Palaeokarst landform developed in the top of Ordovician weathering crust in mideast Ordos Basin controls the reservoiring of natural gas and could be divided into 3 types such as karst highland
karst platform
karst basin and 9 sub types. The karst platform that underwent intense karstification is most favourable for gas enrichment;the terrace in the highland
the gentle hill in the platform and the remnant hill in karst basin are favorable areas of gas accumulation.High yield gas wells are located at the upper part of the slopes in both sides of the eroded karst flute.