河套盆地巨厚弱成岩覆盖区地震勘探成像技术应用研究

Application of seismic exploration imaging technology in huge thick weak diagenetic rocks coverage area in Hetao Basin

河套盆地由于快速堆积、欠压实作用等原因,4000~5000m以上均为弱成岩覆盖,地震资料成像精度受到严重影响。针对巨厚弱成岩引起的勘探难题,开展了基于目的层响应特征的可控震源激发信号设计、基于多信息约束的精细近地表建模及全深度Q值补偿、基于大地坐标的近地表类型分区去噪、基于平面属性的断层解释等技术的应用,资料品质得到了提升。通过相关技术的应用,主要目的层频带拓宽了10Hz左右,断面清楚,断点清晰干脆,能够满足地震解释需求,探明了吉兰泰和巴彦两个油田。通过针对性的采集、处理、解释一体化技术的研究,解决了该区域地震波吸收衰减严重、资料信噪比低、复杂构造区成像精度差、储层难以预测等关键难题,可以指导类似地区的勘探施工。

Due to the rapid accumulation and undercompaction in Hetao Basin,the section with a depth shallower than 4000-5000 m is composed of weak diagenetic rocks,which seriously affects the imaging accuracy of seismic data.In view of the exploration difficulties caused by huge-thick weak diagenetic rocks,multiple technologies have been applied in the study area,including the vibroseis excitation signal design based on the response characteristics of the target layer,multi information constrained fine near-surface modeling and full depth Q-value compensation,geodetic coordinates based near-surface zonal denoising,and plane attributes based fault interpretation,effectively improving the data quality.After the application of relevant technologies,the frequency band of the main target layer has been widened by about 10Hz,showing clear fault plane and distinct breakpoint,which meets the needs of seismic interpretation,and supports to discover two oil fields,i.e.,Jilantai and Bayan.By conducting targeted research on seismic acquisition,processing and interpretation integrated technology,key problems have been solved,such as severe absorption and attenuation of seismic waves,low signal-to-noise ratio of data,poor imaging accuracy in complex structural zones,and difficulty in reservoir prediction,which can be used to guide the exploration and construction in similar areas.