楚雄盆地洒芷油砂地质特征及成藏模式

楚雄盆地洒芷油砂矿位于元谋隆起西部边缘洒芷背斜上。洒芷油砂充填在上三叠统舍资组-干海资组砂岩孔隙和裂隙中，油砂多层分布，厚度变化大。通过薄片分析确定，储集层砂岩有效面孔率为9．13％～12．66％，结构成熟度和成分成熟度中等，储层次生孔隙和裂缝发育。湖相三角洲平原分流河道和三角洲前缘河口坝砂体为有利储层。洒芷油砂是古油藏经历燕山期和喜山期多次强烈构造活动改造而形成，成藏模式可以概括为：成藏-抬升氧化-埋深再成藏-热变质-抬升再氧化。

Geological characteristics and forming pattern of Sazhi oil sand in Chuxiong Basin

Sazhi oil sand mine is located at Sazhi anticline of the western margin of Yuanmou uplift belt in Chuxiong Basin.Bitumen filled in the pores and cracks of sandstone in Upper Triassic Shezi Formation and Ganhaizi Formation.Multilayer oil sands occurred with great variations in thickness.On the basis of thin-section analysis,the area percent of pore of reservoir sandstone ranges from 9.13% to 12.66%,with moderate maturity of composition and texture.Secondary pores and cracks are developed in reservoir sandstone.The sand bodies located in distributary channel of lake facies delta plain and river mouth of delta front are favorable reservoir beds.The oil sand was formed by the Sazhi ancient reservoirs rebuilt,which underwent multiple tectonic deformations and drastic tectonic movements in the Yanshanian and Himalayan stages.The forming model of oil sands can be summarized as follows: pool forming-oxidation during uplift-reforming with imbedding-thermometamorphism-reoxidation with uplifting.