的波场特征主要表现为绕射波和半支绕射,且波组不稳定、不完整、不健全,主要目的层基本
没有稳定的水平反射同相轴。理论计算和模型正演分析表明,目前地震资料的低信噪比特征应该是地下地质结
构的客观反映,预示镇巴地区地下稳定地质体的尺度、规模偏小,已接近甚至小于地震可观测的最小尺度。在提
出地震采集、处理进一步攻关研究具体建议的同时,为切实加快镇巴地区油气勘探进程,建议尽早实施风险钻
探。
关键词:山前带;“双复杂”;波场特征分析;正演数值模拟;低信噪比特征
DOI:10.3969/j.isSn1000-1441.2014.06.016
中图分类号:P631
文献标识码;A
Effect analysis and recognition of seismic exploration
Zhenba area
ing Penggul
(Sinopec Ecploration Company, Chengdu 610041, China)
Abstract Zhenba area is a typical complex piedmont zone because of complex surface and subsurface geological
conditions("dual complex The seismic exploration technology faces severe challenges. Through repeated 2D
Ind 3D seismic exploration, prestack time migration, prestack depth migration and reverse time migration, the a
vailable data shows still low signal-to-noise ratio. The seismic wavefield in single-shot records and stack sections
mainly displays some diffraction or half if ion and their reflection events are instable, incomplete and imper
fect, and no continuous horizontal reflection in general. Theoretical calculation and analysis on forward modeling
show that current low signal-to-noise ratio of seismic data should be the objective reflection of subsurface struc
tures, which indicates that the sub-structure scale in Zhenba area is small, even less than the observable minimum
standards of seismic survey. Therefore, we should carry out further research on the seismic acquisition and pro-
cessing in Zhenba area. Meanwhile, in order to speed up the exploration procedure in Zhenba area, risk drilling
should be determined to proceed as soon as possible.
Keywords piedmont zone, complex surface and subsurface geological conditions, wavefield characteristic analysis
forward modeling, low SNR characteristics
镇巴探区位于川、陕、渝三地交界处,构造上处褶皱带构成;构造类型主要为断层相关褶皱、叠瓦
于南大巴山逆冲推覆前锋变形带-2内。大巴山弧状构造及断层三角带。前期大量的基础地质和沉
形逆冲推覆带西邻米仓山、北靠秦岭造山带、南接积相综合研究表明,镇巴探区存在类似于开江-梁
四川盆地,属于典型的盆山耦合复杂带。构造展布平陆棚两侧的碳酸盐岩台地边缘相带,勘探潜力巨
形态上表现为向西南凸出的弧形,由巨型逆冲推覆大。2006年以来,中国石油化工股份有限公司勘
收稿期:2014-906-10;改回日期:2014-08-08。
作者简介:敬朋贵(1964-),男,高级工程师,主要从事地震资料采集与处理方面的研究工作。