鄂尔多斯盆地黄土塬区多线地震采集技术

Seismic acquisition with a swath of lines in area of loess tableland

东方地球物理勘探公司长庆物探处,宁夏银川750006

Changqing Geophysical Company of BGP, CNPC, Yinchuan 750006, China

鄂尔多斯南部的黄土高原, 黄土巨厚, 干燥疏松, 厚度横向变化剧烈, 对地震波吸收衰减严重, 且相干干扰、次生干扰、黄土谐振干扰极其严重, 加之地形复杂, 黄土塬区一直被视为地震勘探的“禁区”。黄土塬区多线地震采集技术, 即采用二维测线三维观测方法采集, 利用相邻道面元叠加处理, 增加了优选炮点的条件, 保证了全线均匀的高覆盖次数, 有效地压制了干扰, 剖面质量大幅度提高。该项技术已可在黄土复杂区做正规测网, 与黄土塬区高分辨率沟中弯线、黄土塬山地网状三维共同组成黄土塬区地震勘探技术系列, 服务于黄土塬不同的勘探目标。黄土塬区多线地震采集方法, 是压制干扰, 提高剖面信噪比的有效方法, 可在地表复杂区、低信噪比地区推广应用。

It is a real challenge to carry out seismic survey in area of loess tableland in the Loess Plateau, south of Ordos basin. Loess tableland is characterized by huge and rapid lateral changes of thickness, dryness and looseness, as well as complex topography, leading to severe absorption and attenuation of seismic waves, and abundant interference noises such as coherent noise, secondary noise, and harmonic noise. Seismic acquisition with a swath of lines accomplishes 2-D data acquisition with a 3-D layout. This method ensures high and balanced coverage in the whole line due to the flexibility in selection of shot points, suppresses interference noises effectively by stacking adjacent bins in data processing, and can be used to generate regularized survey net in complex area of loess tableland. Seismic acquisition with a swath of lines, high resolution crooked line technique, and the reticulate 3-D technique form a complete suite of seismic acquisition techniques, which can be used to explore different targets of interest in area of loess tableland. Seismic acquisition with a swath of lines can be put into use in areas of complex surfaces.