新一代高精度地震技术的发展方向——超密度地震技术

地震技术已由常规三维经高精度三维发展到高密度三维, 但仍不能满足地表、构造、储层"三复杂"勘探开发目标对地震资料精度的需求。为满足"三复杂"条件下地震成像的需求, 依据高密度地震技术及计算机和物探装备的发展趋向, 提出了"超密度地震技术"的新思路。通过野外小道距采集实验和小网格正演模拟实验, 验证了超密度采集对近地表速度建模与静校正及深层高陡断裂成像的改善。考虑超高密度地震采集的仪器和装备需求及海量数据以及经济可行性, 提出了"变道距+插值"的实施策略及相关仪器、存储、计算配套技术, 分析认为10×10⁴道级节点仪、海量数据存储与计算是实现"超密度地震技术"的基础, "小宽高"高密度地震采集技术、"小平滑面"RTM叠前深度偏移技术和压缩感知或五维插值技术是重要的关键技术。未来更高精度的地震技术应是炮道密度大于200×10⁴道/km²的超密度地震技术, 为此, 需要加快发展超大规模的节点仪单点采集装备、海量数据存储与计算装备及变道距数据插值技术等, 并推进野外地震采集的实践。

Three-D high-density seismic techniques evolving from 3D seismic techniques and 3D high-precision seismic techniques are still not sufficient for hydrocarbon exploration and development in complicated surface, tectonic, and reservoir conditions.To achieve high-precision imaging in complicated surface and subsurface conditions, we present a new idea of "ultra-high-density seismic techniques" based on the development of high-density seismic techniques, computer technology, and geophysical equipment.Field experiments with small group intervals and forward modeling with small grids show improved near-surface velocity modeling, static correction, and imaging of deep-seated steeply dipping fractures by ultra-high-density seismic acquisition.The strategy of "variable group interval+interpolation" is combined with supporting techniques relevant to instruments, storage, and computation to address the issues of acquisition instruments, mass data, and economic feasibility.Nodal seismograph with the level of 10×10⁴ channels and mass data storage and computation are the foundation of utilizing ultra-high-density seismic techniques; key techniques include high-density acquisition with "small trace distance, small bin, wide azimuth, wide band, high coverage, high shot and trace density", prestack reverse-time depth migration with a "small smooth surface", and compressed sensing or 5D interpolation.To further improve the precision of imaging, seismic acquisition with the shot channel density over 200×10⁴ should be developed; associated equipment and techniques to be developed include large-scale single-point nodal seismograph, devices for mass data storage and computation, and interpolation with variable group interval.Field seismic acquisition should also be propelled.