鄂尔多斯盆地鄂托克前旗地区古生界合成地震记录特征

CHARACTERISTICS OF SONIC SYNTHETIC SEISMOGRAMS OF THE PALAEOZOIC AT ERTUOKEQIANQI,ORDOS BASIN

鄂尔多斯盆地鄂托克前旗地区钻井较少且位于周缘，靠在线井外推的地震解释工作难以控制全区，本文通过对有限钻井的古生界进行声波合成地震记录的模拟，根据太原组煤层底界和奥陶系风化壳二者反射的复合程度将本区合成地震记录归纳为高复合型、中等复合型、弱复合型和双相位型四种特征类型，并且同钻井相结合赋予不同类型以古地貌含义，为本区的地震解释及标定工作提供了依据。

The discovery and study of the Middle Gas Field in the Ordos Basin has shown the importance and prospect of Palaeozoic gas exploration, especially the Ordovician weathering crust. Ertuokeqianqi is one of the most favorable regions for gas exploration. One of the important tasks is to recover the morphology of the Ordovician weathering crust in this region.This work mainly was based on 2－D seismic datum and coupled with drilling and well logging datum.However,in this region,there are only few wells scattered at the round,and it is difficult to control the whole region through the liaison of seismic log and wells. In this article,we have mastered the characteristics of objective formations： the different sonic velocity between the upper Paleozoic and the Lower Paleozoic and the two coal formations and their seismic characteristics.Then we simulated the sonic synthetic seismograms with well datum and generalized four types of sonic synthetic seismograms,i.e.,strong compound type,middle compound type,weak compound type and double phase type according to the compound level of the seismic reflections of the TY coal bed and the weathering crust.Each type has its own morphological significance. This research is very valuable to interpret and calibrate the Ordovician weathering crust on seismic log that is helpful to recover the paleogeomorphology of the Ordovician, Ertuokeqianqi,Ordos basin.