鄂尔多斯盆地中央古隆起东部奥陶纪末古岩溶地貌发育,古地貌中沟槽的准确刻画识别对研究油气成藏和提高勘探成功率具有重要意义.沟槽在地震上的响应主要是槽的深度而不是宽度,当地层倾角大于5°时,沟槽的响应特征模糊；而当地层倾角小于5°时,槽的侵蚀深度在10～5 m,它的地震同相轴相位会反转.如果侵蚀深度在30～10m,那么它的同相轴增益会增大；如果侵蚀深度大于30m,它的同相轴会呈复波型.利用井数据和实际地质资料建立沟槽充填模型,应用全波场数值模拟技术生成叠后偏移剖面,结合地震响应特征分析,推测描述了中央古隆起东部马家沟组五段中、下组合中小型沟槽的分布.

Ordovician karst landforms are wide distributed in eastern Central Uplift, Ordos Basin. The accurate characterization and identification of small karst paleogrooves is important to approach hydrocarbon accumulation and improve success rate of exploration. The seismic response of paleogrooves is the depth of the grooves instead of the width of them. It is shown that as the dip angle is more than 5°, the seismic response is unclear. As the erosion depth of them is at 10 m to 5 m, seismic phase axis is reversed. As the erosion depth of them is at 30 m to 10 m, the seismic phase axis gaining even increases. As the erosion depth is greater than 30 m, the seismic displays compound waves. By this method, a group of the middle and small karst paleogrooves have been effectively identified and confirmed in the Middle array of Ordovician Majiagou 5 Submember using well data and available geologic data and post-stack migration profiles.