高精度三维地震数据采集技术在TBM探区的应用

鄂尔多斯盆地北部TBM探区表层地震地质条件较为复杂,低降速层主要为流沙、含水沙层及黄土层,厚度横向变化较大,潜水面变化不定。储层非均质性强,有效储层薄,储层与煤层伴生,严重制约了本区天然气勘探开发步伐。为了解决目前勘探开发所面临的实际问题,在TBM探区部署并实施了100km2的高精度三维地震数据采集,针对探区的地震地质特点和难点,开展了攻关和试验。在高精度三维地震数据采集中,通过观测系统优化、虚反射界面分析和利用、激发岩性优选、试验资料功率谱面积和频宽收敛分析等技术的综合运用,确定了合适的三维观测系统和激发因素,取得了较好的效果。

An application of the high-precision 3D seismic data acquisition technique to the TBM exploration area

The TBM exploration area lies in the northern part of the Ordos Basin,where the low velocity layers are laterally discontimuous,and dominantly made up of drifting sand,water sand and loess layers. The water tables are variable,and the hydrocarbon reservoirs are highly heterogeneous and associated with coal seams. The high-precision 3D seismic exploration is carried out in the area of 100 km2 of the TBM exploration area. The emphasis in the high-precision 3D seismic data acquisition is placed upon the optimization of 3D observation systems,analysis and use of virtual reflection interfaces,selection of excitation lithology,convergence measurements of the power spectrum areas and bandwidths in order to determine appropriate 3D observation systems and excitation factors.