Study On The Microstructure Characteristics Of Paleogene Shale Reservoir In Dongying Sag

Shale oil and gas as unconventional important part,oil and gas reserves and production of key areas,shale oil and gas distribution pattern of gradual impact on the world oil and gas.Compared with conventional reservoirs,shale reservoir rock composition complex,dense structure,poor physical properties,reservoir heterogeneity,and other characteristics,so the study of the microstructure of shale reservoirs for shale gas exploration is important.By rock thin section,core observation,X-ray diffraction analysis,scanning electron microscopy,nitrogen adsorption experiments,high pressure mercury geochemical analysis and testing means of Dongying Sag Paleogene shale rock characteristics,reservoir microscopic structural characteristics,reservoir properties,diagenesis and reservoir distribution characteristics were studied,the results showed that:Dongying Sag Paleogene shale rock composition mainly by the felsic minerals,clay minerals,carbonate minerals and small amounts of pyrite ore,siderite and other minerals from the composition,compared with the traditional marine shale in Dongying Sag continental shale formation has"low clay,high carbonate minerals from diverse"characteristics.Based organic matter content,mineral composition and structural characteristics of the type of Paleogene shale layer is divided into fine sand,poor-organic mixed sedimentary rock,middle-organic laminar mixed fine-grained sediments,organic matter lamellar limestone,organic-rich and organic-rich limestone interlayer sheet-like clay rocks seven major facies.Paleogene shale mainly developed four kinds of pore types and five types of fractures.Including inter-particle porosity and pore holes,intercrystalline pores,and a small amount of organic matter dissolved pore holes,etc;fracture include construction joints,seams between layers,abnormally high pressure differential compaction stitch seam and diagenetic contraction joints and the like.Average porosity of6.8%,excluding the mean porosity of fractured samples measured was 4.3%and average permeability of 0.38 mD,fracture permeability mean removing a sample measured as 0.30mD.Mean specific surface area of mesoporous 4.01nm,mean pore volume 0.012ml/g,a specific surface area mean mean 8.57 m~2/g,an average pore diameter of macropores 2.5?m.Pores of parallel plate-shaped inkwell hole opening at one end or both ends of the pore openings,pores medium to poor connectivity,pore size and roared uniform,pore-throat sorting poor.Paleogene shale in the late diagenesis A whole period,mainly for compaction diagenesis,7 cementation,recrystallization,dissolution,metasomatism and thermal evolution of the role of organic matter.Reservoir development factor of 4 main categories,namely tectonic,mineral composition and structure type,organic carbon content and diagenesis.Based on five indicators porosity,permeability,strength diagenesis,reservoir space types and combinations,will study area mainly developed six facies are divided into three categories.In reservoir evaluation core evaluation parameters,according to Fan Page 1 Well reservoir properties vertical phase change,shale thickness,vertical facies types of phase change characteristics and fracture vertical facies characteristics of Paleogene shale single well reservoir classification and evaluation,reservoir divided into class?,?type reservoir and reservoir?class three levels.Natural gamma ray log and spontaneous potential curve based on combined acoustic travel time and density logs stacked curve,log analysis features of the three reservoirs,the reservoir has a high class?gamma,high natural and the potential difference is large positive amplitude characteristics,?type reservoir having a high gamma characteristics,high natural potential and more substantial difference,and class?reservoirs logging feature is a natural potential and natural gamma medium acoustictime and density logs stacked curves showed high amplitude acoustic time difference is very small.Class?reservoir,?type reservoir and class?reservoirs,on a plane to sag origin at the center ring was zonal distribution.