海洋地震垂直缆在自由状态下的照明情况

Illumination analysis of the marine seismic vertical cable in free state

海洋垂直缆地震数据采集具有高分辨率、高精度真三维成像等特点。作为未来海洋立体观测系统的重要组成部分,有必要全面分析海洋垂直缆观测系统中影响照明的因素,并优选出最佳设计方案。在垂直缆存在倾角的情况下,分析激发点密度、接收点密度、离底高度、倾角变化以及地层倾斜对目标层照明情况的影响,发现激发点密度与接收点密度直接影响目标层的总覆盖次数,海洋垂直缆的倾斜会影响低覆盖带的位置,海底坡度以及目标层的倾角使得照明聚光范围产生移动,地下隆起的目标层覆盖范围更大,照明强度更优。设计观测系统时,不仅考虑上述影响因素,而且垂直缆布设的位置也应当根据地层倾角以及垂直缆倾角,避开低覆盖带而选择高覆盖区域。

Marine vertical cable seismic data acquisition has the characteristics of high resolution and high precision true 3D imaging. As an important part of the future ocean stereoscopic observation system, it is necessary to comprehensively analyze the factors that affect the lighting in the ocean vertical cable observation system, and select the best design plan. Based on the actual situation, the paper analyzes the impact of shot point density, receiver point density, height from the bottom, inclination angle of vertical cable and stratum tilt on the illumination of the target layer, and found that the shot point density and receiver point density directly affect the total coverage of the target layer. The inclination of the vertical cable affects the position of the low coverage zone. The slope of the seabed and the inclination of the target layer make the lighting condensing range move. The underground ridge target layer has a larger coverage area and better lighting. When designing the observation system, not only the above-mentioned influencing factors should be considered, but the position of the vertical cable should also be laid in high coverage area according to the stratum slope and the vertical cable dip.