潜江凹陷马王庙地区古近系新沟嘴组下段物源分析

Provenance analysis of the lower member of Xingouzui Formation of Paleogene System in Mawangmiao Area of Qianjiang Sag

根据重矿物百分含量分区、岩石碎屑组分特征、地层倾角测井特征等对潜江凹陷马王庙地区古近系新沟嘴组下段物源情况进行了分析。研究表明马王庙地区受到北东向的汉川和北西向的汉水两个方向物源影响。在此分析基础上,结合砂岩百分含量分布特征和沉积环境详细阐述了古近系新沟嘴组下段各个油组沉积时期不同物源的影响程度,认为马王庙地区新沟嘴组下段主要受东北部汉川方向物源的影响,西北部物源的影响次之,两物源影响交汇于马10井—马39井区附近。Ⅲ油组沉积时期研究区受到西北物源的影响较小;Ⅱ油组时期东北物源影响较前期增大,受西北部物源影响变化不大;Ⅰ油组时期仍以东北部物源影响为主,但其影响变小,而西北物源影响范围变大。

According to the distribution of heavy mineral percentage,features of clastic constituent of sand rocks,diplog traits,variation of palaeophyte distribution,provenance directions of Mawangmiao area was analyzed in this paper,and the result demonstrated that Mawangmiao area was influenced by two different provenances of northeast Hanchuan and northwest Hanshui.Based on the aforesaid research,combined with the features of sand content distribution and depositional environment,the study detailedly depicted different incidence of the two different provenances of every oil groups and considered the lower member of Xingouzui Formation in Mawangmiao area was mainly influenced by the northeast provenance,and the cross influenced area of the two different provenances convergenced on Ma 10 to Ma 39 well area.In the depositional era of Ⅲ oil group,the study area was minorly influenced by the northwest provenance.In the depositional era of Ⅱ oil group,the influence of the northeast provenance aggrandized than earlier phases and the influence of the northwest provenance had no further change.In the depositional era of Ⅰoil groups,the northeast provenance was still the major provenance but its influence faded down and the influence of the northwest provenance aggrandize than earlier phases.