川东北地区山地三维高分辨率地震采集技术

The 3-D high-resolution seismic acquisition in mountainous of the northeastern Sichuan

为精细查明川东北地区地下裂缝发育带和高陡复杂构造,针对该区碳酸盐岩出露、沟河发育、砾石区分布广等表层地震地质条件,开展了采集方法的研究,总结出一套适合于山地三维高分辨率地震采集的技术和方法,即①采用大排列片、宽方位三维观测系统,以获得更多方位的裂缝地震属性信息;②科学选择激发井深和药量,做好野外激发的阻抗耦合和几何耦合工作,特殊地段采用水中激发和组合井激发方式.以确保整个工区的激发能量和频率的一致性及资料的完整性;③通过研究地层吸收和衰减规律,合理选择检波器的埋置方式和组合参数,以提高记录的分辨率和信噪比;④利用高精度数字卫星地图进行地面物理点设计,以保证实测点位的精度和观测系统属性的一致性。采用以上技术在川东北地区获得了高品质的地震资料,主要目的层的分辨率和信噪比较高,视主频达到了60-80Hz,层间信息丰富,能量强,构造特征、波组关系以及膏岩层和地层陡翼特征清楚。

In order to clarify clearly the underground fracturegrew extents and the highly-steep complex structures, and improve reservoirs resolution in the northeast area of Sichuan. We summarized up a set of 3-D high-resolution seismic acquisition techniques and methods, which are suitable for the mountainous ground of that region.Aiming at the complex surface layer seismic geological conditions such as bare carbonate rocks,rivers, gravels in that region.More azimuthally fracture seismic attribute information have obtained by adopting large-patch and multi-azimuth 3-D geometry. Choose scientifically shooting depths and charges, to impedance coupling and geometry coupling in the field shooting, adopted water-shooting and array-shooting in the especial area, and ensured consistencies of shooting energy and frequency and integrity of data in all area.Reasonably chose geophone planting coupling mode and geophone array parameters by researching the rules of stratum attenuation and absorption, then improved resolution and S/N ratio. The precision of the true measured points and the attribute sameness of the geometry are ensured by making use of the high precision digital satellite map to design physical points of the ground Seismic data quality is improved evidently.