山前带地震成像技术需求与勘探策略分析  

Analysis of seismic imaging technology requirements and exploration strategy in foothill area

作　　者：杨勤勇[1] 王华忠[2] 刘少勇[2] 方伍宝[1] 

机构地区：[1]中国石油化工股份有限公司石油物探技术研究院,江苏南京211103 [2]同济大学海洋与地球科学学院波现象与反演成像研究组,上海200092

出　　处：《石油物探》2012年第6期570-573,535-536,共4页Geophysical Prospecting For Petroleum

基　　金：中国石油化工股份有限公司科技开发部"库东三维地震成像技术研究"项目(P11033)资助

摘　　要：山前带地震勘探困难的根源在于复杂地表条件。由于复杂地表导致采集数据信噪比低和道间时差变化剧烈是制约山前带探区地震成像和进一步油气预测的主要原因。目前,针对山前带地震勘探的正确的地震数据采集和成像处理理念的缺乏,以及针对山前带地震数据特点的处理流程和相应的成像处理软件系统的不成熟是山前带油气地震勘探无法取得有效突破的现实原因。从山前带存在的地震地质问题入手,分析了山前带地震勘探数据采集和成像处理的特殊之处,提出山前带地震勘探的数据采集应该基于Fresnel半波带同相叠加的基本观点。在完整采集到地下任何一个绕射点(或反射点)产生的到达地表的波前面的基础上,尽可能关注高覆盖次数和低频信号(譬如小于6Hz的信号)。成像处理应该在一个贴近地表的较光滑的基准面上,把表层和中深层统一的深度域层速度估计和模型建立作为山前带成像处理的核心,把Beam波积分法叠前深度偏移作为主要的成像技术手段。在正确理念指导下的野外地震数据采集和针对山前带地震数据特点的成像处理流程的软件工程化是目前山前带地震勘探的当务之急。Complex surface conditions is the origin for the difficult seismic exploration in foothill areas,which causes low S/N and serious moveout variation between gathers and is the main reason for constraining seismic imaging and further hydrocarbon prediction in such areas.Nowadays,we yet not own a correct ideology about the seismic acquisition & imaging and lack a suitable seismic data processing procedure and corresponding software,which limit the breakthrough of the oil exploration in the foothill areas.From the seismic and geological reality,we analyzed the peculiarity of the seismic acquisition and imaging in foothill area,and proposed a viewpoint that seismic acquisition should be based on the in-phase stack of the reflections from half Fresnel band.On the basis of the wavefront from any subsurface scattering point(or reflection point) to the surface were collected completely,we should pay much more attention on the high fold and low-frequency signal(such as smaller than 6 Hz).For seismic imaging in foothill area,we should obey the following rules:① seismic imaging should start from a smoothed datum which is close to the real topography and near the surface;② the unified horizon velocity estimation and model building for surface and middle-deep layers is regarded as the core of the procedure;③ beam integral PSDM is chosen as the main migration tool.In general,the urgent matters for the foothill seismic exploration include field acquisition guided by correction ideology and the development of specialized imaging software.

关 键 词：山前带地震成像 复杂地表条件 低信噪比 剧变的道间时差 速度估计与建模 射线束叠前深度偏移 

分 类 号：P631.4[天文地球—地质矿产勘探]