摘要
在四川盆地秋林地区的多分量地震资料解释过程中,发现一类特殊的沙溪庙组砂岩储层:在纵波剖面上反射特征不明显,很难发现;在转换波剖面上反射特征明显,能够清晰地识别。多分量地震资料采用炸药震源激发、DSU3数字三分量检波器接收;资料处理以PP、PS波保幅处理为目标,针对PS波信噪比低的难点,使用分区、分域、分步保真与保幅噪声衰减技术,有效地提高了PS波资料信噪比;在井震标定的基础上,分别解释了PP、PS波目的层,并以PP波层位为基准,将PS波层位校正至PP波时间域,从而使PP与PS波在时间域匹配。根据多分量地震解释结果获得以下认识:(1)由于沙溪庙组砂岩纵波速度对孔隙度较敏感,致使PP波反射振幅受砂岩孔隙度影响较大;在一定孔隙度范围内,纵波速度、密度等弹性参数组合导致隐蔽河道砂岩在PP波剖面上没有明显反射,隐藏在泥岩中难以识别,以往的勘探过程常常漏掉这类储层。(2)PS波反射振幅受孔隙度变化影响小,在预测岩性方面比PP波更具优势,利用多分量地震资料进行属性分析,能够清晰地刻画河道的空间展布特征。钻井结果验证了上述认识,并利用多分量地震资料在沙溪庙组发现了大面积纵波勘探遗漏的河道砂岩,为该区下一步油气勘探部署奠定了良好基础。
A special sandstone reservoir was detected in the Shaximiao Formation in the interpretation of the multicomponent seismic data of the Qiulin area,Sichuan Basin.The reservoir has vague reflection characteristics on P-wave profiles,which can hardly be discovered,while on the converted wave profiles,the reflection characteristics are distinct and can be identified.The multi-component seismic data is acquired by dynamite sources and DSU3 digital three-component geophones.Seismic data processing aims to preserve PP-and PS-wave amplitude.To tackle the low signal-to-noise ratio of PS waves,the amplitude and fidelity-preserved multi-domain and multi-step noise attenuation technology is performed to improve the signal-to-noise ratio of PS-wave data.On the basis of the calibration of logging and seismic data,target PP-and PS-wave horizons are interpreted,and the PS-wave horizon is taken as the benchmark to be corrected to the time domain of PP waves.In this way,the PP waves and PS waves can be matched in the time domain.According to multi-component seismic interpretation results,the following conclusions are drawn:①The P-wave velocity of sandstone in the Shaximiao Formation is sensitive to porosity,and consequently,the reflection amplitude of PP waves is significantly affected by the porosity of sandstone.Due to the combinations of elastic parameters such as P-wave velocity and density of sandstone,concealed channel sandstone has vague reflections on PP-wave profiles within a specific range of porosity,which are concealed in mudstone and thus can hardly be identified.Such reservoirs were often omitted in the exploration.②The reflection amplitude of PS waves is insensitive to porosity changes and thus is superior to that of PP waves in lithology prediction.When the multi-component seismic data is used for attribute analysis,the spatial distribution of channels can be delineated.The above conclusions are validated by drilling results,and extensive channel sandstone which was undetected in previous PP-wave surveys in the
作者
张明
甘利灯
尉晓玮
张昕
孙夕平
于永才
ZHANG Ming;GAN Lideng;YU Xiaowei;ZHANG Xin;SUN Xiping;YU Yongcai(PetroChina Research Institute of Petroleum Exploration&Development,Beijing100083,China)
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2023年第3期713-719,共7页
Oil Geophysical Prospecting
基金
中国石油天然气股份有限公司科技项目“陆相碎屑岩油藏地球物理描述技术研究与现场攻关试验”(2022KT1505)资助。
关键词
多分量地震
转换波
PP波
PS波
沙溪庙组
multi-component seismic data
converted wave
PP wave
PS wave
Shaximiao Formation
