柴达木盆地干柴沟—咸水泉地区渐新统—中新统沉积相分布特征

Sedimentary Facies Distribution Characteristics of Oligocene—Miocene in Ganchaigou—Xianshuiquan Area,Qaidam Basin

柴达木盆地干柴沟—咸水泉地区渐新统—中新统地层虽具有良好的油气勘探潜力,但至今未获突破,沉积相分布特征及规律研究不够深入是其主要原因之一。本文在区域地质背景、野外地质剖面、岩芯分析化验等资料的基础上,通过系统地分析该区渐新统下干柴沟组和中新统上干柴构组岩石类型和颜色、沉积构造、古生物等相标志,识别出冲积扇、扇三角洲、湖泊和湖底扇等沉积相类型及其特征;通过编制单井、剖面和平面沉积相分布图,揭示了沉积相的纵横向分布特征及规律并建立了沉积相模式。结果表明,沿山呈带状分布的各类滩坝和河道沉积砂体是下一步深入勘探寻求突破的主要方向。

There is good potential for petroleum exploration about Oligocene—Miocene Series in the Ganchaigou—Xianshuiquan area,Qaidam Basin,but there are still no breakthrough. Why？ The poor effort to characteristics and regularity of the sedimentary facies distribution in this area is one of the main causality. In this paper,based systematic analysis of the facies marks,such as types and colors of rocks,sedimentary structures,ancient creature etc,the types and their characteristics of the sedimentary facies,such as alluvial fan,fan-shaped delta,lacustrine and sublacustrine fan were identified on the basis of regional geological background,field geological section plane,core analysis etc,and the sedimentary facies distributional characteristics and regularity were revealed and the depositional pattern was builded up by established the distribution diagram about single well,cross section and plane sedimentary facies. The results showed that the main beneficial target for the next petroleum exploration was mainly in connection with all kinds of microfacies sands,such as beach,bar and channel within alluvial fan,fan-shaped delta,lacustrine and sublacustrine fan in the Ganchaigou—Xianshuiquan area,Qaidam Basin.