鄂尔多斯盆地中生界地层探明了大量的天然气,其成因类型是否与古生界相同,是一个值得探讨的问题。利用碳氢同位素分析结果,确定了中生界天然气的成因类型主要为油型气,与古生界天然气存在很大差异;但由于受构造活动强度的影响,中生界不同构造单元的天然气成因类型又存在一定的差异,陕北斜坡地区构造稳定,主要为油型气,西缘断褶带构造活动强烈,主要为混合气。

Many nature gas reservoirs are proved up in the Mesozoic of Ordosbasin, whether the gas reservoirs of Mesozoic different from the gas reservoirs of Paleozoic on the forming cause, need discuss very detailedly. In the paper,the forming cause are gained by the analysis of carbonate and oxygen isotope, the associated gases of oil field are named, the forming causes are different from Paleozoic. Due to the difference of tectonic intension, the forming causes aredifferent in different tectonic zones. Due to tectonic stabilization, the type of the forming cause is the associated gases of oil field on the slope of ShanBei. Due to tectonic intension, the type of the forming cause is the mixed gases on the fault zones of the wester.