塔河地区志留系柯坪塔格组下段沉积相研究

Development of Sedimentary Facies Type in Silurian Lower Kepingtage Formation,Tahe Area

志留系柯坪塔格组作为塔河碎屑岩领域勘探的重点层系之一,随着立体勘探的实施,展现出了良好的勘探前景,但一些沉积相认识上的瓶颈制约着该层系勘探的深入和井位的部署。文章以沉积学、地球物理和地球化学方法为指导,综合利用岩芯、测井和地震资料,并结合粒度、微量元素及重矿物分析,明确了志留系柯坪塔格组下段的沉积相类型及物源方向。研究认为,柯下段主要发育河流相、潮坪相以及浅海陆棚相沉积。其中,下亚段发育河道及潮上—潮间带泥坪沉积,中亚段发育浅海陆棚相沉积,上亚段则发育潮间坪的砂坪—混合坪沉积;柯坪塔格组下段的母岩主要来自于北西方向前寒武系的岩浆岩和变质岩。

Silurian Kepingtage Formation is the key formation of clastic rock exploration in Tahe area. With the implementation of the three-dimensional exploration,showing good potential for further exploration. But lack of intergraded study on sedimentary facies restricts the deep exploration in future and well placement. Core analysis,logging response and seismic data are applied for sedimentary facies identification and source direction in combination of the study of trace elements and grain size in the guidance of Sedimentology,Geophysical and Geochemical. Study suggests that,the lower member of Kepingtage Formation is channel,tidal flat and shallow shelf. And S1k1-1is channel and mud flat deposition,S1k1-2is the continental shelf facies,S1k1-3is sand flat deposition. The origin of rock mainly comes from the igneous and metammorphic rocks of Cambrian in north-west.