姬塬地区长6储层成岩作用及有利成岩相研究

Diagenesis and favorable diagenetic facies of Chang 6 reservoir in Jiyuan area

综合运用岩心资料、铸体薄片、扫描电镜等方法,分析了姬塬地区长6储层的成岩作用及有利成岩相带,结果表明:压实作用是导致长6砂岩原始孔隙度降低的主要因素,长石等易溶矿物经溶蚀作用形成的溶蚀孔则有效提高了储层的物性;长6砂岩整体处于中成岩A期晚期,早成岩期的绿泥石膜对于原始孔隙度的保存具有积极意义;依据成岩作用及沉积特征,划分出5种成岩相带;绿泥石膜胶结残余粒间孔相和长石溶蚀相储层物性最好,是研究区最为有利的成岩相带,主要分布于沙崾岘—张家山和马家山—冯地坑一带的水下分流河道发育区。

By using core data,casting thin section and scanning electron microscope,the diagenesis and favorable diagenetic facies of the Chang 6 reservoir in the Jiyuan area were comprehensively analyzed.The results indicate the compaction is the main factor leading to the decrease of the primary porosity in Chang 6 sandstone,and the dissolution pores formed by the dissolution of the feldspar and other soluble minerals are effective to improve the reservoir physical properties.Chang 6 sandstone is in the late stage of middle diagenesis phase,and the late chlorophyll film in the early diagenetic period has a positive effect on the preservation of the primary porosity.According to the diagenesis and sedimentary characteristics,five diagenetic facies zones were classified.The diagenetic facies belt of feldspar corrosion and chlorite film-intergranular pore are the most favorable diagenetic facies in the study area,which are mainly distributed in distributary channel of ShayaoxianZhangjiashan and Majiashan-Fengdikeng areas.