二、三维地震勘探方法在新疆奥塔北井田的应用

摘要

The Aota north minefield possesses of multiple shallow buried coal seams with varied structure and thickness, thus hard to correlation and outcrop control. So, divided the prophase extracting block into 2D and 3D seismic prospecting areas, in which, 2D area uses small group interval and small shotpoint gap field setup, emphases upon shallow part strata dip angle and coal outcrop control;3D area uses 8 line 8 shotpoint, small CDP grid field setup, emphases upon coal seam structure. During the later processing and interpreta⁃tion, using scaling down processing, to improve high frequency energy in seismic data;using the wave impedance inversion carried out coal seam reflection wave calibration to improve differentiation of coal seam splitting, merging and gangue. The case study of prospect⁃ing in Aota north minefield prophase extracting block has shown that the complimentary prospecting method of 2D and 3D seismic has better effects on geological phenomena determination of coal seam outcrop control, coal seam splitting and merging interpretation, coal seam structure and relationship between coal seams etc.%奥塔北井田煤层多、埋藏浅，煤层结构及煤层厚度变化大，存在煤层对比困难、煤层露头难以控制等问题。为此将先期开采区块划分为二维区与三维区，其中二维区采用小道距、小炮距的观测系统，重点控制浅部地层倾角和煤层露头；三维区采用8线8炮、小CDP网格的观测系统，重点解决煤层结构问题。在后期的处理解释中，采用分频处理方法，以提高地震资料中的高频能量；利用波阻抗反演，进行煤层反射波标定，以提高煤层分叉合并与煤层夹矸的分辨能力。奥塔北井田先期开采区块勘探实例表明，二维与三维地震互补的勘探方法，对控制煤层露头、解释煤层分叉合并、确定煤层结构与煤层间关系等地质现象，具有较好的勘探效果。