东海OBN和三维DAS-VSP数据的联合采集与处理方法研究OA北大核心CSTPCD

Optical fiber sensing has been applied to surface,marine,and borehole seismic acquisition and joint borehole-surface seis-mic acquisition in the latest years.Surface or marine seismic and VSP seismic exploration could be combined to achieve 3D prospec-ting.Using 3D DAS-VSP data,we could obtain accurate time-depth relationship,interval velocity,deconvolution operator,compen-sation factor of spherical spreading,absorption attenuation factor,anisotropy parameters,and high-resolution structure imaging a-round the well bore;above parameters could be used to enhance 3D well-driven land or marine seismic data processing.In this work we performed 3D DAS-VSP data processing and imaging.The 3D DAS-VSP survey was acquired using a downhole armored optical cable with simultaneous OBN data acquisition in the East China Sea.The routine workflow of 3D DAS-VSP data processing includes geometry definition,preprocessing,first break picking,static correction,amplitude compensation,deconvolution,wave field separation,velocity analysis and modeling,and structure imaging using upgoing waves.A new technique of downgoing multiple re-flection imaging is developed to enlarge the migration aperture and imaging area of upgoing reflected waves and obtain better quali-ty of imaging.Compared with 3D vintage OBC data imaging,3D DAS-VSP downgoing multiple imaging yields better results within a large area around the well bore;OBN and 3D DAS-VSP imaging yields better results for high-resolution structure interpretation and fluid detection.Owing to high efficiency and low cost of joint borehole-marine acquisition,it is possible to accomplish fast 3D DAS-VSP imaging and enhanced well-driven resolution processing of 3D marine seismic data.Besides,3D OBN or OBC data and 3D DAS-VSP data could be processed together for joint borehole-surface or borehole-marine migration to significantly improve the im-aging quality of 3D marine seismic data.