营尔凹陷下沟组物源分析与砂体展布规律研究

Provenance analysis and sand body distribution of Xiagou formation in Yinger sag

营尔凹陷下白垩统下沟组为陆相断陷盆地,具有多物源、多沉积相类型的特征。为了进一步明确下沟组物源及砂体展布规律,采用轻重矿物组合特征、重矿物ZTR指数,岩石类型、砂岩百分含量和地震剖面分析等方法,对营尔凹陷下白垩统下沟组西北部物源进行了分析。结果表明:营尔凹陷下白垩统下沟组物源分带性明显,共发育7个物源,主要以北面天泉寺凸起和西面文殊山凸起提供的物源为主,物源与砂体展布对应关系良好,从根本上决定了早白垩世沉积体系的分布格局。

The lower Cretaceous Xiagou formation of Yinger sag is land facies fault basin featured with multiple source and multiple types of sedimentary facies.In order to provenance and sand body distribution,we applied the light and heavy mineral combination characteristic,the ZTR index of heavy minerals,rock types,sand rock content and seismic analysis methods to analyze northwest provenance.The results show that:lower Cretaceous source of Xiagou formation is obviously zoned,which developed in 7 sources,mainly in north Tianquansi convex and west Wenshushan convex,the source and distribution of sand body are in good corresponding relation,which fundamentally determines the distribution pattern of the early Cretaceous deposition system.