鄂尔多斯盆地富县地区延长组物源体系分析

Provenance System Analysis of Yanchang Formation in Fuxian Area of Ordos Basin

物源问题一度成为制约富县地区延长组油气勘探的焦点。作者充分利用了研究区的野外露头、钻孔资料和地震资料,系统分析了能够用于指示古物源方向的6种关键参数——实测古水流方向、砂体展布走向、极端暴露标志(煤)和覆水标志(油页岩)空间分布规律、重矿物组合分异特征、三角洲沉积体系前积结构(地震剖面)、鄂尔多斯盆地区域古构造—古地理特征等。综合研究表明,富县地区晚三叠世延长组的沉积物来自于盆地东北部,研究区不存在南部物源体系。

The oil and gas exploration of Yanchang Formation in Fuxian area has been constrained by the issue of sediment provenance.The authors make full use of the outcrop,borehole and seismic data of the study area to analysis the six kinds of key parameters indicating the direction of paleo-provenance-such as actual measured paleocurrent directions,sand distributed system directions,spatial distribution of extreme exposure signs（coal） and overlying water mark（oil shale）,assemblages and distribution characteristics of heavy minerals,foreset structure of delta depositional system（seismic section）,regional paleotectonic and paleogeographic characteristics of Ordos basin.Comprehensive studies show that the sediments of Yanchang Formation in Fuxian area come from the northeast of Ordos basin,and there is no provenance system from the south of the study area.