鄂尔多斯盆地马家滩地区石千峰组砂岩特征

马家滩地区主体鄂尔多斯盆地西南缘冲断构造带的中段,有含气显示,具有良好的油气勘探前景。为搞清研究区上二叠统石千峰组砂岩的沉积环境,物源特征及展布规律,在区域地质研究基础之上,进行了区内印支旋回构造层序划分,研究了该组砂岩碎屑颗粒组成和成岩作用等特征,并对该套碎屑岩的物源进行了综合分析。结果表明,该组砂岩成分成熟度和结构成熟度均较低,成岩作用较强,但具有发育优质油气储层的物质基础;研究区石千峰组砂岩的物源很有可能是来自于西北方阿拉善地块古元古界变质结晶岩、花岗岩和下古生界火山岩。

Characteristics of sandstones in Shiqianfeng Formation at Majiatan area,Ordos Basin

Located at the central thrust section of the southwestern Ordos Basin,Majiatan area has a promising oil-gas pros- pcct for its gas shows.In order to obtain the sedimentary context,provenance characteristics and the distribution pat- tern,on the basis of study on regional geology,tectonic se- quences of the indosinian cycle at the area are classified;the component characteristics of clastic particles and the litho- genesis in the formation are generalized;and the provenance of the set of clastic rocks are comprehensively analyzed.Re- sults indicate the sandstones in the formation are relatively low in the component maturity and the textural maturity, but have the material basis for high quantity reservoirs.The provenance of sandstones in Shiqianfeng formation most like- ly originated from the metamorphic crystalline rocks and granite of the Paleoproterozoic Erathem,and the volcanics of the lower Paleozoic Erathem.